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Phenolic compounds have been shown to lower the viscosity and water binding capacity of β-glucans, thereby reducing the digestive viscosity of oats products.

Context Cereal fiber modulates the gut microbiome and benefits metabolic health. The potential link between these effects is of interest.0 Objective The aim for this systematic review was to assess evidence surrounding the influence of cereal fiber intake on microbiome composition, microbiome diversity, short-chain fatty acid production, and risk factors for metabolic syndrome. Data Sources and Extraction The MEDLINE, PubMed, CINAHL, and Cochrane Library databases were searched systematically, and quality of studies was assessed using the Cochrane Risk of Bias 2.0 tool. Evidence relating to study design, dietary data collection, and outcomes was qualitatively synthesized on the basis of fiber type. Data Analysis Forty-six primary publications and 2 secondary analyses were included. Cereal fiber modulated the microbiome in most studies; however, taxonomic changes indicated high heterogeneity. Short-chain fatty acid production, microbiome diversity, and metabolic-related outcomes varied and did not always occur in parallel with microbiome changes. Poor dietary data were a further limitation. Conclusions Cereal fiber may modulate the gut microbiome; however, evidence of the link between this and metabolic outcomes is limited. Additional research is required with a focus on robust and consistent methodology. Systematic Review Registration PROSPERO registration no. CRD42018107117

Diabetes mellitus, particularly type 2 diabetes, is a major global health issue, the prevalence of which seems to be on the rise worldwide. Interventions such as healthy diet, physical activity, maintaining a healthy weight, and medication (for those with a diagnosis of diabetes) are among the most effective strategies to prevent and control diabetes. Three-quarters of patients diagnosed with diabetes are in countries with poor financial infrastructure, nutritional awareness and health care systems. Concomitantly, the cost involved in managing diabetes through the intake of antidiabetic drugs makes it prohibitive for majority of patients. Food protein-derived bioactive peptides have the potential of being formulated as nutraceuticals and drugs in combating the pathogenesis and pathophysiology of metabolic disorders with little or "no known" complications in humans. Coupled with lifestyle modifications, the potential of bioactive peptides to maintain normoglycemic range is actualized by influencing the activities of incretins, DPP-IV, α-amylase, and α-glucosidase enzymes. This article discusses the biofunctionality and clinical implications of anti-diabetic bioactive peptides in controlling the global burden of diabetes.

The aim of this work is to review the major mechanisms by which consumption of whole grain oats and barley, and β-glucans, reduces the risk of coronary heart disease, type 2 diabetes, and other noncommunicable chronic conditions. These effects have been predominantly explained by the role of soluble dietary fibers and smaller bioactive compounds, such as phenolic compounds, in oats and barley. These help to reduce the level of serum low-density lipoprotein cholesterol, decreasing postprandial blood glucose and modulating gut microbiota. In the present review, the role of viscosity development of the intestinal content by β-glucans in these mechanisms is discussed, as well as the impact of processing conditions altering the composition or the physicochemical characteristics of β-glucans.

本综述的目标是回顾食用全谷物燕麦、大麦及b-葡聚糖降低冠心 病、2 型糖尿病和其他慢性非传染性疾病风险的主要机制。它们主要 是通过可溶性膳食纤维和分子更小的生物活性物质，如燕麦和大麦中 的酚类化合物来实现上述生理作用。这些生物小分子有助于降低血清 低密度脂蛋白胆固醇，降低餐后血糖，调节肠道菌群。在本篇综述中， 探讨了b-葡聚糖对肠内容物黏度变化的影响，以及加工条件对b-葡聚 糖结构和理化特性的影响

Diversification of plant-based food sources is necessary to improve global food and nutritional security. Pulses have enormous nutritional and health benefits in preventing malnutrition and chronic diseases while contributing positively to reducing environmental footprint. Pulses are rich in diverse nutritional and non-nutritional constituents which can be classified as bioactive compounds due to their biological effect. These bioactive compounds include but are not limited to proteins, dietary fibres, resistant starch, polyphenols, saponins, lectins, phytic acids, and enzyme inhibitors. While these compounds are of importance in ensuring food and nutritional security, some of the bioactive constituents have ambivalent properties. These properties include having antioxidant, anti-hypertensive and prebiotic effects. Others have a deleterious effect of decreasing the digestibility and/or bioavailability of essential nutrients and are therefore termed antinutritional factors/compounds. Various processing techniques exist to reduce the content of antinutritional factors found in pulses. Traditional processing of pulses comprises soaking, dehulling, milling, germination, fermentation, and boiling, while examples of emerging processing techniques include microwaving, extrusion, and micronization. These processing techniques can be tailored to purpose and pulse type to achieve desired results. Herein, the nutritional qualities and properties of bioactive compounds found in pulses in meeting the sustainable development goals are presented. It also discusses the effect of processing techniques on the nutritional and non-nutritional constituents in pulses as well as the health and environmental benefits of pulse-diet consumption. Major challenges linked to pulses that could limit their potential of being ideal crops in meeting the sustainable development goal 2 agenda are highlighted.

To see if the molecular weight (MW) and viscosity of oat &beta, glucan (OBG) when taken before eating determine its effect on postprandial glycemic responses (PPRG), healthy overnight-fasted subjects (n = 16) were studied on eight separate occasions. Subjects consumed 200 mL water alone (Control) or with 4 g OBG varying in MW and viscosity followed, 2&ndash, 3 min later, by 113 g white-bread. Blood was taken fasting and at 15, 30, 45, 60, 90, and 120 min after starting to eat. None of the OBG treatments differed significantly from the Control for the a-priori primary endpoint of glucose peak-rise or secondary endpoint of incremental area-under-the-curve (iAUC) over 0&ndash, 120 min. However, significant differences from the Control were seen for glucose iAUC over 0&ndash, 45 min and time to peak (TTP) glucose. Lower log(MW) and log(viscosity) were associated with higher iAUC 0&ndash, 45 (p &lt, 0.001) and shorter TTP (p &lt, 0.001). We conclude that when 4 g OBG is taken as a preload, reducing MW does not affect glucose peak rise or iAUC0-120, but rather accelerates the rise in blood glucose and reduces the time it takes glucose to reach the peak. However, this is based on post-hoc calculation of iAUC0-45 and TTP and needs to be confirmed in a subsequent study.

Underlying mechanisms responsible for the cholesterol-lowering effect ofβ-glucan have been proposed, yet have not been fully demonstrated. The primary aim of this study was to determine whether the consumption of barleyβ-glucan lowers cholesterol by affecting the cholesterol absorption, cholesterol synthesis or bile acid synthesis. In addition, this study was aimed to assess whether the underlying mechanisms are related to cholesterol 7αhydroxylase (CYP7A1) SNP rs3808607 as proposed by us earlier. In a controlled, randomised, cross-over study, participants with mild hypercholesterolaemia (n30) were randomly assigned to receive breakfast containing 3 g high-molecular weight (HMW), 5 g low-molecular weight (LMW), 3 g LMW barleyβ-glucan or a control diet, each for 5 weeks. Cholesterol absorption was determined by assessing the enrichment of circulating13C-cholesterol over 96 h following oral administration; fractional rate of synthesis for cholesterol was assessed by measuring the incorporation rate of2H derived from deuterium oxide within the body water pool into the erythrocyte cholesterol pool over 24 h; bile acid synthesis was determined by measuring serum 7α-hydroxy-4-cholesten-3-one concentrations. Consumption of 3 g HMWβ-glucan decreased total cholesterol (TC) levels (P=0·029), but did not affect cholesterol absorption (P=0·25) or cholesterol synthesis (P=0·14). Increased bile acid synthesis after consumption of 3 g HMWβ-glucan was observed in all participants (P=0·049), and more pronounced in individuals carrying homozygous G of rs3808607 (P=0·033). In addition, a linear relationship between log (viscosity) ofβ-glucan and serum 7α-HC concentration was observed in homozygous G allele carriers. Results indicate that increased bile acid synthesis rather than inhibition of cholesterol absorption or synthesis may be responsible for the cholesterol-lowering effect of barleyβ-glucan. The pronounced TC reduction in G allele carriers of rs3808607 observed in the previous study may be due to enhanced bile acid synthesis in response to high-viscosityβ-glucan consumption in those individuals.

Pulses are rich in fermentable fibre and phenolic compounds that have the potential to modify baseline function within the gut microenvironment (microbiota and epithelial barrier), thereby mitigating gut-associated diseases. The objective was to assess the gut health promoting effects of dietary chickpea in C57BL/6 mice consuming a 20% cooked chickpea flour diet (CK) or an isocaloric control diet for 3 weeks. Gut health was enhanced by CK including (i) colon crypt mucus content and mucin mRNA expression, (ii) crypt length, proliferation, and epithelial barrier junctional components expression, (iii) anti-microbial defenses, and (iv) altered cecal and fecal microbiota community structure (e.g. increased Prevotella ) with enhanced metagenomic functions (e.g. increased flavonoid biosynthesis, butanoate metabolism), and microbial activity (increased short chain fatty acid production). Collectively, CK modulated the baseline function of the colonic microenvironment (microbiome and epithelial barrier), thereby priming colonic function such that the severity of gut-associated diseases could be mitigated.

Dietary pulses, including lentils, are protein-rich plant foods that are enriched in intestinal health-promoting bioactives, such as non-digestible carbohydrates and phenolic compounds. The aim of this study was to investigate the effect of diets supplemented with cooked red lentils on the colonic microenvironment (microbiota composition and activity and epithelial barrier integrity and function). C57Bl/6 male mice were fed one of five diets: a control basal diet (BD), a BD-supplemented diet with 5, 10 or 20% cooked red lentils (by weight), or a BD-supplemented diet with 0.7% pectin (equivalent soluble fiber level as found in the 20% lentil diet). Red lentil supplementation resulted in increased: (1) fecal microbiota &alpha, diversity, (2) abundance of short-chain fatty acid (SCFA)-producing bacteria (e.g., Prevotella, Roseburia and Dorea spp.), (3) concentrations of fecal SCFAs, (4) mRNA expression of SCFA receptors (G-protein-coupled receptors (GPR 41 and 43) and tight/adherens junction proteins (Zona Occulden-1 (ZO-1), Claudin-2, E-cadherin). Overall, 20% lentil had the greatest impact on colon health outcomes, which were in part explained by a change in the soluble and insoluble fiber profile of the diet. These results support recent public health recommendations to increase consumption of plant-based protein foods for improved health, in particular intestinal health.

Background The viscosity of oat β-glucan (OBG) determines its effect on serum cholesterol and glycemic responses, but whether OBG viscosity affects gastric emptying, appetite, and ad libitum food intake is unknown. Objectives We aimed to determine the effect of altering the amount or molecular weight (MW) and, hence, viscosity of OBG in a breakfast meal on the primary endpoint of food intake at a subsequent meal. Methods Overnight-fasted males (n = 16) and nonpregnant females (n = 12) without diabetes, aged 18-60 y, with BMI 20.0-30.0 kg/m² who were unrestrained eaters participated in a double-blind, randomized, crossover study at a contract research organization. Participants consumed, in random order, breakfast meals equivalent in weight, energy, and macronutrients consisting of white-bread, butter, jam, and 2% milk plus hot cereal [Cream of Rice (CR), or instant-oatmeal plus either 3 g oat-bran (2gOBG), 10 g oat-bran (4gOBG), or 10 g oat-bran plus β-glucanase (4gloMW) to reduce OBG MW and viscosity compared with 4gOBG]. Gastric emptying, subjective appetite, and glucose, insulin, ghrelin, and peptide tyrosine tyrosine (PYY) responses were assessed for 3 h and then subjects were offered an ad libitum lunch (water and pizza). Results Pizza intakes (n = 28) after CR, 2gOBG, 4gOBG, and 4gloMW (mean ± SEM: 887 ± 64, 831 ± 61, 834 ± 78, and 847 ± 68 kcal, respectively) were similar (nonsignificant). Compared with CR, 4gOBG significantly reduced glucose (78 ± 10 compared with 135 ± 15 mmol × min/L) and insulin (14.0 ± 1.6 compared with 26.8 ± 3.5 nmol × min/L) incremental area-under-the-curve and delayed gastric-emptying half-time (geometric mean: 285; 95% CI: 184, 442, compared with geometric mean: 105; 95% CI: 95, 117 min), effects not seen after 4gloMW. Subjective appetite, PYY, and ghrelin responses after 2gOBG, 4gOBG, and 4gloMW were similar to those after CR. Conclusions The results demonstrate that OBG viscosity determines its effect on postprandial glucose, insulin, and gastric emptying. However, we were unable to demonstrate a significant effect of OBG on appetite or food intake, regardless of its viscosity.This trial was registered at clinicaltrials.gov as NCT03490851.

Background β-Glucan, a soluble fiber with viscous property, has a documented cholesterol-lowering effect. The molecular weight (MW) of β-glucan, which contributes to viscosity, and an individual's genotype might influence the cholesterol-lowering efficacy of β-glucan. Objectives This study was designed to determine whether the cholesterol-lowering efficacy of barley β-glucan varied as a function of MW and the daily dose consumed. Our second aim was to determine whether any gene-diet interactions are associated with the cholesterol-lowering efficacy of β-glucan. Methods In a randomized controlled crossover trial, 30 mildly hypercholesterolemic adults [12 men and 18 women, aged 27-78 y; body mass index (in kg/m(2)): 20-40; total cholesterol (TC): 5.0-8.0 mmol/L; LDL cholesterol: 2.7-5.0 mmol/L] were randomly assigned to receive a breakfast that contained either barley β-glucan at 3 g high MW (HMW)/d, 5 g low MW (LMW)/d, or 3 g LMW/d or a control diet, each for 5 wk. The washout period between the phases was 4 wk. Fasting blood samples were collected at the start and end of each phase for blood lipid analysis and genotyping. Results Consumption of 3 g HMW β-glucan/d lowered TC by -0.12 mmol/L (95% CI: -0.24, -0.006 mmol/L) compared with the control diet (P= 0.0046), but the LMW β-glucan, at either 3 g/d or 5 g/d, did not change serum cholesterol concentrations. This effect of HMW β-glucan was associated with gene-diet interaction, whereby individuals with the single nucleotide polymorphism (SNP) rs3808607-G allele (GG or GT) of the cytochrome P450 family 7 subfamily A member 1 gene (CYP7A1) had greater responses to 3 g HMW β-glucan/d in lowering TC than TT carriers (P= 0.0006). Conclusions The HMW β-glucan rather than LMW β-glucan reduced circulating TC effectively in mildly hypercholesterolemic adults. The cholesterol-lowering effect of β-glucan may also be determined by the genetic characteristics of an individual. These data show that individuals carrying theCYP7A1SNP rs3808607-G allele are more responsive to the cholesterol-lowering effect of β-glucan with HMW than TT carriers. This trial was registered atclinicaltrials.govasNCT01408719.

A standard method measuring viscosity (η) of cereal products through in vitro digestion in a Rapid ViscoAnalyzer has been developed previously and is predictive of some physiological effects of cereal foods. This paper proposes a simple mathematical model to analyze quantitatively the digestograms obtained by that method. Digestograms of twelve uncooked and cooked cereal products were generated and data quality was assessed. Experimental data were fitted with a viscosity model ηmodel=η1+η2, where [Formula: see text] and [Formula: see text] were respectively viscosity decrease and viscosity increase components. The model showed very good agreement with experimental data and enabled interpretation of the digestograms in relation to the composition of the products: η1 was interpreted as the decreasing viscosity of digestible polymeric nutrients whereas η2 was interpreted as the viscosity development of viscous dietary fibers. This model may be useful to investigate quantitatively the biological effects of soluble dietary fibers in cereal products and similar products.

Human studies have clearly demonstrated the beneficial impact of consuming oats on cholesterol levels, however, processing can have a significant influence on functionality, which has not yet been fully addressed., Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day–1) play a role in cholesterol reduction; and (3) unrefined β-glucan-rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient.

Regulations allowing health claims linking consumption of food products rich in β-glucan with reduced risk of coronary heart disease have increased the interest of food companies and consumers in such products as healthy food options. Oat and barley cereal products, in particular, have garnered attention due to their high β-glucan contents. Processing oat and barley into food products may affect the physicochemical characteristics of β-glucan and subsequently its physiological effects, however. A new proposed AACCI Approved Method (32-24.01) using RVA to measure β-glucan viscosity in cereal products has been developed and validated. The objective of this method is to determine the viscosity of β-glucan that is soluble under simulated digestion conditions without requirements for pretreatments of cereal products. This viscosity measurement is obtained by mixing an aqueous suspension of ground sample with digestive enzymes in a disposable canister in the RVA. The method can be used by laboratories as a scre...

Whole-grain oats have been identified as a type of food that blunts blood glucose increase after a meal. However, processing of oats changes the physical characteristics of the grain, which may influence human glycaemic response. Therefore, the effect of different processes on acute postprandial glycaemic response, quantified using glycaemic index (GI) measurements, was investigated in a systematic review. A review of the literature identified twenty publications containing fifty-six individual tests. An additional seventeen unpublished tests were found in an online database. Of the seventy-two measurements included in the review, two were for steel-cut oats, eleven for large-flake oats, seven for quick-cooking (small flake) oats, nine for instant oatmeal and twenty-eight for muesli or granola. One granola measurement was identified as an outlier and was removed from the statistical analysis. In all, fifteen clinical tests were reported for rolled oat porridge that did not specify the type of oats used, and thus the effect of processing could not be assessed. Steel-cut oats (GI=55 (se 2·5)), large-flake oats (GI=53 (se 2·0)) and muesli and granola (GI=56 (se 1·7)) elicited low to medium glycaemic response. Quick-cooking oats and instant oatmeal produced significantly higher glycaemic response (GI=71 (se 2·7) and 75 (se 2·8), respectively) than did muesli and granola or large-flake oatmeal porridge. The analysis establishes that differences in processing protocols and cooking practices modify the glycaemic response to foods made with whole-grain oats. Smaller particle size and increased starch gelatinisation appear to increase the glycaemic response.

Consumption of breads containing whole grains or functional ingredients rich in dietary fiber and β-glucans has shown a dramatic increase because of their health benefits. Since bioactivity of β-glucan has been linked with its physicochemical properties, the current study was designed to investigate the effects of straight-, sponge- and sour-dough bread making processes on physicochemical characteristics of β-glucan in whole wheat/oat bread. The presence of β-glucan-degrading enzymes in the whole wheat flour used in this study were found to depolymerize β-glucan at a rate of 0.054 min −1 , causing a significant reduction in β-glucan molecular weight ( M w ) during dough process. Sour- and sponge-doughs had lower rates of β-glucan depolymerization, resulting in breads with medium to high β-glucan M w range (600–1087 kg/mol) compared to straight-dough method. Dough pH, titratable acidity and fermentation plus proofing time showed significant impacts on β-glucan M w and viscosity, but not on solubility. Acetic and propionic acids were present in all doughs, whereas lactic acid was only found in sour-dough. Generally, sour-dough bread showed better potential over yeast-fermented breads in terms of preserving β-glucan M w and viscosity during baking process when a blend of whole wheat flour and oat bran was used.

To better understand the role that dietary fibre plays in the health benefits of pulses, the cell wall polysaccharides of pulses were characterized. To allow comparison between this data and nutritional studies, cooked chickpeas, lentils, beans and peas were used rather than raw seeds. Insoluble fibre, soluble fibre, resistant starch and oligosaccharide fractions were isolated using digestive enzymes at 37 °C. Prebiotic galacto-oligosaccharides, including raffinose, stachyose and verbascose made up between 3.5 and 6.9% of the cooked pulses (dry weight basis). Pulse fibre is pectin rich, with most being found in the soluble fibre fraction. The soluble fibre fraction is a diverse mixture of polysaccharides of varying sizes and solutions of soluble fibre exhibit a range of viscosities depending on the pulse type. The sugars which make up the insoluble fibre fraction suggest a large cellulose component. Microscopic examination of cooked whole pulses showed that a large fraction of the starch was partially gelatinized and contained within intact cell walls whereas boiled flour pastes had few ungelatinized granules. After simulated upper-gut digestion, some starch remained inaccessible to digestive enzymes. Cell walls of pulses modulate starch gelatinization and reduce enzymatic hydrolysis, which may account for the low glycemic response attributed to pulses.

β-Glucan from oat and barley is a viscous soluble fiber with proven health benefits. The highly viscous nature of β-glucan has been shown to be a key factor in improving glycemic response and lowering cholesterol. Because viscosity is a function of β-glucan concentration, solubility, and molecular weight (MW), external factors affecting one or more of these properties have the potential to influence human physiological responses. Processing methods commonly used in the manufacturing and preparation of oat and barley foods include heat treatment of the grain, milling, flaking, baking, freezing, extrusion, dough resting, and addition of ingredients. These processing methods have been shown to impact β-glucan MW and solubility, resulting in altered β-glucan viscosity. Understanding the positive and negative effects of various processing methods on β-glucan is valuable for the development of food products that are high in β-glucan and have physiological benefits.

Incorporation of high molecular weight oat β-glucan into milk to obtain calorie-reduced and cholesterol-lowering dairy products is challenged by the thermodynamic incompatibility and phase separation of milk proteins and β-glucan. Fine tuning the concentrations of the biopolymers in the mixture may result in dairy matrices with unique structure and texture. The thermodynamic incompatibility behaviour may follow Asakura and Oosawa (1958) theory for depletion interactions between non-interacting polysaccharides and colloidal hard spheres. A phase behaviour diagram was developed to describe the separation of the mixtures into a protein-rich (lower) and a β-glucan-rich (upper) phase, but unlike previous literature, the concentration of lactose and ions in the soluble phase was kept constant. Analysis of the protein composition in the lower phase demonstrated that whey proteins did not play a role in phase separation. The experimental phase boundary agreed well with the phase boundary calculated using Vrij's theory (1976) for mixtures of β-glucan and casein micelles demonstrating that phase separation was driven by depletion interactions. Confocal images showed the formation of different structures (droplet-like or bi-continuous) at different points of the phase behaviour diagram. The flow behaviour of the mixtures with concentrations higher than the binodal curve was not only governed by the presence of β-glucan chains, but also by the formation of these structures.

Background: Health claims regarding the cholesterol-lowering effect of soluble fiber from oat products, approved by food standards agencies worldwide, are based on a diet containing $3 g/d of oat b-glucan (OBG). Given the number of recently published randomized controlled trials (RCTs), it is important to update the findings of previous meta-analyses. Objective: The objective was to quantify the effect of $3 g OBG/d on serum cholesterol concentrations in humans and investigate potential effect modifiers. Design: A meta-analysis was performed on 28 RCTs comparing $3 g OBG/d with an appropriate control. Systematic searches were undertaken in PubMed, AGRICOLA, and Scopus between 1 January 1966 and 6 June 2013, plus in-house study reports at CreaNutrition AG. Studies were assessed with regard to inclusion/exclusion criteria, and data were extracted from included studies by reviewers working independently in pairs, reconciling differences by consensus. Estimates of the mean reduction in serum cholesterol from baseline between the OBG and control diets were analyzed by using random-effects meta-analysis models and meta-regression. Results: OBG in doses of $3 g/d reduced low-density lipoprotein (LDL) and total cholesterol relative to control by 0.25 mmol/L (95% CI: 0.20, 0.30; P , 0.0001) and 0.30 mmol/L (95% CI: 0.24, 0.35; P , 0.0001), respectively, with some indication of heterogeneity (P = 0.13 and P = 0.067). There was no significant effect of OBG on high-density lipoprotein (HDL) cholesterol or triglycerides and no evidence that dose (range across trials: 3.0‐12.4 g/d) or duration of treatment (range: 2‐12 wk) influenced the results. LDL cholesterol lowering was significantly greater with higher baseline LDL cholesterol. There was a significantly greater effect for both LDL and total cholesterol in subjects with diabetes compared with those without (although based on few studies). Conclusions: Adding $3 g OBG/d to the diet reduces LDL and total cholesterol by 0.25 mmol/L and 0.30 mmol/L, respectively, without changing HDL cholesterol or triglycerides. Am J Clin Nutr doi: 10.3945/ajcn.114.086108.

When high molecular weight β-glucan is added to milk, macroscopic phase separation occurs due to thermodynamic incompatibility between mixed-linkage β-glucan and milk proteins. In this research, the evolution of microphase separated domains was investigated using ultrasonic and diffusing wave spectroscopy. It was possible to follow the dynamics of phase separation, in situ, without dilution. Immediately after mixing, there was a significant decrease in the initial turbidity of the mixtures, measured using diffusing wave spectroscopy, even at concentrations below macroscopic phase separation. At low and intermediate concentrations of β-glucan (0.1–0.2 w/w) the turbidity parameter, 1/l*, changed after mixing, because of rearrangements within the protein rich domains and growth of the phase separated domains. At high concentrations of β-glucan (0.6 % w/w), after an initial change in 1/l*, no further changes in turbidity were observed, because of the high viscosity of the mobile phase and the low diffusivity of the micelles due to crowding within the phase separated domains. Similar conclusions were drawn by observing the changes in ultrasonic attenuation, when probing at larger length scales. By using these two spectroscopic techniques it was possible to obtain complementary information on the dynamics of phase separation in β-glucan milk mixtures, and determine which systems still show rearrangements within the domains after mixing.

The viscosity of the soluble fibre, β-glucan, has been shown to influence its ability to lower serum cholesterol and postprandial blood glucose levels. The impact of various amylases, proteases and lipase on the solubility and resulting viscosity of β-glucan extracted from oat bran cereals with a range of β-glucan concentrations and molecular weights was investigated. Addition of enzymes increased the final viscosity of high molecular weight β-glucan in cereals by facilitating the release of β-glucan from the food matrix. For cereals with partially depolymerized β-glucan, the addition of digestive enzymes decreased the final viscosity by eliminating the contribution of starch and protein to viscosity. Final viscosity varied depending on enzyme combinations including pancreatin, salivary and microbial α-amylases, microbial protease, porcine protease, trypsin and α-chymotrypsin. Addition of lipase did not significantly affect viscosity or solubility of β-glucan extracted from oat crackers. Addition of lichenase showed that β-glucan was the major contributor of viscosity to the system, with negligible interference from other components. The viscosity of the optimized protocol was compared to physiological results previously obtained. The viscosity of β-glucan extracted with pancreatin plus microbial α-amylase (pH 6.9) was predictive of LDL-cholesterol reduction (R2 = 0.847) and glycemic response (R2 = 0.883).

Peter Wood was an exceptional scientist who helped lay the foundation for our understanding of the health benefits of soluble fiber. As a carbohydrate chemist, he developed methods to characterize polysaccharides and used them to better understand the structure and behavior of cereal (1→3)(1→4)-β- d -glucans. With collaborators, he demonstrated the distribution of these mixed linkage β-glucans in cereal grains and food products. He studied the behavior of β-glucans in solution and demonstrated that, like other high molecular weight polymers, they exhibited shear thinning behavior and viscosity increased exponentially with increasing concentration. By using size exclusion chromatography, with post-column calcofluor detection, Peter was able to determine the molecular weight distributions of β-glucans in unpurified extracts. He investigated the differences in fine structure among oat, barley, rye and wheat β-glucans and showed that the differences influenced the gelation properties of these polymers. He drew together multi-disciplinary collaborations to investigate how the physico-chemical characteristics of oat β-glucans influenced their ability to attenuate post-prandial blood glucose levels and lower serum cholesterol concentrations. Using oat gum extracts which Peter and coworkers had produced, they demonstrated that β-glucan was the major bioactive component of oat bran which affected blood glucose and cholesterol levels in humans. A series of clinical trials showed that solubility and molecular weight of oat β-glucan were modified by food processing, which in turn affected bioactivity. Peter's dedication to excellent science and drive to establish the underlying mechanisms of health benefits of oat fiber have provided us with a wealth of knowledge for future research.

Although many consumers know that pulses are nutritious, long preparation times are frequently a barrier to consumption of lentils, dried peas and chickpeas. Therefore, a product has been developed which can be used as an ingredient in a wide variety of dishes without presoaking or precooking. Dried green peas, chickpeas or lentils were soaked, cooked, homogenized and spray-dried. Proximate analyses were conducted on the pulse powders and compared to an instant mashed potato product. Because the health benefits of pulses may be due in part to their carbohydrate content, a detailed carbohydrate analysis was carried out on the pulse powders. Pulse powders were higher in protein and total dietary fibre and lower in starch than potato flakes. After processing, the pulse powders maintained appreciable amounts of resistant starch (4.4%–5.2%). Total dietary fibre was higher in chickpeas and peas (26.2% and 27.1% respectively) than lentils (21.9%), whereas lentils had the highest protein content (22.7%). Pulse carbohydrates were rich in glucose, arabinose, galactose and uronic acids. Stachyose, a fermentable fibre, was the most abundant oligosaccharide, making up 1.5%–2.4% of the dried pulse powders. Spray-drying of cooked, homogenized pulses produces an easy to use ingredient with strong nutritional profile.

Oat, (Avena sativa) is an excellent source of mixed linkage beta-glucans ((1 -> 3)(1 -> 4)-beta-D-glucan), a dietary fibre with cholesterol lowering properties. Using a mutagenized oat-population we screened 1700 different lines and identified ten lines that displayed beta-glucan levels above 6.7% and 10 below 3.6%. The extreme values were 1.8% and 7.5%. We chose six lines with an increased- and four lines with a reduced beta-glucan content for further study. By longitudinal- and cross-sections of seeds it was shown that localization of beta-glucan varied between the different lines. In addition, beta-glucan quality parameters like molecular weight and solubility were also determined. Although the selection was designed for quantitative differences, qualitative differences between the beta-glucans from the different lines were found. The high and low beta-glucan lines will now be used as a model system to study molecular regulation of beta-glucan biosynthesis as well as possible links between fibre quality and biological activity. (C) 2012 Elsevier Ltd. All rights reserved. (Less)

Oat and barley foods have been shown to reduce human glycaemic response, compared to similar wheat foods or a glucose control. The strength of the evidence supporting the hypothesis that the soluble fibre, mixed linkage β-glucan, reduces glycaemic response was evaluated. A search of the literature was conducted to find clinical trials with acute glycaemic response as an end point using oat or barley products. Of the 76 human studies identified, 34 met the inclusion and exclusion criteria. Dose response and ratio of β-glucan to available carbohydrate as predictors of glycaemic response were assessed. Meals provided 0.3-12.1 g oat or barley β-glucan, and reduced glycaemic response by an average of 48 ± 33 mmol · min/l compared to a suitable control. Regression analysis on 119 treatments indicated that change in glycaemic response (expressed as incremental area under the post-prandial blood-glucose curve) was greater for intact grains than for processed foods. For processed foods, glycaemic response was more strongly related to the β-glucan dose alone (r(2)=0.48, P

Chronic diseases including type 2 diabetes and cardiovascular disease are major health concerns. Mixed-linkage β-glucan is found in members of the grass family, with the endosperm cell walls of oats and barley containing the highest amounts, followed by rye and wheat. Consumption of oat and barley products moderates blood glucose response after a meal. Longer term consumption also reduces LDL cholesterol in hypercholesterolemic individuals. Mixed results have been reported in the use of β-glucan-containing foods for satiety and weight management. Soluble fibers such as β-glucan have little effect on laxation; however, fermentation by colonic flora is associated with improved gut health.

Depolymerization of mixed linkage cereal β-glucans has been observed during the mixing and fermentation of multigrain breads. To maintain the bioactivity of β-glucans in bread and other foods, control of β-glucanase activity during production is needed. β-Glucanase activity in wheat and dairy ingredients was determined by adding them to β-glucan solutions and following the change in the molecular weight of β-glucan at 50 °C for 60 min. The activities in six wheat and six dairy ingredients ranged from undetectable to a 98% reduction in molecular weight. Calcium propionate, potassium sorbate, and sodium benzoate are salts of organic acids commonly used as food preservatives. Low concentrations of these additives (0.1–1.0%) were found to have an inhibitory effect on the β-glucanases found in wheat flour and whey protein isolate. The depolymerization rate of β-glucan was reduced by up to 76% by the three additives.

Oat β-glucan enriched extruded cereals with molecular weights (MWs) ranging from 2,180,000 to 326,000 were produced. Test meals composed of 31 g of available carbohydrate, 8.3–8.7 grams of β-glucan, and milk were administered to subjects and their postprandial blood glucose levels monitored for 2 hr. White bread plus milk and a control wheat bran cereal plus milk were administered, and white bread alone served as a reference food for estimation of glycemic index (GI) of the cereals, after adjusting for the effect of adding milk to white bread. Both oat bran and wheat bran cereals significantly reduced peak blood glucose rise (PBGR) and area under the curve (AUC) versus white bread alone or white bread plus milk. There was a significant inverse relationship between AUC and log10[weight average MW] (r2 = 0.96, P = 0.0192). There was a significant inverse relationship between PBGR and log10[viscosity] of in vitro extracts from all cereals, including the wheat control (r2 = 0.96, P = 0.0031). However...

Pulses, including beans, chickpeas, lentils and peas, are high in dietary fiber, protein, and folate, and low in fat. Although beneficial effects of pulse consumption related to cardiovascular disease (CVD) have been reported in previous studies, many of them have focused on single pulse types in hypercholesterolemic adults, thus creating rationale to extend investigation into multiple pulse types in healthy adults. The purpose of this study was to investigate the effect of chickpeas, lentils and peas on markers of CVD risk and glycemic control in healthy males. Twenty-one healthy adult males participated in a randomized crossover study involving four treatment periods in which they consumed 100 g of spray-dried chickpeas, lentils and peas, and a control (50 g of dehydrated potato flakes) for 28 days each, separated by 28-day washout periods. Fasting blood was collected on days 1 and 29 of each treatment period for analysis of total-cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apolipoprotein B, apolipoprotein A-I, homocysteine, glucose and insulin. Consumption of chickpea, lentil or pea for 28 days did not significantly affect serum lipids, homocysteine or glycemic parameters in a sample of 21 healthy adult males. Further research is required to determine the effectiveness of different pulse types on traditional biomarkers of cardiovascular disease as a preventative measure.

Clinical studies with isolates of β-glucan have shown that the health benefits are regulated not only by the polysaccharide concentration but also by the molecular weight and concentration in solution, because these health benefits are controlled, inter alia, by viscosity in the gut. The degradation of β-glucan in baked products is likely caused by baking ingredients or processes, or by endogenous enzymes in wheat flour. The objectives of the present study were to quantify β-glucanase in wheat kernels and to determine factors that influence the levels of this enzyme. A modified protocol to quantify β-glucanase was developed and then confirmed through high-performance size-exclusion chromatography (HPSEC) with Calcofluor detection. Under this protocol, it was shown that the concentration of β-glucanase activity was the highest in the bran fraction of the kernel in ungerminated wheats, whereas it was distributed throughout the entire kernel following germination. Furthermore, investigation on diffe...

The interaction between oat β-glucan and other food components has the potential to influence starch digestibility and consequently affect its bioactivity in reducing glycemic responses. Blood glucose concentrations were measured before and after ingesting wheat and oat granolas, with 0.6 and 6.2 g of β-glucan, respectively, and two starch doses (40 and 60 g). As the in vitro extract viscosity of β-glucan increased, the in vitro starch digestibility was reduced and the glucose responses were lowered. The peak blood glucose response (PBGR) and the incremental area under the curve (iAUC) were lower in the 40 g than in the 60 g starch formulation. β-Glucan was significantly more active in reducing PBGR and iAUC when the β-glucan/starch ratio was 1.6:10 rather than 1.1:10. This information is valuable for new product development and for quality assessment of bioactive foods containing oat β-glucan.

A better understanding of the functionality of probiotics and dietary fibres with prebiotic activity is required for the development of improved synbiotic preparations. In this study, utilization of β(2–1) fructans, galactooligosaccharides, and plant polysaccharides as prebiotics by lactobacilli, bifidobacteria, and pediococci was investigated. Our results demonstrate that prebiotics with linear chains consisting of galactose units are better utilized by probiotics than are those consisting of glucose and fructose units, and the ability of probiotic bacteria to utilize prebiotics is strain-specific. In addition, rye fructooligosaccharides represent a prebiotic fibre that supports the growth of a wide range of probiotic cultures and as such has a potential to improve the successfulness of probiotic treatments. This study also demonstrates dietary fibre utilization by pediococci and provides data supporting the possible use of pediococci as a probiotic in synbiotic combinations.

Several regulatory bodies have approved a health claim on the cholesterol-lowering effects of oat β-glucan at levels of 3·0 g/d. The present study aimed to test whether 1·5 g/d β-glucan provided as ready-to-eat oat flakes was as effective in lowering cholesterol as 3·0 g/d from oats porridge. A 6-week randomised controlled trial was conducted in eighty-seven mildly hypercholesterolaemic ( ≥ 5 mmol/l and sd 13·8) %, − 7·2 (sd 12·4) % and − 5·5 (sd 9·3) % in the OH, OL and control groups), as did LDL-C ( − 8·4 (sd 18·5) %, − 8·5 (sd 18·5) % and − 5·5 (sd 12·4) % in the OH, OL and control groups), but between-group differences were not significant. In responders only (n 60), β-glucan groups had higher reductions in LDL-C ( − 18·3 (sd 11·1) % and − 18·1 (sd 9·2) % in the OH and OL groups) compared with controls ( − 11·7 (sd 7·9) %; P = 0·044). Intakes of oat β-glucan were as effective at doses of 1·5 g/d compared with 3 g/d when provided in different food formats that delivered similar amounts of soluble β-glucan.

Although soy proteins are known to have a deleterious effect on gluten thermosetting gelation, the causes are still poorly understood. Different sources of soy protein isolates (SPI) were used to investigate the interactions between gluten and soy proteins during hydro-thermal treatments. Commercial SPI and isolates prepared from soybean lines with different subunit composition were used to study the influence of protein denaturation and subunit composition on thermoset gel formation. Rapid Visco Analyser analysis showed that replacement of gluten with more than 1% SPI decreased the peak viscosity and interfered with formation of thermoset gels. However, peak viscosity was higher for 11% gluten + 2% SPI than for 11% gluten alone, suggesting a cooperative effect. After heating and cooling, 11% gluten + 2% SPI rich in A1 and A2 subunits formed a coherent thermoset gel suggesting that the cysteine residue content of soy proteins can affect gel formation.

Pulses are a good source of dietary fibre and other important nutrients. Flours and fibre-rich fractions obtained from pulse crops can be incorporated into processed foods to increase dietary fibre content and/or serve as functional ingredients. This review focuses on research conducted in the past ten years on the non-starch polysaccharides and oligosaccharides found in dry beans (Phaseolus vulgaris), chickpeas (Cicer arietinum), lentils (Lens culinaris), and dry peas (Pisum sativum). The isolation, composition, and structure of these pulse fibres are described. Common terms used to describe the physicochemical properties of fibre fractions are defined and briefly discussed. Recent studies on the effects of processing on the ratio of insoluble to soluble dietary fibre and on the α-galacto-oligosaccharide content of pulses and fibre fractions are cited and summarized. Food applications for pulse fibre fractions and flours in fibre enrichment, nutrient enrichment, fat binding and retention, and texture modification, as well as some non-food applications, are reviewed.

Despite their demonstrated health benefits, consumption of pulses in Western societies has traditionally been low. This is, in part, due to the perception that pulses cause flatulence and gastrointestinal upset. This randomized, double-blind placebo-controlled, cross-over study assessed the impact of 28 consecutive days consumption of 100 g dry weight Kabuli chickpeas, green Laird lentils, and green peas, in comparison to a potato control, on perceived flatulence, abdominal comfort, bowel movements and overall gastrointestinal function using a questionnaire with yes/no and visual analog rankings, in 21 healthy males between the ages of 19–40. Questionnaires were completed during three phases (PRE, EARLY, LATE) of each treatment period. Chi-square (occurrence) and Wilcoxon test (severity rank) analyses revealed minor changes in occurrence and/or severity of flatulence and abdominal comfort, but no changes in overall gastrointestinal function. These results demonstrate that pulses containing oligosaccharides are well tolerated with negligible perceived changes in flatulence and overall gastrointestinal function when incorporated into the diet of healthy adult males.

The influence of soy protein subunit composition on the particle size distribution and solid content of soymilk and various supernatant fractions was investigated. A well-established seed variety (Harovinton), containing all protein subunits, and eleven null soybean genotypes lacking specific glycinin and β-conglycinin subunits were investigated, to determine the effect of protein composition on the physico-chemical characteristic of soymilk. Soymilk made from Harovinton and soybean lines null in glycinin showed significantly higher total solid yields than the other genotypes evaluated. Soymilks prepared from soybeans null for glycinin or lacking glycinin's group I (A 1 , A 2 ) showed a smaller particle size distribution compared to soybean lines containing glycinin. In general, unheated soymilk made from lines having glycinin showed a bimodal size distribution with large particles, with a decrease in the particle size distribution after heating and heating with homogenization. The results of this work will help in the evaluation of breeding lines with a specific protein composition tailored to a specific processing functionality.

The kinetics of phase separation and microstructure of oat β-glucan/whey protein binary mixtures varying in concentration (4–16% w/v protein, 0.3–1.2% w/v β-glucan) and β-glucan molecular weight (1.3 × 106, 640 × 103, 180 × 103, and 120 × 103 g/mol) was investigated by turbidimetry and fluorescent microscopy. The phase separation of the mixed systems was followed at pH 7.0 and at room temperature under quiescent conditions. Application of first principles revealed that phase separation of the systems follows first-order kinetics. Acceleration of the phase-separation process was observed with increase of β-glucan concentration for the three lowest-MW samples but the highest molecular weight (1.3 × 106 g/mol) exhibited the opposite trend. Changes in the polysaccharide molecular weight resulted in considerable differences in β-glucan aggregate morphology in the mixed systems. The change in the continuity of the mixed system from polysaccharide-, to bi-, to protein-continuous was confirmed for a wide range of mixed systems differing in biopolymer concentration, and β-glucan molecular weight.

The isothermal (5 °C) equilibrium phase behaviour of high molecular weight oat β-glucan/whey protein isolate binary mixtures was investigated. The mixtures were studied at different pH values (3.0 and 7.0) in the presence or absence of sucrose (10% w/v) by means of phase analysis, electrophoresis, viscosity measurements, and fluorescent microscopy. The mixtures are incompatible in a wide range of concentrations as revealed by phase diagram construction. Decrease of pH from 7.0 to 3.0 and sucrose addition enhances miscibility, and the latter effect is more pronounced at pH 3.0. Viscosity measurements of the mixed systems revealed that flow is pseudoplastic at all concentrations studied and the behaviour changes from protein- to polysaccharide-controlled as the biopolymer concentration varies in the mixtures. This is also reflected in the topology of the mixed systems where a transition in the continuity of the microstructure is observed from protein- to bi- to polysaccharide-continuous.

Soy protein isolates (SPI) were prepared from 12 soybean lines grown in Harrow, Ontario and by-products (fibers and wheys) from SPI making were saved. The identification and quantification of soluble sugars in defatted flours, fibers and wheys were carried out using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) and with a colorimetric method for uronic acids. Defatted flours and fibers were acid hydrolyzed, then analyzed by HPAEC-PAD for monosaccharide composition. The results showed varietal differences in the carbohydrate composition suggesting different applications for these defatted flours and their SPI by-products.

This study focussed on the evaluation of thermal denaturation at three different stages during soy protein isolation and the effect of subunit composition on the formation of heat-induced soy protein gels. Soy protein isolates (SPI) were prepared from 12 high protein lines, Harovinton variety and 11 derived null-lines which lacked specific glycinin (11S) and β-conglycinin (7S) protein subunits. Protein denaturation during SPI processing was monitored by differential scanning calorimetry (DSC). The results showed that hexane extraction of oil from soybean flours at 23 °C or 105 °C did cause changes in protein conformation. Rheological measurements showed that lines with different subunit compositions and 11S:7S ratio had distinctive gelation temperatures and resulted in gels with different network structures. All lines formed particulate gels at 11% protein. The 11S:7S ratio was not correlated to final stiffness, measured as the storage modulus G′, of SPI gels. Lower gelation temperatures were usually observed for 7S-rich lines. The absence of A3 and the combination of A1, A2 and A4 subunits of 11S fraction may suggest the formation of stiffer gels. A more detailed study of the frequency dependence of G′ for the various networks formed also indicated that differences in subunit composition influenced the network structures.