M.A. Thesis:

Extraction Convolvulus arvensis Lesf and Study of The Antioxidant Effect and Stability on Soybean Oil in storage

The Effect of Antioxidant Extract of Convonvulus Arvensis on Soybean Oil Stability During Storage There are many ways to prevent oxidation of oils. One method is to add synthetic antioxidants. Synthetic antioxidants have adverse effects on the human body, such as mutagenicity and carcinogenicity; so the discovery of natural antioxidants to replace synthetic ingredients is essential. In this study at first the methanol extract of convonvulus arvensis leaves was extracted. Then, the extract in different concentrations (100, 200, 400, 800 ppm) was added to refined soybean oil without antioxidants; and oxidative stability of samples at 65°C was measured for three days by measuring the peroxide index, acid index and index TBA, finally the stability of the measurement was compared with the antioxidant activity of synthetic BHT at 200 ppm. Overall the results showed increasing the concentration of Convonvulus arvensis leaves extract from 100 ppm to 800 ppm at a time constant maintenance, increases the oxidative stability index, the amount of polyphenolic compounds and Inhibitory Activity of free radicals in the oil, While reduces the peroxide index and TBA index. The study of the oxidative stability of oils containing different concentrations of the extract showed that the concentration of 800 ppm is more effective in the oxidative stability of soybean oil extract compared with other concentration and control as well as in comparison with synthetic antioxidant BHT at a concentration of 200 ppm; this is due to higher levels of polyphenolic and tocopherol compounds. It is thus possible ivy leaves at the level of 800 ppm was introduced as a good source of natural antioxidants.

Keywords: Key words: Natural antioxidants, Convonvulus arvensis leaves, Soy oil, Oxidative stability