Coagulation temperature affects the microstructure and composition of full fat Cheddar cheese

Abstract

An understanding of coagulation and factors that affect cheese microstructure is important, as this microstructure influences cheese texture and flavour. Of particular importance to many producers is the loss of milk fat during the cheese-making process, which reduces the inherent value of the product. The aim of this study was to investigate the effect of coagulation temperature on the microstructure of gel, curd and cheese samples during the manufacture of full fat Cheddar cheese. The microstructure of the gel formed at 27 °C consisted of a fine interconnected protein network as compared to a coarse, irregular and more discontinuous protein network in gel formed at 36 °C. At a higher coagulation temperature (36 °C), the size of the casein micelle aggregates in the protein strands increased when observed using confocal laser scanning microscopy possibly due to increased hydrophobic and ionic interactions and the rearrangement of casein micelles. This characteristic microstructure observed in the gel was retained in the curd collected prior to whey draining and may be responsible for the increased loss of fat in the whey. The concentration of fat in dry matter in cheese prepared from cheese-milk coagulated at 27 °C and 30 °C was significantly (P < 0.05) higher than in cheese made from milk coagulated at 33 °C and 36 °C possibly due to the observed differences in microstructure and the direct effect of coagulation temperature on physical properties of the fat and the casein micelles. Our results suggest the need to control milk coagulation temperature, as this parameter may affect product microstructure and fat retention.