THE CHANGE OF ORGANIC ACIDS CONTENTS AT FRUIT MUSTS FERMENTATION

Abstract

The change o f organic acids contents at fruit must fermentation and determining its causes is a significant problem o f wine technology o f different types. It troubles scientists and experts, biologists, chemists, technologists have been engaged in it for several centuries and even nowadays. It is connected not only with manufacturing o f wine and other drinks o f high quality, but also with additional expenses at manufacturing, which are caused by insufficient mass concentration o f titrating acids and its improvement with the help o f organic acids adding. So, studying the factors, which affect organic substances in fruit must at fermentation, and analysis o f their influence force is o f essential importance for regulating the process in the targeted direction. Achieving set results means getting products o f high quality. A lot o f researches observed a tendency to reduction and improvement o f titrating acids contents at apple musts fermentation. The issue o f introducing differentiated standards o f titrating acids wastes at fermentation is up to date. The change o f organic acids contents at fruit musts fermentation highly depends on the environmental conditions, especially on mass concentration o f titrating acids o f fermentation in must. Increasing pasteurized musts contents is caused by their fermentation with a high original concentration o f sugars in a pure yeast crop from apples and pears with concentration o f titrating acids in must to fermentation, that is less than 4,0 g/dm3. Apple acid is usually almost lost during that process. But lactic acid, amber acid and volatile acids appear and balance its losses. The result o f organic acids biotransformation is the increase o f drink biological evaluation, ability to reduce citric acid losses at manufacturing.The increase o f titrating acids mass concentration (y, %) can be prognosticated by an equation o f the third order: y = 4,2258x3 - 55,45x2 + 267,04x -505,25, where x - actual mass concentration o f titrating acids in must to fermentation, o(x) = 15,96%. The area o f use: x < 4,0 g/dm3. Titrating acids losses (y) at fruit musts fermentation can be prognosticated with an equation o f a curve o f the third order: y = -0,1672x3 + 4,3807x2 - 35,96x + 99,42, where x - actual mass concentra­ tion o f titrating acids in must to fermentation, an average quadratic deviation o f losses - o(x) = 2,2%. The area o f use: x > 5,0 g/dm3. The direction o f titrating acids concentration change at fruit must fermentation cannot be exactly prognosticated in the area with the mass concentration of titrating acids in musts (x = 4 -5 g/dm3).