Study of phenolic compounds and lipids of grape pomace

North-Caucasian Federal Scientific Center of Horticulture, Viticulture, Winemaking, Im. 40-letiya Pobedy Str. 39, Krasnodar, 350901, Russian Federation

^* Corresponding author: ageyeva@inbox.ru

Abstract

The article is devoted to the research of the makeup of phenolic compounds and fatty acids of grape pomace. The phenolic compounds were identified in skin and seed extracts and in extracts of skin-and-seed mixtures; the fatty acids – in grape oil generated by direct pressing. It was established that anthocyanins were present mainly in the skins. Low concentrations of ten components of the anthocyanin complex were identified in the Saperavi seeds. Maximum amounts of anthocyanins were found in the Saperavi skins. The concentration of quercetin distinguished by a PP-vitamin activity was by 1.5 to 2.0 times higher in the skin-andseed mixtures, especially of Roesler grapes, than in the skin itself. Maximum amounts of flavan-3-ols, hydroxy-cinnamic and hydroxybenzoic acids and oligomeric procyanidins, as well as the highest antioxidant activity were observed in the skin-and-seed mixture. The highest value of the correlation factor was observed in cases of interaction of antioxidant activity and concentration of procyanidins (r = 0.83), antioxidant activity and concentration of anthocyanins (r = 0.78), and antioxidant activity and concentration of flavan-3-ols (r = 0.75). Among the flavan-3-ols, it was (+)-D-Catechin that prevailed in grape seeds, with its concentration in the Pinot Noir extract (OAO APF Fanagoria) reaching 468 mg/dm³. Maximum concentration of Epigallocatechin-gallate was observed in the Saperavi and Pinot Noir seeds. As regards the concentration of hydroxy-cinnamic acids in the seeds, n-coumaric acid (Ancellotta, Saperavi) stood apart among the others; gallic acid (Saperavi, Ancellotta) came forward among the hydroxy-benzoic acids. In the reviewed samples of grape seeds, procyanidins of groups В₁ , В₂ and В₃ distinguished by high antioxidant activity prevailed. Prevalence of linoleic and oleic acids was established for grape oil extracted from the seeds of such red grape varieties as Cabernet Sauvignon, Pinot Noir and Saperavi. Maximum concentrations of oleic acid were found in the Pinot Noir and Riesling seeds. Palmitic and stearic acids were also available in rather high concentrations in the grape oil.