Abstract: The process conditions of carrot koumiss fermented by Lactobacillus acidophilus were optimized through range and variance analysis of orthogonal test. The optimum fermentation conditions at 37 ℃ are as follows:fermentation time 4 h,inoculation amount 8%(V/V),proportion of carrot juice to milk 4:6(V/V),sugar amount added 9%(W/V) and addition amount of sweet rice wine 10%(V/V). The final product of carrot koumiss has good quality,such as smooth taste,well coagulation state,no fat or whey release occurring,mild acidity and specific alcohol aroma(alcohol content 0.6%,V/V). Besides,40% carrot juice could accelerate fermentation of Lactobacillus acidophilus. After fermentation time of 3 h,the acidity is up to 92 oT and living bacterium number(LBN) is above 109 CFU/ml. During storage(below 4 ℃) after fermentation,the acidity increases slightly,but the LBN is above 108 CFU/ml after 3-d storage,and still above 107 CFU/ml after 15-d storage.

Key words: Lactobacillus acidophilus, carrot juice, koumiss, living bacterium number