Fortification of white flat bread with sprouted red kidney bean (Phaseolus vulgaris)

Protein quantity in diet including the digestibility and bioavailability of protein is of importance to eradicate undernutrition in developing countries. Bread protein is an incomplete source as it lacks an essential amino acid lysine. When they are combined with other plant foods like pulses and legumes, they become a complete source of protein. Since bread is most common staple food the objective of this study is to fortify bread with legumes in order to increase the total protein content of bread to 13-15% which is required to meet at least 1/3rd of protein requirement of an adult recommended daily allowance.

Fortification of flat bread was done by adding sprouted red kidney bean flour (Phaseolus vulgaris) at 5, 15 and 25% to white flour. The composite bread was analysed for crude protein and in vitro protein digestibility using the Kjeldahl and pepsin-pancreatin method.

The protein content of raw beans showed trivial increase on soaking for 17 h and sprouting for 3 days. On the other hand, a remarkable increase was observed in protein digestibility i.e., 8% and 11% respectively. The protein content of control and composite breads increased gradually at 1% and protein digestibility decreased by 12% from control. This is due to the presence of dietary fibers which bind with protein and inhibit its digestibility.

The study infers that sprouting the beans for 72 h did not show any remarkable increase in protein content but a significant increase in in vitro protein digestibility was observed. Overall, breads made using 15% legume flour was comparatively equal in protein content, with overall acceptable quality.