Optimation Formula of Goat Milk Yoghurt and White Oyster Mushroom Powder with Mixture Design Methods

Abstract

Yoghurt is a product of fermented milk using lactic acid bacteria as a starter. As a probiotics, Lactobacillus achidophillus was applied in the making of symbiotic yoghurt with white oyster mushroom powder as a prebiotic source. The objective of this research was to optimize goat milk yoghurt formula by mixture design with three component (white oyster mushroom, skim milk and skim goat milk) and four responses (pH, viscosity, total titrated acid and lactid acid bacteria). The result indicated that the optimum formula was a mixture of 0.5% white oyster mushroom, 3% skim milk and 96% goat skim milk. The optimum formula low pH, high viscosity and high total lactic acid bacteria. Lastly, the optimum formula was further modified by adding spices syrup as a topping (made from ginger extract, mixture extract of cloves-cardamom-anise and mixture extract of cloves-cardamom-anise) in a different volume of addition (2, 4 and 6 mL) with serving size of 100 mL goat milk yoghurt. These hedonic test result showed that the highest score of the taste properties were 4.37 for 4 mL addition of ginger syrup; 4.13 for 6 mL addition of mixture of cloves-cardamom-anise syrup and 4.23 for 6 mL addition of mixture of cloves-cardamom-cinnamon syrup. Based on these results, the consumer’ preference was still at the level of netral rather like.