INFLUENCE OF SUPERCRITICAL CARBON DIOXIDE AND METHANOLIC EXTRACTS OF ROSEMARY ON OXIDATION AND SENSORY PROPERTIES OF WHEAT GERM OIL

Both supercritical CO2 and methanolic extracts from the leaves of rosemary (Rosmarinus officinalis) harvested from three different locations of Turkey at four different times of the year were added at a concentration of 100 mg/kg to wheat germ oil. Wheat germ oil samples were stored in an incubator for 10 days at 50C in order to promote oxidation and for the efficacy of the extracts for stabilization purposes to be examined. Degree of oxidation was determined by peroxide and p-anisidine values, which were performed every 2 days. Extracts from Mersin and Canakkale regions performed better results. Additionally, June and September harvests had lower peroxide values. According to the descriptive sensory analysis, both locations and extraction methods were found to effect flavor. Some flavor attributes, such as wheatlike/starchy, fishy and rubbery/metallic changed during storage regardless of locations and extraction methods. Supercritical CO2 extracts performed better results in terms of both oxidation and sensory properties. PRACTICAL APPLICATIONS From the perspective of the food industry, wheat germ oil stabilized with a natural antioxidant such as rosemary can be marketed as a functional product that can create a niche. Rosemary extracts containing higher amounts of rosmarinic acid and carnosic acid should be preferred in order to provide a better shelf life of an edible oil such as wheat germ oil.