High Pressure Inactivation of Lactobacillus plantarum in a Model Beer System

Butter and milkfat are examples of plastic materials forwhich texture is a critical factor in determining functionality and consumer acceptance. The methods by which butter rheology is characterized are discussed, including large deformation techniques such as cone penetrometry, compression, sectility and extrusion, and methods which involve testing at low levels of strain. Correlations between instrumental tests and sensory-evaluated properties of the fats are explored. Rheological properties, including hardness, spreadability, setting, work softening, and thixotropy are described, and the models which have been proposed to characterize these behaviors are reviewed. Techniques which have been devised recently to quantitatively relate structural measurements to rheology are also examined. Modification of butterʹs rheological properties can be accomplished through alterations in composition or in the manufacturing process. These approaches are discussed and evaluated.