Fruit growing
and viticulture of South Russia

Annotation

A literature review of the main methods for the production of dyes from natural raw materials is carried out, the features of the technology are discussed. The study of the chemical composition was carried out using known chemical methods, the ionic composition was studied using capillary electrophoresis. The main attention is paid to the methods of obtaining natural dyes from onion husks and red pomace of technical grape varieties. The results of the study of the chemical composition, properties of extracts and test results in the production of food products are shown. It is noted that the industrial technology for obtaining dyes from secondary resources of colored food plant materials consists of the following main operations: drying the pomace or by-products during the canning of raw materials, extraction of dyes with an aqueous solution with the addition of various modifiers and subsequent concentration of the extract. The paper shows options for extracting biologically active components from onion husks with water, from dry and wet pomace of red grape varieties by acidified aqueous solutions, sugar syrup, including modified acids. The highest content of biologically active substances and anthocyanins was found in the extract from dry grape pomace of Cabernet-Sauvignon variety, then in cryo-must from the Merlot variety. Sugar syrup extracts were less saturated and more difficult to concentrate. It was found that the addition of acidic modifiers to 50% sugar syrup led to a decrease in the pH of the solution and contributed to an increase in the extraction of anthocyanins when dosing citric acid � 5 times more control (without modifiers), more than 4 times for boric acid and approximately 3 times higher for hydrochloric and acetic acids. The content of water-soluble dry matter, excluding sucrose, in the obtained extracts was 3.3 � 0.25 %. Natural dyes obtained in this way can be used in various branches of the food industry.