Effect of Ripening and In Vitro Digestion on Bioactive Peptides Profile in Ras Cheese and Their Biological Activities

SIMPLE SUMMARY: Milk proteins contain peptides encrypted in their sequence with potential biological activities that can be released after protein hydrolysis as occurs during cheese ripening and gastro-intestinal digestion. The present study was designed to monitor the changes in the bioactive peptides’ profile and biological activities of Ras cheese during ripening (from 30 to 180 days) and in vitro digestion through the application of peptidomics. Results showed that ripening determined an increase in the amount of peptides with angiotensin-converting enzyme (ACE)-inhibitory, dipeptidyl-peptidase-IV-(DPP-IV)-inhibitory and antioxidant activities. The amount of these bioactive peptides was further increased after in vitro digestion. The evolution of bioactive peptides during ripening and in vitro digestion was correlated with the biological activities of cheese. The anti-hypertensive peptides VPP and IPP, with proven in vivo effects, were quantified, and the highest concentrations were found in long-ripened Ras cheese. The presence of bioactive peptides in cheese, especially in the long-ripened one, suggests a possible role of cheese consumption in maintaining human health and in the prevention of cardiovascular diseases and type-2 diabetes. Moreover, the present study allowed the identification of the best ripening time needed for the development of the highest biological activities in Ras cheese after digestion with potential industrial applications. ABSTRACT: The effect of ripening and in vitro digestion on the biological activities, peptide profiles and release of bioactive peptides in Ras cheese has been investigated. Ras cheese ripening largely influenced the extent of protein hydrolysis. The advancement in ripening resulted in an increase in total peptides (from 0.97 to 2.46 mmol leucine/g in samples at 30 and 180 days of ripening, respectively) and bioactive peptides concentration, especially angiotensin-converting enzyme (ACE)-inhibitory, dipeptidyl-peptidase-IV-(DPP-IV)-inhibitory and antioxidant peptides. In vitro gastro-intestinal digestion further promoted protein hydrolysis and the release of bioactive peptides. Digested Ras cheese at 90 and 180 days of ripening displayed the highest bioactive peptides intensity. The variations in bioactive peptides amount during ripening and in vitro digestion were correlated with the changes in ACE-inhibitory, DPP-IV-inhibitory and antioxidant activities. The highest amounts of VPP and IPP were detected in digested Ras cheese at 90 days of ripening (17.44 and 36.50 mg/kg of cheese, respectively), whereas the highest concentrations of APFPE were found in undigested and digested 180-day ripened Ras cheese (82.09 and 52.01 mg/kg of cheese, respectively). The present investigation underlined potential differences in the biological effect after the ingestion of Ras cheese at different ripening times.