Kinetic description of heat‐induced cross‐linking reactions of whey protein‐free casein solutions

Heat treatment of milk products induces several physico‐chemical changes that can compromise rennetability and milk protein functionality. The aim of this study was to investigate the kinetic parameters of heat‐induced polymerisation of whey protein‐free casein micelles in the native environment of skim milk, which were produced by microfiltration and ultrafiltration in a diafiltration mode. The intra‐ or intermolecular polymerisation of casein monomers by covalent cross‐linking of amino acids was analysed by gel‐permeation chromatography. The degree of polymerisation and the amounts of polymerisation products such as lysinoalanine and histidinoalanine leading to cross‐linking of proteins could be described as zero‐order reaction.