Influence of In vitro Digestion on Antioxidative Activity of Coconut Meat Protein Hydrolysates

Purpose: To investigate the antioxidative stability of coconut meat protein hydrolysates (CMPHs) in the gastrointestinal tract, and evaluate the changes in antioxidant activity, amino acid composition and molecular weight distribution of CMPHs during gastrointestinal (GI )digestion
Methods: A two-stage in vitro digestion model (pepsin treatment for 2 h followed by pancreatin treatment for 2 h, both at 37 °C) was used to simulate the process of GI digestion to determine changes in antioxidant activities, namely, 1,1- diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging and reducing power, of CMPHs previously prepared by papain digestion.
Results: Based on the in vitro pepsin–pancreatin simulated GI digestion, it was found that there were more free amino acids and smaller oligopeptides with MW < 500 Da in the final GI digests. Compared with blank, enzymatic breakdown of the GI digests increased their hydroxyl (by 11.8 %) and reducing power (by 71.8 %).
Conclusion: CMPHs are high value-added antioxidants and possess a potential capacity to resist gastrointestinal digestion, which makes them promising ingredients for formulation of functional foods.

Keywords
Coconut meat protein; Hydrolysates; Simulated gastrointestinal digestion; Antioxidative stability; Oligopeptides; Functional foods