تاثير مخلوط آنتي اكسيدان هاي طبيعي برپايداري اكسيداتيو مارگارين

The effect of natural antioxidant mixtures on the oxidative stability of margarine

Background and objective: The oxidative stability of oils and fats is affected by physical and chemical factors, resulting in rancidity. Synthetic antioxidants may have toxic and carcinogenic effects. The purpose of this study was to find mixtures of natural antioxidants that would promote the oxidative stability and shelf-life of margarine, to be used as a substitute for the synthetic antioxidant tertbutylhydroquinine (TBHQ). Materials and Methods: Margarine samples were produced with 0.89% trans fatty acids, a high nutritional value (P/S+T=2.34), and other desirable characteristics. Antioxidant treatments included 10 mixtures (F1-F10) containing tocopherols (Toe), ascorbyl palmitate (AP), rosemary extract (Ros), and lecithin(Lec), a control (F0, with no antioxidant), and a sample (F11) with TBHQ. The shelf life of the samples kept at 60°C (oven test) for 25 days was assessed by determinig the peroxide value (PV), anisidinc value (AV), the induction period in Rancimat (110°C); samples were also kept at 4°C for 14 weeks, followed by PV measurement. The antioxidant treatments were ranked on tha basis of the time (days) to reach a PV=20 meq/kg at 60°C and a PV=5 meq/kg at 4°C, the stabilization factor (SF) calculated sing the Rancimat test results, and the cost of each treatment. Results: In the oven test, the PVs and AVs of the majority of the treatments were in good agreement. The results were as follow; F2>F8>F10. On the basis of the time to reach a PV=20 meq/kg, treatments F7>F10 were not significantly different from Fll. Ranking based on SF revealed a significant difference between the antioxidant activity of Fll>F10>F9 and other samples(p<0.05). Based on the time to reach a PV=5 mcq/kg at 4°C, treatments F10, F11, F9, F2, and F5 (not different significantly) were significantly better than other samples (p<0.05). The shelf- life of margarine samples at 4°C varied from one month (F0, Fl, and F7) to three months (F10). and F11). The overall ranking was as follows: F2, F10>F5, F9> F8>F1, F3, F4>F6, F7. Conclusion: Treatments F2 (200ppm Ap+ 200ppm Ros) and F10 (200ppm Ros + 200ppm Toe + 1000 ppmLec) can be recommended as substitutes for TBHQ to maintain the quality and increase the shelf-life of margarine.