Hydrolysis of casein and β-lactoglobulin by immobilized papain after pre-treatment with immobilized trypsin

摘要

Protein hydrolysis using immobilized proteases may present problems, which are mainly caused by the diffusion of macromolecular substrate. Pre-hydrolysed substrate could be a viable alternative in this process. The aim of this work was to test the casein and β-lactoglobulin hydrolysis using immobilized papain on glyoxyl-agarose, following substrate pre-treatment with immobilized trypsin. Although immobilized papain showed difficulties to degrade the milk proteins, after 10 min of trypsin pre-hydrolysis, the immobilized papain was able to achieve the maximum degree of hydrolysis in shorter time. For pre-hydrolysate casein, the immobilized papain reached 98.9% at 60 min total reaction (including the 10 min pre-digestion). As for β-lactoglobulin, immobilized papain was capable of achieving maximum levels after just 60 min of reaction, where the free enzyme only achieved 60% of its maximum. Pre-hydrolysis with trypsin appears to have worked well as a pre-treatment method to increase the proteolytic action of immobilized papain.ud