Lactic acid fermentation of pasteurized and powdered milk and optimizing the factors affecting the fermentation process

Abstract

Yogurt is a basic dairy product that has been consumed for centuries as a part of the diet, even when its beneficial effects were neither fully known nor scientifically proven. With time, yogurt has been continuously modified to obtain a product with better appeal and nutritional effects. In this study, both spontaneous and inoculated fermentation of pasteurized and powdered milk was performed in order to study the quality of the yogurts. In addition to that, bacteria were isolated from both types of yogurts and their microscopic characteristics had been observed under the microscope. Several factors are required to produce a good quality yogurt; such as, temperature, pH, NaCl concentration, liquid and powdered milk concentration etc. These fundamental factors were optimized in such a way that the yogurt was produced in a short incubation period and the efficiency of the fermentation process was enhanced due to optimal conditions. Moreover, the quality and texture of the yogurt remained unchanged up to 5 days.