The effect of incubation time to the physicochemical and microbial properties of yoghurt with local taro (Colocasia esculenta(L.) schott) starch as stabilizer

Abstract

The effect of incubation time by using three culture starters (Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophiles) and Taro (Colocasia Esculenta) starch as a stabilizer on the physicochemical and microbial characteristics of yoghurt were investigated. One of the problems in making yoghurt is the occurrence of syneresis caused by the unstable casein micelles. The addition of natural stabilizers is known to be able to solve the problem. In this research, local taro was added to the yoghurt as stabilizers followed by different incubation time (18-h, 24-h, 30-h, 36-h and 42-h). The results showed that incubation time had a highly significant effect (p<0.01) on viscosity, whey holding capacity (WHC), moisture content, carbohydrates, pH value, total acidity, and total lactic acid bacteria. During the fermentation process, the prolonged incubation time resulted in increased acidity, viscosity, WHC, and total lactic acid bacteria, while simultaneously decreased the pH value, moisture and carbohydrate content. The research concluded that 36 h incubation time produced the best yoghurt characteristics made with Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophiles as culture starters and taro starch as a local Indonesia stabilizer.