Enhance nutritional composition and protein digestibility of sprouted bean-fortified bread

Pulses serve as a vital nutritional source worldwide, providing proteins, carbohydrates, fiber, and phytochemicals. With approximately 21-25% protein content, pulses play a crucial role in meeting protein requirements, particularly for people in developing countries. Despite their health benefits, pulses contain antinutritional factors such as phytate and enzyme inhibitors, affecting digestibility [1]. Currently, sprouting is gaining attention as a low-cost, sustainable, and effective way to increase not just the levels of health-promoting components but also the nutrients' digestibility. This study explores the nutritional properties and digestibility of bread enriched with flour from 72-hours germinated cowpea (Vigna unguiculata). The selected sprouting time corresponds to the almost complete breakdown of the antinutritional factors. To minimize processability issues and to ensure a significant nutritional impact, 25% of unsprouted or sprouted cowpea flour was added to wheat flour. Samples were characterized in terms of protein content and profile, residual anti-nutritional factors (trypsin inhibitors and phytates), glucose and starch content (total, slowly and rapidly digestible, resistant), and content in gut-fermenting oligosaccharides. The slight increase in total protein in bean-fortified breads was related to the incorporation of a legume-derived component with Mr around 45 kDa. Analysis of the starch fraction revealed a decrease in total, rapidly digestible, and total digestible starch in bread enriched with either sprouted or unsprouted bean flour, whereas the content of resistant starch and glucose increased in the sample containing flour from sprouted beans. The sprouted bean flour breads also exhibited the lowest levels of trypsin inhibitors and phytates. The bread sample were subjected to in vitro digestion following the INFOGEST protocol to evaluate the degree of protein at the end of the gastric phase, as well as in the middle and at the end of the intestinal phase. SDS-PAGE at various time of “in vitro” digestion showed that large and medium-sized proteins bands were no longer present at the end of gastic phase, which appeared more intense in sprouted cowpea flour-enriched breads. Duodenal digestion produced small-size peptides, most of them are not retain in the SDS-PAGE gel. Further analysis is underway to identified the nature of protein hydrolysis products and their bioaccessibility. All together hese data indicated that bread enriched with sprouting bean flour could be a very promise food with improved nutritional properties.