[Evaluation of antiradical activity of Malva sylvestris extract and its application in oil system]

Because of some adverse effect of chemical food additives such as synthetic antioxidants, it has been considered by researchers to replacing these materials by natural products. To measure the total phenolic content of Malva sylvestris extract [MSE]; to evaluate the antiradical activity of this extract by DPPH°, ABTS°+ and beta-carotene bleaching methods [BCB] and to study its application as natural antioxidant in soybean oil. Total phenolic content [TPC] of MSE was determined by Folin- Ciocalteau method. Antiradical activity was measured by DPPH°, ABTS°+ and BCB methods and compared with synthetic antioxidant BHA. The antioxidant activity of extract was studied in soybean oil [oven test at 70°C] by measuring peroxide value [PV], thiobarbituric acid value [TBA] and conjugated diene [CD] and compared with BHA and BHT [at two level 100 and 200 ppm]. MSE was possess 4.5% phenolic compounds in base of dry matter. In DPPH° assay, EC50 of MSE was 0.37 +/- 0.01 mg/ml. In ABTS°+ assay, maximum antioxidant activity was related to 5 mg/ml concentration of MSE [70% inhibition]. In BCB test, maximum antioxidant activity of 0.05 - 10 mg/ml concentration of MSE was related to its 10 mg/ml concentration of it [52.6%]. This extract could retard oxidation process of soybean oil at 400 ppm that was almost equal to BHA at 100 ppm. MSE showed antiradical activity and it seems it can be applied as natural antioxidant in foods containing edible oils

[Evaluation of antioxidant activity of Lavandula angustifolia essential oil in crude soybean oil system]

It has been considered by researchers to study the possibility of replacing chemical food additives such as synthetic antioxidants by natural products especially medicinal plants. The aims of this study were as follow: [i] to determine the major components of the essential oil of Lavandula angustifolia. [ii] to evaluate the antiradical activities of this essential oil by DPPH°, ABTS°+ and beta-carotene bleaching assays and [iii] to evaluate the antioxidant activity of this essential oil in crude soybean oil. The main chemical components of essential oil were identified by GC/MS. Antiradical activities of mentioned essential oil was measured by different methods and finally, its antioxidant activity was determined in crude soybean oil system by Oven method. Six main compounds were identified: linalool [27.89%], camphore [10.82%], 1, 8 cineol [9.05%], inalol acetate [8.86%], borneol [7.29%] and alpha-terpineol [5.04%]. EC50 of essential oil was 35.54 +/- 1.58 mg/ml. In ABTS°+ assay, maximum antioxidant activity was related to 40 mg/ml concentration of essential oil. In beta-carotene bleaching assay, maximum antioxidant activity of essential oil was related to the 10 mg/ml concentration of it [54.4 percent radical scavenging activity]. In oven test, essential oil could inhibit of primary and secondary oxidation products of crude soybean oil at 0.8 mg/ml that was almost equal to BHA at 0.2 mg/ml. Antiradical activity of essential oil of Lavandula angustifolia was proved and it seems that after complementary examination, it can be used as natural antioxidant in food, especially those containing edible oils