Role of microbial exopolysaccharides on moisture retention, texture and functionality of low-fat mozzarella cheeses

Abstract

Capsular and ropy microbial exopolysaccharides (EPS) produced by selected strains of Streptococcus thermophilus were used to make low-fat mozzarella cheeses containing 6% fat in a small-scale pilot study. The effects of EPS on moisture retention and textural and functional characteristics were investigated over 28 days of storage at 4°C. Texture profile analysis (TPA), meltability, stretchability, and pizza bake performance were analysed. Control cheeses made with non-EPS strains had the lowest moisture content of 53.77%. Control cheeses exhibited poor meltability and stretchability and greater hardness, springiness and chewiness. Capsular and ropy EPS increased moisture retention in cheeses to 57.17% and 58.39%, respectively, and EPS was isolated from curd at 31.09 mg/g and 51.65 mg/g, respectively. Cheeses made with EPS were softer, showed lower degree of springiness and chewiness and exhibited better stretchability and meltability as compared to control cheeses, although meltability of capsular EPS cheeses was not significantly different to the control (p>0.05). Adhesiveness and cohesiveness were greater in EPS cheeses compared to control cheeses. Adhesiveness of the two types of EPS cheeses was similar, but cohesiveness was greater in ropy-EPS cheeses. Pizza bake performance was poor for all cheeses although those made with EPS showed greater Hunter L-values and lower a-values to signifying less scorching.