Angiotensin converting enzyme and dipeptidyl peptidase-IV inhibitory activities of transglutaminase treated sodium caseinate hydrolysates

Angiotensin converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitory activities of crosslinked and non-cross-linked sodium caseinate (NaCN) hydrolysates were studied. Three different samples were generated: NaCN hydrolysed with Prolyve 1000 (TM) (Prolyve), NaCN cross-linked with transglutaminase (TGase) pre-Prolyve hydrolysis and NaCN cross-linked post-Prolyve hydrolysis. Gel filtration and reverse phase HPLC analysis of the resulting samples indicated that the hydrolysates had similar peptide profiles. Hydrolysates showed higher (p 0.05) differences in activity were found between cross-linked and non-cross-linked hydrolysate samples. Hydrolysate IC50 values for ACE and DPP-IV inhibition ranged from 0.10 to 0.17 mg mL(-1) and 0.85-1.18 mg mL(-1), respectively. Simulated gastrointestinal digestion had no significant (p > 0.05) effect on the bioactivities of the hydrolysates. The results demonstrated that incubation with TGase before or after NaCN hydrolysis with Prolyve had no effect on ACE or DPP-IV inhibitory activities. (c) 2017 Elsevier Ltd. All rights reserved.