EFFECT OF DIFFERENT COOKING VESSELS ON HEAT INDUCED LIPID PEROXIDATION OF DIFFERENT EDIBLE OILS

Abstract

Sunflower, coconut, palm and sesame oils were evaluated for heat induced peroxidation as assessed from malondialdehyde (MDA) generation when heated in iron, copper, stainless steel, aluminium and glass vessels on a controlled flame for 0, 5, 10 and 20 min. The MDA generation on heating was time dependent in all the oils. The extent of heat-induced change was the least in coconut oil followed by sesame oil. The heat induced MDA generation was the maximum in sunflower oil. The change was very less in aluminium and glass vessel but was very high in iron and copper vessels. The results show that aside from the level of anti-oxidants and unsaturation of oils, the transitional element used in cooking vessels also determine the extent of heat-induced peroxidation of oils, the impact of which is discussed in light of the harmful effects of MDA on health. PRACTICAL APPLICATIONS Contrary to the view that unsaturated oils are better than saturated oils, the present study shows that MDA generation on heating in relatively saturated oil, like coconut oil, is less in comparison to unsaturated oils. So for frying purposes, coconut oil may be better than other unsaturated oils. In spite of high unsaturation level, heat-induced MDA generation in sesame oil was lower in comparison to sunflower oil probably because of the presence of more antioxidants. Sesame oil may be better than sunflower oil for frying purpose. In view of harmful effects of MDA, heating oil for frying of foodstuffs in vessels made up of transitional metal(s) is probably not a good practice. Aluminium or glass vessel may be better for this purpose.