Identification of bioactive peptides in commercial Cheddar cheese

This study examined the presence of antimicrobial, antioxidant and antihypertensive peptides in three commercially available Australian Cheddar cheeses. Peptide extracts as well as fractionated peptide extracts were examined. Commercial cheese A peptides exhibited the greatest inhibition against Bacillus cereus and also commercial cheese A fractionated peptides greater than 10 kDa showed the highest inhibition against B. cereus. Commercial cheese A peptides also showed the highest inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH), a free radical used to measure antioxidant activity. All cheese fractionated peptides greater than 10 kDa demonstrated higher inhibition of DPPH after fractionation. Antihypertensive peptides were determined by inhibition of the angiotensin-converting enzyme (ACE). Overall, commercial cheese A had the lowest concentration required to inhibit ACE and commercial cheese A fractionated peptides lower than 5 kDa had the lowest inhibition after fractionation. These preliminary findings suggest that peptide extracts of three commercial Australian Cheddar cheeses exhibit antimicrobial, antihypertensive and antioxidant properties.