Production and fermentation characteristics of antifungal peptides by synergistic interactions with Lactobacillus paracasei and Propionibacterium freudenii in supplemented whey protein formulations
Yujia Xie, Xiaojie Peng, Zheng Li, Juan Wang, Mingyi Li, Shanshan Xiao, Shaohui Zhang
Abstract
Whey protein, as a nutrient-rich waste from dairy industry, several studies have investigated its bioconversion. This study aimed to convert whey protein into antifungal peptides by synergistic interactions with Lactobacillus paracasei and Propionibacterium freudenreichii. The response surface methodology was employed for optimization. The optimum fermentation medium contained 26.69 g/L lactose, 28.44 g/L nitrogen sources (soytone: whey protein = 2:1, m/m) and the inoculum size was at 3.72% (v/v). The fermentate was sensitive to proteolytic enzymes, strong alkaline (pH > 10.0) and high temperature. A total of 156 peptides were identified by nanoliter liquid phase-Q Exactive quadrupole ultra-high resolution orbitrap mass spectrometer (Nano LC-Q Exactive Plus) and screened by PEAKS X software. Finally, the decisive factors of antifungal function were determined by principal component analysis. The research provided experimental and theoretical support for the process optimization and mechanistic explanation of whey protein fermentation to produce antifungal substances.