Cheese rheology and texture

Abstract

Texture of foods were all the rheological and structural attributes of the product perceptible by means of mechanical, tactile, and, where appropriate, visual and auditory receptors. The textural attributes of cheese is one of the important characteristics that determine its identity and quality. Commonly, texture is characterized by parallel-plate uniaxial compression tests. Since cheese is a viscoelastic material, relaxation tests become important, as well. The material is submitted to a constant deformation for a limited time while stress changes are recorded. Mechanical models such as Maxwell and generalized Maxwell models are used to describe solid food response to the applied force. All cheeses contain three major constituents (casein, fat and water) which each contribute to the structure and therefore to the rheological properties in their own specific way. The casein forms an open, mesh-like structure. The solid nature of cheese is mainly determined by the casein. The water, usually containing dissolved salt which has been added in the manufacture, is a major constituent of cheese. Fat in cheese is present as globules contained within the protein matrix network. Fat content in the cheese is responsible for its many desirable functional, textural, and sensory properties. Changes in moisture content, salt concentration, pH, and protein contents affecting cheese texture have been reported in several cheese varieties. Cheese ripening involves a complex series of biochemical, and probably some chemical events, that leads to the characteristic taste, aroma and texture of each cheese variety. Freezing of foods helps to preserve their shelf-life, colour, flavour, and nutritive value. Commercially, cheeses are frozen and stored to stop ripening and to prolong shelf-life during marketing. The alterations produced by freezing depend on the operating variables of the process and on the ripening time of the product before freezing and/or after thawing.