Impact of Heat Treatment on Some Properties of Goat Milk Yoghurt.

Abstract

This study aimed to investigate the impact heat treatment on goat's milk yoghurt. Fresh goat's milk from three breed groups (Damascus, Zaraibi and Baladi) during the lactation period (March to August) were used in making fresh and stored yoghurt using yoghurt culture (YC-380DVS). The first treatment was served as control (A) where it was treated thermally with 90 0 C /5 min, second treatment (B) was treated with 90 0 C /10 min, third treatment (C) was treated with 85 0 C /30 min. Treatment (A) showed the higher SN (0.36) in fresh and stored yoghurt and also higher TVFA (1.73) in fresh yoghurt. Treatment (B) characterized with higher acidity (0.95 and 0.97) % in fresh and stored yoghurt, respectively. Higher fat content (3.17%) was found in stored yoghurt and higher TVFA (1.73 and 1.83) in fresh and stored yoghurt, respectively. Treatment (C) showed the higher pH value (4.6 and 4.47) in fresh and stored yoghurt, respectively, higher T.S (15.2 and 15.81) was detected in fresh and stored yoghurt, respectively, higher Fat content (3.03%) in fresh yoghurt, higher TN (0.65 and 0.68%) and protein (4.15 and 4.36%) in fresh and stored yoghurt, higher curd tension (CT)