Ostroukhova O. Development of a Methology for Managing the Quality of Grape Wines by the Use of Enzyme Catalysis

The Thesis is concerned with the development of theoretical and methodological foundations of managing the quality of grape wines based on the systematization of endogenous parameters underlying the quality formation, from grapes to the finished product, and on the intensity regulation of the extraction and oxidation-reduction processes of the technological cycle by the use of enzyme catalysis. The regularities of the wine quality formation have been revealed that establish the interrelationships between the potentials of the grape berry's carbohydrate-acid, aromaforming, phenolic and oxidase complexes, the dynamics of the levels of components and the degree of their oxidation in the system "grapes - crush/must - wine material - wine" on the one hand, and the sensory characteristics of the wine on the other. The regularities of the wine quality formation during the crush maceration and fermentation have been revealed and found to be determined by the intensity of the extraction and oxidation-reduction processes, depending on the grape berry's phenolic and oxidase systems differentiated for the first time into two types, catalytic activity of exogenous enzyme systems as well as the regimes and conditions of the former two processes. It has been established that the intensity of the oxidative transformation of components of the wine materials dur-ing maturation depends on the mass concentration of phenolics, the degree of their oxida-tion and the proportion of flavonoid polymers in the young wine materials. Another find-ing has been that the maturation of the wine materials becomes intensified as a result of the use of exogenous hydrolytic systems in the crush maceration and fermentation. The established regularities have led to the development of an improved system for managing wine quality by the use of enzyme catalysis. The developed system relies upon the established parameters for monitoring wine quality in the system "grapes - crush/must - wine material - wine" and for optimizing the processes of the technological cycle; optimization agents such as exogenous enzyme systems with different catalytic activities; antioxidase and antioxidant preparations, the temperature regimes and duration of the processes; and algorithms for the use of enzyme catalysis in the production of different types of wines. The system has been tested, followed by its commercial introduction, and the relevant normative and technological documents have been developed and affirmed.