Influence of Probiotic Lactobacillus acidophilus\ud and L. helveticus on Proteolysis, Organic Acid\ud Profiles, and ACE-Inhibitory Activity of cheddar\ud Cheeses Ripened at 4, 8, and 12 ◦C

The influence of adjunct bacteria on composition of cheeses, organic acid profiles, proteolysis, and ACE-inhibitory activity during ripening at 4, 8, and 12 ◦C for 24 wk was investigated. cheddar cheeses were made with starter lactococci (control), Lactobacillus acidophilus L10, and starter lactococci (L10), and L. acidophilus L10, L. helveticus H100, and starter lactococci (H100). The counts of L. acidophilus in L10 cheeses remained at >106 colony forming units (CFU)/g after 24 wk of ripening at 4, 8, and 12 ◦C. Concentrations of lactic, acetic, and propionic acids of the L10 and H100 cheeses were significantly higher than those of the control cheeses after 24 wk of ripening (P < 0.05). Proteolysis of the cheeses was improved as the ripening temperature increased. Water-soluble nitrogen, trichloroacetic acid soluble nitrogen, and phosphotungstic acid soluble nitrogen of L10 and H100 cheeses were significantly higher than those of the control cheeses (P < 0.05). Increase in ripening temperature from 4 ◦C to 8 and 12 ◦C increased the percentage of ACE inhibition. The IC50 value among cheeses ripened at 4, 8, and 12 ◦C, however, was not significantly different (P > 0.05). Hence, probiotic L. acidophilus L10 can be added into cheddar cheeses to improve proteolysis and ACE-inhibitory activity