Effects of barley beta-glucan-enriched flour fractions on the glycaemic index of bread.

The aim of this research was to evaluate beta-glucan-enriched flours, obtained from barleys with either normal or waxy starch, for their effects on the glycaemic index (GI) and the quality of bread. Rheological results confirmed that when barley flour was included in the dough the overall quality of bread slightly worsened. However, positive consequences on glycaemia were obtained with the normal starch barley: the GI of all-wheat bread (82.8 +/- 7.2) was significantly reduced (57.2 +/- 7.9) when 40% of wheat flour was substituted with beta-glucan-enriched barley flour (6.0% +/- 0.1 beta-glucan in the final flour blend). In contrast, this positive effect was significantly reduced (GI: 70.1 +/- 9.1) when 40% of wheat flour was substituted with the beta-glucan-enriched flour of a waxy barley (CDC Alamo; 6.6 +/- 0.2 beta-glucan in the final flour blend), suggesting that the ability of beta-glucans to lower the GI was affected by the barley starch-type.