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Effect of yeast-fermented and sour-dough making processes on physicochemical characteristics of β-glucan in whole wheat/oat bread

Gamel, Tamer H., Abdel-Aal, El-Sayed M., Tosh, Susan M.
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2015 v.60 no.1 pp. 78-85
baking, beta-glucans, bioactive properties, breadmaking, breads, depolymerization, dietary fiber, dough, enzymes, fermentation, functional foods, lactic acid, molecular weight, oat bran, oat flour, oats, pH, propionic acid, solubility, titratable acidity, viscosity, wheat, whole wheat flour
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 (Mw) during dough process. Sour- and sponge-doughs had lower rates of β-glucan depolymerization, resulting in breads with medium to high β-glucan Mw 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 Mw 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 Mw and viscosity during baking process when a blend of whole wheat flour and oat bran was used.