Variation of the Oxidation Index of Soybean Oil in Home-made Oxidation Device at Different Time

[Objective]The research aimed to discuss a new method for the rapid and repeatable oxidation of soybean oil and an evaluation index system for its oxidation degree.[Method] In home-made oxidation device and under oxidation conditions,the acid value(AV),peroxide value(POV),iodine value(IV),thiobarbituric acid reactive substances(TBARS) and fat acid of the unrefined soybean oil were determined at 0,7,14,16 and 18 d repectively.[Result] under 80 ℃ in the home-made device,the POV and TBARS of the soybean oil changed significantly,therefore,they could act as an indicator of rapid oxidation,the oxidation rate slowed down after 18 days;the AV,IV and TBARS of the soybean oil and the oxidation duration showed a quadratic variation,while its POV and oxidation duration showed a exponential variation.Compare with 0 d,AV,POV and TBARS significantly increased respectively by 1.7,29.0 and 19.0 times(P0.05),but IV significantly decreased by 0.91 times(P0.05);UFA significantly decreased from 84.0% to 82.2%(P0.05).There were no significant difference of POV,TBARS,SFA and UFA betewen 16 d and 18 d of oxidation(P0.05).[Conclusion] The research determined the variation of the oxidation index in the home-made device at different time and provided references for the test model of the hepatopancreas damage of fishes.