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.
This study is set out to ascertain the suitability of groundnut oil as a hydraulic fluid. Benchmark tests and experiment were carried out to ascertain the physio-chemical property of groundnut oil. The key steps will be to experiment the viscosity of groundnut oil at 40oC and 100oC respectively, specific gravity, viscosity index, acid value, Pour point, flash point, fire point, peroxide and iodine value using refined groundnut oil as sample. The result showed that the viscosity at 40oC and 100oC are 34.1mm2/s and 7.08mm2/s which exceeded the international standard organization (ISO) specification of (12-100) mm2/s and 5mm2/s for 40oC and 100oC respectively. The flash point (249.1oC), the fire point (255.2oC), acid value (0.3942mg (KOH)/g) all exceed the ISO specification. The result showed a good peroxide value and iodine value from oil sample. The low temperature flow property (pour point) is the only result that does not meet ISO specification with -3oC but can be handled by addition of cold flow property depressant (additive). However this work has demonstrated the feasibility of using groundnut oil as a hydraulic fluid.