Bioactive Protein Hydrolysate Obtained from Canned Sardine and Brewing By-products: Impact of Gastrointestinal Digestion and Transepithelial Absorption

Abstract

A sardine protein hydrolysate (SPH) was prepared by hydrolysis of sarcoplasmic proteins from canned sardine by-product with proteases from brewer’s spent yeast (BSY). The SPH presented in vitro angiotensin converting enzyme-inhibitory (ACE-I) and ferric reducing antioxidant potential (FRAP). However, the challenge before in vivo efficacy studies is to understand the impact of ultrafiltration (UF), simulated gastrointestinal (GI) digestion, and the intestinal cell permeability. Thus, this work was carried out to study the influence of these parameters on SPH bioactivity; two predictive models for human intestinal absorption were compared. Results showed that ACE-I and antioxidant activities were improved after UF of SPH through a 10 kDa cut-off membrane; simulated GI increased the FRAP value whereas the ACE-I remained similar. The apparent permeability coefficients of < 10 kDa fraction evaluated using Caco-2 and Caco-2/HT29-MTX cell models were 5.89 × 10−6 cm/s and 10.93 × 10−6 cm/s, respectively. Mass spectrometry revealed that molecules with m/z between 1000 and 5000 were transported across Caco-2/HT29-MTX cell monolayer. Basolateral permeates presented antioxidant activity but no ACE-I activity was detected. These results suggest that SPH prepared by BSY proteases is promising as functional ingredient with enhanced antioxidant activity and justifies further in vivo studies to confirm its pharmacological efficacy.