Get access

HEAT-INDUCED PROTEIN AGGREGATES AND DIFFERENCE IN THE TEXTURAL PROPERTIES OF WHOLE MILK GEL

Authors


TEL: +86-451-86282901; FAX: +86-451-86282906; EMAIL: lanweizhang@yahoo.com.cn

Abstract

ABSTRACT

The effects of heat on milk protein aggregates and the changes in the textural properties of whole milk gels induced by acid or rennet were investigated. Milk samples were heated at 70, 80 and 90C for 15, 30, 45 and 60 s. Acid gels prepared from heating whole milk showed larger values for hardness, adhesiveness and viscosity than the gels from unheated milk, while the corresponding rennet gels showed lower values when compared with the gels from unheated milk. These results reflect the changes in the heat-induced protein aggregates, which were examined by size exclusion chromatography using Sephacryl S-500 High Resolution (GE, Piscataway, NJ). It was also demonstrated that the protein aggregates were an important factor for milk gelation by active influence on acid gels and negative influence on rennet gels.

PRACTICAL APPLICATIONS

Heat-induced whey protein-rich cheeses are gaining in popularity for various reasons such as reducing the risk of pathogens and improving the cheese yield. However, the heat treatment can lead to changes in texture. As a part of the whole study on whey protein-rich cheese, the research analyzed the effects of high pasteurization on textural properties of the whole milk gels induced by rennet or acid. The results observed should guide the study on modification of protein aggregates, such as the use of an acidifier, and enable manufacturer to make rennet gel with textural properties close to raw milk.

Ancillary