Investigation of the influence of milk protein genotype on the process of fermentation of milk curds by mesophilic lactic acid streptococci

Abstract

The relevance of this study lies in the fact that the majority of commercial milk processed into fermented dairy products is a mixture of β-casein genotypes. The increasing use of A2 milk in the dairy industry necessitates the development of scientifically grounded technologies for the production of fermented products, as casein genotype modifications can affect the course of technological processes and require adjustments to production parameters. The study aimed to determine the impact of genetic modification of the β-casein protein in cow’s milk on the fermentation process of milk mixtures during the production of fermented dairy products. Research methods included chemical, physical, organoleptic, and microbiological methods (determination of the quality indicators of raw milk and fermented milk curds), and technological methods (determination of acid formation activity and viscosity). The initial characteristics of raw milk were investigated according to genotype, revealing no direct correlation. Changes in the physicochemical, microbiological, and organoleptic properties of fermented milk curds during biotechnological processing and storage were examined. Optimal technological process regimes were selected, and technological methods were chosen to minimise the influence of secondary factors on the experiment. A mixed culture preparation of mesophilic lactic acid lactococci, including L. Lactis ssp., was chosen as a starter culture. It was established that all 13 milk samples were suitable for biotechnological processing using mixed cultures of mesophilic lactic acid bacteria. As a result, it was concluded that the production of fermented dairy products from raw milk with the presented β-casein genetic modifications, A1A1, A1A2, and A2A2 – using L. lactis ssp. cultures – is possible using the classical technology and does not require adjustment of the technological conditions. The obtained results can be used in the dairy industry when developing technologies for fermented dairy products from A2 raw milk