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 (Torfrida 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-GA. 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.