In vitro Determination of the Release Kinetics of Peptides and Free Amino Acids During the Digestion of Food Proteins

Abstract

The kinetics of peptide release during in vitro digestion of 4 protein sources (casein, cod protein, soy protein, and gluten) were investigated. Samples were sequentially hydrolyzed with pepsin (30 min) and pancreatin (2, 4, or 6 h) in a dialysis cell with continuous removal of digestion products. Nondialyzed digests were fractionated by ion-exchange chromatography and ultrafiltration. Animal proteins were digested at a greater rate than plant proteins. Target amino acids of specific enzymes appeared more rapidly in the dialyzed fractions when compared to other amino acids. Throughout the hydrolysis, nondialyzed digests contained a higher proportion of peptide mixtures with basic-neutral properties. Except for gluten, peptide fractions with molecular weights that exceeded 10 kDa (basic-neutral, BN > 10) were rapidly hydrolyzed during the first 2 h of pancreatin digestion. The kinetics of release and the composition of peptide fractions were different when the protein sources were compared. The analysis of amino acids revealed that threonine and proline proportions were relatively high in BN > 10 and in peptide fractions with molecular weight between 10-1 kDa (BN 10-1), while tyrosine, phenylalanine, lysine, and arginine predominated in the low molecular weight (<1 kDa) fractions. More resistant peptides were generally rich in proline and glutamic acid. The role of in vitro digestion assays in dietary protein quality evaluation is discussed.

Effect of fish meal replacement by plant protein blend on amino acid concentration, transportation and metabolism in juvenile turbot (Scophthalmus maximusL.)

“…In this regard, we speculated that FM‐based diet can release more basic AA‐binding peptides than plant protein sources because of the high basic AAs content. Indeed, in vitro digestion by pepsin and pancreatin indicates that FM is tend to release more small molecular peptides than plant proteins (Savoie, Agudelo, Gauthier, Marin, & Pouliot, ). Therefore, compared with FM diet, the plant protein blend incorporation coupled with extra crystalline AAs in PP40 diet would release more free AAs after feeding which were absorbed by various AA transporters in the digestive tract.…”

Application of in vitro digestibility methods in aquaculture: constraints and perspectives

“…While animal nutritionists are more concerned with protein digestibility either true or apparent, digestive physiologists are more interested in the digestion process itself, as well as in the composition and amounts of products released to the intestinal lumen and potentially absorbed. (Savoie et al 2005). It seems that results obtained with in vitro assays that evaluate differences in the release rate of amino acids after hydrolysis (M arquez et al 2012) or their intestinal absorption (Mart ınez-Montaño et al 2010; Mart ınez-Montaño & Lazo 2012) avoiding the interference with intestinal microbiota can correlate better to the potential bioavailability of protein than to its in vivo digestibility measured under the conventional conditions.…”

Charge properties of peptides derived from casein affect their bioavailability and cytoprotection against H2O2-induced oxidative stress

“…Picariello et al (2010) reported that peptides containing more neutral and basic AA underwent faster degradation compared with those with more acidic AA. Savoie et al (2005) observed that peptides rich in proline and glutamic acids are more resistant to pepsin and pancreatin activity. Burrell (1993) reported that peptides with the C-terminal end of lysine and arginine are preferentially cleaved by trypsin.…”