Differences in the microstructure and rheological properties of low-fat yoghurts from goat, sheep and cow milk

Abstract

Goat and sheep milks have long been used to produce a range of dairy products due to their nutritional value and health benefits. Information about the microstructure and rheology of goat and sheep yoghurts, however, is scarce. In this study, the microstructure, texture and rheological properties of cow, goat and sheep yoghurts were investigated and compared. The results show that a longer fermentation and gelation time was required for goat yoghurt with a lower storage modulus compared to cow and sheep yoghurts. Cooling resulted in an increase in the storage modulus at different magnitudes for cow, goat and sheep yoghurts. Goat yoghurt had a smaller particle size and a softer gel, which is linked with a more porous microstructure. The results obtained here demonstrate the effect of different milk types on the properties of yoghurts and provide a better understanding into the link between the microstructure and physical properties of the product.

Keywords: Fermentation kinetics; Gelation; Goat yoghurt; Microstructure; Rheology; Sheep yoghurt; Texture.