STABILIZATION OF OLIVE OIL BY MICROWAVE-HEATING

Olive fruits of Picual and Shemlalli cultivars were exposed to microwa ves generated from an oven at low and moderate power settings for 9 an d 12min. The gross chemical compositions of the non-microwaved and mic rowaved fruits of both cultivars were determined. In general, the data show that microwave treatment did not cause any change in the fruit c omponents of Picual and Shemlalli cultivars. The stability of extracte d olive oil samples from the fruits of both cultivars was followed up by determining the lipase and lipoxygenase activities during storage. The effect of microwave heating on the lipase and lipoxygenase activit ies of olive oil samples was dependent upon the oven power level, the moderate power setting of the microwave oven produced the least free f atty acid and hydroperoxide contents respectively. The results demonst rated that microwave treatment obviously decreased the enzyme activiti es during storage and consequently increased the stability of olive oi l.