Towards the production of sustainable food: the biochemical facets of bread improvement through enrichment with sprouted beans flour

Background Legumes have a balanced nutritional profile, but their use as a staple food is hindered by the presence of anti-nutrients and by digestibility issues. Among processes that could overcome these limitations, sprouting provides an effective and sustainable option with positive effects on the nutritional profile. The first part of the study aimed to investigate the impact of short time sprouting (24, 48 and 72 h) on the changes in the macro- and micromolecular profile of cowpea seeds. In the second part, bread was prepared using wheat flour with added 72h germinated cowpea flour, with non-sprouted bean flour as a control. This work was carried out within the OnFoods project (www.onfoods.it) Methods The sprouted beans and the bread samples underwent protein profiling, along with protein hydrolysis and quantitation of fermentable oligosaccharides, of digestible/resistant starch, and of anti-nutritional factors. The INFOGEST protocol was used for in vitro static digestion on bread samples, monitoring protein digestion at the end of the gastric phase, as well as at the middle and final steps of the intestinal phase. Results The germinated (72h) bean flour exhibited a significant decrease in anti-nutritional factors, such as phytatesand protease inhibitors, and fermentable oligosaccharides, along with increased peptide release. Protein profiling indicates the absence of interactions between wheat and cowpea proteins, regardless of the germination step. Cowpea proteins in both types of bread were completely degraded to small peptides after gastric digestion. Peptide profiling is currently underway to identify any potential bioactive peptides. Moreover, bread containing sprouted bean flour had slightly higher levels of resistant starch compared to both the non-enriched bread and the bread enriched with non-sprouted cowpea flour. Conclusions The results evidenced as sprouting can be considered a sustainable and effective process to improve the nutritional features of legumes enriched bakery products.