加工因素对橄榄叶提取物抗氧化活性的影响

研究在橄榄叶加工过程中,加工因素对橄榄叶提取物中抗氧化活性的影响,这些因素包括:(1)干燥方式(微波炉干燥,烘箱干燥,低温冷冻干燥和熏蒸及烘箱结合干燥);(2)提取方式(超声波提取和搅拌式提取);(3)提取溶剂的酸度(pH 4、7、10).实验将总多酚含量和清除自由基活性作为衡量提取物抗氧化有效成分和活性的指标.研究结果表明,通过低温冷冻干燥、调节pH至4和采用超声波提取的方式,橄榄叶提取物中的抗氧化有效成分最多.本研究对橄榄叶等天然植物中抗氧化成分提取工艺的制定具有参考价值.

Effect of Procedure Parameters on the Antioxidant Property of Olive Leave Extracts

The aim of this study was to determine the procedure parameters,including drying,extracting and pH on the antioxidant activity and antioxidative compounds in olive leaves.The extraction of antioxidants from olive leaves is studied considering different drying (microwave drying,oven drying,freeze drying,steam and oven drying) and extracting (stirring and ultrasound) procedures to investigate the selectivity of the process.The radical-scavenging activity (RSA) of 1,1-diphenyl-2-picrylhydrazyl (DPPH·) and the determination of the total phenolic content (measured with the Folin test) are applied to evaluate the antioxidant activity and antioxidative compounds of the olive leave extracts.The highest antioxidant activity is observed for the extract obtained by freeze drying,extracting by ultrasound with 80% methanol adjusted at pH 4(44030.7 μmol Trolox eq./100 g).The antioxidant compound extraction yield was also the highest at these extraction conditions (3795.3 mg gallic acid eq./100 g).The total phenol contents among the olive leave extracts produced by different drying procedures were similar,while the antioxidant activities were different.This concluding that the amount of phenolic compounds extracted was similar but the type and probable structure of the phenolic changed during heat-drying procedure providing in this way.Our study showed that proper process technology could ultimately extract compounds potentially effective against diseases related to free radical oxidation.