The effects of a simulated in vitro digestion model on the viscosity of solutions of locust bean gum, guar gum, fenugreek gum, xanthan gum, gum Arabic, psyllium, flaxseed gum and soy soluble polysaccharides (SSPS) were examined in this study. All hydrocolloid solutions were formulated for low viscosity (LV), medium viscosity (MV) and high viscosity (HV), which were subsequently subjected to 3 treatments of equal volumes each. The treatments consisted of 1) H2O-dilutions, 2) acid and alkali in the absence of enzymes/bile and 3) an in vitro digestion model simulating the gastric and duodenal phases with pH changes in the presence of hydrolytic enzymes and bile salts. All hydrocolloids showed substantial reductions in viscosity, with dilutions exerting the greatest effect. Depending on the concentration, xanthan gum retained 20-50% of its initial viscosity while the other solutions were in a lower range of 1-16%, thereby showing considerable resilience to the 3 simulated conditions. / NSERC

Six field pea (Pisum sativum) varieties from five different growing locations in Saskatchewan in the 2006 and 2007 growing years were analyzed to determine the effect of genotype, environment and year on the total dietary fibre, insoluble dietary fibre, soluble dietary fibre, total phenolic content, simple phenolic content and antioxidant activities. Samples were analyzed for dietary fibre using the enzymatic-gravimetric method of fibre analysis in accordance to the AACC method 32-05. Growing location had a very significant effect (p<0.0001) on the IDF, SDF and TDF content. Genotype had a strong effect (p<0.0001) on both IDF and TDF while having no significant effect (p=0.4556) on SDF content. Crop year also displayed a significant effect on SDF and TDF (p<0.0001) while having a smaller effect on IDF content (p=0.0139). Green varieties yielded significantly higher IDF (p=0.0041) and TDF (p=0.0028) than yellow varieties. Significant genotype x location (0.0155) and location x year (p=0.0002) interaction terms were also observed for TDF. The total phenolic contents were assessed using the Folin-Ciocalteu method of total phenolic content (TPC) analysis, while the contents of 10 individual simple phenolic acids were assessed using reversed-phase UPLC. A significant genotype, environment, and genotype by environment (G x E) interaction effect on the TPC was observed. The seed coat colour and growing season did not show a significant effect on the TPC. The UPLC analysis showed that ferulic acid comprised the majority of the phenolic content of the field pea samples. There was also a genotype, seed coat colour, location, growing season and G x E effect on the total simple phenolic acid content. As well, a modified microplate method for antioxidant activity using the free radical DPPH was assessed against the conventional cuvette method based system. Both methods showed that genotype (p<0.05) and location (p<0.05) had a significant effect on antioxidant activity. A larger, significant effect was seen in the genotype by environment (G x E) interaction (p<0.0001) in the 2007 and 2008 growing years. Growing year did not have a significant on antioxidant activity. Although there was some variation in the resulting AOA values between the two methods, these differences were found not to be statistically significant by means of a folded F-Test (p < 0.05), and the AOA between the two methods was highly correlated (R² = 0.8866). This indicates that a microplate may be used in place of cuvettes to determine AOA using the DPPH free radical to increase testing speed while reducing the amount of sample and reagent used in testing. The research performed on the influence of genotype and environment could potentially allow plant breeders, food scientists and nutraceutical manufacturers to manipulate field pea genotypes and growing conditions to attain an ideal nutritional profile for use in functional foods and nutraceuticals.

Six field pea (Pisum sativum) varieties from five different growing locations in Saskatchewan in the 2006 and 2007 growing years were analyzed to determine the effect of genotype, environment and year on the total dietary fibre, insoluble dietary fibre, soluble dietary fibre, total phenolic content, simple phenolic content and antioxidant activities. Samples were analyzed for dietary fibre using the enzymatic-gravimetric method of fibre analysis in accordance to the AACC method 32-05. Growing location had a very significant effect (p<0.0001) on the IDF, SDF and TDF content. Genotype had a strong effect (p<0.0001) on both IDF and TDF while having no significant effect (p=0.4556) on SDF content. Crop year also displayed a significant effect on SDF and TDF (p<0.0001) while having a smaller effect on IDF content (p=0.0139). Green varieties yielded significantly higher IDF (p=0.0041) and TDF (p=0.0028) than yellow varieties. Significant genotype x location (0.0155) and location x year (p=0.0002) interaction terms were also observed for TDF. The total phenolic contents were assessed using the Folin-Ciocalteu method of total phenolic content (TPC) analysis, while the contents of 10 individual simple phenolic acids were assessed using reversed-phase UPLC. A significant genotype, environment, and genotype by environment (G x E) interaction effect on the TPC was observed. The seed coat colour and growing season did not show a significant effect on the TPC. The UPLC analysis showed that ferulic acid comprised the majority of the phenolic content of the field pea samples. There was also a genotype, seed coat colour, location, growing season and G x E effect on the total simple phenolic acid content. As well, a modified microplate method for antioxidant activity using the free radical DPPH was assessed against the conventional cuvette method based system. Both methods showed that genotype (p<0.05) and location (p<0.05) had a significant effect on antioxidant activity. A larger, significant effect was seen in the genotype by environment (G x E) interaction (p<0.0001) in the 2007 and 2008 growing years. Growing year did not have a significant on antioxidant activity. Although there was some variation in the resulting AOA values between the two methods, these differences were found not to be statistically significant by means of a folded F-Test (p < 0.05), and the AOA between the two methods was highly correlated (R² = 0.8866). This indicates that a microplate may be used in place of cuvettes to determine AOA using the DPPH free radical to increase testing speed while reducing the amount of sample and reagent used in testing. The research performed on the influence of genotype and environment could potentially allow plant breeders, food scientists and nutraceutical manufacturers to manipulate field pea genotypes and growing conditions to attain an ideal nutritional profile for use in functional foods and nutraceuticals.

The extraction yields of insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) from seven whole-grain cereals (WG) ranged from 11.73% to 23.71% and 2.28% to 5.15%, respectively. Eight monomeric phenolic acids and four diferulic acids were identified and quantified in cereal alkaline extracts by reversed phase high performance liquid chromatography coupled with quadrupole - time of flight mass spectrometry. IDF alkaline extracts had significantly (p < 0.05) higher levels of total phenolic content (TPC) and DPPH radical scavenging activity than WG and SDF extracts. Corn IDF (C-IDF) extracts exhibited the highest TPC and DPPH, followed by red rice. MTT cell viability assay indicated that 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or xanthine-xanthine oxidase (X-XO) induced cell loss can be effectively reduced by pre-incubating Caco-2BBe or FHs 74 Int cells with certain levels of C-IDF extracts. This effect was speculated to be associated with the antioxidant activity of C-IDF linked phenolic compounds.

The extraction yields of insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) from seven whole-grain cereals (WG) ranged from 11.73% to 23.71% and 2.28% to 5.15%, respectively. Eight monomeric phenolic acids and four diferulic acids were identified and quantified in cereal alkaline extracts by reversed phase high performance liquid chromatography coupled with quadrupole - time of flight mass spectrometry. IDF alkaline extracts had significantly (p < 0.05) higher levels of total phenolic content (TPC) and DPPH radical scavenging activity than WG and SDF extracts. Corn IDF (C-IDF) extracts exhibited the highest TPC and DPPH, followed by red rice. MTT cell viability assay indicated that 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or xanthine-xanthine oxidase (X-XO) induced cell loss can be effectively reduced by pre-incubating Caco-2BBe or FHs 74 Int cells with certain levels of C-IDF extracts. This effect was speculated to be associated with the antioxidant activity of C-IDF linked phenolic compounds.

Constipation is a serious problem in the pediatric population and often requires medical management with laxatives and enemas. Participants (2-10 years of age, n=13) with a history of mild constipation were assigned randomly to a fibre treatment or placebo group. After three weeks, subjects were crossed over to the other treatment. Pea hull fibre (4.0-7.6 g/day = 3.6-6.8 g/day of dietary fibre) was added to snack foods and an inulin supplement (5.0 g/day = 4.5 g/day of dietary fibre) was given, whereas the placebos were non-fortified snacks and maltodextrin (5.0 g/day).<p> Subjects or their parents documented stool frequency, stool consistency, occurrence of abdominal pain and intake of snack foods and the supplement. Over the final two weeks, there was a trend towards an increase in the mean number of daily bowel movements in the fibre treatment group compared to the placebo group (n=11, 0.68 ± 0.18 vs. 0.59 ± 0.26, p=0.064). Exclusion of one subject with diarrhea-type stools led to a significant difference between groups (n=10, 0.54 ± 0.18 vs. 0.67 ± 0.22, p=0.002). Stool consistency, using the Bristol Stool Form Rating Scale, showed no significant differences in stool consistency between groups (p=0.379) nor was there a difference in the incidences of abdominal pain (p=0.129). Not all subjects experienced abdominal pain. The inulin supplement (91% compliance rate; 1 serving per day) was consumed more consistently than were the snack foods fortified with pea hull fibre (77% compliance rate; 2 servings per day). There were no significant differences in the intake of the snacks or supplement when the placebo and treatment groups were compared. Energy intake was significantly lower during the fibre treatment period compared to placebo (n=12, 1307 ± 296 kcal/day vs. 1441 ± 285 kcal/day, p=0.035). The addition of pea hull fibre to typical snack foods and an inulin supplement to beverages were well accepted by children and no adverse effects were reported. Fibre fortification of snack foods with pea hull fibre and fibre supplementation of beverages with inulin may provide an alternative means to treat pediatric constipation.

Constipation is a serious problem in the pediatric population and often requires medical management with laxatives and enemas. Participants (2-10 years of age, n=13) with a history of mild constipation were assigned randomly to a fibre treatment or placebo group. After three weeks, subjects were crossed over to the other treatment. Pea hull fibre (4.0-7.6 g/day = 3.6-6.8 g/day of dietary fibre) was added to snack foods and an inulin supplement (5.0 g/day = 4.5 g/day of dietary fibre) was given, whereas the placebos were non-fortified snacks and maltodextrin (5.0 g/day).<p> Subjects or their parents documented stool frequency, stool consistency, occurrence of abdominal pain and intake of snack foods and the supplement. Over the final two weeks, there was a trend towards an increase in the mean number of daily bowel movements in the fibre treatment group compared to the placebo group (n=11, 0.68 ± 0.18 vs. 0.59 ± 0.26, p=0.064). Exclusion of one subject with diarrhea-type stools led to a significant difference between groups (n=10, 0.54 ± 0.18 vs. 0.67 ± 0.22, p=0.002). Stool consistency, using the Bristol Stool Form Rating Scale, showed no significant differences in stool consistency between groups (p=0.379) nor was there a difference in the incidences of abdominal pain (p=0.129). Not all subjects experienced abdominal pain. The inulin supplement (91% compliance rate; 1 serving per day) was consumed more consistently than were the snack foods fortified with pea hull fibre (77% compliance rate; 2 servings per day). There were no significant differences in the intake of the snacks or supplement when the placebo and treatment groups were compared. Energy intake was significantly lower during the fibre treatment period compared to placebo (n=12, 1307 ± 296 kcal/day vs. 1441 ± 285 kcal/day, p=0.035). The addition of pea hull fibre to typical snack foods and an inulin supplement to beverages were well accepted by children and no adverse effects were reported. Fibre fortification of snack foods with pea hull fibre and fibre supplementation of beverages with inulin may provide an alternative means to treat pediatric constipation.

Functional foods constitute a growing focus for research, product development and consumer interest in recent years. This study investigated the factors that affect willingness to pay for high fibre food on the market as well as respondents’ attitude towards the purchase of these products. The results indicated that those consumers in the high income group were more health conscious than their low income counterparts and willing to pay for high fibre products. The results showed that health risk perceptions as well as regulatory programmes affected consumers’ willingness to pay. The results also showed that at low percentage prices consumers were willing to pay for high fibre products. Gender and marital status did not seem to have an influence on willingness to buy for any of the selected products. Findings of the study could encourage food manufacturers to carry on with developments of functional foods since willingness to pay increased with increase in income. / Agriculture, Animal Health and Human Ecology

By-products of fruit, cereal and vegetable processing are often regarded as waste while they contain significant amounts of dietary fibre and phytochemicals that can positively contribute to the human diet when reused as food ingredient. The application of fibre from by-products in baked goods could increase the sustainability of the processing chain but is usually associated with changes in product characteristics, such as lower volume, denser structure and increased hardness. In the current study, the interactions of fibres from by-products and wheat macromolecules were analysed in muffins, starch slurries and wheat doughs. The three selected fibres differed significantly in their chemical composition and technofunctional properties. In muffins wheat flour replacement by apple fibre was assessed by rheological measurements of batter and determination of product characteristics. Water proportion adaption based on batter viscosity to create isoviscosity was evaluated as a promising method to develop muffins with satisfying characteristics, where a wheat flour replacement of 30 % is suggested. The addition of apple fibre influenced starch gelatinisation in muffins during baking as indicated by the results of pasting experiments and in vitro starch digestion. Starch slurries with apple and wheat fibre were analysed in pasting experiments. Soluble dietary fibre, mainly pectin, strongly influenced the pasting profile of wheat starch, in comparison to insoluble dietary fibre, that acted as an inert filler and did not interact with the starch. Wheat doughs with fibre from by-products were analysed for rheology, texture and microstructure. The gluten development was negatively influenced by the fibres, which resulted in less extensible doughs. Soluble dietary fibre resulted in increased dough stickiness and limited dough handling at high application levels. It can be reasoned that dough with 10% fibre from by-products would produce products with satisfying characteristics, whereas higher application levels cannot be recommended without using additives to increase the gluten strength. Fibres from by-products are suitable wheat flour replacers in bakery products, where the negative effects of the high water binding capacity of the fibre, can be partly balanced by water proportion adaption, especially in products were gluten development is not that dominating for product structure, like in muffins or cakes. / Nebenprodukte der Obst-, Getreide- und Gemüseverarbeitung werden oft als Abfall betrachtet, wobei sie signifikante Gehalte an Ballaststoffen und sekundären Pflanzeninhaltsstoffen aufweisen, und bei der Verwendung als Lebensmittelzutat positiv zur menschlichen Ernährung beitragen können. Die Anwendung von Fasern aus Nebenprodukten in Backwaren könnte die Nachhaltigkeit der Verarbeitungskette erhöhen, ist jedoch mit Änderungen der Produkteigenschaften verbunden, wie verringertes Volumen, dichtere Struktur und erhöhte Härte. In der vorliegenden Studie wurden die Wechselwirkungen von Fasern und Weizenmakromolekülen in Muffins, Stärkesuspensionen und Weizenteigen analysiert, wobei sich die drei ausgewählten Fasern in ihrer chemischen Zusammensetzung und ihren technofunktionellen Eigenschaften unterschieden. In Muffins wurde die Mehlsubstitution durch Apfelfaser anhand von Teigrheologie und Produkteigenschaften analysiert. Die Anpassung des Wassergehaltes basierend auf der Teigviskosität wurde als vielversprechende Methode zur Entwicklung von Muffins mit akzeptablen Eigenschaften bewertet, wodurch ein Mehlersatz von 30% möglich war. Die Zugabe von Apfelfasern beeinflusste die Stärkeverkleisterung in Muffins, wie durch die Ergebnisse von Verkleisterungsexperimenten und In vitro-Stärkeverdauung gezeigt wurde. Stärkesuspensionen mit Apfel- und Weizenfasern wurden auf ihr Verkleisterungsverhalten analysiert. Lösliche Ballaststoffe beeinflussten das Verkleisterungsprofil von Weizenstärke im Vergleich zu unlöslichen Ballaststoffen, die als inerter Füllstoff fungierten und nicht mit der Stärke in Wechselwirkung traten. Weizenteige mit Fasern wurden auf Rheologie, Textur und Mikrostruktur untersucht. Die Glutenentwicklung wurde durch die Fasern negativ beeinflusst, was zu weniger dehnbaren Teigen führte. Lösliche Ballaststoffe führten zu einer erhöhten Teigklebrigkeit. Weizenteig mit 10% Faser besitzt zufriedenstellenden Eigenschaften, während höhere Fasermengen nicht zu empfehlen sind, ohne Zusatzstoffe, um die Glutenfestigkeit zu erhöhen. Fasern aus Nebenprodukten sind geeignet als Mehlersatz in Backwaren, wobei die negativen Auswirkungen der hohen Wasserbindekapazität der Faser teilweise durch Wasseranpassung ausgeglichen werden können, insbesondere in Produkten, bei denen die Glutenentwicklung nicht die Produktstruktur dominiert, wie in Muffins oder Kuchen.

Fine tuning a nutritional strategy by incorporating dietary fibre (DF) in pig diets can help to improve gut health. Fermentation of DF, especially the soluble fraction, in pig intestines yields short-chain fatty acids (SCFA) and lactic acid, which have been found to improve gut health by favouring the growth of health-promoting bacteria such as <i>Lactobacilli</i> and <i>Bifidobacteria</i>, at the expense of pathogenic ones like <i>Clostridium</i> or <i>Salmonella</i>, which may enhance the health of host species. The presence of fermentable fibre in the pig diet can also contribute to reducing nitrogen (N) excretion, which can have a positive impact on the environmental footprint, one of the main concerns of a modern commercial pork production.<p> The overall objective of this thesis project was to evaluate the fermentation characteristics of a selection of feedstuffs in the pig intestines and their potential impact on the gut environment and nitrogen excretion. The evaluation was performed by executing two projects using both <i>in vitro</i> and in <i>vivo studies</i>.<p> The first project focused on the fermentation characteristics of hulless barley in comparison to hulled barley and oats and their effects on the gut environment, especially the production of fermentation metabolites. The rate of fibre fermentation in the intestines was first studied by means of an in vitro gas production technique. The results demonstrated that hulless barleys have higher fermentability and produce higher amounts of SCFA than hulled barley and oats. An experiment carried out on pigs confirmed that the fermentation of the soluble fibre fraction of hulless barley in the gut leads to increased production of SCFA and lactic acid, which in turn contribute to the growth of potentially beneficial microbiota and decrease potentially harmful bacteria, an indicator of improved gut health. This finding shows that gut health parameters may be modulated. Thus gut health could potentially be improved through feed formulation by a judicious selection of feed ingredients with specific fibre fractions, not only by the addition of isolated fibres, which is commonly recommended at present.<p> The second project was executed to study the effect of some feedstuffs differing in their DF and protein content on fermentation characteristics and N excretion in pigs. The feedstuffs included wheat bran, wood cellulose, peas, pea hulls, pea inner fibre, sugar beet pulp, flax seed meal and corn distiller's dried grains with solubles. The results showed that peas and pea fibre-based diets produced higher amounts of SCFA and reduced N excreted, compared to others. In a parallel <i>in vitro</i> study, fermentation characteristics and bacterial protein synthesis was also studied using the same feed ingredients. The findings of the <i>in vitro</i> study corraborated the results of the <i>in vivo</i> experiment. These studies showed that peas and pea fibres have the potential to be used in pig diets in order to gain gut health-benefits and reduce N excretion.<p> From this thesis, it can be concluded that sources and type of dietary fibre have a significant effect on the production of fermentation metabolites in the pig intestine and on N excretion. Among the feed ingredients studied, hulless barley and pea fibres seem to have the greatest potential to be included in pig diets as a source of fermentable fibre to modulate the gut environment, which in turn, extend possibly health-promoting properties and reduce N excretion from pigs. However, further research is needed to understand the specific health benefits of these fibre sources and to quantify the specific fibre components required to achieve these benefits.