Effect of antioxidants on shelflife of edible oils

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Ali, Hanady Abdallah Mansour Mohamed
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This study was carried out to examine the effect of addition of antioxidants on shelf life of refined edible oils stored under conventional conditions . Groundnut oil and cottonseed oil were stored after addition of the antioxidants (200mg/kg oil) Butylated hydroxy anisole (BHA) and Ascorbic acid , in plastic containers at room temperature for 6 months . The effect of addition of antioxidants on edible oils was examined by changes in chemical properties as peroxide values , free fatty acids and iodine values of oils besides the changes in physical properties of oils as color and viscosity during storage of these oils . Chemical tests for both types of oils showed that the rise in the peroxide value was limited to oils that containing antioxidants while the refined oils not contain antioxidants showed great increase for the peroxide value during storage . Both groundnut and cottonseed oil containing the antioxidants ascorbic acid or Butylated hydroxy anisole (BHA) gave a peroxide value (PV) of 17 meq/kg after storage of 6 months while the same oils that not contain antioxidants gave a peroxide value of 45 meq/kg for groundnut and 52 meq/kg for cottonseed oil . During the storage of refined edible oils the free fatty acids increased during storage at ambient temperature irrespective of antioxidants used . Refined oil containing antioxidants recorded free fatty acids of 0.28 % as oleic compared to 0.24% as oleic found in refined oil that not contain antioxidants. Saponification value to refined oils containing antioxidants showed no changes compared with refined oil not containing antioxidants . Physical tests showed no changes in color and refractive index of refined oils containing antioxidants compared with those not containing antioxidants , however decrease in viscosity of refined oils containing antioxidants were observed compared with refined oils not containing antioxidants during the storage Period . Addition of antioxidants to oils improved their color and storage stability .
University of khartoum