Impact of caseinomacropeptide on heat-induced gel strength of neutral whey protein concentrates: model system study.

摘要

The characteristics of heat-induced acid whey protein concentrate (AWPC) gels with added caseinomacropeptide (CMP; up to 25%) were studied in a model system prepared from freshly prepared AWPC and purified CMP derived from raw milk. The resultant AWPC was compared with commercial WPC and found to be quite similar based on its overall chemical composition. As CMP was added to the AWPC, the strength of the heat-induced gels decreased significantly as did the measured degree of intermolecular disulfide bond formation. SEM shows that the gels with higher CMP content developed a coarser structure with larger pores and a looser structural network when compared with gels prepared from AWPC only. CMP was also capable of forming weak gels that were structurally very different from AWPC gels, being more of an aggregate than a 3-dimensional network. DSC results demonstrate that increasing the level of CMP induced substantive changes in denaturation behaviour. Based on these results and literature data, it is concluded that CMP has a strong negative impact on the strength of WPC gels, indicating that an evaluation of the CMP content in commercial WPC formulations should be considered if gelation is an important functional requirement.