Production and evaluation of yogurt with concentrated grape juice

Fruit yogurt was prepared by adding concentrated grape juice (pekmez) CGJ, to milk. Optimum CGJ concentration and its Influence on duality and fermentation process of yogurt were evaluated. The pH, titratable acidity, protein content, viscosity, whey syneresis, starter bacteria, mold and yeast counts were determined weekly at 4 degrees C for 1 month. Addition of 10% CGJ provided desired sweetness. After 4h incubation of 5-10-15% CGJ-added yogurts the pH was 4.44, 4.98 and 5.90, respectively and the control was pH 4.26. CGJ addition increased fermentation time and decreased viscosity. During storage, acidity of 10% CGJ-added yogurt remained lower (P<0.05) than controls. CGJ did not affect (P>0.05) protein content and molds or yeasts were not detected.