THE EFFECT OF GRAPE SEED OIL FORTIFICATION WITH EXTRACTS OF NATURAL ANTIOXIDANTS

Abstract

Grape seed oil (GSO) consists mostly of triglycerides of polyunsaturated fatty acids, which are sensitive to oxidation and to the high temperatures. The aim of this research was to study the effect of GSO fortification with hydroalcoholic extracts of antioxidants from grape seeds, up to and after 12 months. It was established that the immediate effect of the oil fortification was the increase of the total polyphenol content (TPC) in the oil, by up to 141.34 mg GAE/kg of oil, and the increase of the DPPH• antioxidant activity by up to 0.580 mmol TE/kg (in the control sample, refined grape oil, these values were 1.57 mg GAE/kgand 0.003 mmol TE/kg, respectively). After 12 months, TPC and DPPH• antioxidant activity decreased nearly 10-fold in all of the fortified oil samples. The difference between the oxidative status of the oil was assessed (UV-Vis). In the case of the GSO sample, treated with n-octyl gallate, the absorbances remained unchanged after 12 months. When compared to the synthetic antioxidant n-octyl gallate, grape seed polyphenolic extracts were found to have a less protective effect on the oil during storage under environmental conditions.

Keywords

• antioxidant activity
• extract of polyphenols
• grape seed
• octyl gallate
• oil
• uv-vis