Enhancement of the oxidative stability of butter oil by seamum oil through interesterification

Abstract

Butter oil was chemically interesterified with sesamum oil at three different levels i.e. T1 (75 % butter oil and 25 % sesamum oil) T2 (50 % butter oil and 50 % sesamum oil) T3 (25 % butter oil and 75 % sesamum oil). All these treatments were compared with a control (To). Free fatty acids were in the range of 0.09 to 0.11 % (oleic acid) before intereseterification and decreased after rearrangement of esters. Iodine value did not change before and after reaction (P > 0.05). Melting point increased from 36.42 to 41.40, 25.50 to 35.80, 19.40 to 32.50 and 16.70 to 29.3 °C in To, T1, T2 and T3, respectively, after interesterification. Free fatty acids of control increased to 0.11 % as compared to 0.05 % in T2. Peroxide value and para anisidine value of T2 were 0.68 meq/kg., 13.56 and 1.20 meq/kg., 17.82 for the control at the end of storage period. Induction period of T2 was 5.8 h. at 120 °C in contrast of control; 4.5 h. Results of Schaal oven test revealed that control sample had peroxide value of 5.32 meq/kg and T2 had 2.45 meq/kg. All the treatments remained homogenous and no separation of solid and liquid fractions was observed during storage of 120 days. The results of this study suggest that interesterified blend containing 50 % butter oil and 50 % sesamum oil can be used in the formulation of functional and shelf stable fat.