Application of liquid and solid rheological technologies to the textural characterisation of semi-solid foods

Rotational rheometers and texture analysers are commonly used to test liquid and solid samples, respectively. This paper explores data provided by a texture analyser and a rheometer compared with that provided by a trained taste panel for semi-solid food.Associations are shown to exist for four different types of cream cheese with respect to the findings of a taste panel, rotational rheometry and texture profile analysis (TPA). Hardness, cohesiveness and adhesiveness are discussed for both taste panel and TPA. Good relationships were found between these techniques for hardness and adhesiveness, cohesiveness exhibited a less satisfactory correlation. In the case of the rheometer, yield stress, complex viscosity and viscoelastic moduli were measured. Yield stress was found to relate to hardness and adhesiveness, and complex viscosity and viscous modulus had relevance for cohesiveness. Elastic modulus, measured by the rheometer, and TPA elastic quality also correlated well. The relationships between textural measurements and microstructural engineering of the products have been discussed. The presence of vegetable gums, in particular addition of guar in instances where fat content is low can reduce the textural impact of the fat removal. The effects of high levels of calcium in spreadable products can be reduced by the addition of citric acid, which has been shown in the past to solubilise colloidal calcium phosphate.Combining instrumental techniques with a taste panel can increase the efficiency product quality assurance and design.