Increase of milk heat stability by addition of casein glycomacropeptide

Abstract

The effect of caseinglycomacropeptide (CMP) addition on the heat stability and physicochemical characteristics of milk was studied. The heat coagulation time (HCT) of milk samples with different CMP concentrations added were analysed and was observed that HCT increased when CMP was added in concentrations between 0.4 and 1.25% (w/w). Therefore, a more detailed physicochemical study was carried out in milks with CMP concentrations of 0.4, 0.6 and 0.8% (w/w). Also, the effect of two heat treatments to milk with CMP addition, applying conditions similar to UHT and in container sterilisation, was monitored. Two opposing effects were observed. On the one hand, CMP bound calcium conferring heat stability and, on the other, increased total electrical conductivity decreased the pH, slightly destabilising serum proteins and, hence, inducing colloidal instability. Therefore, there is a concentration range in which this peptide may act as heat stabiliser and as a nutritional additive in milk.