Fatty Acid and Tocopherol Composition of Pomace and Seed Oil from Five Grape Varieties Southern Spain

Abstract

Grape pomace and seeds are important winemaking by-products. Their oils are rich in bioactive compounds such as fatty acids and tocopherols. We have characterized oils from both by-products from five Spanish grape varieties (Palomino Fino, Pedro Ximenez, Muscat of Alexandria, Tempranillo and Tintilla de Rota). A high content of UFAs was found in all the analyzed samples. Grape pomace oils generally had the same oleic acid (PUFA(omega-6)) content as seed oils, and lower PUFA contents; they also had a markedly higher linolenic acid (PUFA(omega-3)) content, improving the PUFA(omega-6)/PUFA(omega-3) ratio. All the oil studied show good indicators of nutritional quality: low values of the atherogenicity (0.112-0.157 for pomace, 0.097-0.112 for seed) and thrombogenicity indices (0.30-0.35 for pomace, 0.28-0.31 for seed) and high values of the relationship between hypo- and hypercholesterolemic fatty acids (6.93-9.45 for pomace, 9.11-10.54 for seed). Three tocopherols were determined: alpha-, gamma- and delta-tocopherol. Pomace oils have higher relative contents of alpha- and delta-tocopherol, whereas seed oils have higher relative contents of gamma-tocopherol. A significantly higher content of total tocopherols has been found in pomace oil; it is higher in the oils from red varieties of pomace (628.2 and 706.6 mg/kg by-product), and in the oils from pomace containing stems (1686.4 mg/kg by-product). All the oils obtained can be considered as a source of vitamin E, and their consumption is beneficial for health.