| As an important components of food, edible oils was easy oxygenated and eating themcan lead to cancer, Cardiovascular disease, quicken airframe ageing and other diseases.Besides fine processing, sealing packing, lipid peroxidation can be reduced or controlled byantioxidant. Synthetic antioxidants, such as BHA, BHT, TBHQ, can effectively restrain thelipid peroxidation, but research shows that safety of them should be doubted, so it isnecessary to develop safe, efficient and natural antioxidant. Grape polyphenols, as animportant secondary metabolites of grape, mainly exists in grape seed and skins, also presentin the branches, tendrils and leaf. In this paper, the basic elements and antioxidant activity ofgrape skins extracts were detected, and antioxidative effect of grape skins extracts to lard,rapeseed oil, sesame oil, soybean oil, peanut oil, sunflower seed oil and til oil, seven kinds ofcommon oil of dietary was reflected through the determination to POV and acid value. Thiswork can provide the theory basis to develop a practical natural antioxidant. The results wereas follows:1. Grape skins contained a number of phenolics, and confirmed that it have goodantioxidant activity.2. Grape skins extracts was added to edible oils according to certain mass fraction of oils,at the condition of71±1℃, POV and acid value were determined in a certain time. Meanwhileother conditions such as different temperature, different antioxidant and synergy weredetermined to reflect the influence to lipid peroxidation of edible oils. The results were asfollows:(1) For lard, the more grape polyphenols extracts added, the slower POV changed andthe quicker acid value changed. The best adding amount of rapeseed oil, sesame oil, soybeanoil is0.02%, and peanut oil, sunflower seed oil and til oil is0.10%.(2) Acid value and POV of lard, rapeseed oil, sesame, soybean oil, peanut oil andsunflower seed oil changed quickly under the condition of high temperature. On the contrary,the changes were slowly at15±1℃and5±1℃. The low temperature conditions is helpful fortheir preservation. But for til oil, its POV was better controlled under high temperaturecondition than low temperature. (3) The antioxidant activity of grape polyphenols to lard and til oil was not ideal; torapeseed oil, soybean oil, the controlling to POV was basic equal to BHT and TBHQ and forsunflower seed oil and sesame oil, the controlling was better than BHT, and also better thenTBHQ to sesame oil. But the effect of the three antioxidants on peanut oil was not verysignificant, POV was not easy to control. In addition, the acid values of edible oils, addedgrape polyphenols, were higher than BHT and TBHQ. The controlling to acid value of BHTto peanut oil and rapeseed oil and TBHQ to other edible oils was better.(4) When the ratio of grape polyphenols: Vc was1:4, the antioxidant effect on rapeseedoil and soybean oil was the best; All of the synergy were not ideal to acid value of lard,sesame oil and consideration of POV, the suitable ratio was1:4and2:3respectively. Theacid values of peanut oil treated with different ratio were not exceeding critical value, butPOV changed a lot. To sunflower seed oil, the synergy effect was significant and the best ratiowas2:3. Acid values of til oil were not exceeding critical value in30days and performedsmall values, and its best ratio was3:7.3. According to Arrhenius equation and the calculation principle of shelf life, shelf life ofedible oils in this test were predicted, inorder to provide the theory reference for the followingapplication. |
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