Meatballs with 3% and 6% dietary fibre from rye bran or pea fibre ‐ Effects on sensory quality and subjective appetite sensations

    Meatballs with 3% and 6% dietary fibre from rye bran or pea fibre - Effects on sensory quality and subjective appetite sensations Ursula Kehlet, Mette Pagter, Margit D. Aaslyng, Anne Raben PII: DOI: Reference:

S0309-1740(16)30332-1 doi:10.1016/j.meatsci.2016.11.007 MESC 7128

To appear in:

Meat Science

Received date: Revised date: Accepted date:

30 September 2016 27 October 2016 2 November 2016

Please cite this article as: Kehlet, U., Pagter, M., Aaslyng, M.D. & Raben, A., Meatballs with 3 % and 6 % dietary fibre from rye bran or pea fibre - Effects on sensory quality and subjective appetite sensations, Meat Science (2016), doi:10.1016/j.meatsci.2016.11.007

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT Meatballs with 3% and 6% dietary fibre from rye bran or pea fibre - effects on sensory quality and subjective appetite sensations

RI P

T

Ursula Kehlet1, Mette Pagter2, Margit D. Aaslyng1, Anne Raben2

1

SC

Danish Meat Research Institute (DMRI), Gregersensvej 9, DK-2630 Taastrup, Denmark

2

NU

Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Rolighedsvej

AC CE

PT

ED

MA

26, DK-1958 Frederiksberg C, Denmark

1

ACCEPTED MANUSCRIPT Abstract This study investigated dose-response effects of rye bran and pea fibre added to meatballs on sensory

RI P

T

quality and subjective appetite sensations. Pea fibre or rye bran was added to meatballs in doses ranging from 3 g to 6 g dietary fibre per 100 g. In a sensory profile, a trained panel (n=9) evaluated the meatballs in

SC

terms of odour, appearance, texture and flavour attributes. In a cross-over appetite study, 27 healthy men were served five test meals. Subjective appetite sensations were assessed over a 4-hour period. The

NU

addition of rye bran to the meatballs increased the grainy odour, texture and flavour. Pea fibre resulted in a more crumbly, firm and gritty texture with increasing doses of fibre. The sensory changes followed a dose-

AC CE

PT

ED

MA

response relationship. Subjective appetite sensations were not affected by the addition of fibre.

2

ACCEPTED MANUSCRIPT Keywords

AC CE

PT

ED

MA

NU

SC

RI P

T

Pork, sensory profile, satiety, meat, protein, meatballs, nutritional claims

3

ACCEPTED MANUSCRIPT 1. Introduction In the context of the ever-increasing obesity epidemic, the development of healthier food products that

RI P

T

target appetite control is needed. Nutritionally, dietary protein has been reported as being the most satiating macronutrient (Westerterp-Plantenga, Nieuwenhuizen, Tomé, Soenen, & Westerterp, 2009) and is

SC

also believed to affect metabolic targets for weight loss and weight maintenance (Leidy et al., 2015). Dietary fibres have also been shown to enhance satiety and reduce energy intake (Howarth, Saltzman, &

NU

Roberts, 2001; Slavin & Green, 2007). However, the effect may depend on the chemical structure and physicochemical properties of the fibre, with viscous fibre being shown to have a greater effect on satiety

MA

and energy intake than less viscous fibre (Slavin & Green, 2007; Wanders et al., 2011). Satiety signals are generated both pre- and post-absorptively as described in the satiety cascade by Blundell

ED

(2010). Dietary fibre and protein affect satiety through different mechanisms. Dietary fibre increases

PT

chewing time, leading to increased exposure time to food in the mouth, increases gastric distention, leading to delayed gastric emptying, and changes the concentration of gut hormones (Slavin & Green,

AC CE

2007). In contrast, the satiating effects of protein are mainly mediated through changes in metabolites (e.g. amino acid) and hormones (e.g. insulin, gastrointestinal hormones) (Westerterp-Plantenga et al., 2009). Therefore, the consumption of high protein, fibre-rich foods could be an effective approach to weight management, since they combine several satiating mechanisms. The addition of dietary fibre to meat products has been suggested by several reviews as a way to improve the nutritional and health quality of meat and at the same time increase fibre intake among consumers (Mehta, Ahlawat, Sharma, & Dabur, 2015; Talukder, 2015; Verma & Banerjee, 2010). However, to our knowledge, only one study has investigated the satiating effects of fibre addition to a meat product (Vuholm et al., 2014). Here, rye or wheat bran added to sausages increased satiety, and furthermore the satiating effect appeared to be more pronounced when rye bran was added to sausages than when added to bread. The study demonstrates the potential of combining animal protein and fibres, although more

4

ACCEPTED MANUSCRIPT research is still needed with respect to understanding the importance of fibre type and dose on satiety. Dietary fibre as a satiety-enhancing ingredient has been tested mostly in low protein foods such as

T

breakfast cereals, breads and beverages (Clark & Slavin, 2013; Wanders et al., 2011). In a recent review,

RI P

Clark & Slavin (2013) concluded that in general neither the fibre type nor the fibre dose affects appetite and energy intake. However, these conclusions were based on a comparison across studies varying in study

SC

design, fibre doses and administration of the fibre. Different fibre types and doses need to be compared

NU

within the same study design, test food and study population in order to draw any definite conclusions in this regard.

MA

From an industrial perspective, it is of interest to achieve minimum fibre doses of 3 g or 6 g dietary fibre per 100 g in order to meet the requirements for the nutritional claims “Source of dietary fibre” and “High fibre

ED

content”, respectively. These claims could increase market potential for fibre-rich meat products and provide consumers with a healthy food choice. To achieve these levels, it is crucial to investigate the

PT

sensory quality, since this could be influenced by the addition of fibre. The sensory effects of fibre addition

AC CE

to meatballs have been investigated, with different fibre types such as rye bran (Petersson et al. 2014a; Petersson et al. 2014b; Yilmaz 2004), wheat bran (Yilmaz 2005), oat bran (Petersson et al., 2014b), rice bran (Huang, Shiau, Liu, Chu, & Hwang, 2005) and barley fibre (Petersson et al., 2014b) being added in doses ranging from 1% to 20%. These studies showed considerable challenges when fibre addition exceeded 10% of the meatball recipe in order to maintain an acceptable sensory quality. Physico-chemical properties such as particle size, viscosity and WHC of dietary fibre could be of importance for both the sensory quality of a given fibre food and for the ability of dietary fibre to increase satiety. Fibres with high water-holding capacities are expected to retain water in the food matrix to which they are added and hereby increase or maintain juiciness. Also, particle size could have a negative impact on the sensory properties (Petersson, Eliasson, Tornberg, & Bergenståhl, 2013). In appetite regulation, viscous

5

ACCEPTED MANUSCRIPT fibres have been proposed to improve short-term satiety by delaying gastric emptying rate and/or physically inhibit nutrients absorption in the small intestine (Kristensen & Jensen, 2011).

RI P

T

Rye bran and pea fibre are potential fibre ingredients to be added to meat products. In rye bran, the main dietary fibre is arabinoxylans (Nilsson et al., 1997), with up to 27% classified as soluble (Glitsø & Bach

SC

Knudsen, 1999) . Cellulose is the main dietary fibre in pea fibre and is regarded as insoluble. Although pea fibre and rye bran mainly consist of insoluble dietary fibre, rye bran has a higher content of soluble

NU

arabinoxylans than pea fibre and is therefore expected to have more favourable physico-chemical properties regarding satiety.

MA

Investigations of both the nutritional properties in terms of satiating effects and the sensory changes

ED

resulting from addition of rye bran and pea fibre to meatballs have not been reported previously. The aim of this study was therefore to investigate the dose-response effects of these two types of dietary

PT

fibre added to meatballs with regard to sensory quality and subjective appetite sensations. Also, the physico-chemical properties of the two fibres and the test meals were characterized. The dietary fibre

AC CE

concentrations in the meatballs were of industrial relevance, since they met the criteria for nutritional claims. We hypothesized that the sensory characteristics would be affected by the addition of rye bran and pea fibre to meatballs in doses required for the nutritional claims for fibre. Furthermore, we hypothesized that dietary fibre would improve subjective appetite sensations dose-dependently and that rye bran would enhance satiety more than pea fibre.

2. Materials and methods The study consisted of two parts: a sensory profile in which the eating quality of rye bran and pea fibre meatballs was assessed and, subsequently, an appetite study including the most optimal meatballs for each

6

ACCEPTED MANUSCRIPT fibre type from a sensory point of view. Physico-chemical properties of rye bran, pea fibre and test meals in the appetite study were also determined.

RI P

T

2.1. Fibre ingredients

Rye bran (Bornholm Valsemølle, Denmark) and pea fibre (Fibradan 20, DLG Ingredients, Denmark) were

SC

investigated. Rye bran had a total dietary fibre content of 45% (w/w) (manufacturer data sheet). The fibre composition was arabinoxylans (60%), cellulose (17%), Klason lignin (10%) and β-glucan (5%) (Nilsson et al.,

NU

1997). The pea fibre was made from heat-treated pea shells from yellow and green peas and consisted of cellulose (48.5%), hemicellulose (18%), pectin (14%), lignin (2%) and other compounds (17.5%)

2.2. Meatballs with dietary fibre

ED

MA

(manufacturer data sheet). The total dietary fibre content was 90% (w/w

PT

The ingredients of the meatballs are given in Table 1. Two different recipes were developed specifically for

AC CE

rye bran and pea fibre, since differences in their fibre concentration and WHC had to be taken into account in order to retain an acceptable sensory quality. For rye bran and pea fibre, a control meatball without any fibres added and seven fibre meatballs were prepared. In the fibre meatballs, rye bran or pea fibre was added to achieve a dietary fibre content of 3.0, 3.5, 4.0, 4.5, 5.0, 5.5 and 6.0 g per 100 g final product. Wheat flour was added to the control meatballs, acting as a “replacement ingredient” for fibre. For example, wheat flour was replaced by either rye bran or pea fibre in the fibre meatballs in order to keep the other ingredients constant. This was important in the sensory analysis when studying the doseresponse effects of fibre addition. The meatballs were produced at the Danish Meat Research Institute (DMRI) in Denmark. Prior to preparation, the meat was minced one time through a 3 mm perforated disc. The minced meat was mixed with salt, pepper, eggs, flour and fibres. Fibres were added in their dry form without any pre-treatment. When a homogenous mix was achieved, chopped onions were added and thoroughly mixed within the meat. Additionally, skimmed milk powder and ice water were added to the 7

ACCEPTED MANUSCRIPT mass before mixing for 6 min. The meat was left for approximately 30 min at 10°C before the meat balls were formed (45 g ± 1 g). The meatballs were pan-fried in canola oil and butter (180°C) on a tilting frying

T

pan (Fribergs, model FBLB 40/6, Sweden) until they reached a core temperature of 75°C. The eight

RI P

meatballs for each fibre type were included in the sensory profiling in order to investigate dose-response effects. In the appetite study, meat balls with 3.0 and 5.5 g fibre were included for both rye bran and pea

SC

fibre, representing a “low” and “high” fibre addition. The fibre dose of 5.5 g was chosen because it was the

NU

highest dose that compromised the sensory attributes the least. A control without added fibres was also

MA

included in the appetite study.

ED

2.3. Sensory profiling

The sensory profiling was performed at the sensory laboratory accredited DS/EN ISO/IEC 17025:2005 at

PT

DMRI in January 2015. The sensory panel consisted of nine trained assessors (three men and six women aged between 46 and 69 and with 1 to 21 years of experience in the sensory assessment of meat and meat

AC CE

products). Two sensory profiling analyses were carried out – one for rye bran and one for pea fibre meatballs. The meatballs were evaluated using a set of established attributes from a training session conducted prior to the sensory evaluation for each fibre type. The same approach was used for training and evaluation for pea fibre and rye bran meatballs. Each training session included group discussions and sensory training on two of the extreme meatballs (0 and 6% fibre) in order to learn to distinguish the attributes from each other. In the sensory evalution, rye bran meatballs were evaluated in terms of odour (meatballs, grain/bread), appearance (pigmented interior), flavour (meatball, meat, spice, sour, grain) and texture (firmness, sticky, juiciness, grainy). Pea fibre meatballs were evaluated in terms of odour (meatball), flavour (meatball, meat, spice, sour, grainy/flour), taste (bitter and sweet) and texture (firmness, juiciness, crumbly, gritty). The evaluation procedure for each attribute was performed as described in Arildsen Jakobsen et al. (2014). Prior to serving, the meatballs were heated in a microwave oven (LG, Wavedom,

8

ACCEPTED MANUSCRIPT model: MC-8483NLA RS com) at 700 watts for 3 min and 10 sec until a core temperature of 75°C was reached. The temperature was controlled using a cooking thermometer (Testo 926; Buch & Holm,

T

Denmark) inserted lengthwise into one of the meatballs for each heating. The meatballs were served on a

RI P

preheated porcelain plate marked with a three-digit number and with a foil tray used as a lid. To reduce session-to-session variation, all meatballs were evaluated on the same day in two replicates. The meatballs

SC

were served in a randomised order (one block randomisation for each replicate). In the sensory evaluation,

NU

the panellists were instructed to clean their mouth with water, cucumber or flatbread between the samples. The sensory attributes were evaluated using a continuous 150 mm line scale anchored 1 cm from

MA

each end and with the endpoints “None” and “A lot”.

ED

2.4. Appetite study

PT

2.4.1. Study design

AC CE

The appetite study had a cross-over design with five test meals and was carried out at DMRI in Denmark from April to June 2015. The study participants were blinded to the test meals, since there was no clear difference in the appearance of the meatballs. Study participants were randomly assigned to a sequence of the five test meals using a randomised block design. This was done by the study coordinator. The test meals were separated by a minimum of five days. Between the study days, the participants were instructed to maintain their normal diet and lifestyle. Prior to each study day, the participants were instructed to follow a standardised fasting procedure from 10 p.m. but were allowed to drink up to 500 mL between 10 p.m. and the time of the test meal the following day. They were also instructed to abstain from alcohol and physical activity for 24 hours prior to the study day. On each study day, the study participants arrived in the morning at the study site. Before the test meals were served, appetite sensations were assessed using visual analogue scales (VAS) while the participants were still in the fasting state (time point 0). During the intake of the test meal, the participants were seated in individual booths and were told to consume the test

9

ACCEPTED MANUSCRIPT meal within 15 min. After consumption of the test meal (time point 15 min), appetite sensations and liking were assessed. The participants then went to their work place and remained there for the following 3.5

T

hours and were given a bottle of water (0.33 L) and six VAS questionnaires marked with time points. The

RI P

participants were instructed to fill out a VAS questionnaire as soon as they received a text message reminder on their mobile phones. Appetite was assessed 30 minutes after the test meal (time point 30 min)

SC

and continuously every half an hour for four hours in total (60-240 min). The participants were also

NU

instructed not to eat or drink anything in the period from leaving the study site and the following four hours but were allowed to drink from the bottle of water given to them. At time point 240 min., the

MA

participants met with the study personnel again and filled out the last questionnaire and returned their bottles of water. The amount of water left in the bottles was recorded, and the water intake for the test

ED

meal was calculated. On the first study day, the height of the study participants was measured to the nearest 0.5 cm using a stadiometer (Hultafors AB, Hultafors, Sweden). The weight of the participants,

PT

wearing light clothes and having emptied their bladder, was measured to the nearest 0.05 kg (Lindeltronic 8000, Copenhagen, Denmark). The study was carried out in accordance with the Helsinki Declaration. The

AC CE

Ethical Committee of the Capital Region, Denmark assessed the study as not requiring ethical approval since no biological material was taken. 2.4.2. Study participants

Potential study participants were recruited from the Danish Technological Institute, Denmark through recruitment pamphlets in the canteen and an in-house study participant database. The inclusion criteria were as follows: subjects who provided written consent, healthy men, 18-60 years of age, BMI ranging from 18.5 to 30 kg/m2 and pork eaters. The exclusion criteria were: food allergy, dislike or special diet of relevance to the study; regular use of prescription medication; irregular eating schedule; currently dieting or having experienced a weight change (±3 kg) in the previous three months; known chronic diseases; vigorous physical activity > 10 hours per week; smoking; working in appetite or related research areas;

10

ACCEPTED MANUSCRIPT participation in other clinical studies; unable to comply with the study protocol. All of the study participants received verbal and written information about the study before giving their written consent. To detect a

T

difference of 10% in satiety ratings with a statistical power of 90% and a significance level of 0.05, a sample

RI P

size of 24 participants was needed (Flint et al. 2000). In the recruitment procedure, a drop-out rate of 15%

SC

was taken into account. 2.4.3. Test meals

NU

The five test meals were served in sensory booths as breakfast meals, and their nutritional composition is presented in Table 2. Each meal consisted of five meatballs (Table 1), a wheat ciabatta bun (70 g, Kohberg

MA

Bakery Group A/S, Denmark) with butter (16 g, Lurpak, Denmark), cucumber (100 g) and an optional drink (coffee, tea or water). The choice of drink was noted on the first study day, and the same drink was served

ED

to each participant on the remaining study days. The meatballs were produced in one batch per fibre type

PT

at DMRI according to the recipe in Table 1. The meatballs were stored at -18 °C until further use. Prior to each test day, the meatballs were thawed at 5 °C for 24 hours and were heated in a microwave oven for

AC CE

3.5 min at 600 watts prior to serving. The buns were oven-heated for 5 min at 195 °C prior to serving. 2.4.4. Measurements

Appetite sensations and liking were assessed using VAS. The VAS scale was 100 mm in length, with words anchored at each end expressing the most positive and the most negative rating of the subject’s sensations. The following appetite sensations were assessed: how satisfied do you feel? (I am completely empty – I cannot eat another bite); how hungry do you feel? (I am not hungry at all – I have never been more hungry); how full do you feel? (not at all full – totally full); how much do you think you can eat? (nothing at all – a lot). The VAS questions were provided in small booklets, with one question at a time. On each test day, the subjects received instructions on how to rate their appetite using VAS, and they were not allowed to discuss their ratings with each other. The VAS has been shown to be both reproducible and valid for measurement of appetite sensations (Flint et al., 2000) . The habitual fibre intake of the study participants

11

ACCEPTED MANUSCRIPT was measured by a food frequency questionnaire (FFQ) on the first study day. In the questionnaire, the subjects stated the portion size and frequency of their intake of fibre-rich food items during the last month.

T

The habitual daily fibre intake for the subjects was estimated based on the average fibre content of the

RI P

products represented in the questionnaire. The fibre FFQ has been validated against a 7-day weighed food

SC

record and has been shown to be reproducible and valid for assessing fibre intake (Vuholm et al. 2014b).

NU

2.5. Physico-chemical analyses

MA

Physico-chemical properties were measured for the two fibres (rye bran and pea fibre) and the five test meals included in the appetite study. These properties included water-holding capacity (WHC) and

ED

viscosity. Moreover, particle size distribution was determined for the fibre ingredients. Measurements of WHC and viscosity were performed under a control condition (samples soaked in distilled

PT

water) and under an in vitro digestion condition simulating gastrointestinal digestion from mouth to

AC CE

duodenum. The in vitro simulated gastrointestinal digestion was performed according to Turnbull et al. (2005) with modifications in the amount of samples and types of reagents. Reagents included α-amylase from human saliva (A1031, Sigma-Aldrich), pepsin from porcine gastric mucosa (P7000, Sigma-Aldrich), bile extract (B8631, Sigma-Aldrich) and pancreatin from porcine pancreas (P1750, Sigma-Aldrich). The meals were homogenized prior to analyses. The components of the meals were homogenized separately in a knife mill grinder (Grindomix GM 200, Retsch) to ensure proper homogenization (meatballs: 7 sec. at 7500 rpm three times; wheat bun: 7 sec. at 7500 rpm twice; cucumber: 7 sec. at 7500 rpm four times). Afterwards, the components were homogenized in a food porcessor (Kenwood Multipro Excel FP980) for 15 sec at speed 4 twice. The same amount of homogenized sample (0.8 g) was used for WHC and viscosity measurements. WHC was measured in triplicate based on the method of McConnell et al. (1974). For the control condition, each sample (0.8 g) was soaked for 24 hours in distilled water (20 ml) and then centrifuged at 5000 rpm for 12

ACCEPTED MANUSCRIPT 30 min at 20°C. The supernatant was discarded, and the tubes containing the pellet and the absorbed water were left to drain inverted for 15 min prior to weighing. Samples that had undergone in vitro digestion

T

were centrifuged immediately after in vitro digestion. WHC was expressed as gram water per gram dry

RI P

sample when corrections were made for the moisture content of the original samples.

SC

Viscosity of the samples after the control condition and in vitro digestion was measured at 37°C using a rheometer (model Kinexus Pro+, Malvern, United Kingdom). For all the samples, a shear rate of 122/sec

NU

was used, and viscosity readings were recorded after 1 min.

MA

Particle size distribution was determined using a sieve shaker (J. Engelsmann A, model JEL 200, Germany).

ED

2.6. Statistical analysis

Statistical analysis was performed separately for the sensory profiling data and the appetite data. Both

PT

analyses were carried out using R (version 3.1.2, R Core Team, 2015), apart from the principal component

AC CE

analysis (PCA analysis) of the sensory data, in which PanelCheck was applied (vers. 1.4.0, Nofima, Norway). A significance level of 0.05 was used. Data from the sensory profiles were collected electronically using the FIZZ software (FIZZ, version 2.46B, France). Afterwards, panel performance was analysed in PanelCheck (version 1.4.0, Nofima), and a PCA was performed. The SensMixed package (version 2.0-9, Kuznetsova et al, 2016) was used to perform a two-way ANOVA for mixed models, with meatball as fixed effect and replicate, assessor and assessor-meatball interaction as random effect. The model corrected for scaling effects among the assessors. Significant product effects (meatball) were compared using Bonferroni correction. For both rye bran and pea fibre, the relationship between fibre dose and the intensity of the sensory attributes was analysed using a linear regression model with the sensory attribute as response variable and product (meatballs) as fixed effect.

13

ACCEPTED MANUSCRIPT In the appetite study, the effect of meal on satiety, hunger, fullness, and prospective intake was investigated using repeated measurements as well as a summary measure: incremental area under the

T

curve (iAUC) or incremental area over the curve (iAOC). Repeated measurements were analysed using

RI P

linear mixed models including the meal-time interaction, visit, age, BMI, liking, and baseline as fixed effects and subject and within-visit subject as random effects. Liking was included in the model, since liking

SC

differed significantly between the meals. Moreover, residual errors in the repeated measurement models

NU

were assumed to be serially correlated within each visit for each subject, following a Gaussian correlation structure with exponentially decreasing correlation with increasing time gaps squared increase. Model

MA

checking for variance homogeneity and normal distributions were based on residual plots and normal probability plots. The iAUC and iAOC were calculated using the trapezoidal method. For iAUC/iAOC and

ED

ratings of liking, linear mixed models were used including meal, visit, age, BMI, and liking as fixed effects and subjects as random effects. In case of significant main effects of meal, post hoc comparisons were

PT

performed with Tukey’s test for multiple comparison.

AC CE

A one-way ANOVA and Tukey’s test for multiple comparison were performed on the physico-chemical data to detect differences between the meals.

3. Results

3.1. Sensory profiling For both rye bran and pea fibre meatballs, the main variation depended on whether fibre was added or not (data not shown). To explore the difference between the meatballs with added fibres at different levels, a PCA was performed on the fibre meatballs excluding the control meatballs (Fig. 1). This was done for visual purposes only in the PCA plot whereas the subsequent statistical analyses included the control meatballs. The principal component (PC) 1 explained 93.8% and 83.8% of the variation for rye bran and pea fibre, respectively, and showed that the main variation was dose-dependent. An increase in rye bran dose 14

ACCEPTED MANUSCRIPT resulted in a more grainy odour and flavour and a more grainy texture and pigmented interior. For pea fibre, the main difference was in the texture, which became more gritty, crumbly and firm and less juicy

RI P

T

with increasing doses, while the odour and flavour were only partially influenced by pea fibre.

SC

3.1.1. Linear relationship between fibre dose and intensity of sensory attributes

The linear regression analysis showed a significant linear relationship between the attributes and the

NU

concentration of fibres for most of the sensory attributes in both rye bran and pea fibre meatballs (Table 3).

MA

With increasing fibre doses, the meatball odour and flavour and the meat flavour decreased linearly, whereas firmness increased. These results were valid when either rye bran or pea fibre was added to

ED

meatballs. For pea fibre, an increase in fibre dose linearly decreased juiciness; however, no significant relationship was found for juiciness when rye bran was added.

PT

When a linear relationship existed, the gradient indicated the degree to which a sensory attribute changed

AC CE

with increasing fibre doses, i.e. the steeper the slope, the more a sensory attribute was affected by fibre. For rye bran, an increase in fibre dose largely affected grainy attributes such as pigmented interior, grainy odour, flavour and texture compared to the meat-related and the other texture attributes. For pea fibre, it was the texture attributes such as firmness, crumbliness, grittiness and juiciness that were affected the most with increasing fibre doses.

3.1.2. Sensory quality when rye bran or pea fibre was added in levels required for nutritional claims Nutritional claims for dietary fibre require ≥ 3 or ≥ 6 g dietary fibre per 100 g. Meatballs without any addition of fibre were therefore compared to meatballs with fibre doses of 3 g and 6 g for rye bran and pea fibre (Table 4).

15

ACCEPTED MANUSCRIPT Rye bran: For texture attributes, the addition of 3 g fibre resulted in a more grainy texture (P < 0.001); however, sticky texture and firmness did not change significantly compared to meatballs without added rye

T

bran fibre. Increasing the fibre dose from 3 g to 6 g fibre further increased grainy texture (P < 0.001) and

RI P

firmness (P = 0.005) and decreased sticky texture (P < 0.001). Juiciness was not affected by the addition of rye bran. Meat-related flavour attributes such as meatball flavour and odour decreased significantly, but

SC

only when 6 g fibre from rye bran was added to meatballs (P < 0.001), since there was no difference

NU

between the control and meatballs with 3 g fibre for these attributes (P = 0.36 and P = 0.09, respectively). Also, the meatballs became less spicy when 6 g fibre was added (P < 0.001). On the other hand, grainy

MA

flavour and odour increased when 3 g fibre was added to meatballs (P < 0.001) and increased further from 3 g to 6 g fibre (P < 0.001). The appearance of the meatballs was also affected by the addition of fibre from

ED

rye bran. The meatballs became more pigmented in the interior when 3 g fibre was added (P < 0.001), and this was even more pronounced when 6 g fibre was added (P < 0.001).

PT

Pea fibre: The sensory changes when pea fibre was added to meatballs followed nearly the same pattern as

AC CE

for rye bran. The addition of 3 g and 6 g pea fibre resulted in a more firm (P < 0.001), more crumbly (P < 0.001), more gritty and less juicy texture (P < 0.001) compared to the control without pea fibre. Also, grain/flour flavour increased when 6 g pea fibre was added (P < 0.001) but not for 3 g pea fibre compared with the control. Meatball and meat flavour significantly decreased when 3 g and 6 g pea fibre was added (P < 0.001). Bitter taste and sweetness were also evaluated for pea fibre meatballs but were not affected by the addition of 3 g or 6 g pea fibre.

3.2. Appetite study 3.2.1. Baseline characteristics In the appetite study, 74 subjects were assessed for eligibility according to the inclusion and exclusion criteria, with 28 subjects deemed eligible and enrolled in the study. During the study, one subject dropped 16

ACCEPTED MANUSCRIPT out due to a job reassignment and four subjects completed only four test meals. Data analysis was performed on data from 27 subjects. Baseline characteristics of the study participants were as follows

T

(means ± SD): age (41.6 ± 12.2 years), BMI (25.8 ± 2.4 kg/m2) and habitual fibre intake (25.2 ± 13.5 g/day).

RI P

The habitual fibre intake varied among the participants, ranging from 9.2 g to 64.7 g fibre per day.

SC

3.2.2. Appetite ratings and liking

In the repeated measurements model, there were no significant time x diet effects or meal effects on

NU

satiety, hunger, fullness nor prospective food intake (Fig. 2). Likewise, the corresponding iAUC for satiety and fullness and iAOC for hunger and prospective food intake showed no effect of the meal (data not

MA

shown). There was a diet effect on liking of the meals, P < 0.001 (Fig. 3). Post hoc analyses showed that liking of the meal with pea fibre meatballs with 5.5 g fibre was significantly lower than for all of the other

PT

3.3. Physico-chemical properties

ED

meals (P < 0.01), while no significant difference existed among the others.

AC CE

The physico-chemical properties of the two fibre ingredients and the test meals in the appetite study are presented in Table 5. Pea fibre had a higher WHC than rye bran (P < 0.001) whereas the viscous properties did not differ between the two fibres nor between the five meals. The meals consisting of meatballs with pea fibre or rye bran had a higher WHC than the meal without any fibres added to meatballs (P < 0.05). However, no difference in WHC was found between the four meals with fibres. Under simulated gastrointestinal conditions, the WHC of the meals decreased compared to the control condition, however, the viscous properties were not affected. Rye bran and pea fibre differed in their structure, with a coarse and very fine structure, respectively. Most of the rye bran (76%) had a particle size of ≥ 250 µm, whereas pea fibre was finely ground to a particle size of < 250 µm (92%).

17

ACCEPTED MANUSCRIPT

T

4. Discussion

RI P

The present study investigated dose-response effects of two types of dietary fibres in meatballs on sensory characteristics and on subjective appetite sensations. We can confirm one of our hypotheses, namely that

SC

the sensory characteristics were affected by the addition of rye bran and pea fibre in doses of 3 g and 6 g fibre per 100 g. However, our hypotheses on appetite were rejected, as neither rye bran nor pea fibre

MA

NU

addition to meatballs enhanced satiety compared to the control.

4.1. Effect of fibre dose on sensory characteristics

ED

The sensory profiling showed significant dose-response effects on the meat- and grain-related attributes as well as texture attributes when either rye bran or pea fibre was added to meatballs. Specifically for rye

PT

bran, the grain-related attributes were affected the most compared to the other sensory characteristics

AC CE

with increasing fibre doses. The grainy flavour in rye bran meatballs is assumed to be ascribed to the addition of rye bran, since the rye bran fraction has been shown to have an intense cereal flavour and bitter taste compared to the endosperm (Nordlund et al., 2013). The present study showed that the cereal flavour of rye bran was pronounced when mixed into a meat product (mean rating of 117 on the 150 mm line scale). However, bitter taste, which could have been expected from rye bran, was not present and might therefore have been masked by the grain or meat flavour. Changes in the grain-related properties in odour and flavour from cereal bran addition have only been reported when rye bran was added to sausages (Arildsen Jakobsen et al., 2014), whereas other studies using rye bran did not include these grain-related attributes in their sensory analysis (Petersson et al. 2014a; Petersson et al. 2014b; Yilmaz 2004). This is surprising, since grainy odour, flavour and texture seemed to be noticeable properties of rye bran meatballs and rye bran sausages. Whether the grainy characteristics (odour, flavour and appearance) of rye bran meatballs could compromise consumer liking cannot be concluded from the sensory profiling, as this 18

ACCEPTED MANUSCRIPT was a description of the sensory quality and not a validation of liking. However, in the present appetite study, the participants liked the meatballs with 3 g or 5.5 g fibre from rye bran compared to meatballs

T

without fibre. Other studies also showed that palatability did not change when 5% and 10% rye bran was

RI P

added to meatballs (Yilmaz 2004). In comparison, 11% rye bran was used in the recipe for meatballs in our study to provide 6.0 g dietary fibre per 100 g (Table 1). Sausages with 4.55 g dietary fibre from rye bran per

SC

100 g have also been shown to be well liked by Danish consumers and comparable to sausages without

NU

fibres (Arildsen Jakobsen et al., 2014). However, it should be noted that the present appetite study included only 27 subjects, which limits any conclusions that can be drawn regarding consumer acceptance. It would

MA

therefore be relevant to investigate consumer acceptance in future studies that include more subjects. For pea fibre, gritty texture and crumbly texture were increased and juiciness was decreased with

ED

increasing fibre doses. The gritty texture and crumbly texture could be ascribed to the small particle size of the pea fibre (<250 µm). The gritty texture was not present in the rye bran meatballs as they had a more

PT

coarse structure (> 250 µm). Petersson et al. (2013) have shown that the threshold for the sensation of

AC CE

grittiness in rye bran particles of the same size as the pea fibre in the present study was very low. This could affect the palatability of the pea meatballs. In the appetite study, the meal containing 5.5% pea fiber meatballs was rated lower in liking than the other meals which thus could be ascribed to the gritty texture. In the present study, the results from the sensory profile were used in the selection of the meatballs with “highest” fibre dose for the appetite study. This approach enabled us to include fibre meatballs for which most of the sensory attributes were maintained in order to enhance liking among the study participants. This was achieved for the rye bran meatballs, but not for the pea fibre meatballs, since the meatballs with 5.5 g fibre per 100 g were rated significantly lower in liking than the other pea fibre meatballs (Fig. 4). Juiciness was affected differently for rye bran meatballs and pea fibre meatballs. A dose-response effect was found for pea fibre, with an increase in dose resulting in decreased juiciness, whereas juiciness was not affected by the addition of rye bran. The cooking loss in rye bran meatballs did not increase with increasing

19

ACCEPTED MANUSCRIPT fibre dose as compared to pea fibre (Table 1). This could explain the differences in juiciness between the two fibres. Pea fibre had a higher WHC than rye bran (Table 5), and it was therefore surprising that pea

T

fibre was not capable of retaining more water when the fibre dose was increased. In meat products,

RI P

juiciness is considered to be an important quality parameter for consumer liking (Resurreccion, 2004). Thus, the fact that pea fibre addition resulted in less juicy meatballs could be a disadvantage in terms of market

SC

potential. However, this was only the case when 6 g fibre was added. The differences in juiciness could also

NU

be ascribed to differences in pork and water content in the recipes for rye bran meatballs and pea fibre meatballs as more water was added to the rye bran recipe than to the pea fibre recipe. It is therefore

MA

difficult to draw any direct comparisons between pea fibre and rye bran with regard to the sensory characteristics.

ED

Rye bran and pea fibre were added to meatballs in doses that met the requirements for the nutritional claims “Fibre source” (3 g fibre per 100 g) and “High in fibre” (6 g fibre per 100 g). This approach is unique

PT

to the present study. Thus, other sensory studies solely report the amount of fibre ingredient added and

AC CE

not the effects of fibre addition on the dietary fibre content and thus whether a nutritional claim can be applied. In order to meet the “High in fibre” claim with a final dietary fibre content of 6 g, 5.2% and 11.0% of pea fibre and rye bran, respectively, were added to the meatball recipes, in which the frying loss was taken into account. To meet the “Fibre source” claim, 2.1% pea fibre and 4.5% rye bran were added. Different amounts of fibre were added for rye bran and pea fibre, since pea fibre has a higher fibre concentration (90 g per 100 g) compared with rye bran (45 g per 100 g). Other dose-response sensory studies investigating the addition of fibres to meat products are limited. Yilmaz et al (2004) found that the addition of 5% and 10% rye bran to meatballs did not change juiciness, texture, flavour intensity and overall palatability compared with a control, whereas the addition of 15% and 20% decreased these attributes. Dose-response studies with rice bran (Huang et al., 2005), oats and wheat bran (Talukder, 2015) used the same fibre doses in the recipes as Yilmaz (2004). However, the effect on dietary fibre content was not reported, and the sensory analysis only included a limited number of sensory attributes.

20

ACCEPTED MANUSCRIPT

T

4.2. Satiating effects of fibre addition to meatballs

RI P

Rye bran and pea fibre were added to meatballs in order to increase the dietary fibre content and thereby improve the nutritional profile of the meatballs. Viscous dietary fibre is capable of increasing the viscosity

SC

of the digesta, which could prolong and enhance feelings of satiety. However, the satiating effect has been shown to depend on the fibre type, since physico-chemical properties vary among fibres (Wanders et al.,

NU

2011). Rye bran and pea fibre were used in the present study, because they differed with regard to their fibre composition and particle size. A larger particle size has been shown to increase viscosity (Sun, Wu, Bu,

MA

& Xiong, 2015) and could therefore be important for appetite. However, measurement of the viscosity of the five meals under simulated gastrointestinal conditions was rather low. Also, viscosity did not differ

ED

between the meals, which could explain why we did not find an effect on subjective appetite from either

PT

rye bran or pea fibre addition. This was unexpected, since we have previously found that the addition of rye bran addition to sausages in a similar dose (3 g dietary fibre) enhanced satiety (Vuholm et al. 2014a). The

AC CE

absence of an effect from fibre addition in this study could also be explained by the high and variable habitual fibre intake among the study participants (Table 5). The provided fibre doses in the present study were relatively small compared to their daily fibre intake, which could diminish a potential effect. These speculations arise from the protein change theory postulated by Bosse and Dixon (2012). Thus, there must be a sufficient deviation from the habitual intake to determine a success of additional protein in weight management. However, it is not known whether this theory also applies to dietary fibre and appetite. Fibre addition to meat products has not been widely studied in terms of subjective appetite sensations, and the evidence is limited to the aforementioned study (Vuholm et al. 2014a). In bread, dose-response effects on appetite have been investigated with either rye bran or an intermediate rye fraction (Isaksson, Fredriksson, Andersson, Olsson, & Aman, 2009). Here, the rye bran bread enhanced satiety in a dosedependent manner with 0 g, 5 g and 8 g dietary fibre, whereas the other rye product only increased satiety

21

ACCEPTED MANUSCRIPT in doses of 5 g. In the review by Clark & Slavin (2013), rye bran was one of several dietary fibres pointed out as being a fibre that improved satiety. It was therefore expected that rye bran addition per se would affect

T

appetite sensations in the present study. The evidence for pea fibre and appetite is limited to a few studies.

RI P

A low- and high-fibre test meal given to ten lean, healthy men demonstrated that a high-fibre meal (25.5 g dietary fibre per portion) consisting of pea fibre bread increased 6-hour postprandial fullness and

SC

decreased the desire to eat compared with a low-fibre meal (9.2 g dietary fibre per portion) including plain

NU

wheat bread (Raben, Christensen, Madsen, Holst, & Astrup, 1994). However, the fibre composition of the pea fibre was mainly soluble β-glucans, which differed from the pea fibre used in our study (composed of

MA

insoluble cellulose), and therefore it may be difficult to draw comparisons. Contrary to these findings, two other studies investigating pea fibre-rich foods with doses of 10 g, 12 g or 22 g dietary fibre per portion

ED

were unable to show a dose-response effect on subjective appetite (Mollard, Luhovyy, Smith, & Anderson, 2014; Smith, Mollard, Luhovyy, & Anderson, 2012).

PT

Dose-response effects of dietary fibre are strongest when comparing doses within the same study design

AC CE

and using the same food matrix to which the fibre is added. The recent systematic review included 44 publications that measured appetite and/or energy intake from a fibre treatment in humans, with a view to recommending fibre types and fibre doses that could be effective in reducing satiety (Clark & Slavin, 2013). The review explored the fact that the consumption of dietary fibre or unavailable carbohydrates in the range of 5.0-7.4 g and 10.0-14.9 g demonstrated some satiating effects, whereas fibre given in the range of 30.0-49.9 g showed only a small effect on appetite. However, fibre type and dose could be interrelated, since the effectiveness of the fibre dose may vary between fibres.

4.3. Food matrix as a determinant for satiating properties? Based on the absence of results for a dose-response effect of rye bran and pea fibre on appetite, we speculate that the satiating effects of dietary fibre may depend on the food matrix and proccessing. We

22

ACCEPTED MANUSCRIPT have previously shown that the addition of 3 g dietary fibre from rye bran to sausages affected appetite (Vuholm et al. 2014a). However, in the present study using meatballs, the effect was absent even at a

T

higher dose of 5.5 g rye bran. The absence of an effect on appetite could be explained by the type of food

RI P

matrix selected which could impair the water-fibre interactions, thus decreasing viscosity in the gut lumen. Amongst other physico-chemical properties, viscosity has been highlighted as an important property of

SC

dietary fibre in order to mediate the physiological response in relation to appetite regulation (Kristensen &

NU

Jensen, 2011; Wanders et al., 2011). Meatballs have a more particulate structure that does not create as dense and strong a meat protein network as in sausages (Tornberg, 2005) and this could have an influence

MA

on the satiety properties. The meat protein network has been shown to be a determinant of the water holding capacity of meat products (Tornberg, 2005). The moisture loss resulting from frying and re-heating

ED

of the investigated meatballs was higher than in sausages (data not shown), and less water would therefore

AC CE

4.4. Practical application

PT

be available for the water-fibre interactions.

Meatballs with pea fibre or rye bran are examples of healthy alternatives to traditional meat products. Although the addition of fibre did not enhance satiety, the nutritional profile was improved in terms of the increased dietary fibre content. Meatballs with dietary fibre could thus become a dietary source of fibre. In Denmark, the average intake of dietary fibre among the adult population is only 22 g per day (National Food Institute, 2015), which does not meet the recommendation of ≥25 g and 35 g per day for women and men, respectively (Nordic Council of Ministers, 2014). Therefore, from a public health point of view, it could be easier for some consumers to achieve the recommended levels by consuming a wider variety of foods containing dietary fibre. The addition of fibre to meat products could also improve the health value of processed meat products. Processed meat, defined as meat that has been preserved by smoking, curing or salting, or by the addition

23

ACCEPTED MANUSCRIPT of preservatives, has been associated with an increased risk of colorectal cancer (Aune et al., 2013). However, a high fibre intake has been shown to reduce the risk associated with red meat and processed

RI P

T

meat (Norat et al., 2005). Lastly, in order to achieve consumption of healthier meat products, the sensory attributes must be well

SC

liked and meet the expectations of consumers. Important sensory attributes of meat products, such as juiciness and firmness, were maintained when rye bran was added to meatballs in doses of 3 g fibre per 100

NU

g compared to doses of 6 g fibre per 100 g. Producing meatballs with a dietary fibre content of 3 g per 100 g could therefore be a promising approach towards improving the nutritional value while maintaining the

MA

quality attributes of the meatballs.

ED

5. Conclusions

To conclude, the addition of rye bran and pea fibre in doses of up to 6 g dietary fibre per 100 g affected the

PT

sensory quality in meatballs. There was a dose-response effect on odour, flavour and textural attributes in doses required for nutritional claims for dietary fibre. However, whether or not these sensory changes

AC CE

affect consumer acceptability is something that needs to be confirmed in consumer studies. The addition of rye bran or pea fibre improved the nutritional composition of meatballs. No effect on satiety was found for rye bran and pea fibre. Future studies should be conducted to investigate whether these results could be ascribed to the choice of food matrix.

Acknowledgement We would like to thank The Danish Agency for Science, Technology and Innovation and the Danish Pig Levy Fund for financial support to carry out the study. Also, Bornholms Valsemølle (Bornholm, Denmark) and DLG Ingredients (Roslev, Denmark) are thanked for kindly providing the rye bran and pea fibre, respectively. We also thank the sensory panel at the sensory laboratory at DMRI and the study participants

24

ACCEPTED MANUSCRIPT in the appetite study for their participation. Furthermore, the staff at the pilot plant and the sensory laboratory at DMRI are kindly thanked for their assistance in the production of meatballs and assistance in

T

the sensory profiling, respectively. Also, we would like to thank Pia Krall Faurschou and Kirsten Jensen at

RI P

the chemical laboratory at DMRI for analyzing the viscosity of the samples. Lastly, Kira H. B. Hamann and Christian Ritz at the Department of Nutrition, Exercise and Sports are kindly thanked for their assistance in

SC

the nutritional calculations of the test meals and statistics, respectively .

AC CE

PT

ED

MA

NU

The authors have no conflict of interests.

25

ACCEPTED MANUSCRIPT References

RI P

T

Arildsen Jakobsen, L. M., Vuholm, S., Aaslyng, M. D., Kristensen, M., Sørensen, K. V., Raben, A., & Kehlet, U. (2014). Sensory characteristics and consumer liking of sausages with 10% fat and added rye or wheat bran. Food Science & Nutrition, 2(5), 534–46. http://doi.org/10.1002/fsn3.126

SC

Aune, D., Chan, D. S. M., Vieira, A. R., Navarro Rosenblatt, D. A., Vieira, R., Greenwood, D. C., … Norat, T. (2013). Red and processed meat intake and risk of colorectal adenomas: a systematic review and meta-analysis of epidemiological studies. Cancer Causes & Control;: CCC, 24(4), 611–27. http://doi.org/10.1007/s10552-012-0139-z

NU

Blundell, J., de Graaf, C., Hulshof, T., Jebb, S., Livingstone, B., Lluch, A., … Westerterp, M. (2010). Appetite control: methodological aspects of the evaluation of foods. Obesity Reviews;: An Official Journal of the International Association for the Study of Obesity, 11(3), 251–70. http://doi.org/10.1111/j.1467789X.2010.00714.x

MA

Bosse, J. D., & Dixon, B. M. (2012). Dietary protein in weight management: a review proposing protein spread and change theories. Nutrition & Metabolism, 9(1), 81. http://doi.org/10.1186/1743-7075-981

ED

Clark, M. J., & Slavin, J. L. (2013). The effect of fiber on satiety and food intake: a systematic review. Journal of the American College of Nutrition, 32(3), 200–11. http://doi.org/10.1080/07315724.2013.791194

AC CE

PT

Flint, A., Raben, A., Blundell, J. E., & Astrup, A. (2000). Reproducibility, power and validity of visual analogue scales in assessment of appetite sensations in single test meal studies. International Journal of Obesity and Related Metabolic Disorders;: Journal of the International Association for the Study of Obesity, 24(1), 38–48. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10702749 Glitsø, L. V., & Bach Knudsen, K. E. (1999). Milling of Whole Grain Rye to Obtain Fractions with Different Dietary Fibre Characteristics. Journal of Cereal Science, 29(1), 89–97. http://doi.org/10.1006/jcrs.1998.0214 Howarth, N. C., Saltzman, E., & Roberts, S. B. (2001). Dietary fiber and weight regulation. Nutrition Reviews, 59(5), 129–39. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11396693 Huang, S. C., Shiau, C. Y., Liu, T. E., Chu, C. L., & Hwang, D. F. (2005). Effects of rice bran on sensory and physico-chemical properties of emulsified pork meatballs. Meat Science, 70(4), 613–9. http://doi.org/10.1016/j.meatsci.2005.02.009 Isaksson, H., Fredriksson, H., Andersson, R., Olsson, J., & Aman, P. (2009). Effect of rye bread breakfasts on subjective hunger and satiety: a randomized controlled trial. Nutrition Journal, 8, 39. http://doi.org/10.1186/1475-2891-8-39 Kristensen, M., & Jensen, M. G. (2011). Dietary fibres in the regulation of appetite and food intake. Importance of viscosity. Appetite, 56(1), 65–70. http://doi.org/10.1016/j.appet.2010.11.147

26

ACCEPTED MANUSCRIPT Kuznetsova, A., Brockhoff, P.B., Christensen, R.H.B. (2016). SensMIxed: Aanlaysis of Sensory and Consumer Data in a Mixed Model Framework. R package version 2.0-9. https://CRAN.Rproject.org/package=SensMixed

RI P

T

Leidy, H. J., Clifton, P. M., Astrup, A., Wycherley, T. P., Westerterp-Plantenga, M. S., Luscombe-Marsh, N. D., … Mattes, R. D. (2015). The role of protein in weight loss and maintenance. American Journal of Clinical Nutrition. http://doi.org/10.3945/ajcn.114.084038

SC

McConnell, A. A., Eastwood, M. A., & Mitchell, W. D. (1974). Physical characteristics of vegetable foodstuffs that could influence bowel function. Journal of the Science of Food and Agriculture, 25(12), 1457–64. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/4437150

NU

Mehta, N., Ahlawat, S. S., Sharma, D. P., & Dabur, R. S. (2015). Novel trends in development of dietary fiber rich meat products-a critical review. Journal of Food Science and Technology, 52(2), 633–47. http://doi.org/10.1007/s13197-013-1010-2

MA

Mollard, R. C., Luhovyy, B. L., Smith, C., & Anderson, G. H. (2014). Acute effects of pea protein and hull fibre alone and combined on blood glucose, appetite, and food intake in healthy young men - a randomized crossover trial. Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition et Métabolisme, 39(12), 1360–5. http://doi.org/10.1139/apnm-2014-0170

ED

National Food Institute (2015). Dietary habits in Denmark 2011-2013. Main results. DTU Food, 1.edition.

AC CE

PT

Nilsson, M., Åman, P., Härkönen, H., Hallmans, G., Knudsen, K. E. B., Mazur, W., & Adlercreutz, H. (1997). Content of Nutrients and Lignans in Roller Milled Fractions of Rye. Journal of the Science of Food and Agriculture, 73(2), 143–148. http://doi.org/10.1002/(SICI)1097-0010(199702)73:2<143::AIDJSFA698>3.0.CO;2-H Norat, T., Bingham, S., Ferrari, P., Slimani, N., Jenab, M., Mazuir, M., … Riboli, E. (2005). Meat, fish, and colorectal cancer risk: The European prospective investigation into cancer and nutrition. Journal of the National Cancer Institute, 97(12), 906–916. http://doi.org/10.1093/jnci/dji164 Nordic Council of Ministers (2014). Nordic Nutrition Recommendations 2012. Integrating nutrition and physical activity. Nord 2014:002. Nordlund, E., Heiniö, R.-L., Viljanen, K., Pihlava, J.-M., Lehtinen, P., & Poutanen, K. (2013). Flavour and stability of rye grain fractions in relation to their chemical composition. Food Research International, 54(1), 48–56. http://doi.org/10.1016/j.foodres.2013.05.034 Petersson, K., Eliasson, A.-C., Tornberg, E., & Bergenståhl, B. (2013). Sensory Perception of Rye Bran Particles of Varying Size and Concentration in a Viscous Phase. Journal of Texture Studies, 44(6), 459– 467. http://doi.org/10.1111/jtxs.12034 Petersson, K., Godard, O., Eliasson, A.-C., & Tornberg, E. (2014a). The effects of cereal additives in low-fat sausages and meatballs. Part 1: Untreated and enzyme-treated rye bran. Meat Science, 96(1), 423– 428. http://doi.org/10.1016/j.meatsci.2013.08.020

27

ACCEPTED MANUSCRIPT Petersson, K., Godard, O., Eliasson, A.-C., & Tornberg, E. (2014b). The effects of cereal additives in low-fat sausages and meatballs. Part 2: Rye bran, oat bran and barley fibre. Meat Science, 96(1), 503–508. http://doi.org/10.1016/j.meatsci.2013.08.019

RI P

T

Raben, A., Christensen, N. J., Madsen, J., Holst, J. J., & Astrup, A. (1994). Decreased postprandial thermogenesis and fat oxidation but increased fullness after a high-fiber meal compared with a lowfiber meal. The American Journal of Clinical Nutrition, 59(6), 1386–94. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/8198065

SC

Resurreccion, A. V. A. (2004). Sensory aspects of consumer choices for meat and meat products. Meat Science, 66(1), 11–20. http://doi.org/10.1016/S0309-1740(03)00021-4

NU

Slavin, J., & Green, H. (2007). Dietary fibre and satiety. Nutrition Bulletin, 32(SUPPL.1), 32–42. http://doi.org/10.1111/j.1467-3010.2007.00603.x

MA

Smith, C. E., Mollard, R. C., Luhovyy, B. L., & Anderson, G. H. (2012). The effect of yellow pea protein and fibre on short-term food intake, subjective appetite and glycaemic response in healthy young men. The British Journal of Nutrition, 108 Suppl , S74–80. http://doi.org/10.1017/S0007114512000700

ED

Sun, Q., Wu, M., Bu, X., & Xiong, L. (2015). Effect of the Amount and Particle Size of Wheat Fiber on the Physicochemical Properties and Gel Morphology of Starches. PloS One, 10(6), e0128665. http://doi.org/10.1371/journal.pone.0128665

PT

Talukder, S. (2015). Effect of dietary fiber on properties and acceptance of meat products: a review. Critical Reviews in Food Science and Nutrition, 55(7), 1005–11. http://doi.org/10.1080/10408398.2012.682230

AC CE

Tornberg, E. (2005). Effects of heat on meat proteins - Implications on structure and quality of meat products. Meat Science, 70(3), 493–508. http://doi.org/10.1016/j.meatsci.2004.11.021 Turnbull, C. M., Baxter, A. L., & Johnson, S. K. (2005). Water-binding capacity and viscosity of Australian sweet lupin kernel fibre under in vitro conditions simulating the human upper gastrointestinal tract. International Journal of Food Sciences and Nutrition, 56(2), 87–94. http://doi.org/10.1080/09637480500081080 Verma, A. K., & Banerjee, R. (2010). Dietary fibre as functional ingredient in meat products: a novel approach for healthy living - a review. Journal of Food Science and Technology, 47(3), 247–57. http://doi.org/10.1007/s13197-010-0039-8 Vuholm, S., Arildsen Jakobsen, L. M., Vejrum Sørensen, K., Kehlet, U., Raben, A., & Kristensen, M. (2014). Appetite and food intake after consumption of sausages with 10% fat and added wheat or rye bran. Appetite, 73, 205–211. Vuholm, S., Lorenzen, J. K., & Kristensen, M. (2014). Relative validity and reproducibility of a food frequency questionnaire to assess dietary fiber intake in Danish adults. Food & Nutrition Research, 58, 24723. Retrieved from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=4258638&tool=pmcentrez&rendertype= abstract

28

ACCEPTED MANUSCRIPT

T

Wanders, A. J., van den Borne, J. J. G. C., de Graaf, C., Hulshof, T., Jonathan, M. C., Kristensen, M., … Feskens, E. J. M. (2011). Effects of dietary fibre on subjective appetite, energy intake and body weight: a systematic review of randomized controlled trials. Obesity Reviews, 12(9), no–no. http://doi.org/10.1111/j.1467-789X.2011.00895.x

RI P

Westerterp-Plantenga, M. S., Nieuwenhuizen, A., Tomé, D., Soenen, S., & Westerterp, K. R. (2009). Dietary protein, weight loss, and weight maintenance. Annual Review of Nutrition, 29, 21–41. http://doi.org/10.1146/annurev-nutr-080508-141056

SC

Yilmaz, I. 2004. Effects of rye bran addition on fatty acid composition and quality characteristics of low-fat meatballs. Meat Science, 67, pp.245-249.

AC CE

PT

ED

MA

NU

Yilmaz, I. 2005. Physicochemical and sensory characteristics of low fat meatballs with added wheat bran. Journal of Food Engineering, 69, pp.369-373.

29

ACCEPTED MANUSCRIPT

AC CE

PT

ED

MA

NU

SC

RI P

T

Graphical abstract

30

ACCEPTED MANUSCRIPT Legends to figures

T

Fig. 1.

RI P

Principal Component Analysis (PCA) loading plot of sensory profiling data for rye bran (A) and pea fibre (B) meatballs using a trained sensory panel (n=9). The PCA plot presents the meatballs with doses of 3.0, 3.5,

SC

4.0, 4.5, 5.0, 5.5 and 6.0 g dietary fibre per 100 g. Letters in parentheses indicate the category of the

MA

NU

sensory attribute: appearance (A), odour (O), texture (TX), taste (T) and flavour (F).

Fig. 2.

Fig. 3.

AC CE

PT

ED

Unadjusted ratings of subjective appetite sensations presented as changes from baseline.

Ratings of liking (means ± SEM) of the test meals consisting of meatballs with 3.0 g pea fibre (PEA3), 5.5 g pea fibre (PEA5.5), 3.0 g rye bran (RYE3), 5.5 g rye bran (RYE5.5) and no fibre added (Control). There was an overall meal effect (p < 0.05) and PEA 5.5 differed significantly from the other meals, p ≤ 0.01 (ANOVA, followed by Tukey’s test).

31

AC CE

PT

ED

MA

NU

SC

RI P

T

ACCEPTED MANUSCRIPT

32

AC CE

PT

ED

MA

NU

SC

RI P

T

ACCEPTED MANUSCRIPT

33

AC CE

PT

ED

MA

NU

SC

RI P

T

ACCEPTED MANUSCRIPT

34

ACCEPTED MANUSCRIPT Table 1. Ingredients of the meatballs with rye bran and pea fibre and their subsequent heating loss from frying and reheating. All of the meatballs were included in the sensory analysis, whereas meatballs marked with * were included in the appetite study.

A a

PT

AC CE

ab

T

RI P

SC

a

ab

ab

6.0 54.0 5.0 1.9 0 1.0 0.2 25.3 11.0 1.0 0.6

22.3 0.2

21.5 0.3

23.4 1.0

b

20.7 0.5

21.1 0.2

21.0 0.3

21.1 0.4

0* 62.4 10.0 5.0 0.97 5.2 1.0 0.2 13.6 0 1.0 0.6

3.0* 62.4 10.0 5.0 0.97 3.1 1.0 0.2 13.6 2.1 1.0 0.6

3.5 62.4 10.0 5.0 0.97 2.6 1.0 0.2 13.6 2.6 1.0 0.6

4.0 62.4 10.0 5.0 0.97 2.1 1.0 0.2 13.6 3.1 1.0 0.6

4.5 62.4 10.0 5.0 0.97 1.6 1.0 0.2 13.6 3.6 1.0 0.6

5.0 62.4 10.0 5.0 0.97 1.1 1.0 0.2 13.6 4.1 1.0 0.6

5.5* 62.4 10.0 5.0 0.97 0.6 1.0 0.2 13.6 4.6 1.0 0.6

6.0 62.4 10.0 5.0 0.97 0 1.0 0.2 13.6 5.2 1.0 0.6

A

ab

5.5* 54.0 5.0 1.9 1.1 1.0 0.2 25.3 9.9 1.0 0.6

20.6 0.4

ED

PEA FIBRE Boneless pork shoulder (ESS Food no. 1313) Onion Eggs Skimmed milk powder Wheat flour Salt Pepper Water Pea fibre Butter (for pan-frying) Rape-seed oil (for pan-frying)

Dietary fibre content g/100 g 3.5 4.0 4.5 5.0 54.0 54.0 54.0 54.0 5.0 5.0 5.0 5.0 1.9 1.9 1.9 1.9 5.5 4.5 3.4 2.1 1.0 1.0 1.0 1.0 0.2 0.2 0.2 0.2 25.3 25.3 25.3 25.3 5.5 6.5 7.6 8.9 1.0 1.0 1.0 1.0 0.6 0.6 0.6 0.6

3.0* 54.0 5.0 1.9 6.5 1.0 0.2 25.3 4.5 1.0 0.6

MA

Heating loss (%) Mean SD

0 54.0 5.0 1.9 11.0 1.0 0.2 25.3 0 1.0 0.6

NU

Ingredients (%) RYE BRAN Boneless pork shoulder (ESS Food no. 1313) Onion Eggs Wheat flour Salt Pepper Water Rye bran Butter (for pan-frying) Rape-seed oil (for pan-frying)

a

Heating loss (%) a ab ab b bc c c c Mean 27.4 27.2 27.7 29.6 29.8 31.5 31.4 31.5 SD 0.3 0.5 0.3 1.2 0.7 0.7 0.2 1.3 Different letters in the same row indicate significant difference (P < 0.05) A Includes the combined loss from frying on a tilting frying pan at 180°C until a core temperature of 75°C was reached and from reheating in a microwave oven at 700 watt for 3 min. and 10 sec. (n=4).

35

ACCEPTED MANUSCRIPT Table 2. Nutritional composition of the five test meals in the appetite study. CONTROL meal Meatballs (185 g) Wheat bun (70 g) Butter (16 g) Cucumber (100 g) 371 g 2585 46.8 22.5 30.7

RYE 3.0 meal Meatballs (175 g) Wheat bun (70 g) Butter (16 g) Cucumber (100 g) 361 g 2564 43.2 21.7 35.1

RYE 5.5 meal Meatballs (185 g) Wheat bun (70 g) Butter (16 g) Cucumber (100 g) 371 g 2528 45.1 21.8 33.1

PEA 3.0 meal Meatballs (165 g) Wheat bun (70 g) Butter (16 g) Cucumber (100 g) 351 g 2491 45.6 23.5 30.9

T

Meal composition

PEA 5.5 meal Meatballs (175 g) Wheat bun (70 g) Butter (16 g) Cucumber (100 g) 371 g 2522 46.5 23.2 30.3

AC CE

PT

ED

MA

NU

SC

RI P

Meal weight Energy (kJ) Fat (E%) Protein (E%) Carbohydrates (E%) Dietary fibre (g) 4.0 7.4 13.2 7.0 12.6 CONTROL: meatballs without any dietary fibre added; RYE 3.0: meatballs with 3.0 g dietary fibre/100 g; RYE 5.5: meatballs with 5.5 g dietary fibre/100 g; PEA 3.0: meatballs with 3.0 g dietary fibre/100 g; PEA 5.5: meatballs with 5.5 g dietary fibre/100 g.

36

ACCEPTED MANUSCRIPT Table 3. Linear relationship between fibre dose and the intensity of the sensory attributes related to odour (O), appearance (A), flavour (F), taste (T) and texture (TX). The regression coefficients are given as estimates and confidence interval.

Meatball (F) Meat (F) Spicy (F) Sour (T) Grainy, flour (F)

-

<0.001

-

0.06 [-0.099 – 0.23] 0.01 [-0.14 – 0.16] 0.68 [0.45 – 0.91]

<0.001

-

-

-

0.42

7.92 [7.27 – 8.57]

-0.79 [-0.94 - -0.64]

<0.001

<0.001

-

-

-

4.34 [3.23 – 5.45] 3.14 [2.10 – 4.17]

0.75 [0.50 – 1.01] 0.72 [0.48 – 0.96]

-

-

-

Sweet (T)

-

-

-

-

0.26 [0.10 – 0.42] -0.49 [-0.68 - -0.30] -0.07 [-0.26 – 0.11] 1.73 [1.52 – 1.93]

-

-

-

-

-

-

PT

4.08 [3.38 – 4.77] 7.27 [6.45 – 8.08] 4.49 [3.70 – 5.28] 1.93 [1.04 – 2.81]

AC CE

Gritty (TX)

ED

Bitter (T)

Crumbly (TX)

-

3.54 [2.83 – 4.24] 3.21 [2.56 – 3.86] 3.90 [2.90 – 4.91]

0.35

<0.001

Grainy (TX)

-

-

0.032

1.67 [1.45 – 1.89]

Juiciness (TX)

-

-

0.0028

2.33 [1.38 – 3.28]

Sticky (TX)

-

-0.32 [-0.47 - -0.17] -0.31 [-0.47 - -0.15] -0.03 [-0.20 – 0.14] -0.14 [-0.28 – 0.00] 0.33 [0.08 – 0.57]

-

Firmness (TX)

0.006

6.98 [6.34 – 7.63] 4.44 [3.76 – 5.13] 6.52 [5.79 – 7.25] 4.84 [4.22 – 5.45] 3.64 [2.59 – 4.69]

<0.001

-

Grainy (F)

p-value

T

<0.001

RI P

Pigment, interior (A)

<0.001

SC

Grainy/bread (O)

p-value

PEA MEATBALLS α β (intercept) (slope) 6.33 -0.24 [5.58 – 7.07] [-0.41 - -0.07]

NU

Meatball (O)

RYE MEATBALLS α β (intercept) (slope) 5.34 -0.46 [4.70 - 6.00] [-0.61 - -0.31] 2.08 1.48 [1.01 – 3.15] [1.23 – 1.73] 2.58 1.73 [1.62 – 3.53] [1.51 – 1.96] 5.80 -0.37 [5.09 – 6.51] [-0.54 - -0.21] 3.30 -0.26 [2.56 – 4.04] [-0.44 - -0.09] 6.58 -0.20 [5.78 – 7.38] [-0.39 - -0.02] 4.04 -0.07 [3.42 – 4.66 ] [-0.21 – 0.08]

MA

y (sensory attribute)

0.0018

37

<0.001 <0.001 0.74 0.049 0.0089 0.44 0.89 <0.001

<0.001 <0.001

ACCEPTED MANUSCRIPT Table 4. Mean intensity ratings of the sensory attributes in fibre meatballs.

4.3 b 7.0 b 8.6 a 5.1

Meat (F) Spice (F) Sour (F)

3.2 a 6.4 4.0

a

2.5 a 6.2 3.7

b

2.1 c 11.1 c 12.4 b 3.4

b

c

1.7 b 5.0 3.7

a

<0.001 <0.001 <0.001 <0.001

6.2 -

0.001 0.006 0.67

4.4 6.6

7.1

a a

4.8

ab a

8.3 a 4.8 a 6.4 4.1 b 7.7 -

11.7 b 6.0 b 4.5 3.4 c 11.8 -

<0.001 0.007 <0.001 0.16 <0.001 -

Gritty (TX)

-

-

-

-

c

ED

b

b

6.1

b

3.7 6.8

a

5.0

a

4.1 3.6 3.3

NU

1.4 a 4.3 a 7.2 4.3 a 1.1 -

a

3.8 3.5 3.2 4.1 -

a

MA

Grainy/flour (F) Grainy (F) Bitter (T) Sweet (T) Firmness (TX) Sticky (TX) Juiciness (TX) Grainy (TX) Crumbly (TX)

a

6.6 -

7.5 4.3 2.9

a

a a

b

4.6 -

b

5.4 -

b

6.6 -

b

6.3

b

5.2

c

5.1

c

2.5 6.5

b

4.3

b

6.1 3.9 3.3

c

8.3 -

c

3.0 -

c

8.7

PT

AC CE

c

7.1

O=odour, A=appearance, F=flavour, T=taste, TX=texture. Different letters in the same row indicate significant difference (P < 0.05).

38

T

a

5.0 a 1.6 a 1.8 a 5.5

0.001 <0.001

RI P

a

Meatball (O) Grain/bread (O) Pigment interior (A) Meatball (F)

PEA MEATBALLS Fibre dose (g/100 g) p-value 0 3 6

SC

RYE MEATBALLS Fibre dose (g/100 g) p-value 0 3 6

<0.001 0.16 <0.001 <0.001 0.50 0.92 <0.001 <0.001 <0.001 <0.001

ACCEPTED MANUSCRIPT Table 5. Physico-chemical properties of the fibre ingredients (rye bran and pea fibre) and the five test meals included in the appetite study. Data on the water-holding capacity and viscosity are presented as means ± SD (n=3). CONTROL meal

RYE 3.0 meal

RYE 5.5 meal

11.1 25.7 39.3 21.5 2.4 3.78 ± 0.03* 1.49 ± 0.01

0 0.5 7.3 14.2 78 4.51 ± 0.09 1.53 ± 0.03

A 2.84 ± 0.06 1.41 ± 0.00

B 3.51 ± 0.11 1.42 ± 0.01

B 3.49 ± 0.20 1.42 ± 0.01

PEA 3.0 meal

RI P

T

Pea fibre

SC

Particle size (%) ≥ 650 μm 500 μm 250 μm 160 μm ≤ 75 μm A Water-holding capacity B Viscosity

Rye bran

B 4.05 ± 0.43 1.41 ± 0.02

PEA 5.5 meal B 3.48 ± 0.13 1.40 ± 0.01

For the test meals, different letters in the same row indicate significant difference (P < 0.05). For the two fibre ingredients, a * indicates significant difference (P < 0.05).

ED

MA

NU

gram water per gram dry matter mPa*sec. At a shear rate 122/sec at 37°C.

PT

B

AC CE

A

39