Viscosity, smoothness and stability of yogurt as affected by structure and EPS functionality

摘要

The texture of three types of yogurts, set-style yogurt (yogurt gel), stirred yogurt and yogurt drink is evaluated. For set-style yogurt, gel firmness and gel structure are important features, which are mainly affected by protein content and denaturation of whey protein. For stirred yogurt a high viscosity and a smooth homogeneous texture are important quality characteristics. The smoothness, which is characterised by the particle size, is mainly related to the structure (permeability) of the yogurtgel. The viscosity is mainly affected by protein content, whey protein denaturation and the viscosity enhancing effect of exopolysaccharides (EPS). The key-factors for the viscosity enhancing effect are recently elucidated: molar mass, polysaccharide stiffness, which is related to the chemical structure of the repeating unit, and the concentration of EPS.