Effects of baking on dietary fibre, with emphasis on beta-glucan and resistant starch, in barley breads

In this study, 50% sifted barley flour from six different varieties and 50% refined wheat flour was used to bake bread. The flour mixture and the bread crumb and crust were analysed for content and composition of total dietary fibre, arabinoxylan, fructan, beta-glucan, starch and resistant starch. Total dietary fibre content and extractability were not changed significantly by bread making. The extractability of mixed linkage (1 -> 3), (1 -> 4)- beta-D-glucan (beta-glucan) increased with baking, while the average molecular weight of beta-glucan decreased. However in one variety, SW 7, higher average molecular weight was maintained and a different pattern was apparent in the molecular weight distribution. SLU 7 is thereby promising for inclusion in bread where a higher molecular weight of beta-glucan is preferred, especially since the content of beta-glucan in SLU 7 is high. The resistant starch formed positively correlated with amylose content. The high amylose variety yielded 2.9% resistant starch in the bread crumb, making an important contribution to total dietary fibre. (C) 2017 Elsevier Ltd. All rights reserved.