Proximate Analysis of Goat Milk Yogurt Powder Produced by Freeze Drying and Vacuum-Oven Drying and in Comparing with Freeze-Dried Yogurt Powder Prepared with Tualang Honey
This study was carried out to produce powdered yogurt from goat milk with longer shelf life.Two methods of drying process of yogurt were used which are vacuum-oven drying (VD) and freezedrying (FD). Goat milk yogurt powder prepared with added Tualang honey (TH) was produced by freeze-drying method. In this study, four formulations of yogurt were prepared with the addition of commercial yogurt containingas starter culture.Granulated sugar was added about 8% into the yogurt as control sample. While other three yogurts were prepared with 8% of Tualang honey, 6% of Tualang honey with 2% of sugar and 4% of Tualang honey with 4% of sugar. The proximateanalysis was used in order to identify the proximate composition and pH value of the yogurt. The moisture content of goat milk yogurt, VD goat yogurt powder and FD goat yogurt powder were 79.20%, 8.22% and 9.66% respectively. While, the moisture content for FD goat yogurt powder with addition of 4%, 6% and 8% Tualang honey were 15.12%,15.92% and 13.53% respectively.While the value of ash content for FD goat milk yogurt powder with addition of 4%, 6% and 8% Tualang honey were 0.37%, 0.35% and 0.50% respectively. The total protein content for goat milk yogurt was 4.61% whilein VD goat yogurt powder and FD goat yogurt powder were 15.04% and 15.07% respectively. The value of protein content for FD goat milk yogurt powder with addition of 8% of Tualang honey was 15.38%. The pH value ofgoat milk sample and fresh yogurt goat milk were 6.52 and 3.82. The pH values for fresh yogurt with addition of 4%, 6% and 8% of Tualang honey were 4.64, 4.68 and 4.73.Vacuum-oven drying method and freeze-drying method did not show any significant different in moisture, ash and protein content but showed significant different in pH value.