The production of drinking yoghurt from rambutan juice and survival of lactic bacteria

Abstract

The study aimed to investigate appropriate formula for drinking yoghurt production. The conditions were ratio of yoghurt : concentrated rambutan juice at 100 : 0, 90 : 10, 85: 20 and 75: 25, the effect of concentrated rambutan juice on physical and chemical and microbiological, lactic acid bacteria survival, appropriate proportion of syrup and lactic acid bacteria survival during storage of drinking yoghurt from rambutan juice. It was found that proportion of concentrated rambutan juice had no effect in color (L*, a*) of the yoghurt (p>0.05) but its impact to b* and viscosity were significant (p≤0.05), they increased with the increased proportion of the concentrated rambutan juice. Yoghurt with 15% concentrated rambutan juice had 88% survival rate of lactic acid bacteria after stimulated digestive system. The results showed that optimal production formula of drinking yoghurt from concentrated rambutan juice and syrup were 90:10 Z(yoghurt: concentrated rambutan juice; 85:15) : syrup) Drinking yoghurt stored in the refrigerator at 4±1oC for 15 day was evaluated and found that LAB survival numbers were 9.90 log CFU/mL.