Uma Tiwari

Meta-analysis of the effect of β-glucan intake on blood cholesterol and glucose levels.

OBJECTIVE A meta-analysis was performed on epidemiologic studies to assess the relation between β-glucan consumption from oats and from barley on blood cholesterol level, triglyceride/triacylglycerol (TGL/TAG) level, and blood glucose level (BGL) in humans. In addition, the effect of β-glucan on total cholesterol (TC) and BGL was translated into an empirical dose-response model. METHODS Thirty research articles that evaluated the effect of different exposure levels of β-glucan on blood cholesterol and BGL were analyzed, yielding 126 clinical studies. RESULTS There was a significant inverse relation in TC (-0.60 mmol/L, 95% confidence interval [CI] -0.85 to -0.34), low-density lipoprotein (-0.66 mmol/L, 95% CI -0.96 to -0.36), and TGL/TAG (-0.04 mmol/L, 95% CI -0.15 to 0.07) after consumption of β-glucan. In contrast, an increase in high-density lipoprotein cholesterol was noted (0.03 mmol/L, 95% CI -0.06 to 0.13) with the random-effect model. The analysis showed a significant change in BGL (-2.58 mmol/L, 95% CI -3.22 to -1.84) with high heterogeneity between (I(2) = 97%) and across (τ(2) = 5.88) the studies. The fixed-effect model showed a significant change in TC, low-density lipoprotein, and BGL, whereas it showed no significant changes in high-density lipoprotein and TGL/TAG. The dose-response model showed that a 3-g/d dose of oat or barley β-glucan was sufficient to decrease TC. CONCLUSION Consumption of 3 g/d of oat or barley β-glucan is sufficient to decrease blood cholesterol, whereas the effect on BGL is still inconclusive, with high heterogeneity, and requires further clinical research studies with longer intervention periods.

Factors Influencing β-Glucan Levels and Molecular Weight in Cereal-Based Products

ABSTRACT The beneficial role of soluble dietary fiber in human nutrition is well documented and has lead to a growing demand for the incorporation of β-glucan, particularly from oats and barley, into foods. β-Glucan with high solubility and high molecular weight distribution results in increased viscosity in the human intestine, which is desirable for increased physiological activity. Molecular weight, level, and solubility of β-glucan are affected by genotype, environment, agronomic input, and the interactions of these factors and food processing methods. Available literature reveals that the level of β-glucan in a finished product (e.g. bread, cake, muffins) depends upon several factors in the production chain, whereas food processing operations are major factors affecting molecular weight and solubility of β-glucans. Therefore, to avail themselves of the natural bioactive compounds, food manufacturers must pay attention not only to ensure sufficient concentration of β-glucan in the raw material but als...

A Modelling Approach to Estimate the Level and Molecular Weight Distribution of β-Glucan During the Baking of an Oat-Based Bread

Oat and oat products containing β-glucans are associated with many health claims. Both the level and molecular weight of β-glucans play an important role in determining the physiological efficacy of β-glucan in terms of health benefits, including reducing blood cholesterol levels. The objective of this study was to develop a probabilistic model to investigate the effect of various process stages in bread making on the level of β-glucan (BG) and its molecular weight (Mw) distribution using Monte Carlo simulation techniques. Various composite flours were formulated by substituting wheat flour (WF) with oat whole flour (OWF), oat refined flour (ORF), oat bran (OB) or rolled oats (RO). The baseline model predicted an overall mean reduction of 49% in BG in baked bread. The mean Mw of β-glucan in all composite flours was reduced following processing and baking from 1.22 to 0.77 × 106 (g/mol) for OWF + WF, 1.07 to 0.68 × 106 (g/mol) for ORF + WF, 1.17 to 0.75 × 106 (g/mol) for OB + WF and 1.25 to 0.80 × 106 (g/mol) for RO + WF. In all formulated breads, high molecular weight β-glucan was observed to be more susceptible to degradation compared with medium molecular weight and to lower molecular weight. A sensitivity analysis highlighted the negative influence of WF on β-glucan content and the BG reduction with fermentation time. The scenario analysis showed a positive influence on the level of BG with increase addition of oat flour in all formulated breads. The model was validated with experimental data and values were found to be within the confidence interval of predicted BG levels. This model facilitates the optimisation of various steps in the bread making process and highlights the potential for oat flour to improve the nutritional quality of baked bread.

Functional and physicochemical properties of legume fibers

This chapter highlights legume fibers and their functional and physicochemical properties, and evaluates the effects of processing technologies on the quantity and quality of legume fibers. Legume (including pulse) fibers are reputed to have several beneficial health effects including delaying the release of carbohydrates, lowering of blood lipids, prevention of colon cancer, increasing the fecal transit time, and improving digestion. Legume fibers enhance nutritional, biological, and physicochemical properties by decreasing the transition time through the small intestine and also affecting innate immune responses of the gut mucosa both directly and indirectly. Many researchers and food processors are working to meet consumer demand by incorporating legume fibers in different food products (e.g. bread) as new functional ingredients. Several literature sources indicate that, in legumes, the levels of insoluble fibers are higher compared to the soluble fibers. This may speed the passage of foods through the stomach and intestines, and reduce the risk of colorectal cancer.

A comparison of oat flour and oat bran‐based bread formulations

Purpose – The purpose of this paper is to compare and evaluate for quality characteristics and β‐glucan analysis during different stages of the oat flour and/or oat bran based bread baking process.Design/methodology/approach – A 100 per cent wheat flour (WF) formulation was substituted with 30, 50 and 70 per cent oat flour (OF) or oat bran (OB) to improve its nutritional quality characteristics of bread. The flour blends were evaluated for quality characteristics (loaf volume, texture profile analysis) and β‐glucan analysis during different stages of the bread baking process.Findings – A significant decrease in specific volume, number of cells and crumb brightness was observed with increasing WF substitution levels with OF or OB. The crumb hardness was observed to be negatively correlated with specific volume of OF (r =−0.90, p<0.0001) and OB (r =−0.84, p<0.0001) bread. The level of β‐glucan was significantly reduced by 37.8 −42.9 per cent in dough during 45 min fermentation time, which indicating the enz...

Functional and physicochemical properties of non-starch polysaccharides

This chapter explains nonstarch polysaccharides (NSPs), which are the major part of dietary fiber (DF) and includes cellulose, pectins, glucans, gums, mucilages, inulin, and chitin. NSPs are the principal components of the plant cell wall and constitute a major source of fiber in the diet. They are classified into soluble and insoluble fractions. The insoluble fraction of NSP is normally found on the outer protective layer of plants, whereas soluble NSP is normally found in the inner parts of plants The key aspect of NSPs is that they are plant materials that are not digested by the enzymes of the human digestive tract but remain fermentable in the large intestine. NSPs are the principal components of dietary fiber and the lack of small intestinal digestibility explains the majority of their principal physiological properties. The physicochemical properties of NSPs result in a number of physiological effects that are related to certain health benefits. They are claimed to modulate blood glucose and insulin responses to foods to lower blood cholesterol and to have beneficial effects on the prevention and treatment of certain diseases like gallstones, diverticular disease, obesity, constipation, or colon cancer.