Evaluation of milk source on physicochemical, texture, rheological and sensory properties of yogurts

Abstract

Yogurt is one of the world's most widely consumed dairy products and can be produced from different types of milk. The present research aimed to compare the effects of utilizing whole raw milk from cattle viz. cows, buffaloes, sheep, and goats in four different milk-type yogurts, T1- cow’s milk (CM), T2- buffalo’s milk (BM), T3- sheep’s milk (SM), and T4- goat’s milk (GM) on their physicochemical, texture, rheological, and sensory qualities. The physiochemical testing included estimating pH, the percentages of moisture, fat, protein, ash, and total acidity, and the sensory assessment of the yogurt. The rheological tests also included the viscosity test, spontaneous whey separation, water-holding capacity, firmness, cohesiveness, and springiness. The results showed that T2- BM yogurt and T3- SM yogurt excelled in the percentage of fat, protein, lactose, and ash, where the ratio (4.35, 8.4, 4.70, 0.8) (5.55, 7.45, 4.80, 1.1) was for each of T2- BM yogurt and T3- SM yogurt respectively. The rheological properties were the spontaneous whey separation for each of T1-CM, T2-BM, T3-SM, T4-GM yogurt were 4.1, 2.2, 2.1 and 5.3, respectively, while the water holding capacity was 55, 60, 71 and 53 and the viscosity was 7000, 8900, 6700 and 1510 respectively. The results of the texture properties were 126.2, 199.5, 176.3, and 38.9 for firmness, while the cohesiveness values were 0.41, 0.63, 0.65, and 0.4, respectively. Finally, T2-BM and T3-SM yogurt excelled in the value obtained for sensory evaluation. The importance of the present study lies in the fact that milk with a high percentage of total solids gives good-quality yogurt.