The effect of incorporation of goat milk and soy milk as a cow milk replacement on the quality of yogurt

Abstract

This study was conducted to determine the effects on physical and sensory characteristics of yogurts when incorporation with goat milk and soy milk as a cow milk replacement. There are six sample of yogurts were prepared in which one sample control with 100% of cow milk and five samples which are yogurt with 100% of goat milk, 100% of soy milk, 50% of goat milk and 50% of soy milk, 25% of goat milk and 75% of soy milk and also 75% of goat milk and 25% of soy milk. Research shown that increasing proportions of goat milk caused decreasing in pH value. 'L' value of colour and yogurt's texture were increased by increasing the proportions of soy milk. A group of 50 consumer panels were involved in the sensory evaluation. Affective test of yogurt showed significant differences (p<0.05) between 100% of cow milk and 100% of goat milk and 50% of goat milk, 50% of soy milk and 100% of soy milk samples in overall acceptance. Besides the control sample, yogurt with 100% goat milk is widely acceptable by consumers while yogurt with 100% soy milk is the least acceptable by consumers. Yogurt with 100% goat milk also showed highest mean score for attribute colour, texture and taste of sourness. Overall, goat milk is suitable to replace cow milk in yogurt production. Soy milk is not suitable for yogurt making as the texture became solid.