The significance of arabinogalactan-peptide for wheat flour bread-making

The effects of wheat flour water-extractable arabinogalactan-peptide (WE-AGP), arabinogalactan from larch wood (LW-AG) and gum arabic from acacia tree (AT-GA) (1.0% and 2.0% substitution levels) on mixing characteristics of doughs from flour from two wheat Varieties (Torii-ida and Soissons) and the volumes of the resulting breads were studied. Baking absorption (500 Brabender Units line) decreased in the case of substitution of a limited proportion of flour (1% and 2%) with wheat flour WE-AGP, LW-AG and AT-GX. AT-GA decreased baking absorption less than wheat flour WE-AGP or LW-AG. Extended mixing times were required to obtain optimum Torfrida flour doughs (consistency of 500 Brabender Units) in the case of arabinogalactan(-peptide) substitution. However, this effect was not clear in the case of Soissons flour dough-making. Micro-extension tests on doughs (consistency of 500 Brabender Units and optimum mixing) illustrated that all arabinogalactan(-peptide)s caused a significant increase in maximum resistance to extension and a significant decrease in dough extensibility. The effects were less pronounced in the case of AT-GA substitution. In straight dough bread-making, arabinogalactan(-peptide)s caused a slight decrease in bread volume. (C) 2000 Academic Press.