Acid and rennet-induced coagulation behavior of casein micelles with modified structure

Abstract

This review summarizes the effects of heating, acidification, high pressure treatment and enzymatic modification on coagulation (acid or rennet) behavior of casein micelles. Heating improves acid coagulation of casein micelles while it impairs rennet coagulation. Acidification results in the dissociation of colloidal calcium phosphate (CCP) and facilitates rennet-induced casein aggregation. Partial-rennet treatment of casein micelles improves acid gelation and leads to the formation of acid gels with higher elastic modulus and strength. Transglutaminase (TG) treatment increases casein micelle integrity and forms acid gels with homogeneous network and increased water holding capacity (WHC). TG treatment before renneting prohibits rennet coagulation while TG treatment following renneting produces gels with improved elastic modulus and WHC. The disintegration of casein micelles during high pressure treatment favors rennet coagulation while whey protein denaturation hinders coagulation. In contrast, high pressure treatment favors acid gelation, resulting in the formation of gels with increased rigidity and strength.

Keywords: Acidification; Casein micelle; Coagulation; Functionality; Heating; High pressure treatment; Rennet; Structure.