Microbiological and Physicochemical Dynamics in Traditional and Industrial Fermentation Processes of Koumiss

Abstract

Koumiss, a traditional fermented beverage made from mare’s milk, is typically consumed by nomads. Industrialized production of koumiss has been increasingly applied recently due to the increased demand for the beverage and awareness of its potential health benefits. However, it is unknown whether industrial koumiss is comparable to the traditional koumiss in terms of quality. In this study, we compared the microbiological and physicochemical properties in the industrial and traditional koumiss fermentation processes synchronously using culture-dependent and culture-independent approaches. Although Lactobacillus and Kazachstania species were similarly dominant in the bacterial and fungal communities, respectively, in both processes, the microbial counts and diversity in the traditional koumiss were significantly higher than those in the industrial koumiss. Furthermore, the traditional koumiss fermentation consumed more lactose, produced more flavor substances including acetic acid, lactic acid, ethanol, and free amino acids, and reached a lower pH value at the final stage. The physicochemical characters of traditional koumiss were mainly associated with Lactobacillus and Kazachstania species, which, in turn, were positively correlated with each other but negatively correlated with other non-dominant microbes. The starter was the major source of the microbial community of industrial koumiss, whereas both the starter and environment were the major sources of traditional koumiss. Random forest analysis recognized 11 significantly important genera as microbial indicators to distinguish industrial from traditional koumiss. Overall, this study shows that the microbial and physicochemical dynamics during the traditional and industrial fermentation of koumiss differ significantly, and the results obtained are valuable for improving the quality of industrial koumiss.