Oat Bran Fermentation by Rye Sourdough
ABSTRACT Hydration of oat bran including fermentation by rye sourdough was studied. Three types of oat bran suspensions were prepared (a control, one with whole meal rye flour added, and one with rye starter added). The suspensions were incubated for 1, 2, 3 and 4 hr. beta-Glucan content and solubilities of protein and beta-glucan were analyzed. Viscosity of the supernatants of oat bran suspensions was determined. Neither the rye sourdough nor the rye flour alone had a significant. effect on the total beta-glucan content of oat bran suspensions. However, the addition of rye, either as whole meal rye flour or as sourdough starter, markedly increased the solubility of beta-glucan and proteins and simultaneously decreased the viscosity of the water-soluble fraction of oat bran suspension. This suggests that a hydrolysis of beta-glucan had occurred that could change the rheological properties of oat bran in baking and the physiological potential of oat bran in nutrition.
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- "Recently, Storsley at al (2003) reported that there were no residual endo β-glucanases in barley flours following deactivation with hot 85% ethanol, and extracts of barley and oat flours were stable in water after 2 hr of treatment with boiling 80% ethanol (Papageorgiou et al 2005). However, there have also been reports of trace residual activity following reflux with aqueous ethanol (Beer et al 1996; Knuckles and Chiu 1999; Fomins et al 2002; Rimsten et al 2003; Andersson et al 2004; Flander at al 2007). Thus, it was important to ensure elimination of endogenous enzymes in this study. "
ABSTRACT: Oat and barley (1→3)(1→4)-β-D-glucans (β-glucan) are readily extracted by hot water but rye β-glucan is resistant to such extraction. This poor extractability might be due to entrapment within a matrix of arabinoxylan (AX) cross-linked through phenolic constituents. AX are the major nonstarch polysaccharides of the rye kernel. In this study, several approaches were compared in an effort to determine optimum conditions for extraction of high yields, high molecular weight (MW), and high purity of β-glucan from Canadian rye whole meal. Variables investigated included sodium hydroxide concentrations, extraction time, sample prehydration, extraction under low temperature, and prior extraction of AX with barium hydroxide. There was a linear relationship between the strength of NaOH and amount of β-glucan extracted and because MW was essentially the same up to 1.0N NaOH, this extraction agent, at room temperature for 90 min, was selected to isolate rye β-glucan. The β-glucan was then purified and structure and molecular weight distribution studied.Cereal Chemistry 05/2008; 85(3-3):283-288. DOI:10.1094/CCHEM-85-3-0283 · 1.23 Impact Factor
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- "Processes involving enzymatic breakdown of beta-glucan may affect the physical state of beta-glucan and reduce its viscosity (Mälkki and Virtanen 2001). Enzymatic breakdown of beta-glucan in processes, including breadmaking were shown in studies where enzyme active ingredients were used (Jaskari et al. 1995, Degutyte-Fomins et al. 2002, Salovaara et al. 2003). However, most of the clinical studies on oats and oat products have paid little attention to describing of the physical state of the beta-glucan. "
ABSTRACT: Oats contain 3-5% of mixed linked beta-glucan, or (1-3), (1-4) β-D-glucan, referred to hereafter as beta-glucan. Oat beta-glucan is a viscous, and soluble dietary fibre component. Soluble and viscous dietary fibres, including the beta-glucan present in oats are associated with two major health promoting effects, i.e. the attenuation of postprandial plasma glucose and insulin levels and the control of cholesterol. Increased viscosity in the intestine delays absorption of glucose and suppresses absorption of cholesterol and reabsorption of bile acids. In spite of its apparent key role physiologically the viscosity of beta-glucan has been discussed relatively little in terms of analytical procedures. In clinical studies performed with oats, the viscosity of beta-glucan has been properly documented in only a few cases. Viscosity of beta-glucan in foods and in the food digest depends on solubility, concentration and molecular weight. A food manufacturer aiming at health-promoting products must pay attention not only to sufficient concentration of beta-glucan (dose) in the raw material, but also to the processing methods that will ensure sufficient solubility of beta-glucan and minimize enzymatic or mechanical breakdown of the beta-glucan molecule. We have been working both with different food processes utilising oat fractions high in beta-glucan and with the development of a method for viscosity determination of the soluble beta-glucan fibre. This review discusses some of the aspects related to the development with a method that could predict the behaviour of beta-glucan in oat processing with respect to its anticipated physiological functions.Agricultural and Food Science 09/2004; 13(1):80-87. DOI:10.2137/1239099041838012 · 1.20 Impact Factor
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ABSTRACT: Thesis (doctoral)--University of Helsinki, 2005. Includes bibliographical references.