Volatile And Migration Rules Of Butylated Hydroxytoluene(BHT) And Its Antioxidation Activity Under Food System

The antioxidant capacity of food antioxidant2,6-Di-tertbutyl-4-methylphenol (BHT) indifferent oil&fat systems were evaluated in this paper. The key factors influencingantioxidant ability of BHT were assessed with the Rancimat test. The key factors influencingthe loss of BHT were investigated using oven experiments. In addition, the conversion formsof BHT in soybean oil were determined, and its antioxidant mechanism was elucidated. Theloss ways of BHT were discussed in food system, meanwhile, the impact on physico-chemicalproperties of frying oil and shelf-life were evaluated.The antioxidant effects of BHT in oil systems were evaluated by Rancimat method andthe data were analysis by kinetic model, the results showed BHT has significant antioxidanteffect on animal fat, and the antioxidant effects depends strongly on BHT dosage, with fasterrate at high dosage. The correlation coefficient of activation energies(Ea) and BHT dosage is0.927(R2), and the kinetic rate constant rate also had a good correlation with BHT dosage (|r|≥0.779). The antioxidative activity of BHT showed insignificantly to vegetable oils (such asplam oil, soybean oil, teaseed oil, sunflower oil and linseed oil), but significantly related tounsaturated degree of oils, which showed higher effect on activation energies(Ea) than BHTdosage. A linear relationship was established between antioxidant effects of BHT andtemperature both in animal&vegetable oil systems. The natural logarithms of the kinetic rateconstant (k value) varied linearly with respect to temperature(R2>0.99). The order of factorsinfluencing antioxidant effects of BHT in vegetable&animal oils were determined usingresponse surface methods, is found to be:Temperature> Oil unsaturation degree> BHTdosage.The factors influencing BHT loss rate were investigated using oven experiments.Soybean oil and lard were selected for model oils on BHT loss under60℃~180℃, whichshowed that BHT loss was positively related to temperature. Loss dosage, loss rate and lossaccelerated speed of BHT were positively correlated to its initial dosage. BHT loss rate wasenhanced by the presence of air in oil systems. A linear correlation between heating time andBHT loss rate of5kinds of vegetable oils was established(R2>0.97). The iodine value is highly related to BHT loss rate, comparatively, correlation coefficient|r|≥0.895among2h、4h、12h、24h、36h and48h. Peroxide value of soybean oil had slight effect on BHT loss rate,while, fatty acid content&type of soybean oil had no significant effect.The factors influencing BHT loss rate were investigated using oven experiments.Soybean oil and lard were selected for further study on BHT loss under60℃~180℃, whichshowed that BHT loss was positively related to temperature. Loss dosage, loss rate and lossaccelerated speed of BHT were positively correlated to its initial dosage. BHT loss rate wasenhanced by the presence of air in oil systems. A linear correlation between time and BHTloss rate of5kinds of vegetable oils was established(R2>0.97). The iodine value is highlyrelated to BHT loss rate, comparatively, the correlation coefficient|r|≥0.895among2h、4h、12h、24h、36h and48h. Peroxide value had weak significant effect on BHT loss rate, but fattyacid content&type had no significant effect on BHT loss rate.BHT and its derivatives extracted with methanol from soybean oil at180℃,120℃and60℃were analyzed by HPLC and HPLC-MS. The results showed that the derivatives ofBHT in oil systems were1,2-two-(3,5-di-tert-butyl-4-hydroxyphenyl) ethane and2,6-di-tert-butyl-4-methyl anisole under180℃, however, the content of derivative is less than1%；While, according to our results, the conversion reactions of BHT will not occur at120℃and60℃after4h heat treatment. BHT can not absorb oxygen molecules in oil system,maybe it only can inhibit chain propagation of auto-oxidation of oil&fats by donating theproton.The related indexes of different kinds of frying oils, obtained by adjusting the add way ofBHT and fried food category, were determined. The results were as follows： volatile loss>migration loss and transformation loss, the volatile loss mainly in its parent form. Theaddition of BHT reduced the level of physico-chemical properties, such as Peroxide value,Anisidine value, Totox Value, Color and Induction time, but for acid value and fatty acidcomposition(C18:2/C16:0). Both BHT dosage and initial Totox Value of the oil haveimportant effects on the shelf-life of oil, moreover, BHT dosage less relevant than TotoxValue of the oil. In the food frying systems, the antioxidative activity of TBHQ wassignificantly higher than BHT in the same concentration. Comparatively, its loss rate is muchhigher than BHT. It is suggested that mixture of BHT, TBHQ or other antioxidants is chosen for frying processing.