Antioxidant Peptides Derived from Cheese Products via Single and Mixed <i>Lactobacillus</i> Strain Fermentation

Probiotics are used in cheese fermentation to endow the product with unique functional properties, such as enhanced flavor and aroma development through proteolysis and lipolysis. In this study, two probiotic <i>Lactobacillus</i> strains, <i>Lactobacillus plantarum</i> A3 and <i>Lactobacillus reuteri</i> WQY-1, were selected to develop new probiotic cheeses in the form of single- and mixed-strain starters. The results demonstrated that the <i>L. plantarum</i> A3 single-strain group and the <i>L. plantarum</i> A3/<i>L. reuteri</i> WQY-1 mixed fermentation group exhibited superior product performance, particularly the release of functional hydrolysates during cheese ripening. Furthermore, Label-free quantitative proteomic analysis revealed 26 unique antioxidant peptides in the <i>L. plantarum</i> A3 single-strain group and 53 in the <i>L. plantarum</i> A3/<i>L. reuteri</i> WQY-1 mixed fermentation group. Among these, CMENSAEPEQSLACQCL (β-lactoglobulin), CMENSAEPEQSLVCQCL (β-lactoglobulin), and IQYVLSR (κ-casein) have been found to possess potential antioxidant properties both <i>in vitro</i> and <i>in vivo</i>. This confirmed that milk-derived protein peptides in cheese products exhibit potential antioxidant functions through the hydrolysis of probiotic strains.