The Effects of Lactic Acid Bacteria Fermentation on Protein Gelation and Gastrointestinal Digestive Characteristics from Four Pulses

The current study investigated the effects of lactic acid bacteria fermentation on the protein gelation and digestive characteristics from four pulses, namely, chickpea, red kidney bean, lentil and pea. Protein extracted from the four pulses was named CP, RKP, LP and PP. Protein gels were prepared by using Lactobacillus plantarum B1-6, and the least gelation concentration (LGC), texture characteristics, microstructure, and color were investigated. The gels were subsequently subjected to an in vitro dynamic gastrointestinal digestion, and the protein digestive characteristics and the protective effect on vitality of lactic acid bacteria were studied. The results showed that the LGC of CP, RKP, LP and PP gels was 1.6% (w/v), 1.6% (w/v), 1.4% (w/v) and 1.2% (w/v), respectively. The hardness of CP and LP gels was significantly higher than that of RKP and PP gels (P<0.05), and the gels formed by CP and LP demonstrated a relatively dense and uniform three-dimensional protein gel network, whereas the microstructure of gels formed by RKP and PP was relatively loose. The results obtained from the gastrointestinal study showing the CP and LP gels demonstrated a significantly higher protective effect on Lactobacillus plantarum B1-6 vitality compared with RKP and PP gels. The two gels (CP and LP) also gave higher soluble protein and peptide contents at the early and medium stages of gastrointestinal digestion. The results showed that the four pulse proteins exhibited different gelling capacities and digestibility characteristics during lactic acid bacterial fermentation. This study provided valuable information on the effects of lactic acid bacterial fermentation on fermentation performance, gelation property, and nutritional characteristics of different pulse proteins.