Studying the vitamin-synthesis and antioxidant activity of the microbial consortium

The purpose of research is to study the dynamics of ascorbic acid and antioxidant activity during the fermentation of cow's milk by a microbial consortium. A study of the dynamics of ascorbic acid was carried out during the fermentation of milk by a microbial consortium and antioxidant activity during the ripening of the resulting product. The original combined starter (kefir starter + L. acidophilus + L. bulgaricus + L. helveticus in the ratio 1: 0.5: 0.5: 0.5, respectively) was used as control samples. To determine the vitamin C content, a titrimetric method was used, based on the interaction of ascorbic acid with sodium 2,6-dichlorophenolindophenolate. The antioxidant activity of the samples was assessed by the amperometric method using a Tsvet Yaruza-01-AA liquid chromatograph. Skim cow's milk was pre-pasteurized at 86 ± 2 °C for 10 min and cooled to a fermentation temperature of 30 ± 2 °C. 5 % starter was added to the prepared milk. In milk fermented by a microbial consortium, the accumulation of ascorbic acid continued during 24 hours of cultivation. In control samples, vitamin synthesizing activity decreased after 8 hours of cultivation. The study of antioxidant activity was carried out at a temperature of 30 ± 2 °C for 3 days of ripening. In the sample with the microbial consortium, an increase in antioxidant activity was observed within 72 hours against the background of its decrease in the control samples (kefir starter and combined initial starter). The pronounced antioxidant activity is probably due to the fact that the method of obtaining a microbial consortium develops mechanisms for maintaining a balance between the production of antioxidants and the development of oxidative processes that are independent of changes in cultivation temperature.