Comparison of Α-Tocopherol with Some Nigerian Spices as Natural Antioxidants in Stored Crude Groundnut Oil (Published)
The antioxidant effects of M. myristica, M. tenuifolia and A. danielli in comparison to α-tocopherol in crude groundnut oil stored at room temperature for 24 weeks were studied. Crude groundnut oil samples mixed with 200 ppm each of the grits (0.5 mm) and n-hexane extracts of the three spices were compared to two controls: untreated crude groundnut oil and crude groundnut oil mixed with 200 ppm α-tocopherol and all were stored for 24 weeks at room temperature. Samples were tested for free fatty acid and peroxide value after the fourth and eighth week of storage and afterwards, every two weeks, until the 24th week. At the 24th week, % FFA was highest (3.67 %) in untreated (control 1) samples and lowest in α –tocopherol-treated (control 2) samples. Again, peroxide value was highest (33.59 meq/kg) in untreated (control 1) samples and lowest in α-tocopherol-treated samples. Both the spice grits and their extracts significantly reduced peroxide value and % FFA better than the untreated samples, with the spice extracts performing better than their grits. The study suggests that crude groundnut oil can be stored with 200 ppm grits and n-hexane extract of the three spices and better results might be achieved at even higher concentration.