Impact of germination and enzymatic hydrolysis of cowpea bean (Vigna unguiculata) on the generation of peptides capable of inhibiting dipeptidyl peptidase IV

The objective of this work was to determine the impact of germination of cowpea (Vigna unguiculata), combined with enzymatic hydrolysis on the generation of bioactive peptides with dipeptidyl peptidase IV (DPP-IV) inhibition activity and antioxidant capacity. Germination (25 degrees C, up to 48 h) and alcalase hydrolysis (up to 4 h) significantly increased antioxidant capacity of cowpea proteins from 293.4 to 993.7 mu mol TE/g soluble protein (SP). The non-germinated and 1 h alcalase hydrolysates showed the highest DPP-IV inhibition (IC50 = 0.58 mg SP/mL), after in vitro simulated gastrointestinal digestion. Selected peptides in the hydrolysates were analyzed by computational modeling. The TTAGLLE peptide interacted with S2 (GLU205, GLU206) and S3 (SER209, ARG358, PHE357) pockets of DPP-IV, and it is expected to inhibit DPP-IV by blocking its active site. Cowpea short time germination (24 h) and alcalase protein hydrolysis (1 h) can be used to produce ingredients with high antioxidant capacity and DPP-IV inhibition. (C) 2014 Elsevier Ltd. All rights reserved.