Protein Bioaccessibility of Unfermented Chickpea Milk and Lactiplantibacillus plantarum Fermented Chickpea Milk as Evaluated by In Vitro Gastrointestinal Digestion

In this study, In vitro gastrointestinal digestion (GIS) was utilized to investigate the protein bioaccessibility of chickpea milk nonfermented and fermented with Lactiplantibacillus plantarum. The soluble protein, peptide, and free amino acid contents; protein degradation; peptide profiles; degree of hydrolysis (DH); and particle size were investigated before digestion and during the oral, gastric, and intestinal digestion phases. Results showed that the soluble protein content of L. plantarum fermented chickpea milk (LFCM) was lower than that of unfermented chickpea milk (UFCM) after digestion. Proteolysis resulted in increased release of peptides and free amino acids. Smaller peptides gradually increased, and LFCM reached a higher peptide content after digestion. The electrophoretic profiles also indicated fast proteolysis. High-performance liquid chromatography (HPLC) presented more peaks in the digested LFCM profile than that of UFCM after digestion. Moreover, LFCM showed a higher degree of hydrolysis (DH) and a smaller particle size at the end of in vitro GIS. These data suggested that chickpea milk fermented with L. plantarum and the subsequent digestion was more effective in proteolysis, thus showing more potential protein bioaccessibility than the digestion of chickpea milk alone.