The Impact of Incorporating Coarse Wheat Farina Containing Intact Endosperm Cells in a Bread Recipe on Bread Characteristics and Starch Digestibility

Intact or broken wheat kernels containing clusters of intact cells can be used in wheat bread recipes to lower starch digestibility but result in very dense bread crumb. We hypothesized that a smaller wheat milling fraction [i.e. coarse farina (CF; average diameter 705 mu m)] that still contains intact cells can result in lower starch digestibility without a substantial deleterious effect on bread quality. We thus studied the impact of different levels of CF incorporation on bread characteristics and starch digestibility. A portion of the CF cell walls seemingly retained integrity throughout the bread making process. Bread volume and crumb softness linearly decreased with increasing levels of CF, yet remained acceptable. Unexpectedly, the extent and rate of in vitro starch digestion were not influenced by CF incorporation. In the complex bread crumb matrix, the reduced starch digestibility as a result of the inclusion of intact CF cells in the recipe may well be counterbalanced by increased starch digestibility as a result of the presence of a less elaborated gluten network and thus weaker gluten-starch interactions. Overall, modulation of starch digestibility in wheat bread is an inherently difficult task and incorporation of clusters of intact cells only appears effective at reducing starch digestibility when very large particles at plant tissue level are added.