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Breakfast cereals
Breakfast cereals Janice Johnson, Julie Schuette Cargill, Inc., Minneapolis, MN, United States
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10.1 Breakfast cereals Whether in the form of traditional hot cereals, ready-to-eat (RTE) cereals or cereal bars, grains have been a large part of the breakfast diet for many years. Early European grains were largely consumed in a cooked, hot form called porridge and made from wheat, oats, or barley. In the United States, cereals were made from corn (grits or hominy). Other grains, such as sorghum, quinoa, and amaranth, are commonly used in South America (Taylor and Emmambux, 2008). However, use of these ancient grains has grown in popularity globally due to the nutrient value they provide. Traditional hot cereals are still consumed today, but the majority of the cereals consumed are RTE cereals, which were introduced as a nutritious alternative in the United States during the latter half of the 19th century by brothers William K. and Dr. John Kellogg. More recently, cereal bars were introduced to the breakfast cereal market to meet consumers’ desire for convenience and portability. From a nutritional standpoint, breakfast cereals and breakfast goods help contribute fibre, vitamins, minerals, and protein to the diet. Vitamins and minerals are naturally present in cereals, but many are lost during the milling process. Therefore, many manufacturers began to fortify breakfast cereals in the United States to increase essential vitamins and minerals, like thiamine and iron, respectively (Brooke, 1968). During cereal production, the essential amino acid lysine can participate in the Maillard reaction. Studies report 20%–54% decreases in lysine bioavailability due to this browning reaction (Rutherfurd et al., 2007; Torbatinejad et al., 2005). Many breakfast cereals are consumed with milk, which provide additional protein, vitamins, and minerals. Recent emphasis on nutrient density of breakfast cereals has led to an increase in certain nutrients, such as protein and fibre, and a decrease in others, such as sugar and sodium. In general, the sodium content in breakfast cereal is relatively low compared to other food categories (e.g. deli meats) on a per 100-g basis. Similar to other grain products (e.g. breads), breakfast cereals are consumed throughout the day and the frequency of consumption can lead to a significant sodium contribution to the overall diet. In the United States, cereals were not identified as one of the top 10 foods contributing sodium to the diet across the entire population (Centers for Disease Control and Prevention, 2012). Examining individual age groups, individuals aged between 2 and 5 years had breakfast cereals ranked number 10 as a foods source of sodium in the diet. Breakfast cereals did not make the top 10 list for any other age group.
Reducing Salt in Foods. https://doi.org/10.1016/B978-0-08-100890-4.00010-X Copyright © 2019 Elsevier Ltd. All rights reserved.
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10.2 Breakfast cereals market size The breakfast cereals market has grown significantly since the introduction of RTE cereals. In 2001, Bouvier and Campanella (2001) reported the global consumption rate of breakfast cereals (e.g. hot cereals, RTE, cereal bars) to be approximately 3 million tons (or 2.7 metric tonnes). By 2016, the breakfast cereal and cereal bars volumes were 5 metric tonnes and the market grew to a US$34.9 billion category (Euromonitor International, 2017). The breakfast cereals market size (total volume) varies significantly by country and differences can be attributed to factors such as cultural food preferences and the degree of developed economies (Fig. 10.1). In 2016, the United States led the list in term of largest volume, nearly three times as much as the next highest country, followed by the United Kingdom, Canada, Germany, and China. Comparing growth rates between 2011 and 2016 for the top 10 largest volume production, the United States has the greatest decline (−8.8%) followed by Mexico (−4.7%) and Australia (−3.5%). Growing competition in the retail space and fast food restaurants led to a decrease in breakfast consumption at home, which impacts cereal purchases by the consumer (Schierhorn, 2016). Within the top 10 list of top breakfast producers, the greatest growth rate is observed in China (40%), South Africa (28.1%), and Russia (14%). Considering other countries, the greatest growth rate for breakfast cereals is in India (168%) followed by Japan (130%) and Vietnam (91%). The observed increase in many of these countries is most likely due to recent economic growth, which led to an increase in consumer spending. The greatest decrease in total volume growth rates for breakfast cereals was observed for South Korea (−36.5%), Belarus (−32.7%), and Greece (−27.5%). 1800
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Fig. 10.1 Total volume market size ('000 tonne) and growth rate (%) of breakfast cereals in various countries between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.2 Total volume per capita (kg per ‘000 people) and growth rate (%) of breakfast cereals in various countries between 2011 and 2016 (Euromonitor International, 2017).
Examining the market size on a per capita basis provides insights on population consumption rates and changes in cereal purchasing patterns, and can be used to help determine market opportunities (Fig. 10.2). In 2016, the top five countries that led in volume per capita are Ireland, United Kingdom, Denmark, New Zealand, and Canada. Comparing growth rate between, 2011 and 2016, the greatest increases for the top 10 largest per capita volume were in Norway (21.8%), Sweden (10%), Ireland (7.1%), and Denmark (5.6%), whereas the greatest decreases occurred in the United States (−12.4%), Australia (−10.6%), and Canada (−7.7%). Examining other countries, the greatest volume per capita growth rates for breakfast cereals between 2011 and 2016 was India (152.6%), Japan (132.5%), and Vietnam (80.2%). The greatest decrease in volume per capita growth rates was South Korea (−37.8%), Belarus (−32.7%), and Greece (−25.3%). Examining total volume of various breakfast cereal subgroups provides further insights into changes in market growth (Figs. 10.3–10.5). For all top 10 countries except China and South Africa, RTE subgroup commands the largest volume, which is 4%–20% greater than the next largest subgroup. Hot cereals are the largest volume for China, South Africa, and Russia, suggesting that these three countries have the biggest opportunity for RTE cereal growth. Breakfast bars are the lowest subgroup in all countries except Mexico and France. Reporting the subgroups on a per capita basis further provides insights on population consumption rate and potential market opportunities (Figs. 10.6–10.8). Comparing 2011 to 2016 in Fig. 10.6, the growth rate of RTE cereals has decreased for every country except Switzerland (0.5%), Israel (1.3%), and Sweden (12.8%). Conversely, every country has experienced an increase in hot cereal growth rate,
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Fig. 10.3 Total volume market size ('000 tonne) and growth rate (%) of ready-to-eat cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.4 Total volume market size ('000 tonne) and growth rate (%) of hot breakfast cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.5 Total volume market size ('000 tonne) and growth rate (%) of cereals bars in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.6 Total volume per capita (kg per ‘000 people) and growth rate (%) of ready-to-eat cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.7 Total volume per capita (kg per ‘000 people) and growth rate (%) of hot breakfast cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Fig. 10.8 Total volume per capita (kg per ‘000 people) and growth rate (%) of cereals bars in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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ranging from 4% to 43.2% (Fig. 10.7). The smallest cereal category, cereal bars, is more similar to the RTE than hot cereals in growth rate. As shown in Fig. 10.8, most countries show an increase in volume per capita growth rate with the exception of New Zealand (−1.4%), Australia (−9.3%), United Kingdom (−11.6%), and United States (−10.2%). Considering market opportunities, brand extension or new market entries into the hot cereal subcategory may be an option for market declines in RTE cereals and cereal bars.
10.3 Types of breakfast cereals The breakfast cereal market is quite diverse compared to the early days of Kellogg’s and Post where the major emphasis was on nutrition and health. The cereal connection between nutrition and health is still a major marketing focus today and has expanded to include fitness (Schierhorn, 2016). Cereal manufacturers have expanded the nutritional benefits to include whole and ancient grains, added fibres, proteins, phytonutrients (e.g. blueberries, cranberries), and probiotics. Products are marketed with emphasis on heart health, weight loss, enhanced cognitive performance, and digestive wellness. Although nutrition may be a determining factor for the adults, the kid’s cereal market is mostly about fun. Therefore, cereal manufacturers focus on shapes, colours, flavour, movie promotion tie-ins, and a ‘prize inside’ to gain product awareness with this target audience. The basic formula for breakfast cereals is very similar, using typical grains such as wheat, oat, barley, rice, and corn. Heightened health awareness by consumers has led to the introduction of ancient grains, such as sorghum, quinoa, and amaranth, into cereal formulations. Grains can be used individually or in combinations when producing cereals. To further differentiate products, food manufactures leverage ingredients that provide unique flavours and colour, sweeteners, salt, and inclusions (e.g. chocolate bits, nuts, and fruit). With advancements in extrusion technology, cereal manufacturers also leverage cereal size and shape for visual appeal. The breakfast cereals are classified as follows, which are explained in greater detail: ●
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Hot cereals Ready-to-eat cereals, and Granola and muesli
10.3.1 Hot cereals In general, hot cereals have the least amount of processing compared to the other types of breakfast cereals. The basic processing steps include separating the hull from the kernel (groats), cutting the groats (steel cut), separating and grinding the kernel to the desired particle size. At this stage, cereals such as steel cut oats can be eaten after an extensive simmering process. Steel cut oats have gained popularity with consumers; however, the long preparation time deters home preparation. To add convenience, cereal manufacturers further process steel cut oats to shorten the cooking time. In this case, the grains are soaked or
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steamed, rolled to the desired thinness, cooled and dried to increase water uptake and decrease preparation time. Three options available are steel cut (chopped groats), old fashioned (steamed and rolled), instant (steamed, rolled, and chopped), which differ based on cooking process. The fastest one, instant oatmeal, incorporates other ingredients, such as gum, to further aid in water uptake and preparation simply requires the addition of hot water with no further cooking time. Other popular grains used in hot cereals include corn, wheat, barley, and rice, with wheat being the second most consumed cereal. Farina is debranned and degermed endosperm, and is the most popular of the wheat-based cereals. The wheat granules may be consumed at this stage or further ground and sifted (bolting) to a very fine particle size. A favourite southern breakfast side dish in the United States is corn grits, which are produced through a dry milling process that cleans white corn followed by grinding and sieving to the desired particle size. Removing the hull and germ from corn produces hominy and it may be alkalised (nixtalmalisation) to produce the desired taste and texture. Alkalisation can be a source of sodium depending on the type of agent used in the process. Consumers tend to consume hot cereals with milk or add sweeteners, such as brown sugar, maple syrup, or honey. For added convenience and appeal, food manufacturers began adding inclusions, such as dried fruits, nuts, flavours, and sweeteners to instant cereals. Salt may be added to mask the grain bitterness and enhance other flavours. Preparation of these cereals simply requires adding hot water or milk.
10.3.2 Ready-to-eat cereals RTE cereals are regarded as cereal products that need no further preparation prior to consumption. Convenience is the greatest appeal for this cereal category. Similar to hot cereals, typical grains include corn, wheat, barley, oat, or rice, and can be processed from either grain or flour. Production of RTE cereals is more complicated and extensive than hot cereals. Regardless of RTE cereal type, the grains all go through a similar process; cleaning, cutting or milling, cooking, tempering, and drying. Some flavours, colours, vitamins and minerals, sweetener and salt may be added during the process. To increase visual appearance or prevent degradation of heat-labile compounds (e.g. flavours, colours, and vitamins), ingredients may be sprayed onto the surface of cereals (Culbertson, 2004). Spraying the surface of the cereal with carbohydrate polymers (e.g. sugars, maltodextrins) also helps extend the bowl shelf-life to maintain crispness and texture after adding milk (Culbertson, 2004). The basic types of RTE cereals include: 1. 2. 3. 4. 5.
Flaked extruded shredded puffed, and granola/muesli.
Type of equipment and operating conditions differentiate the finished form (size and shape) and texture of the cereals.
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10.3.2.1 Flaked cereals From an historical perspective, flaked cereals were one of the first RTE cereals introduced into the market and are still quite popular today. They can be large or small in diameter with a surface that is rough with noticeable bubbles. The texture can sometimes be manipulated to have multiple textures via inclusions into the flake. Corn, wheat, and rice are typical grains used in flaked cereals. Depending on the grain source, various parts of the kernel are used to make the flaking grit. For corn flakes, the bran and germ are removed and parts of the endosperm are used for production. Considering wheat grain, the whole kernel is used to make the flaking grit. Kernels are exposed to steam and broken by passing through rollers. Rice is the most versatile in that the flaking grit can originate from whole kernel or parts of the endosperm, and requires the least amount of pre-processing, milling to form polished head rice (Caldwell et al., 2000). The intact grain, or fraction of it, is used to help determine the desired flake size, since one particle produces one flake. Alternatively, grains are pelletised before flaking to create a grit with many particles. A typical formula will include grit (28%–32%), granulated or liquid sugar, malt syrup, salt, and water. The ingredients are mixed and cooked using pressure and steam in a batch cooker to a final moisture content up to 32% (w/w) (Fast, 2000). In some cases, the pressure is reduced until the starch is gelatinised. The resulting cooked mixture is dumped onto a conveyer belt that passes through a delumping process to obtain individual grits. Air can be circulated to help cool the grits and these are then dried under controlled humidity to control case hardening. The grits are then tempered to allow moisture equilibration, flaked through a pair of rollers and toasted in a fluidised bed. Further cooling and tempering will promote amylose starch retrogradation, which impacts texture and colour of the finished product. Flakes may also be made through a more rapid extruded process using either single- or twin-screw extruders (Fast, 2000). In this case, grits are created by crushing grains through the extruder. Alternatively, flour may also be used as the starting material. As grits or flour pass through the barrel, other ingredients (e.g. sugar, salt, moisture) can be metered in. Heat is introduced near the centre section of the barrel, and along with the mechanical shear induced by the screws, the cooking process begins. The mash that is formed reaches the end of the barrel and passes through a cool section to prevent puffing and a die that helps create the shape. Rotating knives cut the product to appropriate pellet size. The drying, cooling, and flaking steps needed to complete the process are similar to the traditional flaked method. Product characteristics differ slightly depending on the flaking method due to differences in operating conditions (Bouvier and Campanella, 2001). Largest differences are in the texture and colour of the finished cereal product. Extruded flakes tend to be paler in colour, which may be adjusted by adding ingredients such as dyes, cocoa powder, and malt syrups.
10.3.2.2 Direct expansion Extrusion technology can also produce cereals by direct expansion. In this process, a dough is created; therefore, flour may be used as a starting material (Fast, 2000). Dry mixtures of flour, starch, sugar, salt, malt, flavour, colour, and micronutrients are
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added into the extruder. Steam is added to introduce moisture in the screw chamber and the dough is exposed to shear, pressure, and heat. As the fluidised mass exits the chamber through a die, rapid expansion takes place as due to the pressure differential and steam vaporisation. The ability to alter the die shape lends itself to many options for size and shape of the finished product, which is appealing for kid’s cereals. In addition, extrusion offers the option for co-extrusion, which allows for cereals with different textures or coloured centres.
10.3.2.3 Puffed cereals Traditional puffed grained cereals were made using whole grains and leveraged the internal moisture to help expand the grain when subjected to heat (Jour et al., 1974). Technology advancement led to the gun-puffed method, which leverages heat, internal moisture, and a pressure drop to expand the grain (Fast, 2000). The steam formed within the grain under heat and pressure expands upon exposure to atmospheric pressure causing the grain to expand. Today, most puffed cereals production start as flours, extruded without expanding, tempered (creating a half product), and passed through a continuous puffing operation. Typical grains used for this process are rice or wheat. To prevent wheat grains from losing their bran during the puffing process, the grains are pre-treated with a saturated salt brine solution. In some cases, it is desired to remove part of the bran and it can be removed using a process called pearling (Bhatty, 1997). For rice, the grain is milled to polish the surface.
10.3.2.4 Shredded biscuits Shredded cereals are typically made from wheat, although corn, rice, and other grains have been used. Grains are batch cooked in kettles with excess of water slightly below boiling temperature. Steam is then injected into the water to begin the cooking process. Cooked grains are removed from the kettle and cooled to stop the cooking process and surface dry the grain. The material is then held in bins to allow for tempering, which promotes starch retrogradation and aids in the cutting process (Fast, 2000). The grains are then pressed between rolls, one smooth and one with grooves, to help form long strands of cereal. These strands are then formed, cut, and baked in a continuous oven or fluid bed. The pillowed shapes of shredded biscuits are limited to squares, rectangles, or triangles in order to minimise waste since there is no ability to rework excess cereal trimmings back into the process. Shredded biscuits may also be produced using extrusion. In this case, meal or flour is used as the raw material, which allows for more than one grain to be used in the formula. The ingredients are mixed, extruded, cooled and tempered, shredded and formed into smaller, bite-sized biscuits.
10.3.3 Granola and muesli Granola and muesli are popular breakfast cereals or cereal bars in many countries and are typically made from rolled or cut oats that are mixed with other dry ingredients such as dried fruit, nuts, spices, sugar, syrups and salt. Liquids such as oil, water, flavours, and spices are blended with the dry ingredients until evenly coated. The mixture is spread thinly and baked to approximately 3% moisture (Fast, 2000). Muesli
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is similar to granola in that it is made from rolled oats; however, they are not baked and generally consumed raw. In its final preparation, muesli can contain inclusions similar to granola and is typically mixed with fluids such as milk, yogurt, or fruit juice.
10.4 Sodium and breakfast cereals 10.4.1 Breakfast cereals contributions to sodium intake Although the sodium content of breakfast cereals is relatively low compared to other food products (e.g. processed meats), they are consumed throughout the day and the frequency of consumption can make this category a significant contributor of sodium in the overall diet. Differences in sodium contribution will depend on age and geography of a specific population. Using data collected by the National Health and Nutrition Examination Surveys, Drewnowski and Rehm (2013) reported that breakfast cereals contribute between 1.5% and 3.5% of sodium to the diet, with children between ages 6 and 11 years consuming the most. In the French population, Meneton et al. (2009) reported that breakfast cereals contribute 5.2% and 7.5% of the sodium intake for adults and children, respectively. Ni Mhurchu et al. (2011) also examined the sources of sodium in the diet and reported that cereal products (breakfast cereals, cereal bars, pasta, couscous, rice, and savoury noodles) contribute 5% of sodium to the diet of British households. Compared to other food categories, breakfast cereals are not generally considered major contributors to sodium in the diet.
10.4.2 Sodium content of breakfast cereals The mean sodium content in breakfast cereals and cereal bars has been reported in many geographical studies (Table 10.1). When reported, the mean sodium content and sodium content range for hot cereals was lower than other forms of cereal products and, in general, RTE cereals have the highest. The United States has the highest mean sodium content in RTE cereals, followed by Canada while the remaining countries had similar content. Comparing private and branded-labelled breakfast cereals and cereal bars, Trevena et al. (2015) observed that there were no significant differences between the two labels. They observed a similar result for new cereal products introduced in 2013. Ni Mhurchu et al. (2011) compared the weighted and unweighted mean sodium content to provide insights on the market leaders’ contribution of sodium. The unweighted and weighted sodium means were 274 and 346 mg sodium per 100 g cereal, respectively, suggesting that the market leaders contain higher sodium than smaller market brands. A similar finding was observed for cereal bars.
10.4.3 Progress on sodium reduction of breakfast cereals Many geographies have initiated governmental voluntary and mandated programs to reduce sodium in the food supply chain as a means to reduce high blood pressure (Webster et al., 2014). In their analysis, Webster et al. (2014) identified 83 countries that have initiated or implemented strategies for sodium reduction. Many of these
Cereal product type
Australiaa
Breakfast cereal, branded label Breakfast cereal, private label Cereal bar, branded label Cereal bar, private label Ready-to-eat Hot Other Cereal bars Ready-to-eat All cereals Cereal for kids Biscuits & bites Brans Bubbles, flakes & puffs Muesli Oats Breakfast cereal Breakfast cereal Cereal bars
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Canadac New Zealandd
United Statese United Kingdomf
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Trevena et al. (2015). Webster et al. (2010). Arcand et al. (2014). d Devi et al. (2014). e Gillespie et al. (2009). f Ni Mhurchu et al. (2011). b c
No. of products analysed
Mean (±SD) (mg/100 g)
191
144 (±160)
85
197 (±193)
137 46 218 42 20 160 230 247 32 20 14 65 67 45 148 965 413
137 (±101) 197 (±110) 264 23 113 144 375 (±246) 193.31 (±87.9) 298 (±249.9) 294.6 (±81.5) 294.3 (±105.2) 293.3 (±180.6) 94.4 (±110.9) 32.2 (±69.8) 513 (±219) 274 186
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Data collection year 2013
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2008
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Table 10.1 Mean sodium content (mg sodium per 100 g) of various breakfast cereals in various geographies
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geographies are working with the food industry to establish sodium targets in key food categories, including breakfast cereals, and the authors reported 38 of these countries have established voluntary or mandated programs. In another review, Trieu et al. (2015) report 75 countries with national sodium reduction strategies. Various types of monitoring programs were put into place for a majority of the countries including self-reporting, label surveys, and chemical analysis. Various studies examined the change in sodium content of many breakfast cereal products over a given period of time (Table 10.2). In all cases, the mean sodium content of the cereals decreased from the baseline year (Year 1) to the monitored year (Year 2). Evaluating Canadian products, Arcand et al. (2016) reported a significant decrease in Table 10.2 Sodium reduction progress of various breakfast cereals as measured by mean sodium content (mg sodium per 100 g product) over a given period of time
Country Australiaa
Australiab Canadac
Irelandd
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Cereal product type Branded label, breakfast cereal Private label, breakfast cereal Branded label, cereal bars Private label, cereal bars Breakfast cereal RTE breakfast cereal Instant hot cereal Granola, cereal bar Cornflake based cereal Rice based cereals Branded label Private label
Trevena et al. (2015). Trevena et al. (2014). Arcand et al. (2016). d Food Safety Authority of Ireland (2015). e Monro et al. (2015). b c
No. of products reviewed (year 1, year 2)
Year 1, mean (±SD) (mg/100 g)
Year 2, mean (±SD) (mg/100 g)
97
180 (±188)
164 ± 169
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185 (±214)
179 (±207)
50
145 (±100)
142 (±100)
12
163 (±114)
163 (±114)
86, 107 39, 52 230, 250
316
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375 (±246)
301 (±242)
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453 (±141)
385 (±155)
172, 200
279 (±108)
254 (±99)
761 (±132)
309 (±117)
555 (±168)
307 (±70)
320 (±247) 406 (±320)
201 (±167) 279 (±237)
73, 146 36, 30
Year 1, year 2 2011, 2013
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2003, 2013
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sodium of RTE and instant hot cereals by 19.7% and 15.0%, respectively, between 2010 and 2013. Trevena et al. (2014) also reported a 25% decrease in Australian breakfast cereals between the same 3-year period. Eyles et al. (2013) studied the impact of the UK Food Standards Agency’s (FSA) voluntary sodium reduction program for processed foods and observed that 81% of products analysed using Nutrition Information Panels (NIP) in 2011 met the 2010 target (300 mg sodium per 100 g product) for breakfast cereals, a 59% increase from 2006. Monro et al. (2015) observed the largest sodium reduction for food products analysed (NIP) between 2003 and 2013 was breakfast cereals with a reported 28% decrease. Comparing private and branded-labelled products, Trevena et al. (2015) observed that Australian private-label cereal products had a 37% higher mean sodium content than branded-label. Similarly, Monro et al. (2015) reported that the New Zealand private-label cereals were higher in sodium content than branded-label. In other studies, the sodium content of cereal products was compared to the governmental voluntary targets. Devi et al. (2014) compared sodium content of retail cereal products to that recommended by the National Heart Foundation in New Zealand and observed that on average, the targets were met (Table 10.1). Webster et al. (2014) compared the sodium content of breakfast cereals produced in 2008 to the voluntary targets of the 2012 UK FSA. In their analysis, RTE and hot cereals were 77% and 100% below the FSA target, respectively. By way of comparison to historical data, Kent and Evers (1994) published sodium content of RTE cereals manufactured in the United Kingdom. The mean sodium content was 0.625 mg and sodium content range was 0.01–1.2 g sodium per 100 g cereal, respectively. With the exception of Ireland in Table 10.2, the mean sodium values were lower than values reported by Kent and Evers (1994).
10.5 Sources and functional role of sodium in breakfast cereals In cereal formulations some ingredients are added because of their specific functional roles (e.g. flavour, colour, texture, shelf-life) that help define the sensory and quality attributes of the product. Many of these ingredients contain sodium and contribute to the overall sodium content. Removing these ingredients as a means to reduce sodium has the potential to alter desired attributes to varying degrees, thereby creating technical challenges for food scientists while managing consumer expectations. Table 10.3 contains a summary of the sodium-containing ingredients, their functional roles, and alternative solutions.
10.5.1 Salt Salt, or sodium chloride, is one of the most versatile ingredients in many processed food products. Most consumers recognise it for its salty flavour and flavour enhancement properties. However, food scientists appreciate its contributions towards the food characteristics beyond flavour. Salt impacts colour formation, assists in the expansion of extruded cereals, and decreases simple sugars (Maillard reaction) and p olyacrylamide formation (Lajoie et al., 1996; Bouvier and Campanella, 2001). The role of salt in breakfast cereals is explained further now, contributing to colour & flavour and expansion:
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Table 10.3 Functional role of salt and other sodium-containing ingredients, and alternative non- or low-sodium-containing ingredients for breakfast cereals Ingredient Salt
Functional role of sodiumcontaining ingredient Impart salty flavour and flavour enhancement
Decrease starch retrogradation—to alter texture and staling properties Alter starch glass transition temperature—to impact crispness Nucleation/leavening agent
Sodium bicarbonate Sodium citrate, sodium metabisulphite, sodium ascorbate Cocoa powder
Colour and flavour— browning reactions Leavening agents Preservative (e.g. microbial, oxidative)
Colour and other flavours
Alternative solutions Potassium chloride, lithium chloride, choline chloride, magnesium chloride, calcium chloride, trehalose, arginine, gluconate, whey protein, fermented milk proteina Lithium ion, magnesium ion, calcium ion, potassium ionb
Potassium ion, ammonium ion, lithium ion, magnesium ion, calcium ionc Increase trapped air inclusions, small undissolved particles including starch hilum, undissolved amylopectin, bran, tripotassium phosphated Potassium bicarbonate, carbonate, colouring agentse Potassium bicarbonate, Potassium carbonate Potassium citrate, potassium metabisulphite, potassium ascorbate
Cocoa alkalised with potassium carbonate, potassium hydroxide, or other non‑sodium-containing alkalisers, artificial or natural colours
a
Dotsch et al. (2009). Wang et al. (2015). Beck et al. (2011). d Moraru and Kokini (2003). e Lajoie et al. (1996). b c
10.5.1.1 Colour and flavour Salt is added to breakfast cereal to help bring salty flavour and flavour enhancement to cereals. Salt is also known to mask the bitterness of whole grains and other ingredients used in cereals. Salt also impacts the Maillard browning and caramelisation reactions, which influences the overall brown colour and flavour. The presence of salt in cereal formulations helps develop colour and flavour during the heated extrusion or drying and toasting process of cereal production. Cereals
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c reated without salt look pale in colour and lack the characteristic toasted flavours associated with Maillard browning and caramelisation, two non-enzymatic browning reactions (Hill and Ferry, 2006). The complex Maillard reaction involves a condensation reaction between a free amino acid (e.g. lysine or terminal amino acid) and a reducing sugar, which results in products that are highly aromatic and darker in colour (Bouvier and Campanella, 2001). Considering processing conditions and formulation, non- enzymatic browning reactions are dependent on temperature, heating time, moisture content, water activity, pH, and type of reducing sugar and amino acids in the cereal. The role of moisture content or water activity (Aw) in non-enzymatic browning is to dissolve reactants, which aids mobility. This is important because it is a determining factor in the reaction rate. Too high of moisture dilutes reactants and decreases reaction rates. Similarly, too low of moisture decreases the reaction rate. The optimal Aw for greatest reaction rates in cereals is between 0.3 and 0.5 (Bouvier and Campanella, 2001). Salt is known to affect Aw, which is known to impact the Maillard reaction. Lajoie et al. (1996) observed an increase in brown colour formation and decrease in simple sugars as the salt increased in cereal formulations. The effect of salt on non-enzymatic browning reactions may be linked to the role salt plays as a plasticiser in starch systems (Moreau et al., 2009). Previous theories suggest that salt lowers glass transition temperature of starch systems (Farahnaky et al., 2009). Movement of reactants would be greater in the rubbery state versus the glassy state. More time in the rubbery state would extend the non-enzymatic browning reactions. Another theory proposed that the hygroscopicity of salt retains more water during the cereal cooking, which aids reactant mobility and prolongs the browning reaction (Moreau et al., 2009). Taylor et al. (2010) examined a pre-gelatinised corn starch system to look at the hygroscopic effect of salt during cooking of a cereal and found no relationship between salt levels and water retention. In addition, the glass transition temperatures (Tg) in the pre-gelatinised corn starch system had similar Tg for all treatments thereby, suggesting that salt does not impact Tg. However in a cassava and potato starch systems study, Farahnaky et al. (2009) observed a decrease in Tg in the presence of salt compared to a no-salt treatment. In another study using waxy maize starch in suspension with different cations, Beck et al. (2011) observed that salt changes starch crystallisation and browning rates, suggesting a direct correlation between browning and crystallinity. Salt and starch may interact to change Tg and starch crystallisation characteristics in several different starch systems including cassava, potato, and native waxy maize, but it is unknown if this effect would be observed in other starch systems.
10.5.1.2 Cereal expansion Salt is believed to impact the cereal expansion, which contributes towards the characteristic texture. Expansion in extruded products is complex and is related to the combination of biopolymer structural transformations and phase transitions, extrudate swell, bubble nucleation, subsequent growth and collapse (Moraru and Kokini, 2003). Chinnaswamy (1993) studied the effect of salt on cereal expansion of corn with various amylose contents and observed that salt increased the expansion ratio by 0.5– 5.5 units. Compared to the other additives (urea and sodium bicarbonate) and native
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starch, salt had the highest expansion ratio. In a potato starch pellet study, Norton et al. (2011) observed less expansion of the pellets formulated with lower sodium levels (0.125 wt%) compared to levels that are typically found in snack products (2 wt%). Although theories have been postulated, the mechanism of salt’s relationship to expansion remains unclear. Salt is believed to effect starch phase transitions by prolonging rubbery state, which allow the cereal to expand to a greater extent, but may also act as a point of nucleation (Moreau et al., 2011). In a low moisture system, such as in the case of extrusion, small inclusions of salt particles that stay heterogeneous in the starch matrix may be nucleation sites for bubble growth. An increase in the number of nucleation sites results in an increase in smaller bubbles formation, and greater amount of expansion.
10.5.2 Leavening agents Leavening agents are used in food products to help create structure and texture through gas expansion as a result of a chemical reaction, or as the nucleation seed for gas formation. It is well known that sodium bicarbonate generates carbon dioxide gas in the presence of various acids within the cereal dough (Lajoie et al., 1996). Other commonly used sodium-containing ingredients such as trisodium phosphate and sodium ascorbate have been suggested to act as nucleation sites (Lajoie et al., 1996; Moraru and Kokini, 2003). These nucleation points are distributed throughout the dough and can lead to steam expansion in localised areas within dough during the heating process of cereal production. More nucleation sites result in dough structure that has more uniform air cell distribution, thinner cell walls, and greater resistance to shear.
10.5.3 Preservatives Breakfast cereals are fresh and crisp immediately after production, but will lose their sensory quality (e.g. oxidative off notes, discoloration, staling) over time. Typically food manufactures add ingredients to minimise the occurrence of these sensory defects and some of these preservatives can be a source of sodium. Commonly used ingredients in breakfast cereal production include sodium ascorbate, sodium citrate, and sodium metabisulphite. Sodium ascorbate is added to foods as an antioxidant, and can also lower pH. Sodium citrate can be added to foods to lower pH, and act as a sequestering agent, which helps extend shelf life by binding metal ions (e.g. iron, copper) that participate in oxidation reactions. Sodium metabisulphite can be added as a bleaching agent to prevent discoloration.
10.5.4 Cocoa powder Chocolate flavoured cereal is a popular among consumers and is easily produced by the addition of alkalised cocoa powder. The cocoa alkalisation process enhances the flavour of cocoa, making it more smooth and rich, and less bitter in flavour. Alkalisation process uses a variety of different agents, singly or in combination, including sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium
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carbonate. Alkalising agents may add sodium to the cocoa powder; therefore when considering sodium reduction, it is important to choose cocoa alkalised with products produced using non‑sodium solely or in combination with sodium-alkalising agents.
10.5.5 Cereal grains Grains will contain some naturally low levels of sodium and levels vary depending on the type of grain. Grains are an agricultural crop and some variation in sodium is expected from year to year. The sodium content of wheat and yellow corn is 2 and 35 mg per 100 g grain, respectively (USDA, 2006).
10.6 Sources and functional role of non-sodium alternatives for breakfast cereals In order to decrease sodium in cereals, it is important to understand the functional roles of the sodium containing ingredients in food systems. Table 10.3 contains a summary of the functional role of various sodium containing ingredients and non‑sodium alternatives.
10.6.1 Colour and flavour To help compensate for any colour loss due to a decrease in the Maillard or caramelisation reaction by reducing salt, artificial or natural colours may be added to the cereal formulation. Alternatively, non‑sodium ingredients can be beneficial to colour and flavour. Potassium, calcium, and magnesium salts have been shown to provide a lesser degree of brown colour development and toasted flavour than sodium chloride (Moreau et al., 2009; Taylor et al., 2010). Potassium chloride was shown to have similar effects on plasticity as sodium chloride in starch systems (Moreau et al., 2009). Calcium salts combined with added sugar have been studied in low-moisture starch systems, and shown to improve browning and toasted flavour in the absence of sodium chloride. Separately, potassium chloride, calcium chloride, and magnesium chloride were studied in model cereal systems. All were shown to facilitate browning, with divalent cations proving more effective than monovalent cations (Moreau et al., 2011). Flavour impact of calcium and potassium salts was noted as adding bitterness to cereal products. Choline compounds also have been used in conjunction with other salty compounds to provide increased salty flavour in cereal products (Locke and Fielding, 1994). In addition to salt, many ingredients can alter Aw, which influences the Maillard reaction rate. In model systems using glycerol, reducing sugars (lactose, glucose, fructose), and glycine at three different moisture contents (0%, 5%, and 10%), Wang et al. (2015) observed the greatest and lowest amount of browning at 0% and 10% moisture content, respectively, in all treatments. The authors suggest that factors other than Aw are impacting reaction rates and may be due to either the hygroscopic nature or plasticising effect of glycerol.
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In addition to being leavening agents, sodium bicarbonate and potassium bicarbonate have been shown to provide flavour and browning in cereal products. Both raise pH, thereby accelerating the Maillard reaction and production of pyrazine, which is important for aromatic and flavour characteristics (Lajoie et al., 1996; Taylor et al., 2010).
10.6.2 Texture When replacing salt in cereal formulations, it is important to understand the impact of other non‑sodium ionic compounds on Aw and starch gelatinisation in relation to textural changes. Potassium, calcium, and magnesium salts have also been shown to alter texture similarly, but to different extents than salt (Moreau et al., 2009). Potassium chloride altered glass transition temperatures comparably to sodium chloride (Beck et al., 2011). Cations have been shown to slow starch retrogradation in cereal products that contain corn starch. Comparing the valences, divalent cations (Ca, Mg) had slower starch recrystallisation rates than monovalent cations (Na, K, NH4, Li). Moreau et al. (2009) suggest that cations with high charge densities are better able to retain water in starch matrixes compared with lower charge density cations. Since ion type impacts reactions with the starch matrix, there may also be an impact to processing times, heating temperatures required for gelatinisation, staling properties, and resultant textures.
10.6.3 Cereal expansion Potassium, calcium, and magnesium salts are reported as nucleators and leavening agents for cereal expansion (Moraru and Kokini, 2003). The potassium cation has been shown to positively expand extruded cereal pellets (Norton et al., 2011). At high levels of potassium or sodium (2.0 wt%), there is very little difference between the type of cation and the effect on cereal expansion. However at low concentration (0.125 wt%), there were greater differences, with less observed expansion for potassium. Depending on the targeted level of sodium, other potassium alternatives (e.g. potassium chloride, potassium bicarbonate, tripotassium phosphate, potassium ascorbate) may be an option for expansion. Potassium bicarbonate is commonly used to replace sodium bicarbonate, which acts as nucleation points and leavening agent in baked goods. The chemical reaction rate is slightly different than sodium bicarbonate and generally higher levels must be used in order to get a similar effect. Calcium carbonate and calcium bicarbonate, commonly used in baking powder, could also potentially be used to provide nucleation and leavening when combined with acids. Similar to potassium bicarbonate, the chemical reaction rate will be different. The other consideration is the bitter or metallic taste of these non‑sodium alternatives. Another option to consider for cereal expansion is grain components themselves. Rovins et al. (2012) observed that smaller granulation sizes of corn cones and corn bran in formulations have been shown to act as nucleation sites.
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10.6.4 Preservatives Non‑sodium ingredients can be added to cereals to help extend the freshness and shelf-life of cereal products. Potassium ascorbate and potassium citrate can be used to help regulate pH. Potassium citrate also chelates metals that promote oxidation. Other ingredients (i.e. butylated hydroxy-anisole, butylated hydroxy-toluene) may be added to the cereal, or cereal box liners to minimise oxidation, but may not be suitable considering clean label initiatives. Alternatively, mixed tocopherols, vitamin E, or tocopherols are used as anti-oxidants. Consumers are more accepting of unbleached or discoloured products, which may allow for elimination of sodium metabisulphate.
10.6.5 Mechanical options In addition to ingredient formulations, the processing conditions can also influence the texture of the finished breakfast cereal (Robin and Palzer, 2015). Specifically, the starch transformation that occurs during extrusion influences dough viscosity, which in turn influences cereal expansion and texture. Independent factors influencing the viscosity and expansion include feed rate of the dry mix, configuration, screw speed, water content of the dough, and barrel length to diameter ratio of the extruder. Too low of a viscosity will produce a cereal with less expansion and hard texture. Similarly, too high of a viscosity will prevent growth of bubbles and lead to a decrease in volume and hard texture (Robin and Palzer, 2015). Leveraging the mechanical operating conditions of extruders is an option to consider when trying to build back the texture and expansion functional roles of some sodium-containing ingredients.
10.7 Conclusions Recent emphasis on sodium reduction has created challenges for the food scientist to reformulate products to reach a sodium target while maintaining consumers’ expectation of the desired sensory attributes. Critical for success is understanding the functional role of the sodium containing ingredients in the food product to help determine alternative ingredients, or processing conditions that may help recreate the desired effect. However, non‑sodium-containing ingredients may not provide the same functional role of the sodium-containing ingredient. For example, Salt is a unique ingredient that performs many roles in creating the colour, texture, and flavour of cereals; however, the mechanism of these changes is not completely understood. To address colour and flavour, further examination of the effect of starch matrix interactions on browning would be warranted. Possibilities include looking for compounded effects of salt with pH, and change in simple sugars and plasticisers on the Maillard reaction. Further research on mechanism of nucleators and leavening agents to recreate desired expansion and texture is also warranted. In addition, non‑sodium leavening agents generally have a less desirable taste than the sodium version. The most challenging area of research is identifying the salty taste mechanism, which is instrumental for identifying non‑sodium alternative solutions.
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Acknowledgements The authors would like to thank Jody Mattsen and Chad Rieschl for their technical contributions and review of this chapter.
References Arcand, J., Au, J.T.C., Schermel, A., L’Abbe, M.R., 2014. A comprehensive analysis of sodium levels in the Canadian packaged food supply. Am. J. Prev. Med. 46 (6), 633–642. Arcand, J., Jefferson, K., Schermel, A., Shah, F., Trang, S., Kutlesa, D., Lou, W., L’Abbe, M.R., 2016. Examination of food industry progress in reducing the sodium content of packaged foods in Canada: 2010 to 2013. Appl. Physiol. Nutr. Metab. 41 (6), 684–690. Beck, M., Jekle, M., Becker, T., 2011. Starch re-crystallization kinetics as a function of various cations. Starch/Stärke 63 (12), 792–800. https://doi.org/10.1002/star.201100071. Bhatty, R.S., 1997. Milling of regular and waxy starch Hull-less barleys for the production of bran and flour. Cereal Chem. 74 (6), 693–699. Bouvier, J.M., Campanella, O., 2001. Breakfast cereals. In: Guy, R. (Ed.), Extrusion Cooking— Technologies and Applications. Woodhead Publishing, pp. 133–160. Brooke, C., 1968. Enrichment and fortification of cereals and cereal products with vitamins and minerals. J. Agric. Food Chem. 16 (2), 163–167. Caldwell, E.F., Fast, R.B., Faubion, J.M., 2000. The cereal grains. In: Fast, R.B., Caldwell, E.F. (Eds.), Breakfast Cereals and How They Are Made. second ed. American Association of Cereal Chemists, Inc., St. Paul, MN, pp. 1–15. Centers for Disease Control and Prevention, 2012. Vital signs: food categories contributing the most to sodium consumption – United States, 2007–2008. Morb. Mortal. Wkly Rep. 6, 92–98. Chinnaswamy, R., 1993. Basis of cereal starch expansion. Carbohyd. Polym. 21, 157–167. Culbertson, J., 2004. Grains, cereal: ready-to-eat breakfast cereals. In: Smith, J.S., Hui, Y.H. (Eds.), Food Processing: Principles and Applications. Blackwell Publishing, Ames, IA, pp. 239–248. Devi, A., Eyles, H., Rayner, M., Ni Mhurchu, C., Swinburn, B., Lonsdale-Cooper, E., Vandevijvere, S., 2014. Nutritional quality, labelling and promotion of breakfast cereals on the New Zealand market. Appetite 81, 253–260. Dotsch, M., Busch, J., Batenburg, M., Liem, G., Tareilus, E., Mueller, R., Meijer, G., 2009. Strategies to reduce sodium consumption: a food industry perspective. Crit. Rev. Food Sci. Nutr. 49 (10), 841–851. Drewnowski, A., Rehm, C.D., 2013. Sodium intakes of US children and adults from foods and beverages by location of origins and by specific food source. Nutrients 5, 1840–1855. Euromonitor International, 2017. Passport Database, Cereal and Cereal Bars Market Research, Viewed 01, 05 and 07 September 2017. Eyles, H., Webster, J., Jebb, S., Capelin, C., Neal, B., Ni Mhurchu, C., 2013. Impact of the UK voluntary sodium reduction targets on the sodium content of processed foods from 2006 to 2011: analysis of household consumer panel data. Prev. Med. 57, 555–560. Farahnaky, A., Majzoob, M., Shojae, Z.A., 2009. Effect of NaCl and water content on expansion and color of cassava and potato starches on baking. J. Texture Stud. 40, 676–691. Fast, R.B., 2000. Manufacturing technology of ready-to-eat cereals. In: Fast, R.B., Caldwell, E.F. (Eds.), Breakfast Cereals and How They Are Made. second ed. American Association of Cereal Chemists, Inc., St. Paul, MN, pp. 17–54.
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Food Safety Authority of Ireland, 2015. Monitoring of sodium and potassium in processed foods. Viewed 26 June 2016. https://www.fsai.ie/uploadedFiles/Science_and_Health/Salt_ and_Health/Salt_Surveys_2003_onwards.pdf. Gillespie, C., Maalouf, J., Yuan, K., Cogswell, M.E., Gunn, J.P., Levings, J., Moshfegh, A., Jaspreet, A., Ahuja, K.C., Merritt, R., 2009. Sodium content in major brands of U.S. packaged foods. Am. J. Clin. Nutr. 101, 344–353. https://doi.org/10.3945/ajcn.113.078980. Hill, S.S., Ferry, A.L., 2006. Satisfactory salt levels for cereals and health. Food Sci. Technol. 20 (4), 26–30. Jour, M.E., Lazar, M.E., Mossman, A.P., Wallace, J.M., 1974. Air-fluidized toasting of whole kernel wheat-processing variables and functional properties for food applications. J. Food Sci. 39 (2), 239–243. Kent, N.L., Evers, A.D., 1994. Technology of Cereals: An Introduction for Students of Food Science and Agriculture, fourth ed. Elsevier Publishing Limited, Cambridge, England, pp. 244–258. Lajoie, M.S., Goldstein, P.K., Geeding-Schild, D., 1996. Use of bicarbonates in extrusion processing of ready-to-eat cereal. Cereal Foods World AACC Internationals 41 (6), 448–450. Locke, K.W., Fielding, S., 1994. Enhancement of salt intake by choline chloride. Physiol. Behav. 55 (6), 1039–1046. Meneton, P., Lafay, L., Tard, A., Dufour, A., Ireland, J., Menard, J., Volatier, J.L., 2009. Dietary sources and correlates of sodium and potassium intakes in the French general population. Eur. J. Clin. Nutr. 63, 1169–1175. Monro, D., Ni Mhurchu, C., Jiang, Y., Gorton, D., Eyles, H., 2015. Changes in the sodium content of New Zealand processed foods: 2003–2013. Nutrients 7, 4054–4067. Moraru, C.I., Kokini, J.K., 2003. Nucleation and expansion during extrusion and microwave heating of cereal foods. Compr. Rev. Food Sci. Food Saf. 2 (4), 147–165. Moreau, L., Bindzus, W., Hill, S., 2009. Influence of sodium chloride on color development of cereal model systems through changes in glass transition temperature and water retention. Cereal Chem. 86 (2), 232–238. Moreau, L., Bindzus, W., Hill, S., 2011. Influence of salts on starch degradation: Part II – Salt classification and caramelization. Starch-Starke 63, 676–682. Ni Mhurchu, C., Capelin, C., Dunford, E., Webster, J.L., Neal, B., Jebb, S.A., 2011. Sodium content of processed foods in the United Kingdom: analysis of 44,000 foods purchased by 21,000 households. Am. J. Clin. Nutr. 93, 594–600. Norton, A.D., Greenwood, R.W., Noble, I., Cox, P.W., 2011. Hot air expansion of potato starch pellets. J. Food Eng. 105 (1), 119–127. Robin, F., Palzer, S., 2015. Texture of breakfast cereals and extruded products. In: Chen, J., Rosenthal, A. (Eds.), Modifying Food Texture, Volume 1—Novel Ingredients and Processing Techniques. Woodhead Publishing, Cambridge, pp. 203–234. Rovins, F., Schuchmann, H.P., Palzer, S., 2012. Dietary fiber in extruded cereals: limitations and opportunities. Trends Food Sci. Technol. 28, 23–32. Rutherfurd, S.M., Torbatinejad, N.M., Moughan, P.J., 2007. Available (ileal digestible reactive) lysine in selected cereal-based food products. J. Agric. Food Chem. 54 (25), 9453–9457. Schierhorn, C., 2016. Boom time for breakfasts. Food Technol. 70 (3), 22 31. Taylor, J.R.N., Emmambux, M.N., 2008. Products containing other specialty grains: sorghum, the millets and Pseudocereals. In: Hamaker, B.R. (Ed.), Technology of Functional Cereal Products. Woodhead Publishing Limited, Cambridge, England, pp. 281–335. Taylor, A.J., Sivasundaram, L., Moreau, L., Channell, G.A., Hill, S.E., 2010. Effect of physical properties of food matrices on the Maillard reaction. In: Mottram, D.S., Taylor, A.J.
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(Eds.), Controlling Maillard Pathways to Generate Flavors. American Chemical Society, Washington, DC, p. 2010. Torbatinejad, N.M., Rutherfurd, S.M., Moughan, P.J., 2005. Total and reactive lysine contents in selected cereal-based food products. J. Agric. Food Chem. 5 (11), 4454–4458. Trevena, H., Neal, B., Dunford, E., Wu, J.H.Y., 2014. An evaluation of the effects of the Australia food and health dialogue targets on the sodium content of bread, breakfast cereals and processed meat. Nutrients 6 (9), 3802–3817. Trevena, H., Neal, B., Dunford, E., Haskelberg, H., Wu, J.H.Y., 2015. A comparison of the sodium content of supermarket private-label and branded foods in Australia. Nutrients 7, 7027–7041. Trieu, K., Neal, B., Hawkes, C., Dunford, E., Campbell, N., Rodriuez-Fernandez, R., Legetic, B., McLaren, L., Barberio, A., Webster, J., 2015. Salt reduction initiatives around the world – a systematic review of progress towards the global target. Viewed 14 June 2016, PLoS One 10 (7), e0130247. United States Department of Agriculture, 2016. Nutrient Database, Viewed 8 July 2016. https:// ndb.nal.usda.gov/. Wang, C.W., Wijayanti, H.B., Bhandari, B.R., 2015. Maillard reaction in limited moisture and low water activity environment. In: Gutierrez-Lopez, G., Alamilla-Beltran, L., del Pilar Buera, M., Welti-Chanes, J., Parada-Arias, E., Barbosa-Cánovas, G.V. (Eds.), Water Stress in Biological, Chemical, Pharmaceutical and Food Systems. Springer-Verlag, New York, NY, pp. 41–63. Webster, J.L., Dunford, E.K., Neal, B., 2010. A systematic survey of the sodium contents of processed foods. Am. J. Clin. Nutr. 91, 413–420. Webster, J., Trieu, K., Dunford, E., Hawkes, C., 2014. Target salt 2025: a global overview of national programs to encourage the food industry to reduce salt in foods. Nutrients 6, 3274–3287.
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10.1 Breakfast cereals Whether in the form of traditional hot cereals, ready-to-eat (RTE) cereals or cereal bars, grains have been a large part of the breakfast diet for many years. Early European grains were largely consumed in a cooked, hot form called porridge and made from wheat, oats, or barley. In the United States, cereals were made from corn (grits or hominy). Other grains, such as sorghum, quinoa, and amaranth, are commonly used in South America (Taylor and Emmambux, 2008). However, use of these ancient grains has grown in popularity globally due to the nutrient value they provide. Traditional hot cereals are still consumed today, but the majority of the cereals consumed are RTE cereals, which were introduced as a nutritious alternative in the United States during the latter half of the 19th century by brothers William K. and Dr. John Kellogg. More recently, cereal bars were introduced to the breakfast cereal market to meet consumers’ desire for convenience and portability. From a nutritional standpoint, breakfast cereals and breakfast goods help contribute fibre, vitamins, minerals, and protein to the diet. Vitamins and minerals are naturally present in cereals, but many are lost during the milling process. Therefore, many manufacturers began to fortify breakfast cereals in the United States to increase essential vitamins and minerals, like thiamine and iron, respectively (Brooke, 1968). During cereal production, the essential amino acid lysine can participate in the Maillard reaction. Studies report 20%–54% decreases in lysine bioavailability due to this browning reaction (Rutherfurd et al., 2007; Torbatinejad et al., 2005). Many breakfast cereals are consumed with milk, which provide additional protein, vitamins, and minerals. Recent emphasis on nutrient density of breakfast cereals has led to an increase in certain nutrients, such as protein and fibre, and a decrease in others, such as sugar and sodium. In general, the sodium content in breakfast cereal is relatively low compared to other food categories (e.g. deli meats) on a per 100-g basis. Similar to other grain products (e.g. breads), breakfast cereals are consumed throughout the day and the frequency of consumption can lead to a significant sodium contribution to the overall diet. In the United States, cereals were not identified as one of the top 10 foods contributing sodium to the diet across the entire population (Centers for Disease Control and Prevention, 2012). Examining individual age groups, individuals aged between 2 and 5 years had breakfast cereals ranked number 10 as a foods source of sodium in the diet. Breakfast cereals did not make the top 10 list for any other age group.
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10.2 Breakfast cereals market size The breakfast cereals market has grown significantly since the introduction of RTE cereals. In 2001, Bouvier and Campanella (2001) reported the global consumption rate of breakfast cereals (e.g. hot cereals, RTE, cereal bars) to be approximately 3 million tons (or 2.7 metric tonnes). By 2016, the breakfast cereal and cereal bars volumes were 5 metric tonnes and the market grew to a US$34.9 billion category (Euromonitor International, 2017). The breakfast cereals market size (total volume) varies significantly by country and differences can be attributed to factors such as cultural food preferences and the degree of developed economies (Fig. 10.1). In 2016, the United States led the list in term of largest volume, nearly three times as much as the next highest country, followed by the United Kingdom, Canada, Germany, and China. Comparing growth rates between 2011 and 2016 for the top 10 largest volume production, the United States has the greatest decline (−8.8%) followed by Mexico (−4.7%) and Australia (−3.5%). Growing competition in the retail space and fast food restaurants led to a decrease in breakfast consumption at home, which impacts cereal purchases by the consumer (Schierhorn, 2016). Within the top 10 list of top breakfast producers, the greatest growth rate is observed in China (40%), South Africa (28.1%), and Russia (14%). Considering other countries, the greatest growth rate for breakfast cereals is in India (168%) followed by Japan (130%) and Vietnam (91%). The observed increase in many of these countries is most likely due to recent economic growth, which led to an increase in consumer spending. The greatest decrease in total volume growth rates for breakfast cereals was observed for South Korea (−36.5%), Belarus (−32.7%), and Greece (−27.5%). 1800
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ia Ru ss
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an C
do m
Ki te d
d te
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U
U
ng
St
at
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–20
Country
Fig. 10.1 Total volume market size ('000 tonne) and growth rate (%) of breakfast cereals in various countries between 2011 and 2016 (Euromonitor International, 2017).
Breakfast cereals233
2011
2016
%Growth
9000
25.0 20.0
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15.0
7000
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Total volume (kg) per '000 people
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–5.0
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U
ad a Sw ed en Au st ra lia Fi nl an d N or wa U ni y te d St at es
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en N
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Ki
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Ire
la
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Country
Fig. 10.2 Total volume per capita (kg per ‘000 people) and growth rate (%) of breakfast cereals in various countries between 2011 and 2016 (Euromonitor International, 2017).
Examining the market size on a per capita basis provides insights on population consumption rates and changes in cereal purchasing patterns, and can be used to help determine market opportunities (Fig. 10.2). In 2016, the top five countries that led in volume per capita are Ireland, United Kingdom, Denmark, New Zealand, and Canada. Comparing growth rate between, 2011 and 2016, the greatest increases for the top 10 largest per capita volume were in Norway (21.8%), Sweden (10%), Ireland (7.1%), and Denmark (5.6%), whereas the greatest decreases occurred in the United States (−12.4%), Australia (−10.6%), and Canada (−7.7%). Examining other countries, the greatest volume per capita growth rates for breakfast cereals between 2011 and 2016 was India (152.6%), Japan (132.5%), and Vietnam (80.2%). The greatest decrease in volume per capita growth rates was South Korea (−37.8%), Belarus (−32.7%), and Greece (−25.3%). Examining total volume of various breakfast cereal subgroups provides further insights into changes in market growth (Figs. 10.3–10.5). For all top 10 countries except China and South Africa, RTE subgroup commands the largest volume, which is 4%–20% greater than the next largest subgroup. Hot cereals are the largest volume for China, South Africa, and Russia, suggesting that these three countries have the biggest opportunity for RTE cereal growth. Breakfast bars are the lowest subgroup in all countries except Mexico and France. Reporting the subgroups on a per capita basis further provides insights on population consumption rate and potential market opportunities (Figs. 10.6–10.8). Comparing 2011 to 2016 in Fig. 10.6, the growth rate of RTE cereals has decreased for every country except Switzerland (0.5%), Israel (1.3%), and Sweden (12.8%). Conversely, every country has experienced an increase in hot cereal growth rate,
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%Growth
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ric a
ut
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U
Growth rate (%)
Total volume ('000 tonnes)
1600
U
Country
Fig. 10.3 Total volume market size ('000 tonne) and growth rate (%) of ready-to-eat cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
300
2011
2016
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200
200 150 150 100 100 50
50 0
d
a Au st ra lia
In di
ar
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az
D
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ng do So m ut h Af ric a Ru ss ia C an ad a
hi na C U
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at
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0
St ni te d U
Growth rate (%)
Total volume ('000 tonnes)
250
250
Country
Fig. 10.4 Total volume market size ('000 tonne) and growth rate (%) of hot breakfast cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
Breakfast cereals235
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ce
120
az il
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140
m
20
ex ic o
160
es
Total volume ('000 tonnes)
180
U
Country
Fig. 10.5 Total volume market size ('000 tonne) and growth rate (%) of cereals bars in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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%Growth
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Total volume (kg) per '000 people
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Fig. 10.6 Total volume per capita (kg per ‘000 people) and growth rate (%) of ready-to-eat cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
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Sw ed
or
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la
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Ire
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en
Fi n
m
ar
k
0
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Fig. 10.7 Total volume per capita (kg per ‘000 people) and growth rate (%) of hot breakfast cereals in various geographies between 2011 and 2016 (Euromonitor International, 2017).
2011
2016
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%Growth
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80.0
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N
Growth rate (%)
Total volume (kg) per '000 people
1400
Country
Fig. 10.8 Total volume per capita (kg per ‘000 people) and growth rate (%) of cereals bars in various geographies between 2011 and 2016 (Euromonitor International, 2017).
Breakfast cereals237
ranging from 4% to 43.2% (Fig. 10.7). The smallest cereal category, cereal bars, is more similar to the RTE than hot cereals in growth rate. As shown in Fig. 10.8, most countries show an increase in volume per capita growth rate with the exception of New Zealand (−1.4%), Australia (−9.3%), United Kingdom (−11.6%), and United States (−10.2%). Considering market opportunities, brand extension or new market entries into the hot cereal subcategory may be an option for market declines in RTE cereals and cereal bars.
10.3 Types of breakfast cereals The breakfast cereal market is quite diverse compared to the early days of Kellogg’s and Post where the major emphasis was on nutrition and health. The cereal connection between nutrition and health is still a major marketing focus today and has expanded to include fitness (Schierhorn, 2016). Cereal manufacturers have expanded the nutritional benefits to include whole and ancient grains, added fibres, proteins, phytonutrients (e.g. blueberries, cranberries), and probiotics. Products are marketed with emphasis on heart health, weight loss, enhanced cognitive performance, and digestive wellness. Although nutrition may be a determining factor for the adults, the kid’s cereal market is mostly about fun. Therefore, cereal manufacturers focus on shapes, colours, flavour, movie promotion tie-ins, and a ‘prize inside’ to gain product awareness with this target audience. The basic formula for breakfast cereals is very similar, using typical grains such as wheat, oat, barley, rice, and corn. Heightened health awareness by consumers has led to the introduction of ancient grains, such as sorghum, quinoa, and amaranth, into cereal formulations. Grains can be used individually or in combinations when producing cereals. To further differentiate products, food manufactures leverage ingredients that provide unique flavours and colour, sweeteners, salt, and inclusions (e.g. chocolate bits, nuts, and fruit). With advancements in extrusion technology, cereal manufacturers also leverage cereal size and shape for visual appeal. The breakfast cereals are classified as follows, which are explained in greater detail: ●
●
●
Hot cereals Ready-to-eat cereals, and Granola and muesli
10.3.1 Hot cereals In general, hot cereals have the least amount of processing compared to the other types of breakfast cereals. The basic processing steps include separating the hull from the kernel (groats), cutting the groats (steel cut), separating and grinding the kernel to the desired particle size. At this stage, cereals such as steel cut oats can be eaten after an extensive simmering process. Steel cut oats have gained popularity with consumers; however, the long preparation time deters home preparation. To add convenience, cereal manufacturers further process steel cut oats to shorten the cooking time. In this case, the grains are soaked or
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steamed, rolled to the desired thinness, cooled and dried to increase water uptake and decrease preparation time. Three options available are steel cut (chopped groats), old fashioned (steamed and rolled), instant (steamed, rolled, and chopped), which differ based on cooking process. The fastest one, instant oatmeal, incorporates other ingredients, such as gum, to further aid in water uptake and preparation simply requires the addition of hot water with no further cooking time. Other popular grains used in hot cereals include corn, wheat, barley, and rice, with wheat being the second most consumed cereal. Farina is debranned and degermed endosperm, and is the most popular of the wheat-based cereals. The wheat granules may be consumed at this stage or further ground and sifted (bolting) to a very fine particle size. A favourite southern breakfast side dish in the United States is corn grits, which are produced through a dry milling process that cleans white corn followed by grinding and sieving to the desired particle size. Removing the hull and germ from corn produces hominy and it may be alkalised (nixtalmalisation) to produce the desired taste and texture. Alkalisation can be a source of sodium depending on the type of agent used in the process. Consumers tend to consume hot cereals with milk or add sweeteners, such as brown sugar, maple syrup, or honey. For added convenience and appeal, food manufacturers began adding inclusions, such as dried fruits, nuts, flavours, and sweeteners to instant cereals. Salt may be added to mask the grain bitterness and enhance other flavours. Preparation of these cereals simply requires adding hot water or milk.
10.3.2 Ready-to-eat cereals RTE cereals are regarded as cereal products that need no further preparation prior to consumption. Convenience is the greatest appeal for this cereal category. Similar to hot cereals, typical grains include corn, wheat, barley, oat, or rice, and can be processed from either grain or flour. Production of RTE cereals is more complicated and extensive than hot cereals. Regardless of RTE cereal type, the grains all go through a similar process; cleaning, cutting or milling, cooking, tempering, and drying. Some flavours, colours, vitamins and minerals, sweetener and salt may be added during the process. To increase visual appearance or prevent degradation of heat-labile compounds (e.g. flavours, colours, and vitamins), ingredients may be sprayed onto the surface of cereals (Culbertson, 2004). Spraying the surface of the cereal with carbohydrate polymers (e.g. sugars, maltodextrins) also helps extend the bowl shelf-life to maintain crispness and texture after adding milk (Culbertson, 2004). The basic types of RTE cereals include: 1. 2. 3. 4. 5.
Flaked extruded shredded puffed, and granola/muesli.
Type of equipment and operating conditions differentiate the finished form (size and shape) and texture of the cereals.
Breakfast cereals239
10.3.2.1 Flaked cereals From an historical perspective, flaked cereals were one of the first RTE cereals introduced into the market and are still quite popular today. They can be large or small in diameter with a surface that is rough with noticeable bubbles. The texture can sometimes be manipulated to have multiple textures via inclusions into the flake. Corn, wheat, and rice are typical grains used in flaked cereals. Depending on the grain source, various parts of the kernel are used to make the flaking grit. For corn flakes, the bran and germ are removed and parts of the endosperm are used for production. Considering wheat grain, the whole kernel is used to make the flaking grit. Kernels are exposed to steam and broken by passing through rollers. Rice is the most versatile in that the flaking grit can originate from whole kernel or parts of the endosperm, and requires the least amount of pre-processing, milling to form polished head rice (Caldwell et al., 2000). The intact grain, or fraction of it, is used to help determine the desired flake size, since one particle produces one flake. Alternatively, grains are pelletised before flaking to create a grit with many particles. A typical formula will include grit (28%–32%), granulated or liquid sugar, malt syrup, salt, and water. The ingredients are mixed and cooked using pressure and steam in a batch cooker to a final moisture content up to 32% (w/w) (Fast, 2000). In some cases, the pressure is reduced until the starch is gelatinised. The resulting cooked mixture is dumped onto a conveyer belt that passes through a delumping process to obtain individual grits. Air can be circulated to help cool the grits and these are then dried under controlled humidity to control case hardening. The grits are then tempered to allow moisture equilibration, flaked through a pair of rollers and toasted in a fluidised bed. Further cooling and tempering will promote amylose starch retrogradation, which impacts texture and colour of the finished product. Flakes may also be made through a more rapid extruded process using either single- or twin-screw extruders (Fast, 2000). In this case, grits are created by crushing grains through the extruder. Alternatively, flour may also be used as the starting material. As grits or flour pass through the barrel, other ingredients (e.g. sugar, salt, moisture) can be metered in. Heat is introduced near the centre section of the barrel, and along with the mechanical shear induced by the screws, the cooking process begins. The mash that is formed reaches the end of the barrel and passes through a cool section to prevent puffing and a die that helps create the shape. Rotating knives cut the product to appropriate pellet size. The drying, cooling, and flaking steps needed to complete the process are similar to the traditional flaked method. Product characteristics differ slightly depending on the flaking method due to differences in operating conditions (Bouvier and Campanella, 2001). Largest differences are in the texture and colour of the finished cereal product. Extruded flakes tend to be paler in colour, which may be adjusted by adding ingredients such as dyes, cocoa powder, and malt syrups.
10.3.2.2 Direct expansion Extrusion technology can also produce cereals by direct expansion. In this process, a dough is created; therefore, flour may be used as a starting material (Fast, 2000). Dry mixtures of flour, starch, sugar, salt, malt, flavour, colour, and micronutrients are
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added into the extruder. Steam is added to introduce moisture in the screw chamber and the dough is exposed to shear, pressure, and heat. As the fluidised mass exits the chamber through a die, rapid expansion takes place as due to the pressure differential and steam vaporisation. The ability to alter the die shape lends itself to many options for size and shape of the finished product, which is appealing for kid’s cereals. In addition, extrusion offers the option for co-extrusion, which allows for cereals with different textures or coloured centres.
10.3.2.3 Puffed cereals Traditional puffed grained cereals were made using whole grains and leveraged the internal moisture to help expand the grain when subjected to heat (Jour et al., 1974). Technology advancement led to the gun-puffed method, which leverages heat, internal moisture, and a pressure drop to expand the grain (Fast, 2000). The steam formed within the grain under heat and pressure expands upon exposure to atmospheric pressure causing the grain to expand. Today, most puffed cereals production start as flours, extruded without expanding, tempered (creating a half product), and passed through a continuous puffing operation. Typical grains used for this process are rice or wheat. To prevent wheat grains from losing their bran during the puffing process, the grains are pre-treated with a saturated salt brine solution. In some cases, it is desired to remove part of the bran and it can be removed using a process called pearling (Bhatty, 1997). For rice, the grain is milled to polish the surface.
10.3.2.4 Shredded biscuits Shredded cereals are typically made from wheat, although corn, rice, and other grains have been used. Grains are batch cooked in kettles with excess of water slightly below boiling temperature. Steam is then injected into the water to begin the cooking process. Cooked grains are removed from the kettle and cooled to stop the cooking process and surface dry the grain. The material is then held in bins to allow for tempering, which promotes starch retrogradation and aids in the cutting process (Fast, 2000). The grains are then pressed between rolls, one smooth and one with grooves, to help form long strands of cereal. These strands are then formed, cut, and baked in a continuous oven or fluid bed. The pillowed shapes of shredded biscuits are limited to squares, rectangles, or triangles in order to minimise waste since there is no ability to rework excess cereal trimmings back into the process. Shredded biscuits may also be produced using extrusion. In this case, meal or flour is used as the raw material, which allows for more than one grain to be used in the formula. The ingredients are mixed, extruded, cooled and tempered, shredded and formed into smaller, bite-sized biscuits.
10.3.3 Granola and muesli Granola and muesli are popular breakfast cereals or cereal bars in many countries and are typically made from rolled or cut oats that are mixed with other dry ingredients such as dried fruit, nuts, spices, sugar, syrups and salt. Liquids such as oil, water, flavours, and spices are blended with the dry ingredients until evenly coated. The mixture is spread thinly and baked to approximately 3% moisture (Fast, 2000). Muesli
Breakfast cereals241
is similar to granola in that it is made from rolled oats; however, they are not baked and generally consumed raw. In its final preparation, muesli can contain inclusions similar to granola and is typically mixed with fluids such as milk, yogurt, or fruit juice.
10.4 Sodium and breakfast cereals 10.4.1 Breakfast cereals contributions to sodium intake Although the sodium content of breakfast cereals is relatively low compared to other food products (e.g. processed meats), they are consumed throughout the day and the frequency of consumption can make this category a significant contributor of sodium in the overall diet. Differences in sodium contribution will depend on age and geography of a specific population. Using data collected by the National Health and Nutrition Examination Surveys, Drewnowski and Rehm (2013) reported that breakfast cereals contribute between 1.5% and 3.5% of sodium to the diet, with children between ages 6 and 11 years consuming the most. In the French population, Meneton et al. (2009) reported that breakfast cereals contribute 5.2% and 7.5% of the sodium intake for adults and children, respectively. Ni Mhurchu et al. (2011) also examined the sources of sodium in the diet and reported that cereal products (breakfast cereals, cereal bars, pasta, couscous, rice, and savoury noodles) contribute 5% of sodium to the diet of British households. Compared to other food categories, breakfast cereals are not generally considered major contributors to sodium in the diet.
10.4.2 Sodium content of breakfast cereals The mean sodium content in breakfast cereals and cereal bars has been reported in many geographical studies (Table 10.1). When reported, the mean sodium content and sodium content range for hot cereals was lower than other forms of cereal products and, in general, RTE cereals have the highest. The United States has the highest mean sodium content in RTE cereals, followed by Canada while the remaining countries had similar content. Comparing private and branded-labelled breakfast cereals and cereal bars, Trevena et al. (2015) observed that there were no significant differences between the two labels. They observed a similar result for new cereal products introduced in 2013. Ni Mhurchu et al. (2011) compared the weighted and unweighted mean sodium content to provide insights on the market leaders’ contribution of sodium. The unweighted and weighted sodium means were 274 and 346 mg sodium per 100 g cereal, respectively, suggesting that the market leaders contain higher sodium than smaller market brands. A similar finding was observed for cereal bars.
10.4.3 Progress on sodium reduction of breakfast cereals Many geographies have initiated governmental voluntary and mandated programs to reduce sodium in the food supply chain as a means to reduce high blood pressure (Webster et al., 2014). In their analysis, Webster et al. (2014) identified 83 countries that have initiated or implemented strategies for sodium reduction. Many of these
Cereal product type
Australiaa
Breakfast cereal, branded label Breakfast cereal, private label Cereal bar, branded label Cereal bar, private label Ready-to-eat Hot Other Cereal bars Ready-to-eat All cereals Cereal for kids Biscuits & bites Brans Bubbles, flakes & puffs Muesli Oats Breakfast cereal Breakfast cereal Cereal bars
Australiab
Canadac New Zealandd
United Statese United Kingdomf
a
Trevena et al. (2015). Webster et al. (2010). Arcand et al. (2014). d Devi et al. (2014). e Gillespie et al. (2009). f Ni Mhurchu et al. (2011). b c
No. of products analysed
Mean (±SD) (mg/100 g)
191
144 (±160)
85
197 (±193)
137 46 218 42 20 160 230 247 32 20 14 65 67 45 148 965 413
137 (±101) 197 (±110) 264 23 113 144 375 (±246) 193.31 (±87.9) 298 (±249.9) 294.6 (±81.5) 294.3 (±105.2) 293.3 (±180.6) 94.4 (±110.9) 32.2 (±69.8) 513 (±219) 274 186
Range (mg/100 g)
Data collection year 2013
0–1063 0–158 0–600 5–463 0–933
2008
0–941 0–1000 0–612
2010–2013 2008–2009
2010–2011 2013
Reducing Salt in Foods
Country
242
Table 10.1 Mean sodium content (mg sodium per 100 g) of various breakfast cereals in various geographies
Breakfast cereals243
geographies are working with the food industry to establish sodium targets in key food categories, including breakfast cereals, and the authors reported 38 of these countries have established voluntary or mandated programs. In another review, Trieu et al. (2015) report 75 countries with national sodium reduction strategies. Various types of monitoring programs were put into place for a majority of the countries including self-reporting, label surveys, and chemical analysis. Various studies examined the change in sodium content of many breakfast cereal products over a given period of time (Table 10.2). In all cases, the mean sodium content of the cereals decreased from the baseline year (Year 1) to the monitored year (Year 2). Evaluating Canadian products, Arcand et al. (2016) reported a significant decrease in Table 10.2 Sodium reduction progress of various breakfast cereals as measured by mean sodium content (mg sodium per 100 g product) over a given period of time
Country Australiaa
Australiab Canadac
Irelandd
New Zealande a
Cereal product type Branded label, breakfast cereal Private label, breakfast cereal Branded label, cereal bars Private label, cereal bars Breakfast cereal RTE breakfast cereal Instant hot cereal Granola, cereal bar Cornflake based cereal Rice based cereals Branded label Private label
Trevena et al. (2015). Trevena et al. (2014). Arcand et al. (2016). d Food Safety Authority of Ireland (2015). e Monro et al. (2015). b c
No. of products reviewed (year 1, year 2)
Year 1, mean (±SD) (mg/100 g)
Year 2, mean (±SD) (mg/100 g)
97
180 (±188)
164 ± 169
21
185 (±214)
179 (±207)
50
145 (±100)
142 (±100)
12
163 (±114)
163 (±114)
86, 107 39, 52 230, 250
316
237
375 (±246)
301 (±242)
50, 60
453 (±141)
385 (±155)
172, 200
279 (±108)
254 (±99)
761 (±132)
309 (±117)
555 (±168)
307 (±70)
320 (±247) 406 (±320)
201 (±167) 279 (±237)
73, 146 36, 30
Year 1, year 2 2011, 2013
2010, 2013 2010, 2013
2003, 2011
2003, 2013
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sodium of RTE and instant hot cereals by 19.7% and 15.0%, respectively, between 2010 and 2013. Trevena et al. (2014) also reported a 25% decrease in Australian breakfast cereals between the same 3-year period. Eyles et al. (2013) studied the impact of the UK Food Standards Agency’s (FSA) voluntary sodium reduction program for processed foods and observed that 81% of products analysed using Nutrition Information Panels (NIP) in 2011 met the 2010 target (300 mg sodium per 100 g product) for breakfast cereals, a 59% increase from 2006. Monro et al. (2015) observed the largest sodium reduction for food products analysed (NIP) between 2003 and 2013 was breakfast cereals with a reported 28% decrease. Comparing private and branded-labelled products, Trevena et al. (2015) observed that Australian private-label cereal products had a 37% higher mean sodium content than branded-label. Similarly, Monro et al. (2015) reported that the New Zealand private-label cereals were higher in sodium content than branded-label. In other studies, the sodium content of cereal products was compared to the governmental voluntary targets. Devi et al. (2014) compared sodium content of retail cereal products to that recommended by the National Heart Foundation in New Zealand and observed that on average, the targets were met (Table 10.1). Webster et al. (2014) compared the sodium content of breakfast cereals produced in 2008 to the voluntary targets of the 2012 UK FSA. In their analysis, RTE and hot cereals were 77% and 100% below the FSA target, respectively. By way of comparison to historical data, Kent and Evers (1994) published sodium content of RTE cereals manufactured in the United Kingdom. The mean sodium content was 0.625 mg and sodium content range was 0.01–1.2 g sodium per 100 g cereal, respectively. With the exception of Ireland in Table 10.2, the mean sodium values were lower than values reported by Kent and Evers (1994).
10.5 Sources and functional role of sodium in breakfast cereals In cereal formulations some ingredients are added because of their specific functional roles (e.g. flavour, colour, texture, shelf-life) that help define the sensory and quality attributes of the product. Many of these ingredients contain sodium and contribute to the overall sodium content. Removing these ingredients as a means to reduce sodium has the potential to alter desired attributes to varying degrees, thereby creating technical challenges for food scientists while managing consumer expectations. Table 10.3 contains a summary of the sodium-containing ingredients, their functional roles, and alternative solutions.
10.5.1 Salt Salt, or sodium chloride, is one of the most versatile ingredients in many processed food products. Most consumers recognise it for its salty flavour and flavour enhancement properties. However, food scientists appreciate its contributions towards the food characteristics beyond flavour. Salt impacts colour formation, assists in the expansion of extruded cereals, and decreases simple sugars (Maillard reaction) and p olyacrylamide formation (Lajoie et al., 1996; Bouvier and Campanella, 2001). The role of salt in breakfast cereals is explained further now, contributing to colour & flavour and expansion:
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Table 10.3 Functional role of salt and other sodium-containing ingredients, and alternative non- or low-sodium-containing ingredients for breakfast cereals Ingredient Salt
Functional role of sodiumcontaining ingredient Impart salty flavour and flavour enhancement
Decrease starch retrogradation—to alter texture and staling properties Alter starch glass transition temperature—to impact crispness Nucleation/leavening agent
Sodium bicarbonate Sodium citrate, sodium metabisulphite, sodium ascorbate Cocoa powder
Colour and flavour— browning reactions Leavening agents Preservative (e.g. microbial, oxidative)
Colour and other flavours
Alternative solutions Potassium chloride, lithium chloride, choline chloride, magnesium chloride, calcium chloride, trehalose, arginine, gluconate, whey protein, fermented milk proteina Lithium ion, magnesium ion, calcium ion, potassium ionb
Potassium ion, ammonium ion, lithium ion, magnesium ion, calcium ionc Increase trapped air inclusions, small undissolved particles including starch hilum, undissolved amylopectin, bran, tripotassium phosphated Potassium bicarbonate, carbonate, colouring agentse Potassium bicarbonate, Potassium carbonate Potassium citrate, potassium metabisulphite, potassium ascorbate
Cocoa alkalised with potassium carbonate, potassium hydroxide, or other non‑sodium-containing alkalisers, artificial or natural colours
a
Dotsch et al. (2009). Wang et al. (2015). Beck et al. (2011). d Moraru and Kokini (2003). e Lajoie et al. (1996). b c
10.5.1.1 Colour and flavour Salt is added to breakfast cereal to help bring salty flavour and flavour enhancement to cereals. Salt is also known to mask the bitterness of whole grains and other ingredients used in cereals. Salt also impacts the Maillard browning and caramelisation reactions, which influences the overall brown colour and flavour. The presence of salt in cereal formulations helps develop colour and flavour during the heated extrusion or drying and toasting process of cereal production. Cereals
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c reated without salt look pale in colour and lack the characteristic toasted flavours associated with Maillard browning and caramelisation, two non-enzymatic browning reactions (Hill and Ferry, 2006). The complex Maillard reaction involves a condensation reaction between a free amino acid (e.g. lysine or terminal amino acid) and a reducing sugar, which results in products that are highly aromatic and darker in colour (Bouvier and Campanella, 2001). Considering processing conditions and formulation, non- enzymatic browning reactions are dependent on temperature, heating time, moisture content, water activity, pH, and type of reducing sugar and amino acids in the cereal. The role of moisture content or water activity (Aw) in non-enzymatic browning is to dissolve reactants, which aids mobility. This is important because it is a determining factor in the reaction rate. Too high of moisture dilutes reactants and decreases reaction rates. Similarly, too low of moisture decreases the reaction rate. The optimal Aw for greatest reaction rates in cereals is between 0.3 and 0.5 (Bouvier and Campanella, 2001). Salt is known to affect Aw, which is known to impact the Maillard reaction. Lajoie et al. (1996) observed an increase in brown colour formation and decrease in simple sugars as the salt increased in cereal formulations. The effect of salt on non-enzymatic browning reactions may be linked to the role salt plays as a plasticiser in starch systems (Moreau et al., 2009). Previous theories suggest that salt lowers glass transition temperature of starch systems (Farahnaky et al., 2009). Movement of reactants would be greater in the rubbery state versus the glassy state. More time in the rubbery state would extend the non-enzymatic browning reactions. Another theory proposed that the hygroscopicity of salt retains more water during the cereal cooking, which aids reactant mobility and prolongs the browning reaction (Moreau et al., 2009). Taylor et al. (2010) examined a pre-gelatinised corn starch system to look at the hygroscopic effect of salt during cooking of a cereal and found no relationship between salt levels and water retention. In addition, the glass transition temperatures (Tg) in the pre-gelatinised corn starch system had similar Tg for all treatments thereby, suggesting that salt does not impact Tg. However in a cassava and potato starch systems study, Farahnaky et al. (2009) observed a decrease in Tg in the presence of salt compared to a no-salt treatment. In another study using waxy maize starch in suspension with different cations, Beck et al. (2011) observed that salt changes starch crystallisation and browning rates, suggesting a direct correlation between browning and crystallinity. Salt and starch may interact to change Tg and starch crystallisation characteristics in several different starch systems including cassava, potato, and native waxy maize, but it is unknown if this effect would be observed in other starch systems.
10.5.1.2 Cereal expansion Salt is believed to impact the cereal expansion, which contributes towards the characteristic texture. Expansion in extruded products is complex and is related to the combination of biopolymer structural transformations and phase transitions, extrudate swell, bubble nucleation, subsequent growth and collapse (Moraru and Kokini, 2003). Chinnaswamy (1993) studied the effect of salt on cereal expansion of corn with various amylose contents and observed that salt increased the expansion ratio by 0.5– 5.5 units. Compared to the other additives (urea and sodium bicarbonate) and native
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starch, salt had the highest expansion ratio. In a potato starch pellet study, Norton et al. (2011) observed less expansion of the pellets formulated with lower sodium levels (0.125 wt%) compared to levels that are typically found in snack products (2 wt%). Although theories have been postulated, the mechanism of salt’s relationship to expansion remains unclear. Salt is believed to effect starch phase transitions by prolonging rubbery state, which allow the cereal to expand to a greater extent, but may also act as a point of nucleation (Moreau et al., 2011). In a low moisture system, such as in the case of extrusion, small inclusions of salt particles that stay heterogeneous in the starch matrix may be nucleation sites for bubble growth. An increase in the number of nucleation sites results in an increase in smaller bubbles formation, and greater amount of expansion.
10.5.2 Leavening agents Leavening agents are used in food products to help create structure and texture through gas expansion as a result of a chemical reaction, or as the nucleation seed for gas formation. It is well known that sodium bicarbonate generates carbon dioxide gas in the presence of various acids within the cereal dough (Lajoie et al., 1996). Other commonly used sodium-containing ingredients such as trisodium phosphate and sodium ascorbate have been suggested to act as nucleation sites (Lajoie et al., 1996; Moraru and Kokini, 2003). These nucleation points are distributed throughout the dough and can lead to steam expansion in localised areas within dough during the heating process of cereal production. More nucleation sites result in dough structure that has more uniform air cell distribution, thinner cell walls, and greater resistance to shear.
10.5.3 Preservatives Breakfast cereals are fresh and crisp immediately after production, but will lose their sensory quality (e.g. oxidative off notes, discoloration, staling) over time. Typically food manufactures add ingredients to minimise the occurrence of these sensory defects and some of these preservatives can be a source of sodium. Commonly used ingredients in breakfast cereal production include sodium ascorbate, sodium citrate, and sodium metabisulphite. Sodium ascorbate is added to foods as an antioxidant, and can also lower pH. Sodium citrate can be added to foods to lower pH, and act as a sequestering agent, which helps extend shelf life by binding metal ions (e.g. iron, copper) that participate in oxidation reactions. Sodium metabisulphite can be added as a bleaching agent to prevent discoloration.
10.5.4 Cocoa powder Chocolate flavoured cereal is a popular among consumers and is easily produced by the addition of alkalised cocoa powder. The cocoa alkalisation process enhances the flavour of cocoa, making it more smooth and rich, and less bitter in flavour. Alkalisation process uses a variety of different agents, singly or in combination, including sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium
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carbonate. Alkalising agents may add sodium to the cocoa powder; therefore when considering sodium reduction, it is important to choose cocoa alkalised with products produced using non‑sodium solely or in combination with sodium-alkalising agents.
10.5.5 Cereal grains Grains will contain some naturally low levels of sodium and levels vary depending on the type of grain. Grains are an agricultural crop and some variation in sodium is expected from year to year. The sodium content of wheat and yellow corn is 2 and 35 mg per 100 g grain, respectively (USDA, 2006).
10.6 Sources and functional role of non-sodium alternatives for breakfast cereals In order to decrease sodium in cereals, it is important to understand the functional roles of the sodium containing ingredients in food systems. Table 10.3 contains a summary of the functional role of various sodium containing ingredients and non‑sodium alternatives.
10.6.1 Colour and flavour To help compensate for any colour loss due to a decrease in the Maillard or caramelisation reaction by reducing salt, artificial or natural colours may be added to the cereal formulation. Alternatively, non‑sodium ingredients can be beneficial to colour and flavour. Potassium, calcium, and magnesium salts have been shown to provide a lesser degree of brown colour development and toasted flavour than sodium chloride (Moreau et al., 2009; Taylor et al., 2010). Potassium chloride was shown to have similar effects on plasticity as sodium chloride in starch systems (Moreau et al., 2009). Calcium salts combined with added sugar have been studied in low-moisture starch systems, and shown to improve browning and toasted flavour in the absence of sodium chloride. Separately, potassium chloride, calcium chloride, and magnesium chloride were studied in model cereal systems. All were shown to facilitate browning, with divalent cations proving more effective than monovalent cations (Moreau et al., 2011). Flavour impact of calcium and potassium salts was noted as adding bitterness to cereal products. Choline compounds also have been used in conjunction with other salty compounds to provide increased salty flavour in cereal products (Locke and Fielding, 1994). In addition to salt, many ingredients can alter Aw, which influences the Maillard reaction rate. In model systems using glycerol, reducing sugars (lactose, glucose, fructose), and glycine at three different moisture contents (0%, 5%, and 10%), Wang et al. (2015) observed the greatest and lowest amount of browning at 0% and 10% moisture content, respectively, in all treatments. The authors suggest that factors other than Aw are impacting reaction rates and may be due to either the hygroscopic nature or plasticising effect of glycerol.
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In addition to being leavening agents, sodium bicarbonate and potassium bicarbonate have been shown to provide flavour and browning in cereal products. Both raise pH, thereby accelerating the Maillard reaction and production of pyrazine, which is important for aromatic and flavour characteristics (Lajoie et al., 1996; Taylor et al., 2010).
10.6.2 Texture When replacing salt in cereal formulations, it is important to understand the impact of other non‑sodium ionic compounds on Aw and starch gelatinisation in relation to textural changes. Potassium, calcium, and magnesium salts have also been shown to alter texture similarly, but to different extents than salt (Moreau et al., 2009). Potassium chloride altered glass transition temperatures comparably to sodium chloride (Beck et al., 2011). Cations have been shown to slow starch retrogradation in cereal products that contain corn starch. Comparing the valences, divalent cations (Ca, Mg) had slower starch recrystallisation rates than monovalent cations (Na, K, NH4, Li). Moreau et al. (2009) suggest that cations with high charge densities are better able to retain water in starch matrixes compared with lower charge density cations. Since ion type impacts reactions with the starch matrix, there may also be an impact to processing times, heating temperatures required for gelatinisation, staling properties, and resultant textures.
10.6.3 Cereal expansion Potassium, calcium, and magnesium salts are reported as nucleators and leavening agents for cereal expansion (Moraru and Kokini, 2003). The potassium cation has been shown to positively expand extruded cereal pellets (Norton et al., 2011). At high levels of potassium or sodium (2.0 wt%), there is very little difference between the type of cation and the effect on cereal expansion. However at low concentration (0.125 wt%), there were greater differences, with less observed expansion for potassium. Depending on the targeted level of sodium, other potassium alternatives (e.g. potassium chloride, potassium bicarbonate, tripotassium phosphate, potassium ascorbate) may be an option for expansion. Potassium bicarbonate is commonly used to replace sodium bicarbonate, which acts as nucleation points and leavening agent in baked goods. The chemical reaction rate is slightly different than sodium bicarbonate and generally higher levels must be used in order to get a similar effect. Calcium carbonate and calcium bicarbonate, commonly used in baking powder, could also potentially be used to provide nucleation and leavening when combined with acids. Similar to potassium bicarbonate, the chemical reaction rate will be different. The other consideration is the bitter or metallic taste of these non‑sodium alternatives. Another option to consider for cereal expansion is grain components themselves. Rovins et al. (2012) observed that smaller granulation sizes of corn cones and corn bran in formulations have been shown to act as nucleation sites.
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10.6.4 Preservatives Non‑sodium ingredients can be added to cereals to help extend the freshness and shelf-life of cereal products. Potassium ascorbate and potassium citrate can be used to help regulate pH. Potassium citrate also chelates metals that promote oxidation. Other ingredients (i.e. butylated hydroxy-anisole, butylated hydroxy-toluene) may be added to the cereal, or cereal box liners to minimise oxidation, but may not be suitable considering clean label initiatives. Alternatively, mixed tocopherols, vitamin E, or tocopherols are used as anti-oxidants. Consumers are more accepting of unbleached or discoloured products, which may allow for elimination of sodium metabisulphate.
10.6.5 Mechanical options In addition to ingredient formulations, the processing conditions can also influence the texture of the finished breakfast cereal (Robin and Palzer, 2015). Specifically, the starch transformation that occurs during extrusion influences dough viscosity, which in turn influences cereal expansion and texture. Independent factors influencing the viscosity and expansion include feed rate of the dry mix, configuration, screw speed, water content of the dough, and barrel length to diameter ratio of the extruder. Too low of a viscosity will produce a cereal with less expansion and hard texture. Similarly, too high of a viscosity will prevent growth of bubbles and lead to a decrease in volume and hard texture (Robin and Palzer, 2015). Leveraging the mechanical operating conditions of extruders is an option to consider when trying to build back the texture and expansion functional roles of some sodium-containing ingredients.
10.7 Conclusions Recent emphasis on sodium reduction has created challenges for the food scientist to reformulate products to reach a sodium target while maintaining consumers’ expectation of the desired sensory attributes. Critical for success is understanding the functional role of the sodium containing ingredients in the food product to help determine alternative ingredients, or processing conditions that may help recreate the desired effect. However, non‑sodium-containing ingredients may not provide the same functional role of the sodium-containing ingredient. For example, Salt is a unique ingredient that performs many roles in creating the colour, texture, and flavour of cereals; however, the mechanism of these changes is not completely understood. To address colour and flavour, further examination of the effect of starch matrix interactions on browning would be warranted. Possibilities include looking for compounded effects of salt with pH, and change in simple sugars and plasticisers on the Maillard reaction. Further research on mechanism of nucleators and leavening agents to recreate desired expansion and texture is also warranted. In addition, non‑sodium leavening agents generally have a less desirable taste than the sodium version. The most challenging area of research is identifying the salty taste mechanism, which is instrumental for identifying non‑sodium alternative solutions.
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Acknowledgements The authors would like to thank Jody Mattsen and Chad Rieschl for their technical contributions and review of this chapter.
References Arcand, J., Au, J.T.C., Schermel, A., L’Abbe, M.R., 2014. A comprehensive analysis of sodium levels in the Canadian packaged food supply. Am. J. Prev. Med. 46 (6), 633–642. Arcand, J., Jefferson, K., Schermel, A., Shah, F., Trang, S., Kutlesa, D., Lou, W., L’Abbe, M.R., 2016. Examination of food industry progress in reducing the sodium content of packaged foods in Canada: 2010 to 2013. Appl. Physiol. Nutr. Metab. 41 (6), 684–690. Beck, M., Jekle, M., Becker, T., 2011. Starch re-crystallization kinetics as a function of various cations. Starch/Stärke 63 (12), 792–800. https://doi.org/10.1002/star.201100071. Bhatty, R.S., 1997. Milling of regular and waxy starch Hull-less barleys for the production of bran and flour. Cereal Chem. 74 (6), 693–699. Bouvier, J.M., Campanella, O., 2001. Breakfast cereals. In: Guy, R. (Ed.), Extrusion Cooking— Technologies and Applications. Woodhead Publishing, pp. 133–160. Brooke, C., 1968. Enrichment and fortification of cereals and cereal products with vitamins and minerals. J. Agric. Food Chem. 16 (2), 163–167. Caldwell, E.F., Fast, R.B., Faubion, J.M., 2000. The cereal grains. In: Fast, R.B., Caldwell, E.F. (Eds.), Breakfast Cereals and How They Are Made. second ed. American Association of Cereal Chemists, Inc., St. Paul, MN, pp. 1–15. Centers for Disease Control and Prevention, 2012. Vital signs: food categories contributing the most to sodium consumption – United States, 2007–2008. Morb. Mortal. Wkly Rep. 6, 92–98. Chinnaswamy, R., 1993. Basis of cereal starch expansion. Carbohyd. Polym. 21, 157–167. Culbertson, J., 2004. Grains, cereal: ready-to-eat breakfast cereals. In: Smith, J.S., Hui, Y.H. (Eds.), Food Processing: Principles and Applications. Blackwell Publishing, Ames, IA, pp. 239–248. Devi, A., Eyles, H., Rayner, M., Ni Mhurchu, C., Swinburn, B., Lonsdale-Cooper, E., Vandevijvere, S., 2014. Nutritional quality, labelling and promotion of breakfast cereals on the New Zealand market. Appetite 81, 253–260. Dotsch, M., Busch, J., Batenburg, M., Liem, G., Tareilus, E., Mueller, R., Meijer, G., 2009. Strategies to reduce sodium consumption: a food industry perspective. Crit. Rev. Food Sci. Nutr. 49 (10), 841–851. Drewnowski, A., Rehm, C.D., 2013. Sodium intakes of US children and adults from foods and beverages by location of origins and by specific food source. Nutrients 5, 1840–1855. Euromonitor International, 2017. Passport Database, Cereal and Cereal Bars Market Research, Viewed 01, 05 and 07 September 2017. Eyles, H., Webster, J., Jebb, S., Capelin, C., Neal, B., Ni Mhurchu, C., 2013. Impact of the UK voluntary sodium reduction targets on the sodium content of processed foods from 2006 to 2011: analysis of household consumer panel data. Prev. Med. 57, 555–560. Farahnaky, A., Majzoob, M., Shojae, Z.A., 2009. Effect of NaCl and water content on expansion and color of cassava and potato starches on baking. J. Texture Stud. 40, 676–691. Fast, R.B., 2000. Manufacturing technology of ready-to-eat cereals. In: Fast, R.B., Caldwell, E.F. (Eds.), Breakfast Cereals and How They Are Made. second ed. American Association of Cereal Chemists, Inc., St. Paul, MN, pp. 17–54.
252
Reducing Salt in Foods
Food Safety Authority of Ireland, 2015. Monitoring of sodium and potassium in processed foods. Viewed 26 June 2016. https://www.fsai.ie/uploadedFiles/Science_and_Health/Salt_ and_Health/Salt_Surveys_2003_onwards.pdf. Gillespie, C., Maalouf, J., Yuan, K., Cogswell, M.E., Gunn, J.P., Levings, J., Moshfegh, A., Jaspreet, A., Ahuja, K.C., Merritt, R., 2009. Sodium content in major brands of U.S. packaged foods. Am. J. Clin. Nutr. 101, 344–353. https://doi.org/10.3945/ajcn.113.078980. Hill, S.S., Ferry, A.L., 2006. Satisfactory salt levels for cereals and health. Food Sci. Technol. 20 (4), 26–30. Jour, M.E., Lazar, M.E., Mossman, A.P., Wallace, J.M., 1974. Air-fluidized toasting of whole kernel wheat-processing variables and functional properties for food applications. J. Food Sci. 39 (2), 239–243. Kent, N.L., Evers, A.D., 1994. Technology of Cereals: An Introduction for Students of Food Science and Agriculture, fourth ed. Elsevier Publishing Limited, Cambridge, England, pp. 244–258. Lajoie, M.S., Goldstein, P.K., Geeding-Schild, D., 1996. Use of bicarbonates in extrusion processing of ready-to-eat cereal. Cereal Foods World AACC Internationals 41 (6), 448–450. Locke, K.W., Fielding, S., 1994. Enhancement of salt intake by choline chloride. Physiol. Behav. 55 (6), 1039–1046. Meneton, P., Lafay, L., Tard, A., Dufour, A., Ireland, J., Menard, J., Volatier, J.L., 2009. Dietary sources and correlates of sodium and potassium intakes in the French general population. Eur. J. Clin. Nutr. 63, 1169–1175. Monro, D., Ni Mhurchu, C., Jiang, Y., Gorton, D., Eyles, H., 2015. Changes in the sodium content of New Zealand processed foods: 2003–2013. Nutrients 7, 4054–4067. Moraru, C.I., Kokini, J.K., 2003. Nucleation and expansion during extrusion and microwave heating of cereal foods. Compr. Rev. Food Sci. Food Saf. 2 (4), 147–165. Moreau, L., Bindzus, W., Hill, S., 2009. Influence of sodium chloride on color development of cereal model systems through changes in glass transition temperature and water retention. Cereal Chem. 86 (2), 232–238. Moreau, L., Bindzus, W., Hill, S., 2011. Influence of salts on starch degradation: Part II – Salt classification and caramelization. Starch-Starke 63, 676–682. Ni Mhurchu, C., Capelin, C., Dunford, E., Webster, J.L., Neal, B., Jebb, S.A., 2011. Sodium content of processed foods in the United Kingdom: analysis of 44,000 foods purchased by 21,000 households. Am. J. Clin. Nutr. 93, 594–600. Norton, A.D., Greenwood, R.W., Noble, I., Cox, P.W., 2011. Hot air expansion of potato starch pellets. J. Food Eng. 105 (1), 119–127. Robin, F., Palzer, S., 2015. Texture of breakfast cereals and extruded products. In: Chen, J., Rosenthal, A. (Eds.), Modifying Food Texture, Volume 1—Novel Ingredients and Processing Techniques. Woodhead Publishing, Cambridge, pp. 203–234. Rovins, F., Schuchmann, H.P., Palzer, S., 2012. Dietary fiber in extruded cereals: limitations and opportunities. Trends Food Sci. Technol. 28, 23–32. Rutherfurd, S.M., Torbatinejad, N.M., Moughan, P.J., 2007. Available (ileal digestible reactive) lysine in selected cereal-based food products. J. Agric. Food Chem. 54 (25), 9453–9457. Schierhorn, C., 2016. Boom time for breakfasts. Food Technol. 70 (3), 22 31. Taylor, J.R.N., Emmambux, M.N., 2008. Products containing other specialty grains: sorghum, the millets and Pseudocereals. In: Hamaker, B.R. (Ed.), Technology of Functional Cereal Products. Woodhead Publishing Limited, Cambridge, England, pp. 281–335. Taylor, A.J., Sivasundaram, L., Moreau, L., Channell, G.A., Hill, S.E., 2010. Effect of physical properties of food matrices on the Maillard reaction. In: Mottram, D.S., Taylor, A.J.
Breakfast cereals253
(Eds.), Controlling Maillard Pathways to Generate Flavors. American Chemical Society, Washington, DC, p. 2010. Torbatinejad, N.M., Rutherfurd, S.M., Moughan, P.J., 2005. Total and reactive lysine contents in selected cereal-based food products. J. Agric. Food Chem. 5 (11), 4454–4458. Trevena, H., Neal, B., Dunford, E., Wu, J.H.Y., 2014. An evaluation of the effects of the Australia food and health dialogue targets on the sodium content of bread, breakfast cereals and processed meat. Nutrients 6 (9), 3802–3817. Trevena, H., Neal, B., Dunford, E., Haskelberg, H., Wu, J.H.Y., 2015. A comparison of the sodium content of supermarket private-label and branded foods in Australia. Nutrients 7, 7027–7041. Trieu, K., Neal, B., Hawkes, C., Dunford, E., Campbell, N., Rodriuez-Fernandez, R., Legetic, B., McLaren, L., Barberio, A., Webster, J., 2015. Salt reduction initiatives around the world – a systematic review of progress towards the global target. Viewed 14 June 2016, PLoS One 10 (7), e0130247. United States Department of Agriculture, 2016. Nutrient Database, Viewed 8 July 2016. https:// ndb.nal.usda.gov/. Wang, C.W., Wijayanti, H.B., Bhandari, B.R., 2015. Maillard reaction in limited moisture and low water activity environment. In: Gutierrez-Lopez, G., Alamilla-Beltran, L., del Pilar Buera, M., Welti-Chanes, J., Parada-Arias, E., Barbosa-Cánovas, G.V. (Eds.), Water Stress in Biological, Chemical, Pharmaceutical and Food Systems. Springer-Verlag, New York, NY, pp. 41–63. Webster, J.L., Dunford, E.K., Neal, B., 2010. A systematic survey of the sodium contents of processed foods. Am. J. Clin. Nutr. 91, 413–420. Webster, J., Trieu, K., Dunford, E., Hawkes, C., 2014. Target salt 2025: a global overview of national programs to encourage the food industry to reduce salt in foods. Nutrients 6, 3274–3287.