The process of yak milk fermentation by polycomponent starter culture

The paper presents a comparative characteristic of the fermentation processes of yak and cow milk samples with a high fat content of 1.5 and 6 with a multicomponent starter culture, which includes Lactobacillus acidophilus, Bifidobacterium animalis subsp Lactis and Streptococcus thermophiles. Acid formation in the process of milk fermentation under the influence of the starter microflora was assessed by the dynamics of changing in titratable (Ac) and active (pH) acidity over time. The course of the formation of the structure of the resulting clot was monitored on a rheometer, fixing the viscosity characteristics of the fermented milk clot in dynamics. It has been established that the increase in acidity occurs more intensively in yak milk in comparison with cow's milk with a corresponding acceleration of the formation of a fermented milk clot. In conclusion, the resulting clots were subjected to sensory analysis with the identification of the best sample, which was fermented yak milk with a fat mass fraction of 6.

Keyword: cow milk; fermentation; rheological properties; starter culture; yak milk