Stability of Grape Seed Oil and its Antioxidant Tocotrienols
For the experiment three different storage conditions were chosen: storage at room temperature of 22 °C in the light and in the dark and in the dark in a refrigerator at 4 °C. Parameters monitored were: peroxide value and changes in the content of α-, γ-and δ-tocotrienols and α - and γ-tocopherols during storage for 210 days (30 weeks). The peroxide value is an indicator of the content of primary oxidation products of oils. From analytical analyses results that the greatest destruction of grape oil occurs during storage at room temperature and access of light, where a peroxide value increased up to 484 meq. O2/kg oil). The least intrusive method of storage was in terms of temperature refrigerator (4 °C) in the dark, when during 30 days of storage peroxide value had risen only to 71.9 meq. O2/kg oil. Between these values were values stored at room temperature in the dark (after 30 weeks storage 196 meq. O2/kg oil). From these parameters is clearly showed that to the stability of oil contribute significantly both factors - temperature and light conditions. The same trend was also found in tocotrienols. At room temperature and access of light was complete decomposition of α-tocotrienol in the 9th week of storage, γ-tocotrienol at 30 weeks of storage and δ-tocotrienol in the 18th week of storage. The most stable seems γ-tocotrienol > δ-tocotrienol > α-tocotrienol. When stored in the refrigerator in the dark, there was practically no decomposition of α-, γ-and δ-tocotrienols whose contents remained completely unchanged.
Jimmy (C.M.) Kao, Wen-Pei Sung and Ran Chen
J. Lachman et al., "Stability of Grape Seed Oil and its Antioxidant Tocotrienols", Advanced Materials Research, Vols. 1030-1032, pp. 370-373, 2014