Determination Of Changes Occurring In Chemical Properties Of Fat Repeatedly Used For Food Frying

Abstract

Attached

The physical and chemical properties of oil can be changed during deep frying. To investigate those changes three major oils namely Coconut, Palm( olein) and Sunflower oils were taken and subjected to deep fat frying of meat and potatoes at 185°C. Three frying cycles have been undertaken for each oil. After frying, oil has been taken and analyzed for free fatty acid level, Iodine number and composition of fatty acid profiles. Results revealed that major constituent of coconut, palm and sunflower oils was lauric, palmitic and linoleic acids respectively. The FFA values of coconut, palm and sunflower oils were changed from 0.091 to 0.221, 0.086 to 0.171, and 0.060 to 0.121 respectively when meat was fried. And it was changed from 0.091 to 0.234, 0.086 to 0.177, and 0.060 to 0.101 for the same oil when potato was fried. Iodine value of coconut oil has been increased from 8.211 to 12.537 and 8.211 to 8.494 when meat and potato were fried! For palm oil, it has been increased from 54.207 to 70.234 and 54.207 to ?5.930 when same commodities were fried. For sunflower oil, it has been increased from 106.486 to 122.465 and 106.486 to 121.854 for frying of same products, meat and potato. Peroxide value of palm oil has been increased from 3.466 to 6.172 and 3.466 to 6.790 when meat and potato were fried. For sunflower oil, it has been increased from 7.556 to 13.172 and 7.556 to 12.582 when same commodities meat and potato were fried. Peroxide values of coconut oil have been increased from 0.589 to 2.435 and 0.589 to 2.412 when meat and potato were fried respectively. When results are compared against ISO requirements, Sunflower oil showed much stability than coconut and palm oils throughout the frying process. The formation of free fatty acid was low in sunflower oil. And also the degrees of un saturation was within the limits. Therefore, the study revealed that sunflower oil is more stable and more suitable for repeated deepfrying process.