Antioxidant Activity as a Functional Advantage of a Fermented Milk Product During Storage
Background. The study of the antioxidant potential of a fermented milk product during storage is an urgent problem of preventing the formation of reactive oxygen species, activation of peroxidation and oxidative modification, leading to a decrease in the functional value of the food product. Purpose. The purpose of this study is to select and substantiate the shelf life and technological parameters of the preparation of a product from bacterial concentrate based on the antioxidant potential of the symbiosis of microorganisms. Materials and Methods. A symbiotic starter culture consisting of lactobacilli and milk yeast was used as an object of research, from which a bacterial concentrate was prepared and then a fermented milk koumiss product. The meta-analysis method systematized the most significant data on the effect of antioxidant activity on the functional potential of the fermented milk product during storage. The conditions and modes of bacterial concentrate cultivation during the production of fermented milk product were empirically selected, the main physico-chemical and microbiological parameters were determined, including the metabolic products of symbiotic microorganisms that carry out an antioxidant response. The optimal method for the study of antioxidant activity was chosen and the concentration of reduced glutathione in the finished product was determined. Results. The technological parameters of the preparation of a symbiotic product from bacterial concentrate are selected, taking into account its antioxidant activity. The optimal dose of bacterial concentrate is 1.0-1.2 %, which allows you to prepare the product within 12 hours and maximize the antioxidant potential of bacterial symbiosis during storage. The amount of glutathione in the finished product ranges from 23.88 to 27.45 mg /%, during the guaranteed shelf life it changes by no more than 14 %. The changes in the quality indicators of the product during storage and the level of vitamins C and B<sub>12</sub> were investigated. The optimal shelf life of the finished symbiotic product has been established, which is 10 days. Conclusions. The research results showed that the antioxidant activity of the heterofermen-tative product increases, compared with the end of fermentation on the 4th day of storage, this is apparently due to the metabolism of lactic acid bacteria and yeast, the formation of water-soluble peptides, the accumulation of enzymes and vitamins. Based on these data, a guaranteed shelf life of the product of 10 days has been established, which allows you to maximize the antioxidant potential. The amount of pro antioxidants in the product was determined: vitamin C, vitamin B<sub>12</sub>, reduced glutathione, its amount in the product ranges from 23.88 to 27.45 mg/%. During the guaranteed shelf life, it changes by no more than 14 %. The results obtained will make it possible to use the potential of antioxidant activity and the amount of reduced glutathione to predict and increase the shelf life of the fermented milk product