Reserch On Potential Antioxidant Stability Of Sacha Inchi Oil

Sacha Inchi oil is considered as a a functional oil with containing more than 93% unsaturated oil fatty acids,it is susceptible to oxidative deterioration during period of storage and processing,which can destroy its nutritional and economic values.However,compared with other vegetable oils,Sacha Inchi oil had stronger antioxidant capacity.Recentelly,a few research was focus on antioxidant mechanism of Sacha Inchi oil.In this research,we first analyzed the effect of moisture content on oxidation stability of Sacha Inchi oil.Furthermore,the oxidation characteristics of Sacha Inchi oil,Linseed oil and Perilla oil was also evaluated.In addition,antioxidants of polyphenols,vitamin E,sterol involved in Sacha Inchi oil were extracted and purified,and their antioxidant capacity were also evaluated.The major results and conclusions are listed as follows :(1)The moisture content of Sacha Inchi seeds could significantly affected the composition and oxidation stability of Sacha Inchi oil,and the appropriate moisture content of Sacha Inchi seeds is less than or equal to 8%.When the moisture content of Sacha Inchi seeds ranged from 4%-10%,the moisture content is lower,conjugated dienes,trienes and carbonyl compounds content of Sacha Inchi oil rose more slowly during the oxidation process.The lower the moisture content existed in Sacha Inchi seeds,the higher the vitamin E and polyphenol contents in Sacha Inchi oil are,and the lower the loss rates of phytosterol and vitamin E in the oxidation process are.When the moisture content of Sacha Inchi seeds was 8%,the loss rate of polyunsaturated fatty acid was the lowest in the oxidation process,and the loss rate of polyunsaturated fatty acid of 10% wa s significantly higher than that of 4%.(2)During accelerate oxidation process at 60 ?,the average growth rate of conjugated dienes and trienes,peroxide value and carbonyl compounds contents in the oxidation process from low to high as follows: Sacha Inchi oil<Linseed oil<Perilla seed oil.The induction time of 110? from long to short as follows: Sacha Inchi oil<Linseed oil<Perilla seed oil.After 30 days of oxidation,the minimum changes of FT-MIR spectrum was Sacha Inchi oil,and the Perilla oil was maximum.Totally,these results indicated that the oxidation stability of Sacha Inchi oil was strongest,and the second was Linseed oil,Perilla seed oil was the weakest.(3)Changes of the main active components of Sacha Inchi oil,Linseed oil and Perilla seed oil in the accelerate oxidation process at 60? were studied.The results showed that with increasing oxidation time,the loss amounts of sterols and polyphenols from large to small were Perilla seed oil > Sacha Inchi oil > Linseed oil;the loss amount of vitamin E from large to small: Perilla seed oil > Linseed oil > Sacha Inchi oil,which might indicate that polyphenols,sterols and vitamin E were closely related to oxidation stability of the oil.The loss levels of polyunsaturated fatty acids and the increase levels of saturated fatty acids of three oils from low to high were: Sacha Inchi oil<Perilla seed oil<Linseed oil,which further indicated that polyunsaturated fatty acids of Sacha Inchi oil was more stable in the oxidation process than Perilla seed oil and Linseed oil.Furthermore,the correlation analysis showed that ?-,?-tocopherol,polyphenols and unsaturated fatty acids of Sacha Inchi oil could obviously strengthen its antioxidant stability in the oxidation process.(4)Polyphenols,sterols and vitamin E isolated from Sacha Inchi oil was studied on the antioxidant activity to Sacha Inchi oil.The results showed that Vitamin E of Sacha Inchi oil possessed the stronger antioxidant capacity than polyphenols and sterols of Sacha Inchi oil.Vitamin E exhibited the strongest antioxidant capacity on these three systems of superoxide anion,hydroxyl radical,DPPH-free radical,and the second was polyphenols,sterol was the weakest one.The oxidation stability of Linseed oil and Perilla seed oil wih the addition of polyphenols,sterols and vitamin E isolated from Sacha Inchi oil were obviously weaker than Sacha Inchi oil(p<0.05).These results revealed that the composition of Sacha Inchi oil itself was the vital contributor to its antioxidant stability.