Investigation of the dynamics of the chemical composition of fermented apple juices in the process of acetic acid fermentation

The article presents the results of a study aimed at a deep and comprehensive study of the factors that determine the effectiveness of the biochemical oxidation process, the study of the dynamics of the chemical composition of apple materials in the process of acetic acid fermentation. At the first stage of the study, a study of the chemical composition of apple juices was conducted. The pH, the content of solids, titrated acids, volatile acids, extract, sugars, nitrogenous substances, phenolic substances and carbohydrates were determined in the studied juice samples. At the second stage, a study of the chemical composition of apple materials was carried outduring fermentation. Fermentation of apple juice was carried out on a pure culture of yeast Apple-7. Fermentation was carried out at a temperature of 20-22⁰C. The finished fermented juice was alcoholized to 9% by volume and stored before use. Further, acetic acid fermentation was carried out in a deep way. The main technological and biochemical parameters were determined in fresh apple juice, fermented alcoholic juice and vinegar. As a result of determining the fractional composition of nitrogenous, phenolic substances and carbohydrates of apple juices, it was found that the chemical composition of apple juices depends on the method of processing apples and their varietal characteristics In the process of acetic acid fermentation of apple materials, a change in nitrogenous and phenolic substances is observed. At the same time, the carbohydrate composition practically does not change. When apple materials are oxidized by acetic acid bacteria, the processes of aldehyde formation and ether formation are significantly intensified. Thus, the data obtained indicate a variety of chemical composition of apple materials and vinegar obtained from them. In general, the chemical composition of apple materials and vinegar depends on the quality of processed raw materials and technological conditions of production.