A Novel Strategy for the Enzymatic Preparation of High-Digestibility and Low-Bitterness Casein Hydrolysates Based on Release Pattern of Bitter Peptides by Peptidomics and Random Forests Analysis

Abstract

This study revealed the effect of hydrolysis on the digestibility and bitterness of casein hydrolysates (CHs) and provided a novel strategy for the preparation of high-digestibility and low-bitterness CHs. Results showed that both the enzyme and degree of hydrolysis (DH) affected the digestibility and bitterness, while trypsin, alcalase and flavourzyme were more suitable to prepare target CHs. Peptidomics and random forests revealed that for bitter peptides with hydrophobic amino acids (HBAA) at N-terminal and basic amino acids (BAA) at C-terminal (HBAA-BAA type) released by trypsin, the long-chain ones contributed bitterness more than the short-chain ones. For bitter peptides with HBAA at both N-terminal and C-terminal (HBAA-HBAA type) released by alcalase, the short-chain ones contributed bitterness more than the long-chain ones. Furthermore, a low-bitterness hydrolysate contained shorter HBAA-BAA type peptides and longer HBAA-HBAA type peptides was provided. This work is of guiding significance for the preparation of high-digestibility and low-bitterness CHs.

Keywords: casein hydrolysates, hydrolysis, bitterness, digestibility