Evaluation of Rheological, Physicochemical, and Sensory properties of Apple fortified Yoghurt

Abstract

Fruit yoghurt was prepared by adding apple pulp at the rate of 10% (AY1), 20% (AY2) and 30% (AY3) (w/v) respectively into milk. The physico-chemical, sensory and rheological properties of different types of yoghurt were determined. A control (C) was prepared to compare the quality characteristics with apple yoghurt. The pH of the apple yoghurt lies between 3.89-4.01 whereas for control yoghurt it is between 4.14-4.34. The addition of apple pulp lead to decrease the pH, syneresis percentage, viscosity and an increase in total solid (TS), water holding capacity (WHC) of the yoghurt. AY3 revealed the highest WHC (%) whereas the lowest value was observed in case of C. Significant differences (p<0.01) are observed for appearance, color, flavor and mouth feelness of different types of yoghurt. The rheological properties of all the samples were analyzed by using Brookfield rheometer and it was found that all the samples follow pseudo plastic nature by following power law model of viscosity. Flow index for C, AY1, AY2 and AY3were found as 0.57, 0.418, 0.402 and 0.395 respectively. So it can be concluded that Apple yoghurt serves as an excellent food worldwide and can get easily accepted by the consumers.