Study On Extraction And Antioxidant Activity Of Antioxidant Active Substances From Oat

The new extracting techniques for alkaloids and polyphenols from Chinese oat and their antioxidant activity were studied.By use of CO2-Supercritical Fluid Extraction, the extraction of alkaloids from oat bran was studied. Three factors including extraction pressure, temperature and time were selected as the single factor test condition. The extraction process was optimized by orthogonal design with the yield of alkaloids as markers. The results showed that the effect of pressure and temperature is significant. The optimum conditions of CO2-SFE were: pressure 21.2MPa, temperature 40.4℃, time 1.46h for the extraction . The amount of alkaloids extracted was 655.8 ug/g .The effect of 5 factors on polyphenols extraction rate from oat was studied through single factor by using microwave method, and the best technique conditions for extracting polyphenols from oat were screened through orthogonal test. The single factor experiment showed that the optimum effect of extracting the polyphenols from oat could be obtained when the ethanol concn. 70%,extracting time100s, microwave power 450W,solid-liquid ratio 1:50 and pH1. The orthogonal test indicated ,the best technique conditions for extracting polyphenols from oat with microwave method were as: the ethanol concn. was 60%, pH1,solid-liquid ratio1:55,extracting time 100s and microwave power 450W,under these conditions, the concn. of polyphenols that was extracted from oat could be up to 3088.7μg/g. The antioxidant activities of the polyphenols extracts from Chinese oat were evaluated by the DPPH assay,TPTZ assay,ABTS assay.,respectively,The results showed that oat extracts have potent antioxidant activity.,and in a certain range,the mass concentration of polyphenol from oat showed positive correlation with antioxidant activity.When the concentration of oat polyphenol in between 24.91μg/mL～106.87μg/mL,its Fe reducing/antioxidant capacity was amount to the concentraction in between 22.35μmol/l～131.16μmol/L of Trolox;the cleanout activity of DPPH·was amount to the concentraction in between 13.26μmol/l～88.55μmol/L of Trolox;and the cleanout activity of ABTS·+was amount to the concentraction in between 111.93μmol/l～269.07μmol/L of Trolox.