干燥方式对菊苣根多酚含量和抗氧化活性的影响

研究不同干燥方式对菊苣根总酚含量及抗氧化活性的影响。通过测定阴干、冻干和不同温度热风干燥处理过程中菊苣根多酚氧化酶（polyphenol oxidase，PPO）活性变化、干燥根中总黄酮和总酚含量，以及多酚提取液的1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基、2,2’-联氨-双-（3-乙基苯并噻唑啉-6-磺酸）二胺盐自由基（2,2’-azino-bis（3-ehtylbenzothiazoline-6-sulfonic acid）diammonium salt radical，ABTS+·）清除能力和总还原力，确定菊苣根最佳干燥方法。结果表明：经不同干燥方式干制的菊苣根总酚含量差异很大，可能是干燥过程中剩余PPO活性和酚热敏性2 个因素综合作用的结果。综合考虑总黄酮、总酚含量2 项指标，60 ℃热风干燥最优，冻干次之，阴干最差。菊苣根的抗氧化活性与其中的总黄酮含量相关性较小，而与总酚含量相关性较大，DPPH自由基、ABTS+·清除能力和总还原力均与总酚含量呈显著正相关（R2≥0.85，P＜0.05）。为了保留菊苣根干燥样品中较高的多酚含量，建议采用60 ℃热风干燥法干制菊苣根。

Effects of Drying Methods on Polyphenol Contents and Antioxidant Activities of Chicory Root

The study aimed to investigate the impacts of different drying methods on polyphenol contents and antioxidant
activities of chicory root. The changes in polyphenol oxidase (PPO) activity during drying, as well as flavonoid and total
polyphenol contents of dried chicory root were measured. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azinobis
(3-ehtylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+·) radical scavenging capacity and reducing power
of polyphenols extracted from chicory root with different drying methods, including air-drying, freeze-drying and hot airdrying
at different temperatures, were also determined so as to obtain the optimum drying method. The results showed
that the contents of polyphenol in chicory root processed by different drying methods differed significantly, likely due to a
combination of residual PPO activity and heat sensitivity of polyphenol during the drying process. When flavonoid content
and total polyphenol content were taken into account, hot air-drying at 60 ℃ was the best method, followed by freeze-drying
and air-drying methods. The antioxidant activity of chicory root was less closely correlated with the content of flavonoids, but
highly correlated with the content of total polyphenols. The DPPH radical, ABTS+· radical scavenging capacity and reducing power
all displayed a significantly (R2 ≥ 0.85, P < 0.05) positive correlation with the total polyphenol content. In order to achieve higher
polyphenol content in dried chicory root, hot air-drying at 60 ℃ was a recommended drying method for chicory root.