Tryptic hydrolysis of β-lactoglobulin: A generic approach to describe the hydrolysis kinetic and release of peptides

Abstract

Enzymatic hydrolyses of proteins are established processes to release functional peptides that can be used in various food applications. Prediction of hydrolysate composition requires detailed knowledge and understanding of the reaction dynamics of protein breakdown and peptide release. Therefore, degradation of the model substrate β-lactoglobulin, and the time-dependent release and hydrolysis of, in total, 59 peptides were characterised during tryptic hydrolysis (37 °C, pH 8.0, E/S-ratio 0.1%). These data were used to parametrise a parsimonious, generally applicable mathematical model that describes the formation of an enzyme-substrate-complex as a second-order reaction and the release of products via degradation of the complex as first-order reaction. To improve the fit of the model, a dependency of the reaction rate constant on the peptide length of the hydrolysis substrate was included. As only general characteristics are used, the proposed model is easy to use and can give a rough prediction of hydrolysate composition.