Effect of Cratoxylum formosum Extract and Stripping on Soybean Oil Stability

Abstract

Natural tocopherols in soybean oil have a favourable influence on oxidative stability. To study this impact, the antioxidant activity of ethanolic extract of Cratoxylum formosum (Jack) Dyer (C. formosum) was investigated in stripped and non-stripped refined soybean oils comparing to α-tocopherol and BHT. Peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and oxidative stability index (OSI) values were measured. The results of PV, TBARS and OSI values of non-stripped and stripped oils containing C. formosum extract were significantly lower than that of control and sample containing α-tocopherol but higher than other containing BHT. The antioxidant activity of α-tocopherol (at 100 mg.kg^-1) was effective in stripped oil only. In addition, changes of the PV, TBARS and OSI values in non-stripped oil were slower than these in stripped oil. These results suggested that C. formosum can be a promising source for natural antioxidant. Moreover, natural tocopherols in refined soybean oil
affect on the antioxidant property of studied compounds.