M.A. Thesis:

Extract of flowers of lotus (Nymphaea Capensis) and Antioxidant Effects of soy bean oil and its stability during storage

Antioxidants are us to prolong the shelf life and maintain the nutritional quality of lipid -containing foods, and to modulate the consequences of oxidative damage in the human body. There are many ways of preventing oxidation of oils, one of which is the addition of synthetic antioxidants to them. However, given the fact that synthetic antioxidants have adverse effects , such as mutagenic and carcinogenic effects , on the human body, it seems necessary that research and studies should be carried out with the purpose of replacing synthetic antioxidants. In this research, we first obtained methanol extracts of Nymphaea Flowers and identified their constituents. The extracts were then added at various concentrations (50, 100, 150, and 200 ppm) to purified antioxidant-free soya 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 for three days by measuring the peroxide index , the TBA index, acide index. Finally, the activities of the extracts were compared with those of the synthetic antioxidant TBA that, at the concentration of 200ppm, had been added to the purified soya oil. In general, results obtained showed that addition of 50 to 200 ppm extracts of nymphaea flower to soya 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 TBA index, and acide index the increased by increasing the storage period of the oil from one to seven days, but the duration of induction decreased.in general, the results showed that with increasing concern trations of flower extract Nymphaea capensis plant of oil soya 0f 50 to 200 ppm in a fixed holding period the peroxide index, TBA index, acide index are ruuduced. on the other hand, at a constant concentration with increasing oil storage time for 1 to 3 day the peroxide index, TBA index, acide index increases.

Keywords: Natural antioxidants, flower nympha, soya oil, oxidative stability