汽爆对竹叶表面结构、总黄酮含量及抗氧化活性的影响OA

To explore the effects of steam explosion(SE)pretreatment on the surface microstructure,total flavonoids content and antioxidant activity of bamboo leaves,the combination conditions of SE pressures on 0.5,1.0,1.5,2.0 MPa and maintaining pressure time on 2,5,8,10 min were selected for SE pretreatment of bamboo leaves.The surface structure of bamboo leaves before and after SE was observed and the contents of flavonoids and other active components in bamboo leaves were determined.Furthermore,the effects of SE on the extraction properties of bamboo leaf flavonoids were investigated,and the antioxidant activity of bamboo leaf total flavonoids extracts was evaluated.The results showed that after SE pretreatment,the surface structure of bamboo leaves was significantly changed and the content of active substances was significantly increased.The maximum total flavonoids content of 8.39%was obtained under the condition of 2.0 MPa for 8 min,which was 3.38 times that of the untreated sample.HPLC analysis results showed that the composition and content of flavonoids was significantly changed.The extraction time of bamboo leaf flavonoids was obviously shortened,and the extraction was more efficient.In addition,the antioxidant activity of flavonoid extracts from pretreated bamboo leaves was greatly enhanced.The maximum 2,2-diphenyl-1-picrylhydrazyl radical(DPPH·)scavenging capacity,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)radical(·ABTS+)cation scavenging capacity and the ferric reducing antioxidant power(FRAP)reached 59.96,293.95 and 133.62 mg/g,respectively,which were 4.4,6.5 and 4.0 times of untreated bamboo leaves.