Stability during frying of Moringa oleifera seed oil variety Periyakulam 1

The frying performance of the Moringa oleifera seed oil variety Periyakulam 1 (PKM 1) from India, extracted using cold press (CP) and n-hexane (H), during frying of potatoes and cod was studied especially as regards repeated frying operations. The oils were used for intermittent frying of potato slices and cod filets at a temperature of 175 +/- 5degreesC for 5 consecutive days. The chemical changes occurring in the oils were evaluated. Free fatty acid content, peroxide value, specific extinction at 232nm, polar compounds colour and viscosity of the oils all increased, whereas the iodine values, smoke points, polyunsaturated fatty acid content, induction period and tocopherol concentration decreased. The effect of the oils on the organoleptic quality of these fried Foods was also determined by expert panellists. The analytical and sensory data showed that the lowest deterioration occurred in cold pressure produced oil and the highest in n-hexane extracted oil. Therefore, cold pressure oil appears to be the most appropriate for frying. Potatoes and cod were also fried in virgin olive oil in order to have a direct comparison between the different oils. The results clearly indicated that virgin olive oil has the highest resistance to thermal deterioration during frying compared with the other two oils. (C) 2002 Elsevier Science Ltd.