Studies On Naked Oat Bran's Thermal Stability Of Antioxidant Activities And Oat Saponin

Naked oat was one of the most important foodstuffs and it was planted comprehensively in our country. Oat bran was the byproduct of oat with good health protection. In this study, naked oat bran was processed with baking, steaming, extrusive and microwave treatment. Then the effects of heating method and heating level on antioxidant activities and the contents of antioxidant compounds of hydrophilic extracts and lipophlic extracts of oat bran were explored. The relationships between antioxidant activities (detected by the assays of liposome peroxidation, superoxide anions and hydroxyl radical inhibition) and contents of antioxidant compounds (total polyphenol, flavonoid and saponin) were also studied. At the second part of this study, chromatography method was used to isolate the alcohol extract of naked oat bran, and the structure identification was preformed.The main results were as follows:1. The antioxidant activities and content of antioxidant compounds were significantly influenced by the levels of heating treatments (including baking temperature, steaming pressure, extrusive temperature and the power of microwave treatment), water contents of samples and heating time. When the level of heating treatment was strengthened, the antioxidant activities and contents of antioxidant compounds decreased.2. The antioxidant activities and content of antioxidant compounds were also influenced by the initial water content of sample significantly. When water content changed, the antioxidant activities and contents of antioxidant compounds did not change correspondingly at a single direction. The antioxidant activities and content of antioxidant compounds decreased when water content increased on the range of low initial water content. The antioxidant activities and contents of antioxidant compounds increased with the increasing of water content when the water content reach to a certain level. However, when water content increased continuing, the antioxidant activities and content of antioxidant compounds decreased.3. In hydrophilic extracts of oat bran, gallic acid, protocatechuic acid, gentistic acid, chlorogenic acid, t-ferulic acid, sinapinic acid, t-cinnamic acid and benzoic acid were detected. Contents of these phenolic acids were influenced significantly through thermal treatments. Baking treatment has great impact on contents of gallic acid and chlorogenic acid. And protocatechuic acid, gentistic acid, chlorogenic acid, t-cinnamic acid and benzoic acid were destroyed seriously by microwave and extrusive treatment.4. Resin chromatography, silica chromatography and gel chromatography was used to isolate the alcohol extract of oat bran, a single compound with negatively charged was received, molecular weight 330.