Effect of chickpea thermal treatments on the starch digestibility of the fortified biscuits

Flour of roasted and heat-moisture treated chickpeas was used as a partial replacement of wheat flour, facilitating the development of biscuits with delayed digestion properties. The multiscale structural properties of starch and microstructural changes in chickpea flour and fortified biscuits were analyzed. Chickpea thermal treatment reduced the starch digestibility of fortified biscuits by 5.43%–7.33%, enhanced the resistant starch content of chickpea flour by 7.86%–12.28%. For thermal-treated chickpea fortified biscuits, the degree of relative crystallinity, short-range order, and double helix of starch was enhanced, the pasting viscosity was reduced, and the heat-moisture treatment showed a significant effect. Scanning electron microscope showed that fortified biscuits had a continuous and denser microstructure, reducing the accessibility of enzymes to hydrolyze starch molecules. The glycemic index values of fortified biscuits were reduced to below 66 in mice, as seen by their postprandial blood glucose response. Altogether, these results provide guidance for the development of delayed digestion meal replacement biscuits.