Optimization of variable temperature fermentation process of koumiss and its quality analysis

Koumiss was made using fresh mare's milk as raw material. Using sensory score as response value, the variable temperature fermentation process of koumiss was optimized through response surface experiments based on single factor experiments, and the quality of koumiss was analyzed. The results indicated that the optimal variable temperature fermentation process of koumiss was inoculum 4%, Lactobacillus helveticus MX6 and Kluyveromyces marxianus ML25 inoculation ratio 1∶2, initial fermentation temperature 37 ℃, initial fermentation time 6 h and variable temperature fermentation time 30 h, the total fermentation time was 12 h shorter than the mainstream fermentation process. Under the optimized process, the sensory score was 92.8, the protein content was (1.75±0.04) g/100 g, the fat content was (1.42±0.11) g/100 g, and the acidity was (121.5±4.7) °T, the alcohol content was (1.4±0.26)%vol, the viable count of L. helveticus MX6 was 4.56×10⁹ CFU/ml, and the viable count of K. marxianus ML25 was 3.27×10⁷ CFU/ml, all met local standards. A total of 29 volatile flavor compounds were detected from koumiss, with esters being the most abundant and constituting important flavor compounds in koumiss. The results of this study shortened the traditional fermentation time of koumiss and provided a theoretical foundation for its industrial production.