Study into effect of food fibers on the fermentation process of whey
We report the results of research on the effect of food fibers on the fermentation process of whey - the base of beverages. By using the method of IR spectroscopy, we studied various forms of moisture bonds of apple pectin in fiber and orange fruit fibers Citri-Fi with water or whey. The results obtained show the existence of strong hydrogen bonds and high concentration of the movable proton. High sorption capacity for water is observed. This effect is important in terms of regulating the viscosity of wort. By employing mathematical modeling, we established conditions for the preparation and introduction of Citri-Fi to whey for obtaining beverages with enhanced viscosity. The visualization is provided of the transformations of dry Citri-Fi when swelling in whey - an increase in the volume of tubular fibers. For the basic indicators of fermentation (the content of carbon dioxide, the amount of formed ethyl alcohol and yeast cells, the content of reducing sugars) we defined rational conditions for the fermentation of whey-plant wort with enhanced viscosity. During fermentation using the race Zygosaccharomyces lactis 868-K, the most intensive growth of yeast cells at the level from 42.3 to 71.3 mln/cm3 was observed over the interval of 6…24 hours of fermentation. The dynamics of accumulation of carbon dioxide in wort is correlated to the indicators of growth in yeast cells. The data obtained indicate a certain oppression of yeast development in whey-plant wort. This is due to the presence of colloidal substances of whey and the residue of insoluble components of food fibers. We established a fermentation temperature of whey-plant wort with enhanced viscosity - 30…32 °C, at which there is a sufficient accumulation of ethyl alcohol at the level of 0.64...0.69 % by volume. Further increase or decrease in temperature results in a decrease in the amount of alcohol, indicating a decrease in the activity of cell enzymes. We have proven the possibility to apply the results obtained for developing a technology for manufacturing whey-based fermented beverages with enhanced viscosity