Physico-chemical and rheological properties of plain yogurt made from goat's milk during refrigerated storage

Abstract

This study aimed to evaluate the effects of the addition of culture on the physico-chemical and rheological characteristics of plain set goat milk yogurt during four weeks of refrigerated storage. Three goat milk yogurt formulations were prepared, each varying the type of culture used (ABT5, ABY3 and YC380). There were significant differences in the pH values, titratable acidities, moisture content, total solids and percentage syneresis values of all formulations during the storage. All yogurts exhibited shear thinning (thixotropic) flow with different time-independent models for the upward and downward curves. Their viscoelastic behaviour firmly confirmed their weak gel structure that deteriorated during storage time.