Investigation of quality indicators of grape pomace of white and red grape varieties as pectin-containing raw materials used in the design of functional soft drinks

Due to its unique structure, chemical composition, physical and mechanical properties, grapes are one of the most valuable types of plant raw materials, the processing of which produces by-products: grape pomace, grape seeds, grape bunches, yeast sediments. The amount of grape pomace is about 20-25% of the total mass; if not used, this leads to an increase in production costs. Traditionally, grape pomace has been used as fertilizer or animal feed, but only the polyphenol content has been studied. Grape pomace is a complex natural composition of various components: skins, stems, grape seeds (seeds). Red wine marc is a by-product of fermentation, while white and rosé wine marc is removed before alcoholic fermentation, leaving the fermentable sugars in the marc. They contain organic acids, vitamins, microelements, and grape oil extracted from the seeds. The industry is expected to function as a natural ecosystem, with waste from one industry becoming the raw material for another. In order to rationally use natural raw materials, the main emphasis is on the development and implementation of new competitive high-tech safe technologies, as well as the search for new sources of biologically active substances from waste from food enterprises. The purpose of the research is to study the quality indicators of grape marc obtained using the white and red methods of processing grapes as raw materials for the production of functional soft drinks. It has been established that grape pomace is represented mainly by skins (84.8-87%). The main acids in grape pomace are tartaric («Firstborn of Magarach», «Cabernet Sauvignon») and malic. The main cation is potassium («Rkatsiteli»). The rich chemical composition provides enormous potential for the use of secondary grape processing products for the production of functional soft drinks.