Study on resveratrol content in grapes and wine products

Abstract

The current state of the agro-industrial complex and the food industry allows to satisfy the needs of various consumers groups. Among those needs, functional foods enriched with beneficial nutrients are becoming more and more popular. Polyphenols are sometimes used as such additives. The bioflavonoid resveratrol, among the group of polyphenols, has very promising antioxidant, therapeutic, antimicrobial properties. In this regard, studying the potential of its use in the food is highly relevant. Resveratrol is naturally present in the dark grapes. It is localized in the skin of the fruit and passes into the food substance during technological processing. This transition has its own patterns which are outlined in this article. Three varieties of grapes were chosen as the objects of the study: Cabernet Sauvignon, Merlot, Krasnostop. Clarified musts from these grape varieties, concentrated musts and wines were researched. High performance liquid chromatography (HPLC) was utilized as the research method. This method allows to separate liquids of complex composition into components with subsequent identification of the mixture composition. To calibrate the chromatograph, the standard “25 mg European Pharmacopoeia”, produced in France, was used as a standard for the pure substance of resveratrol. As the result of the study, it was found that resveratrol is present in the studied samples in various amounts from 4,4 to 7,0 mg / dm³ in the grape juice, from 6,9 to 12,6 mg/dm³ in the wine materials, from 12,4 to 21,3 mg / dm³ in the concentrated juice. These data help establishing the influence of the processing technology of wine and juice concentrates on the resveratrol content. The article also discusses the potential of using concentrated grape juice, rich in resveratrol, to obtain various food products.