Abstract:

By adding different amounts of inulin to milk before yogurt fermentation, it was found that the added inulin
was able to stimulate the growth of lactic acid bacteria, enhance the water holding capacity, viscosity and sweetness of
yogurt, decrease the pH value, and changed the texture. At the same time, inoculum size and fermentation temperature were
investigated by single-factor experiments, and response surface methodology was designed to optimize the two fermentation
conditions together with inulin concentration. By analyzing the experimental data using Design-Expert V8.0.6, the optimum
fermentation parameters were determined as follows: 47.85 g/L inulin, an inoculum size of 2.34%, and a fermentation
temperature of 42 ℃. Under these conditions, the sensory score of yogurt was 92.12 showing a relative standard deviation of
0.37% compared to the theoretical value of 92.46.

Key words: inulin, yogurt, response surface methodology, rheology, sensory quality