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Six cold-pressed oil samples obtained from the seeds of different grape varieties grown in a Fruška Gora vineyard in the Republic of Serbia were examined for chemical and nutritive quality, as well as antiradical capacity. All the tested samples were of good quality, but the results showed noticeable differences in seed oil properties for red and white grape varieties. The highest content in total tocols, 575.23 ± 4.46 mg/kg, was found in the red grape seed oil of the Merlot variety, but the vitamin E activity of white grape seed oils was significantly higher. Regarding single phenols, the most prevalent fraction in all the oil samples was ursolic acid, up to 336.3 ± 4.8 μg/g in the grape seed oil of the Hamburg variety. The highest content in the total phenolic compounds, 54.92 ± 0.93 μg GAE/g, was detected in the oil of red grape seeds. Although significant differences existed between samples, EC50 values were the lowest for the red grape seed oils, varying from 29.84 ± 1.07 to 65.34 ± 0.32 mg oil/mg DPPH, indicating that these oils had the highest antiradical capacity. Se examinaron seis muestras de aceite prensado en frío obtenid as de semillas de diferentes variedades de uva cultivadas en un viñedo de Fruška Gora en la República de Serbia, para determinar su calidad química y nutricional, así como su capacidad antirradicalaria. Todas las muestras analizadas fueron de buena calidad, pero los resultados mostraron propiedades de los aceites de semillas notablemente diferentes para las variedades de uva roja y blanca. El mayor contenido de tocols totales, 575,23 ± 4,46 mg/kg, se encontró en el aceite de semilla de uva roja de la variedad Merlot, pero la actividad de la vitamina E de los aceites de semilla de uva blanca fue significativamente mayor. Con respecto a los fenoles simples, la fracción prelevante en todas las muestras de aceite contenía ácido ursólico, hasta 336,3 ± 4,8 μg/g en el aceite de semilla de uva de la variedad Hamburg. El mayor contenido de los compuestos fenólicos totales, 54,92 ± 0,93 mg GAE/g, se detectó en el aceite de semillas de uva roja. Aunque existieron diferencias significativas entre las muestras, los valores de EC50 fueron más bajos para los aceites de semilla de uva roja, variando de 29,84 ± 1,07 a 65,34 ± 0,32 mg de aceite/mg de DPPH, lo que indica que estos aceites tenían la mayor capacidad antirradicalaria.

The oxidative properties of sunflower oil supplemented with rambutan extract, (crude extract and its fractionated fraction, SF II) in comparison with synthetic antioxidant were investigated. The supplemented sunflower oils were stored under accelerated conditions for 24 days at 60 °C. For every 6-day interval, the oxidative properties of the supplemented sunflower oil were evaluated based on the following tests, namely peroxide value, p-anisidine value, Thiobarbituric Acid Reactive Substances (TBARS) assay, iodine value and free fatty acids. The total oxidation (TOTOX) values were also calculated based on the peroxide values and p-anisidine values. Rambutan extract is a potential source of antioxidant. The oxidative activities of the extracts at all concentrations were significantly (p < 0.05) higher than the control. Generally, the partially fractionated fraction was more effective than the crude extract. With a 2-year storage period at ambient temperature, the fractionated fraction of the extract, SF II at 300 ppm, was observed to work more effectively than the synthetic antioxidant, t-Tocopherol, and it possessed a protective effect comparable with butylatedhydrioxynanisole (BHA). Therefore, rambutan extract could be used as a potential alternative source of antioxidant in the oil industry or other fat-based products to delay lipid oxidation.