Influence of main production variables to nutritional characteristics of winery effluent Kombucha

Determination of sugar, nitrogen, and phosphorus consumption by kombucha culture is necessary to gain additional insight into the kombucha metabolic pathways and nutritional value of the produced beverages and to set a basis for optimizing the conditions for large-scale production. Kombucha beverage was made using effluent obtained from grape must clarification phase of white wine production. The fermentation medium was prepared by diluting the sterilized initial medium with approximately 16% of total reducing sugars to 3, 5, and 7% of total reducing sugars. The duration of the fermentation was nine days at 20, 25, and 30°C. Sugars, nitrogen, and phosphorus content were measured using DNS, Kjeldahl, and molybdenum blue methods, respectively. The highest sugar content was in the initial medium (16.34%) and the lowest was after nine days of fermentation at 30°C with 3% initial sugar content (0.17%). Residual levels of sugars, nitrogen, and phosphorus after three days were modeled using response surface methodology. The proposed mathematical models for sugars and nitrogen content showed an exceptional correlation with the experimentally obtained values. With this study insight into kombucha’s consumption of basic nutrients, nutritional value of the obtained products, and optimization of product composition was provided.