酶钝化处理对菊苣根PPO活性和菊苣酸含量的影响

Influence of inactivating processing for enzyme on PPO activity and the cichoric acid content of chicory root

为提高药用植物原料干燥菊苣根中的菊苣酸含量,采用水浴、蒸汽和微波3种烫漂方式处理新鲜菊苣根,探讨几种多酚氧化酶(Polyphenol oxidase,PPO)钝化方法的应用效果,进行PPO活性分析,考察PPO钝化效果,测定经烫漂处理后再经空气干燥的菊苣根中菊苣酸含量,分析钝化后PPO活性与干根中菊苣酸含量的关系;同时监测不进行烫漂处理直接进行空气干燥的菊苣根在干燥过程中PPO活性和菊苣酸含量的变化。结果表明:1)空气干燥过程中,PPO始终保持一定的相对活性(≥9.41%);2)水浴、蒸汽和微波烫漂处理可有效抑制PPO活性,且在以上3种处理方式中菊苣酸含量与PPO相对活性均呈显著负相关(P<0.05);3)PPO的活性需要在加工过程中尽快使其失活以防止菊苣酸氧化;4)4种方法中菊苣根菊苣酸的保留能力依次为:直接空气干燥<水浴烫漂后干燥<蒸汽烫漂后干燥<微波烫漂后干燥。在本试验条件下,微波烫漂处理效果最好,当微波(600 W)烫漂鲜根样品4.49min时,干燥菊苣根中菊苣酸含量(1 095.08μg/g)最高,与鲜根相比只降低14.32%,比直接空气干燥根高77.67%。

In order to obtain more cichoric acid in the medicinal plant material of dry root chicory,three kinds of blanching processing methods including water bath,steam and microwave were used to treat the fresh chicory root to explore the application of several inactivating methods for polyphenol oxidase(PPO).For each method,PPO activity was determined immediately to evaluate the inactivated impact on PPO activity,the cichoric acid content of dry chicory root was studied,and the relationship of the two indexes was analyzed.The changes of PPO activity and the cichoric acid content in chicory root without blanching during air drying were also monitored.The results showed that:1)The relative activity of PPO retention was morn than 9.41%during the air drying processing.2)Water bath blanching,steam blanching and microwave blanching processing could inhibit the PPO activity effectively,and the cichoric acid content had a negative correlation with PPO activity in those three processing methods(P<0.05).3)The PPO activity should be inactivated quickly during processing to avoid cichoric acid oxidation.4)Cichoric acid in chicory root retention among the four methods ranked as follows:air drying directly < drying after water bath blanching < drying after steam blanching< drying after microwave blanching.In this experiment,microwave blanching processing was considered asthe best method for inactivating processing for PPO in chicory root before air drying.The dry root had the highest content(1 095.08μg/g)of cichoric acid when treated with microwave(600W)blanching with 4.49min,and the decreasing rate of cichoric acid was only 14.32%compared to the fresh root,and with a rate of 77.67%improved compared to the content in the root of air drying directly.