Abstract: Oat sourdough fermented with Lactobacillus plantarum was studied in this paper, and the acidity and aerobic plate count of the sourdough were analyzed to indicate the growth of Lactobacillus plantarum. Meanwhile, the effect of Lactobacillus plantarum on protein solubility, digestibility, amino acid compositions and nutritional index during the fermentation of oat sourdough was explored. The results indicated that Lactobacillus plantarum grew well in oat sourdough medium and had strong acid-producing capacity. Lactobacillus plantarum fermentation also resulted in a significant increase in protein solubility (P <0.05). Compared with the oat sourdough without fermentation, the protein solubility of oat sourdough with fermentation for 24 h and 48 h was increased by 19.50% and 54.06%, respectively. Protein digestibility was assessed by two-step digestion with pepsin followed by trypsin. Lactobacillus plantarum fermentation could significantly increase in vitro protein digestibility (P <0.05). The amount and compositions of total amino acids in oat protein did not reveal a big change. However, the amino acid score (AAS) in oat sourdough subjected to Lactobacillus plantarum fermentation was increased to 76.60 from 71.53. Moreover, the protein efficiency ratio (PER) was also enhanced.

Key words: Lactobacillus plantarum, fermentation, oat protein, solubility, in vitro protein digestibility, amino acid