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

Abstract

Determination of sugar, nitrogen and phosphorus consumption by kombucha culture is necessary in order to gain additional insight into the kombucha metabolic pathways, nutritional value of the produced beverages, and to set basis for optimising 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 was measured using DNS, Kjeldahl and molybdenum blue method, respectively. The highest sugars content was in the initial medium (16.34%) and the lowest was after nine days of fermentation at 30 ?C with 3% initial sugars content (0.17%). Residual levels of sugars, nitrogen and phosphorus after three days were modelled 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 the insight into kombucha?s consumption of basic nutrients, nutritional value of the obtained products and optimization of products composition was provided