干燥温度对醇提余甘子多酚含量及其抗氧化活性的影响

为探究干燥方式(冷冻真空干燥、热风干燥)和干燥温度(冻干、40、60、80、100℃)对余甘子多酚活性成分的影响,利用高效液相色谱(HPLC)检测不同干燥处理后余甘子醇提液中没食子酸、柯里拉京、鞣花酸、诃子鞣酸的含量,并测定其总多酚含量和抗氧化活性(ABTS⁺自由基清除能力和DPPH自由基清除能力)。结果表明,随着干燥温度的升高,余甘子中没食子酸、柯里拉京、鞣花酸、诃子鞣酸含量均增加,100℃热风干燥时达最高(分别为12.83、6.04、16.89、13.48 mg/g)。总多酚含量与抗氧化活性(ABTS⁺·清除能力和DPPH·清除能力)也随干燥温度升高而增加,80℃热风干燥时达最高(分别为200.92、695.76、725.05 mg/g)。此外,试验结果表明柯里拉京、诃子鞣酸和总多酚的含量与余甘子醇提样品ABTS⁺自由基清除能力呈显著或极显著正相关(P<0.05或P<0.01)。本次试验中,与热风干燥相比,冷冻干燥的样品中4种多酚单体和总多酚含量以及抗氧化活性无明显优势,综合考虑,80℃热风干燥为余甘子的最佳干燥方式。

Effect of Drying Temperature on Phenolic Contents and Its Antioxidant Activity of Phyllanthus emblica L.

In order to explore the effect of drying method(vacuum freeze and hot air drying)and drying temperature(freeze drying,40,60,80,100 ℃)on the phenolic ingredients in Phyllanthus emblica L.(P. emblica),the high performance liquid chromatography(HPLC)was used to analyze the content of four phenolic compounds,gallic acid,corilagin,ellagic acid and chebulagic acid,in the P.emblica dried at different treatment. And the total polyphenol content and antioxidant activity(ABTS+· and DPPH· scavenging ability)of each sample were investigated. The results showed that the contents of four compounds increased with the drying temperature,which reached the highest point at 100 ℃(12.83,6.04,16.89,13.48 mg/g). Apart from this,the total phenolic contents,ABTS+· and DPPH· scavenging increased with the temperature and activity peaked at 200.92,695.76,725.05 mg/g under 80 ℃. Meanwhile,there were significantly or extremly significantly(P<0.05 or P<0.01)positive correlations among phenolic compounds(corilagin,chebulagic acid),total phenolic,and the ABTS+free radical scavenging activity. In this test,compared with hot air drying,the vacuum freeze did not show the obvious advantage in the content of four phenolic compounds and total polyphenol,and the antioxidant activity. Considering comprehensively,it was suggested that 80 ℃ hot air drying should be the optimum drying method for P. emblica.