Study of Antioxidant Effect and Antimicrobial Properties Extract of Ricinus Communis and its Effect on Soybean Oil Stability in Storage Conditions

In this research,we first obtained methanol extracts of Ricinus communis Laef and identified their constituents.the total amount of phenolic compounds in the extract as well as its antioxidant activity were determined by investigating the inhibitory power of DPPH free radicals. The extracts were then added at various concentrations to purified antioxidant-free soya bean oil.The inhibition of the activity of the free radicals by the extracts and the oxidative stability of the oil at 65 degrees centigrade were studied for3 days by measuring the peroxide index,TBA and the Acidite index. Finally, the activities of the extracts were compared with those of the synthetic antioxidant BHT that, at the concentration of 200ppm,had been added to the purified soya bean oil. In general, results obtained showed that addition of 100 to600 ppm extracts to soya bean oil at a given storage time increased the oxidative stability index the quantities of polyphenolic compounds and the inhibition of the activities of the free radicals in the oil, but decreased the peroxide index,the acidite index diene.On the other hand,at a given concentration of the extracts, the peroxide index,the TBA index and the number of the DNA conjugates increased by increasing the storage period of the oil from one to three days,but the duration of induction decreased. Therefore, results obtained from investigating the oxidative stability of the oil extracts at the concentration of 600ppm,as compared with the other concentrations of extracts and the control sample, were more effective with respect to the oxidative stability of soya bean oil. were more effective than the BHT added at the concentration of 200 ppm to the oil. finally, it can be inferred that with regard to the gained results, extract including antimicrobial materials has had antibacterial effects but, it has less antifungoid effect.