Sprouted grains as a food ingredient

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Sprouted grains as a food ingredient Sean Finnie, Vanessa Brovelli and Darrel Nelson Research and Development, Bay State Milling Company, Quincy, MA, United States

Chapter Outline 6.1 Introduction 113 6.2 Processing 114 6.2.1 What happens in the seed 114 6.2.2 What happens in the processing facility 117

6.3 Tools and equipment used to evaluate sprouted grains 6.3.1 6.3.2 6.3.3 6.3.4 6.3.5

6.4 Functionality and applications of sprouted grains 6.4.1 6.4.2 6.4.3 6.4.4 6.4.5 6.4.6

Product differentiation 123 Absorption, starch properties, and granulation 124 Enzyme activity, sugar level, proof time, and shelf life Mixing properties and gluten strength 128 Sensory 129 Specific applications and inclusion rates 132

6.5 Food safety and quality 6.5.1 6.5.2 6.5.3 6.5.4 6.5.5 6.5.6 6.5.7

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Grinding equipment in preparation for analyses 118 Falling number 119 Rapid visco analyzer 121 Sieve analysis 122 Colorimetry 123

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Monitoring 136 Food safety definitions 137 Relationship of exponents and logarithms 138 Log reduction 139 Microbial growth curves 139 Mitigation 139 Specifications 140

References 140 Further Reading 142

6.1

Introduction

Sprouted grains have been used as food ingredients for many years, based on the general belief they impart significant nutritional, flavor, and textural benefits over their unsprouted or sound grain counterparts. An early example of sprouted grains providing a nutritional benefit is their use to combat scurvy in sea voyages of Sprouted Grains. DOI: https://doi.org/10.1016/B978-0-12-811525-1.00006-3 Copyright © 2019 AACCI. Published by Elsevier Inc. in cooperation with AACC International. All rights reserved.

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Captain Cook (Kodicek and Young, 1969). Even with reports of sprouted grains providing benefits, there are also contradictory remarks on whether sprouted grains consistently provided enough ascorbic acid to treat or prevent scurvy on these voyages (Kodicek and Young, 1969). These early reports highlight the enigmatic understanding of the true benefits of sprouted grains. There are two aspects to consider when evaluating the benefits of sprouting grains and how the benefits vary among studies and documented reports, including: (1) how processing conditions contribute to the variation, and (2) how much variability there is in the genetic potential of the starting material. This is evident with regard to nutritional changes in the studies done by Omary et al. (2012) (Fig. 6.1). Additionally, Hu¨bner and Arendt (2013) and others demonstrated that, as one nutritional benefit such as vitamins increased, another, such as beta-glucans, can decrease. This further demonstrates the complex nature of understanding the true health benefits of sprouting grains. Beyond the nutritional benefits, it is logical to assume that flavor and texture benefits of sprouting grains will also vary, due to processing conditions and genetic potential of the starting material. The scope of this chapter includes aspects of sprouted grains related to their use as food ingredients; information on the processing and functionality of sprouted grains, and tools used to assist in the understanding of the impact of sprouting on the ingredient and final product. The definition of grains used in this chapter is broad and includes pseudocereals such as buckwheat as well as traditional grains. Legumes and other seeds have been used as sprouted ingredients in food products, but will not be included in this chapter. A North American perspective will be prominent within this chapter, due to the knowledge and experience of the authors, however, other chapters within this book (such as Chapter 12) will provide perspectives from outside of North America.

6.2

Processing

6.2.1 What happens in the seed Sprouted grains are produced through a controlled germination process overseen by a manufacturer, with the goal of producing a consistent product, batch after batch. Since germination is a complex process, to produce a consistent product it is important to understand what is happening in the grain and how the process will need to be modified, depending on the grain type and cultivar. In this section, wheat is the primary grain discussed. Other grains and seeds-specific germination processes, such as the uptake and flow of water into the seed, may differ from wheat. An intact germ on the grain is required for germination. In this way, germination is not possible on pearled barley, white rice, or on any grain whose germ may have been damaged or removed due to abrasion cleaning, for example, the saponin removal process for quinoa. For germination of wheat to initiate, the kernel must achieve a minimum moisture content range of 35%
45% and be above a minimum temperature of 4 C (Gooding, 2009). Water flows into the wheat kernel through the

Figure 6.1 (A) Polyphenol changes after germination of gluten-free cereals and pseudocereals. All values presented are on a dry weight basis. 1Alvarez-Jubete et al. (2010b); 2 Abdelrahaman et al. (2007); 3Towo et al. (2003); 4Dicko et al. (2005); 5Nwanguma and Eze (1996); 6Subramanian et al (1992). amg gallic acid equivalents per 100 g; bg/100 g; cA725; d A560/g. Pas: proanthocyanidins; 3-Das: 3-deoxyanthocyanocyanidins. (B) Antinutrient changes in germinated gluten-free cereals and pseudocereals. All values presented are on a dry weight basis. T: tannin; P: phytate. 1Lee et al. (2004); 2Fageer et al. (2004); 3Sripriya et al. (1997); 4Mbithi-Mwikya et al. (2000); 5Abdelrahaman et al. (2007); 6Moongngarm and Saetung (2010); 7Obizoba and Atii (1991); 8Subramanian et al. (1992); 9Ahmed et al. (1996); 10 Elmaki et al. (1999); 11Nour et al. (2010); 12Elkhier and Hamid (2008).

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Figure 6.2 Diagram of a wheat grain showing major structures in (A) longitudinal and (B) transverse sections.

micropyle, where it enters the germ and scutellum to initiate germination (Fig. 6.2) (Rathjen et al., 2009), and continues to move throughout the kernel, accumulating between the pericarp and seed coat (Fig. 6.3) (Rathjen et al., 2009). Once the moisture content reaches the minimum requirement, the seed initiates the synthesis and/or release of plant hormones such as gibberellic acid, abscisic acid, and ethylene. The secretion of these plant hormones throughout the seed causes the release of degrading enzymes, amylase, proteases, and lipases. The degradation of starch, protein, and lipids by these enzymes provides an energy source for the developing embryo, however this degradation can have a significant impact on the ingredient’s performance and quality. The increase in amylase will result in a decrease of the starch pasting peak viscosity, impacting the starch properties of the ingredient. The increase in proteases may result in the potential breakdown of gluten-forming proteins, reducing the overall stability of the dough. The increase in lipase enzymes can result in the degradation of lipids and the potential for autooxidation to occur, producing off-flavors in the finished product.

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Figure 6.3 Comparison of MRMI images (transverse and longitudinal slices) of grains Hartog imbibed for (A) 2 h and (B) 12 h. Images 1
4 are transverse slices and images L are longitudinal slices.

6.2.2 What happens in the processing facility Sprouted ingredients can be marketed in two different forms: either a wet-mash form, where the material is stored frozen, or as a dry ingredient, shipped as either flour or as a dried germinated grain. Regardless of whether the material is a wetmash or dried, the first two steps are the same: steeping and germination. In steeping, the grains are soaked in water until they reach the desired moisture content. Once the proper moisture content is achieved, any excess water is drained and the material is allowed to germinate. Germination can occur in a number of different types of vessels. A typical vessel is a germination bed, similar to that used in the malting industry. Regardless of the germination vessel, the germinated grains need to be kept in an aerobic environment with constant and consistent airflow and temperature to ensure a uniform germination rate throughout the material. Once germination is complete, the wet-mash material is processed immediately into the final end-ingredient, or it is frozen for use at a later date. If the sprouted grain is to be processed into flour, the material is moved into a dryer or kiln to remove water to a final moisture content of 10%
14% (wet basis). Drying or kilning can proceed at

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various times and temperatures that are unique to each grain type and manufacturer. These setpoints are optimized, proprietary for product differentiation, and achieve product consistency.

6.3

Tools and equipment used to evaluate sprouted grains

6.3.1 Grinding equipment in preparation for analyses Sprouted sample preparation for analysis is a critical step for accurate data collection, so grinding equipment selection is important. Sprouted grains are sometimes ground and analyzed during the sprouting process as a quality measure, to understand the rate of germination and determine an appropriate end point. As an additional quality measure after drying, many manufacturers will grind a sample from the sprouted dried lot for quality parameter testing. Most sprouted products will grind or mill differently than the unsprouted raw grain; therefore, there may be a need for different grinding or milling equipment and procedures to prepare the sprouted grain for analysis. Particle size will impact moisture, functionality, and other characteristics that are key concerns and should be evaluated prior to choosing a grinding or milling apparatus. There are many manufacturers of sample preparation grinders with a variety of models offered, ranging from hand cranked grinders (Fig. 6.4) to laboratory

Figure 6.4 Example of a hand cranked mill. This is a GrainMaker Grain Mill Model No.116. Photo courteously provided by Bitterroot Tool & Machine, Inc.

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Figure 6.5 Example of a small laboratory mill. This is a Brabender Break Mill SM3. Photo courteously provided by C. W. Brabender Instruments, Inc.

grade mills (Figs. 6.4
6.6) with no two mills or grinders grinding the samples in the same way. Some mills will refine and fractionate the various components, while most simply grind in a single stream. Therefore, it is vital to understand the sprouted ingredient test requirements for proper selection.

6.3.2 Falling number Falling number analysis (Fig. 6.7) is an indirect method of measuring enzyme activity, particularly α-amylase. Originally developed by Perten Instruments to detect field sprout damaged wheat, it is now being used to measure germination or sprouting levels in wheat. According to the AACCI Method 56-81.03, “This method is based on the ability of alpha-amylase to liquefy a starch gel. The activity of the enzyme is measured by a ‘falling number’ (FN), defined as time in seconds required to stir and allow the stirrer to fall a measured distance through a hot aqueous flour or meal gel undergoing liquefaction. Alpha-Amylase activity is associated with kernel sprouting, and both of these are inversely correlated with FN. The method is applicable to both meal and flour of small grains and to malted cereals” (AACCI, 2009b). In other words, the more germination that has taken place, the greater the alpha-amylase activity, resulting in a less viscous starch gel and therefore a lower falling number.

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Figure 6.6 Example of a larger laboratory mill. This is a Chopin LabMill. Photo courteously provided by Chopin Technologies.

Figure 6.7 Falling Number method steps of sample preparation, weighing, dispensing, shaking, stirring and measuring. Image courteously provided by Perten Instruments.

Traditionally, falling number analysis is used on sound wheat and rye, but, as the Method attests, it has applications in sprouted grains, especially because the starch-degrading enzyme alpha-amylase is known to increase as part of the sprouting process. A typical falling number specification for sound wheat is above 350 s, although this is variable based on producer (grower and miller). The falling number of sprouted wheat varies widely among suppliers, but values of 300 s and lower are common.

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6.3.3 Rapid visco analyzer The Perten Rapid Visco Analyzer (RVA) (Fig. 6.8) is another apparatus that indirectly measures enzyme activity. According to AACCI Method 22-08.01, “This method is based on the ability of alpha-amylase to liquefy a starch gel. The enzyme activity is measured as the stirring number (SN), defined as the apparent viscosity in rapid visco units at the 180th sec of stirring a hot aqueous flour suspension undergoing liquefaction. By the action of the hydrolytic enzyme alpha-amylase, viscosity decreases and SN increases. Enzyme activity is also an indication of sprouting of grains. This method is applicable to both meal and flour of all small grains.” (AACCI, 2009b). The original RVA systems typically gave only three data points as results; the viscosity peak, hold time, and the final viscosity. The newer systems employ software that records the viscosity over the duration of the assay (Fig. 6.9). This yields more information about the sprouted grain to produce results having greater discrimination. Rapid Visco Analyzer analysis can be used to compare multiple sprouted flours to one another, and is a good indicator of cook-up or bake performance, when compared to unsprouted flours. It can provide a formulator with indications of pasting and gelatinization temperature, comparative viscosity increase rates, comparative hot viscosities, and starch retrogradation information, all of which are important parameters in new product development.

Figure 6.8 Rapid Visco Analyzer method steps of method selection, weighing, mixing, inserting, stirring and measuring. Image courteously provided by Perten Instruments.

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Figure 6.9 Typical pasting profile produced using a Rapid Visco Analyzer. Figure indicates values for peak viscosity, final viscosity, viscosity, breakdown, setback, pasting temperature and peak time. Image courteously provided by Perten Instruments.

6.3.4 Sieve analysis Many commoditized grains have established relationships between grain size and functionality. However, many of today’s grains marketed after sprouting have limited or no data to indicate what is an acceptable grain size for the sprouted product functionality to remain consistent. Generalizing the shape of a grain to a sphere, the Volume is: V 5 4=3  π  r 3 In terms of grain size, this indicates that the amount of endosperm dramatically increases as the radius increases. Knowing that the endosperm is a key component, defining the desired characteristics of the grain reveals that size is a critical metric. The most common way to express size in grains is sieve analysis, using screens to sort by size. Crop management, growing conditions, and variety are but a few variables that will affect the grain size and functionality attributes. Milling particulate size distribution is another characteristic of interest when evaluating sprouted grain flour. Traditionally, sieve analysis has been employed to ascertain the particle size distribution of flour or ground material. Other methods of analysis are available, such as laser diffraction and dynamic image analysis. These tools will give detailed information regarding particulate size and distribution, and are very efficient and effective in comparative studies (Fig. 6.10).

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Figure 6.10 An example of a particle size distribution curve from a Helos Laser Diffraction System. Image courteously provided by Sympatec GmbH.

6.3.5 Colorimetry Desireable color of ingredient and finished goods is another important, and often overlooked parameter when using sprouted grains. Sprouting grains, and specifically the drying step after sprouting, can have a significant impact on color values and should be assessed to ensure consistent appearance. There are many colorimetry assays, but one of the most utilized is the Lab color system. The Lab color system describes all possible colors in three dimensions. The designation L is for lightness and a designates the green-red color scale while b designates the blue-yellow scale. The L represents black at 0, and the brightest white at 100 (Fig. 6.11).

6.4

Functionality and applications of sprouted grains

6.4.1 Product differentiation Sprouted grains can be incorporated into various food applications, often with minimal formulation changes, and can offer several benefits for product differentiation. After a whole grain kernel has been sprouted and dried, it can be further milled into flour or processed to create various granulations including grits, coarse meals, or flakes. As long as the germ is intact, any of the following grains or pseudocereals can be sprouted and included in various food applications: wheat, rye, spelt, barley, brown rice, oat, sorghum, millet, quinoa, buckwheat, and amaranth. Common applications may include bars, cereals, granola, bread, tortillas, frozen dough, sweet goods, snacks, side dishes, soups, and pasta. Sprouted sorghum, millet, quinoa, amaranth, buckwheat, brown rice, and purity protocol oats are naturally gluten free,

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Figure 6.11 Figure representing the Lab color system. Figure courteously provided by Perten Instruments.

and can also be utilized to improve the nutrition of gluten-free foods. The variety of grains that can, and have been, successfully sprouted commercially gives bakers, food scientists, and chefs tremendous versatility for innovation. It is important, however, to understand and consider the functional differences between sprouted grains and their unsprouted counterparts for successful formulation, processing, and finished product characteristics. A note of importance is that one manufacturer’s sprouted grain is not equal to another manufacturer’s. The germination process and the drying/kilning stage of this process can impact the functionality of these ingredients greatly, as can the grain variety, grain size/shape, and milling technique. The germination of some grains proceeds faster than other grains, and the starchy components of some grains are more susceptible to amylase activity than others (Kaukovirta-Norja et al., 2004), further increasing diversity. By assessing the steps within the sprouting process, a scientist can theorize what physical changes the grain may undergo, which can help predict anticipated functional and sensory differences versus unsprouted grains. The chemical and enzymatic changes as a result of germination, however, are difficult to predict, thus accounting for unique functional properties. Validating the formula and process(es) for each unique food matrix is a must. Some trends can be theorized based on studies and continued work in this area.

6.4.2 Absorption, starch properties, and granulation Grain and flour absorption is important to understand because it helps grasp how much water a grain or flour can hold. In breads, absorption has an impact on

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finished product attributes including loaf volume, yield, and shelf life (Bakerpedia, 2017). Farinographs or mixographs offer good indications of starting absorption of flours, while simple soaking studies can help compare absorptions between grits, flakes, or whole kernels. Several factors can ultimately affect a grain’s absorption, but those regarding sprouted grains are: protein (Pyler and Gorton, 2009a; Bakerpedia, 2017; Tipples et al., 1978), particle size (Bressiani et al., 2017), damaged starch (Tipples et al., 1978; Bakerpedia, 2017; Pyler and Gorton, 2009b), enzyme activity (Tipples et al., 1978; Bakerpedia, 2017), and the sprouting process itself (Ocheme and Chinma, 2008; Kaukovirta-Norja et al., 2004; Ocheme et al., 2015). The level of viscosity-modifying fibers within the grain is also a contributing factor to absorption (Bakerpedia, 2017; Pyler and Gorton, 2009a), and although some studies have shown increases in fiber (Omary et al., 2012), results are inconclusive if this increase occurs during sprouting in all grains. Several studies have observed an increase in absorption or water holding capacity of sprouted grains (Ocheme et al., 2015; Kaukovirta-Norja et al., 2004; Ocheme and Chinma, 2008). One likely cause could lie within the ability of the sprouting process to activate enzymes that degrade some macromolecules, which could inhibit starch swelling such as lipids (Ocheme and Chinma, 2008), also creating an increase in total soluble solids, which bind water (Ocheme et al., 2015). Enzyme activity during sprouting could also physically change starch granules within the grain, leading to an absorption increase. As seen in Fig. 6.12, electronic scanning microscopic images of unsprouted and sprouted sorghum shows visible voids within starch granules, mostly in the germ, but to some extent in the endosperm (Yan et al., 2010). This study is supported by work done in rice, which shows the same voids corresponding with absorption increase (Moongngarm, 2011). Another potential reason for the increase in absorption is partial starch pregelatinization. As explained earlier in this chapter, the sprouting process begins with an increase in grain moisture and is usually halted with further heat to dry or kiln the grain. It may be possible that application of this heat and water at points within the sprouting process could swell some of the starch granules within the grain, but more studies are required for this theory. An increase in the degree of gelatinization with increased germination time has been observed in a study by Ocheme et al. (2015). As mentioned previously, sprouting has the potential to modify starch-pasting properties of the grain flour. Increasing germination time may decrease peak and final viscosity, as seen in RVA studies in both rice (Moongngarm, 2011) and wheat (Juha´sz et al., 2005) (Fig. 6.13). It is important to consider that commercially sprouted grains have not always been taken to the extent of germination as laboratory studies, which likely explains why most commercially sprouted grains still bake well. Pasting temperature theoretically should stay the same (Moongngarm, 2011) because the starch granule properties and starch matrix specific to each grain is unique. However, milling properties could affect the percentage of damaged starch or the particle size, which could, in turn, affect pasting temperature. Grain softening is sometimes seen after sprouting, which in turn affects its milling characteristics, ultimately affecting particle size distribution and percentage of

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Figure 6.12 Scanning electron microscope images of starch granules. (A) Germ of fieldsprouted sorghum; (B) endosperm of field-sprouted sorghum; (C) cell walls of field-sprouted grain sorghums; (D) nonsprouted sorghum.

damaged starch (Yan et al., 2010). Typically, softer kernels have less damaged starch after milling (Pasha et al., 2010), which would suggest lower water absorption, since damaged starch typically holds a significant amount water. This indicates that there are several factors at play, some yet to be understood. Sprouted flour granulation varies greatly among manufacturers, as shown in Fig. 6.14, which displays the results of five different commercially sprouted wheat flours run through particle size analysis. Particle size can affect absorption, rate of hydration, extensibility, and dough development time. Typically, finer granulation flours have higher absorptions and hydrate faster than coarser granulations, while coarser flours require time to hydrate and have longer gluten development times in wheat doughs (Bressiani et al., 2017).

6.4.3 Enzyme activity, sugar level, proof time, and shelf life Of the enzymes shown to increase during sprouting, amylases are especially important because of their potential impact on proof time for yeast-leavened doughs and

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Figure 6.13 RVA curves of ungerminated and germinated wheat samples (cultivar GK Otthalom).

Figure 6.14 Particle size distribution of five commercially available sprouted whole wheat flours, analyzed with a Sympatec HELOS/KR Laser Diffraction Sensor.

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on shelf life. Amylase enzymes break down starches and sucrose into mono- and disaccharides (Kruger and Matsuo, 1982). In yeast-leavened doughs, this can fuel yeast activity and lead to faster dough fermentation. Proof time for yeast-leavened bread and rolls must be monitored when sprouted ingredients are added. Sometimes, a decrease in proof time or a lower temperature proof can achieve the same proof height as for a formula without sprouted ingredients. Because of increased simple sugar formation during sprouting, formula modifications may also be possible to reduce added sugar levels without negatively decreasing sweetness perception. Many of the simple sugars created as a result of amylase activity are reducing sugars that participate in Maillard browning (Kruger and Matsuo, 1982), so flavor and color may change slightly. Crumb softening enzymes are often added as ingredients in sandwich breads, gluten-free bread, and longer shelf life baked goods. The enzyme activity native to sprouted grains may also help a formulator reduce or eliminate these added ingredients, yet still retain antistaling benefits. Success has been seen with germinated sorghum flour in gluten-free bread, where a reduction in bread hardness, as measured by Texture Profile Analysis, was achieved by a replacement of sorghum flour with germinated sorghum flour, up to 100% (Phattanakulkaewmorie et al., 2011). It is possible that an increase in water soluble fibers as a result of germination can lead to a reduction in staling rate, due to increased water binding over the shelf life (Hugo et al., 2003). One study on wheat tortillas found a shelf life increase by using sprouted wheat flour, which contributed to softer texture and greater rollability (Liu, et al., 2016). Fig. 6.15 graphically shows the potential for sprouted wheat flours to maintain a key quality attribute, rollability, more so than unsprouted wheat flour in tortillas, potentially reducing or eliminating the need for dough additives to achieve the same effect.

6.4.4 Mixing properties and gluten strength Since an intact germ is required for sprouting, sprouted grains and flours are always whole grain. Therefore, in 100% sprouted applications, sprouted whole wheat flour is a baker’s primary choice to contribute functional gluten in wheat doughs. Sprouted hard wheat is typically used in applications requiring gluten strength, and the following classes have been sprouted commercially: red winter, white winter, red spring, white spring. Variability in gluten strength can be observed in unsprouted wheat flours, depending on wheat growing location, growing practices, and milling techniques. Similar variability is seen in sprouted wheat flours, with the added variable of sprouting technique. In general, optimized sprouted whole wheat flours perform comparably to, if not better than, unsprouted wheat flours in baking applications. Farinograph or mixograph data is used to give a baker a starting point for absorption, mix time, and stability. Fig. 6.16 shows the farinograph results of three sprouted wheat flours, all from red winter wheat, from three different manufacturers. In this study, wide variations in stability (ranging from B8 to 22 min), absorption (ranging from B65% to 70%), and MTI (ranging from 4 to 33 FE) are

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Figure 6.15 Rollability scores of tortillas made from whole-wheat flour (WWF) blends with sprouted WWF substitution (0 g/100 g, 25 g/100 g, 50 g/100 g, 75 g/100 g, and 100 g/100 g) on 1, 4, 8, 12, and 16 days of storage. 5: no cracking; 4: signs of cracking but no breaking beginning on the surface; 2: cracking and breaking imminent on both sides; 1: unrollable, breaks easily. Results are reported as means 6 standard deviation. 0 g/100 g; 25 g/100 g; 50 g/100 g; 75 g/100 g; 100 g/100 g.

observed. It was possible to successfully make pan bread out of each of these flours, as shown in Fig. 6.17. All doughs made with these three flours exhibited varying degrees of gluten strength and development. With the same method a baker takes to strengthen weak whole wheat dough, such as dough conditioners or vital wheat gluten, a weak sprouted dough can also be improved if necessary.

6.4.5 Sensory The use of sprouted grains can modify the sensory perception of any application, and their contribution to sensory perception can often differentiate a product within a saturated market space. Three important sensory characteristics are flavor (including aroma), appearance, and texture. Flavor notes can be discerned by trained sensory panelists and, generally speaking, a flavor profile can be described as “spiky,” meaning each note stands alone, or “well blended,” referring to a well rounded flavor that is generally preferred by consumers (Fossum, 2017). In the case of whole wheat bread, bitterness usually lingers at the end of mastication and can be considered a negative attribute. Due to increasing simple sugars in the grain resulting from the sprouting process, sprouted flours have been used to increase the overall sweetness perception of foods (Kaukovirta-Norja et al., 2004), which may limit

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Figure 6.16 Farinograph results for three sprouted whole wheat flours are shown on the left, along with their corresponding data for dough development time (DDT), water absorption corrected for default moisture content (WAM), stability (S), and tolerance Index (MTI), on the right.

Figure 6.17 Bread slices taken from the center of three 100% sprouted wheat breads, made using the same formula from three different spouted whole wheat flours. Each graphical square measures 4 mm by 4 mm.

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bitterness perception and help to create a more “well blended” sensory profile. Maillard browning may also occur to a greater extent during bake because these simple sugars are often reducing sugars (Dexter et al., 1990), thus changing the flavor and visual sensory parameters of the product. Other enzyme reactions as a result of sprouting can degrade storage macromolecules into new compounds, which in turn contribute unique flavors. (Kaukovirta-Norja et al., 2004). Further evidence of differentiated and improved flavor is provided in a study on tortillas by Liu et al. (2016), where sprouted wheat tortillas had improved likability among consumers versus tortillas made using flour from unsprouted wheat. Also contributing to flavor is the drying or kilning process that sprouted grains typically undergo after germination. A manufacturer has the ability to control flavor contribution through time and temperature adjustments. Typically, these flavor notes are in addition to the normal flavor of the grain, and are usually described as baked, toasted, browned, or roasted notes. Ancient grains such as millet, quinoa, and amaranth often have polarizing flavor notes, such as green grassy notes, bitterness, and earthy flavors, yet consumer likability could increase by sprouting these grains. Depending on use level, darker colors can result from the use of sprouted grains, based on the level of toasting or roasting that occurs during drying (KaukovirtaNorja et al., 2004). Ancient grains such as amaranth or millet can also take on a reddish/brown hue. Visible sprouts can sometimes be observed as well, as seen in Fig. 6.18 on millet and oats. Sometimes, sprouts are sloughed off during conveyance and transportation, or milled along with the grain during the production of flour. Many sprouted grains, and particulates thereof, maintain piece identity in processed doughs, including quinoa, millet, amaranth, oat groats, and cracked wheat, and the use of these sprouted particulates or whole grains may be used to enhance texture for consumers desiring visually distinct whole grains or grain particulates. Also contributing to textural distinction is the potential for increased crumb softness in bread, as mentioned in the previous section, due to amylase activity, but further work is needed in this area.

Figure 6.18 Sprouted millet (left) and sprouted hulless oats (right) showing visible sprouts.

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6.4.6 Specific applications and inclusion rates The inclusion rate of a sprouted grain in a formula may vary, based on the food manufacturer’s preference for desired finished product attributes and labeling call-outs. There is currently no minimum level of sprouted ingredients required in a finished product to label the product as sprouted. However, the US Food and Drug Administration encourages clear and nondeceptive labeling (US FDA, 2017), and often sprouted inclusion rates range from 20% to 100% of the grain percentage in a food. The type of application can help determine which sprouted grain to use and the inclusion rate. The use level and form of the sprouted grain also plays a role in determining the ingredient’s impact on the formula. For example, sprouted wheat flour used as a one-to-one replacement for 100% of the wheat flour in bread may have a more dramatic effect as part of a reformulation than the incorporation of a grain like quinoa that is typically added at a lower inclusion rate of 10%
20% of the flour.

6.4.6.1 Yeast-leavened bread and tortillas Wheat is typically the primary sprouted ingredient used in bread and tortillas, due to availability, functionality, and cost, and the fact that it can be used to make up to 100% of the flour. Other sprouted grains can be added at lower levels to boost nutrition, flavor, or for labeling reasons. Gluten strength and performance is critical in these applications, and analyzing farinograph data is a helpful guide. It is important to analyze flour particle size and color for any finished product visual requirements, and also for processing considerations. Amylase activity, or the falling number (FN) of a flour is an important factor to understand when formulating, but the old theory that a FN of lower than 250 will not bake is being challenged when applied to intentionally sprouted grains. For example, sprouted wheat may function well in straight doughs or long fermentation formulas. A poolish baguette, made using Reinhart’s formula (Reinhart, 2001) and fermented for 12 h at ambient temperature, showed active fermentation and gluten strand formation as pictured in Fig. 6.19. An additional example used Pyler’s frozen soft roll dough formula (Pyler and Gorton, 2009b) as a starting point to produce a successful roll using 100% sprouted wheat flour with the addition of 2% each of sprouted quinoa, millet, amaranth, and sorghum flours. This roll was slightly bolder with less pan flow than the same formula made with unsprouted grains, as seen in Fig. 6.20. For bread, bakers may see a slight reduction in proof time or increased absorption, which could improve yields. In tortillas, sprouted wheat can help increase softness, prolong shelf life, and improve sensory characteristics (Liu et al., 2016). The potential for sprouted wheat to improve the likability of bread and tortillas could increase whole grain consumption overall, which would be a tremendous milestone in human health, especially because these staples are typically consumed daily. According to Peter Reinhart, an American artisan bread revolution began in the 1980s (Reinhart, 2014), and bread continues to evolve, with sprouted ingredients at the forefront of innovation.

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Figure 6.19 Poolish made with 100% sprouted hard red wheat flour, and allowed to ferment for 12 h, showing fermentation, gas retention, and some gluten matrix formation. Source: Poolish formula courtesy of Reinhart, P. (2001) Bread Bakers Apprentice. Berkeley: Ten Speed Press.

Figure 6.20 Unsprouted multigrain rolls (left) and sprouted multigrain rolls (right), prepared from frozen dough. Rolls were made with 51% whole grain flour, and 2% each of the following flours: quinoa, amaranth, millet, and sorghum. All whole grains were substituted for sprouted whole grains in the sprouted formula, and no other formulation changes were made. (Starting formula for frozen soft roll dough formula is courtesy of Pyler and Gorton, 2009a) Each graphical square measures 4 mm by 4 mm.

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6.4.6.2 Gluten-free bread and tortillas Rice flour is often the primary grain in gluten free (GF) bread and tortillas (typically 20%
50% inclusion rate). It can be supported by millet, sorghum, corn, oat, quinoa, buckwheat, and amaranth flours (typically 1%
10% inclusion rate). Sprouted versions of these grains exist with varying degrees of prevalence. In the absence of gluten, starches from these grains play a large role in the strength and structure of GF breads and tortillas. Without gluten, a supplemental protein network is usually required, such as soy, egg, or milk (Casper and Atwell, 2014). This protein network is additionally important as insurance, especially with the addition of sprouted GF grains, because of enzyme degradation of some of the functional starches and gums that make up the majority of GF bread formulas. Rice starch performance properties can be modified with sprouting (Moongngarm, 2011). A good tool to analyze these changes and their potential impact on products, is the RVA. Due to the use of white rice and starches as the major components in gluten-free bread, the nutrient density of gluten-free products is often low. This information, coupled with the fact that persons affected by celiac disease and required to eat glutenfree foods often have intestinal damage that limits nutrient absorption (Casper and Atwell, 2014), identifies an opportunity for improved nutrition with sprouted whole grains in place of white rice and starch. There is also potential to increase nutrients such as protein, fiber, and polyphenols and their absorption, while decreasing starch and antinutrients as part of the sprouting process as shown in sprouted amaranth, corn, buckwheat, millet, quinoa, sorghum, and rice varieties (Omary et al., 2012).

6.4.6.3 Sweet goods Sweet goods, including muffins, cakes, cookies, and brownies made with sprouted grains offer the consumer a healthy indulgence. Often these are incorporated at low use levels, below 20% of the flour for marketing purposes or distinction. Sprouted flours are often utilized versus particulates or whole grains, resulting in a stealthhealth effect. Sprouted wheat, spelt, barley, oat, and rice flours have neutral flavor profiles, compared to the other grains, even after sprouting, and these can be incorporated to provide the potential for increased nutrition, without sacrificing an indulgent experience.

6.4.6.4 Snack-Bars, granola, and oatmeal Texture and nutrition are important to consumers of bars. Cold-pressed granola bars have been produced using 35% sprouted whole grains, including sprouted oats, quinoa, millet, and amaranth, as shown in Fig. 6.21. There is a potential for sprouted oats to soften during steeping and germination (Kaukovirta-Norja et al., 2004), which could create reduced toothpacking and a decrease in the hardness of a bar. An increase in softness could also be a desired characteristic, increasing the ability for sprouted grains to be incorporated into instant oatmeal. For marketing appeal, sprouted whole grains also offer the opportunity to display a visible sprout in a cold-pressed bar or loose granola.

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Figure 6.21 Sprouted granola bar made with sprouted rolled oats, sprouted whole quinoa, sprouted whole millet, sprouted whole amaranth. Total sprouted grain inclusion level is 35%.

6.4.6.5 Snacks Corn and rice, and to some extent sorghum, are three grains commonly used in direct expanded snacks produced by extrusion processes. The starches in these grains gelatinize during extrusion and exhibit elasticity resulting in superheated water entrapment, which creates an instant increase in volume or “puff” as the snack piece exits the extruder die (Chanlat et al., 2011). Grits are generally used in single screw extrusion, or flour if a twin screw extruder is used. More research is needed to confirm any differences in starch expansion properties of sprouted corn, rice, and sorghum versus their unsprouted counterparts. The RVA is a useful tool to evaluate sprouted flours, to understand starch pasting differences, and hypothesize sprouted grain potential in puffed snacks. Crackers and tortilla chips are snacks where sprouted ingredients are prevalent today. Sprouted grain inclusions such as quinoa and amaranth are common and offer visual particulates, yet are small enough to avoid tearing the sheeted masa or cracker dough at typical use levels of 2%
20%. It is important to monitor cracker dough activity and feel during lay-time because enzyme activity could modify the sheeting properties of the dough during relaxation. Hard pretzels offer a growth opportunity for sprouted grains, and with their use, it may be possible to reduce or eliminate the malt (diastatic and nondiastatic) that is typically added, because of the natural enzyme activity and flavor contribution of sprouted grains.

6.4.6.6 Pasta Sprouted durum may be substituted for unsprouted durum up to 100% of the semolina in pasta, with no effect to cooked pasta firmness or resilience (Dexter et al., 1990), although drying temperatures may need to be lower due to increased

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absorption. The study by Dexter et al. (1990) on sprouted durum showed comparable results for breaking strength to traditional semolina over a dried pasta shelf life. Compared to other high water matrices, amylase has been shown to decrease in activity from flour to pasta dough to finished pasta (Kruger and Matsuo, 1982; Dexter et al., 1990). Some increases in solid loss during boil may be experienced, due to an increase in water soluble sugars and dextrins (Kruger and Matsuo, 1982). Gluten-free pasta can be produced with sprouted flours such as millet and rice, with potential advantages including increased nutrition (Omary et al., 2012) and improved flavor, as previously discussed. Because GF pasta usually incorporate a pregelatinized starch as the continuous phase to surround native starch granules (Casper and Atwell, 2014), limiting amylase activity may be helpful for cook-up quality and proper dough structure after extrusion.

6.4.6.7 Side dishes and main meal incorporation Sprouted whole grains can be boiled in soups or prepared as side dishes to replace their unsprouted counterparts. Shorter cook times are possible, and many of the nutritional and sensory advantages discussed earlier can be utilized in this application.

6.5

Food safety and quality

6.5.1 Monitoring The scale of sprouting operations can vary drastically, from in house to small batch industrial producers to large industrial processes. As such, the processing systems will vary from traditional malt houses, which leverage large dedicated compartments for steep, germination, and kilning, down to single tank systems producing a wet-mash for smaller scale users. Regardless of scale, monitoring of these sprouting systems must be employed to ensure food safety and quality, while maintaining consistency for the end user. Traditional sprouted process monitoring metrics are time, temperature and moisture. Often, the optimal combination of these parameters for a given product are considered proprietary information of the manufacturer. There are two main paths by which a sprouted ingredient can leave a facility where it is manufactured; either as a Ready-To-Eat (RTE) or a Not-Ready-To-Eat (NRTE) product. The clear line of distinction between the two is that the NRTE product requires further processing before reaching the consumer. This further processing must contain a “kill step” somewhere in the production of the finished product. Furthermore, the sprouted ingredient should contain a disclaimer statement such as: THIS FOOD INGREDIENT IS DERIVED FROM A RAW AGRICULTURAL PRODUCT AND HAS NOT BEEN PROCESSED TO CONTROL PATHOGENS. AS A RESULT, THIS FOOD INGREDIENT REQUIRES FURTHER PROCESSING TO CONTROL FOR PATHOGENS.

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Kill steps are most frequently some form of heat, steam, pressure, or a combination thereof. Products that are RTE require kill steps before reaching the end user, validated to ensure the effectiveness of the kill steps. The Codex Alimentarius defines validation as “Obtaining evidence that a control measure or combination of control measures, if properly implemented, is capable of controlling the hazard to a specified outcome.” (Food and Agricultural Organization, 2008). Validation is critical to ensure there are no microbial concerns and the end product is safe to eat. An example of an RTE sprouted food would be a bread product that has undergone a complete bake, or an extruded snack that has been exposed to temperatures high enough to generate steam. No matter whether a sprouted product is dried or a wet-mash, microbiological safety can be of concern. This holds true for both raw material and sprouted finished goods. Raw material that is identified as contaminated should be rejected and not processed. Food safety is paramount and while microbial concerns must be addressed, there are other safety concerns. Foreign materials, whether from the field, transportation, or production facility need to be managed. Any product produced, whether RTE or NRTE, needs a proper and effective Food Safety Plan, such as those required under the Food Safety Modernization Act. The FDA (https://www.fda.gov) and many other food regulatory departments have resources available on their websites for generating such plans.

6.5.2 Food safety definitions Frequently, terms and concepts such as 5-log reduction, logarithms, exponents, and decade graphs, used when referring to microbial food safety and mitigation are often not well understood. In addition, there is often confusion around microbial specifications and assaying. It is important to establish a firm grasp of these concepts and related terminology. Below are definitions with examples of the mathematical terms commonly used when evaluating food safety.

6.5.2.1 Definition of exponent The exponent of a number indicates how many times to multiply it by itself. In 82, the 2 indicates to multiple 8 two times: 82 5 8 3 8 5 64

6.5.2.2 Definition of logarithm The logarithm (log) of x in base b is written logb x and is defined as: logb x 5 y if and only if by 5 x, where x . 0 and b . 0, b 6¼ 1. It is important to remember that the result of a logarithm is an exponent. That is, logb x is asking, “What exponent on the base b will give the result x?” Logs can

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have any base number imaginable but it is most common to use a base of 10, because the base of 10 is intuitive and allows the use of decade graphing.

6.5.3 Relationship of exponents and logarithms The relationship between an exponent and a logarithm is important to understand Logarithmic form isy 5 logb X and the expontial form is by 5 X This shows that logarithms are the inverse form of exponents. In the graph below, the axis of symmetry is a mirror (Fig. 6.22). When the exponent curve goes one direction the logarithm curve goes equally but oppositely along the axis of symmetry.

6.5.3.1 Graphing The use of decade graphing (logarithm scale) allows an exponent and/or a logarithm to be graphed linearly. A decade is a factor of 10, representing the difference between two numbers (an order of magnitude difference) measured on a logarithmic (10) scale. The distance between 100
1000, 1000
10,000, and 10,000
100,000 are single decades. What is not intuitive of decade graphing are the axis values. For example, what value lies halfway between the graduation for 1000 and the one for 10,000? Since we tend to linearize your first guess might be the average of those two values, 5500, but that would be incorrect. Values are not spaced equally on a logarithmic axis. The logarithm of 1000 is 3.0, and the logarithm of 10,000 is 4.0, so the logarithm of the midpoint is 3.5. What value has a logarithm of 3.5? The answer is 103.5, which is 3162. So the value half way between 1000 and 10,000 on a logarithmic axis is 3162.

6.5.3.2 Microbial specifications and assaying If we have a microbial specification of 50,000 Colony Forming Units (CFU) and the standard error on the assay is 6 0.5 logs, what is the expected range to the nearest thousand?

Figure 6.22 The graph on the left is standard graphing compared to the graph on the right which is using decade or logarithmic scaling on the y axis.

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NOTE: All assays have a standard of error which represents the expected variability inherent in the method. When developing or interpreting microbial counts, specifications, or limits the variability expressed as standard of error should be considered. The first thing to do is to put the numbers into log form: Log 50,000 5 4.7 log Bottom end of range of error: 4.7 log
0.5 log 5 4.2 log 5 104.2 5 16,000 CFU Top end of range of error: 4.7 log 1 0.5 log 5 5.2 log 5 105.2 5 158,000 CFU

Thus, a CFU assay targeting 50,000 CFU with a standard of error range 6 0.5 logs has a range of: 16,000
158,000 CFU One might also try generalizations to half-log units, which would help approximate a log reduction for a quick reference. We can approximate these using half-log units: 1, 3, 10, 30, 100, 300, etc. In the previous example there were 50,000 CFU 6 0.5 logs. Estimating the half logs equals: Bottom end of range of error: 50,000 CFU
30,000 CFU 5 20,000 CFU Top end of range of error: 50,000 CFU 1 100,000 CFU 5 150,000 CFU

6.5.4 Log reduction Whole number logs, with base ten, change by a whole number for each order of magnitude change. Meaning, 10 is 1 log, and if increased by an order of magnitude, gives 100, or 2 log. Going further, 3 log is 1000, 4 log is 10,000 and so on. So regarding to log reductions, the orders of magnitude are less than the starting point. The reduction is 10-fold for each order of magnitude. In a percentage format, a 90% reduction in CFUs occurs for each log reduction. Meaning, 1 log gives a 90% reduction, 2 log gives is a 99% reduction, and so forth. Applying this, a 5 log reduction would be a 99.999% reduction of a microbial load (population) from the initial starting point.

6.5.5 Microbial growth curves As stated earlier, exponents and logarithms can be linearized by log (decade) graphs. However, there can be a point of confusion regarding microbial growth. The exponential growth phase is sometimes called the log phase, which is a misnomer. The true log phase is the death phase, where the population is decreasing, becaues exponents and logs are inverse relationships.

6.5.6 Mitigation The conditions during sprouting, including moisture, aeration, and sometimes temperature elevation, can be conducive for microbial growth of both beneficial and potentially deleterious microorganisms. Accordingly, every ingredient and process should be evaluated and assessed to conclude whether microbial risk mitigation is

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necessary or warranted. Sprouted ingredients that are classified as Not Ready-to-Eat (NRTE) must be further processed by an end user to include a kill step that can be validated, such as baking or pasteurizing. Often, even with ingredients that are considered low risk, an end use manufacturer may require monitoring and mitigation strategies to be in place at the vendor level before allowing that ingredient into their manufacturing plant. There are many strategies and technologies, such as microwave heating, steam treatment, chemical treatment, and ultrasonication that are available to implement either a validated 5 log reduction step for microorganism load reduction. A microorganism load reduction is a mitigation event that reduces the starting load but has no validation, and therefore no guarantee, of the amount of reduction.

6.5.7 Specifications Sprouted ingredients have a variety of end uses in many food systems. The specification requirements vary by application, type of grain, and manufacturer, but specifications are important for consistency, even at a minimal level such as moisture. As sprouted grains penetrate the market and new food systems, the demand for consistency will continue to increase. End use consistency parameters can include but are not limited to: hydration, functionality, color, nutrition, and flavor. Many of the sprouted ingredients are new to the marketplace and are being leveraged in unique product matrices, which may require novel solutions for assigning specifications.

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Further Reading Association of Cereal Chemists International, 2009a. Determination of Falling Number. Available at: http://methods.aaccnet.org/summaries/56-81-03.aspx (Accessed: 25th August 2017).