Effect of postharvest handling on valerenic acids content of fresh valerian (Valeriana officinalis) root

Valerian (Valeriana officinalis) is a medicinal herb native to Europe and North Asia, the roots and rhizomes of which are used as a sedative for nervous tension, sleeplessness, anxiety and stress. The impact of washing and drying on the valerenic acids concentration in valerian roots was investigated. The valerenic acids content of roots that were washed, soaked or cut prior to drying was not significantly different from that of whole valerian roots that were dried without washing, but cutting markedly decreased the drying time. Increasing the drying temperature from IS to 70 degrees C reduced drying time by 176 h, with a 23% loss of valerenic acids from 15 to 40 degrees C. A further 36% loss occurred from 40 to 50 degrees C but no further significant change was evident at higher temperatures. The use of a heat pump dryer reduced the drying time at 40 degrees C by 25% compared with a hot air drier operated at the same temperature with no significant difference in the level of valerenic acids. There was no significant change in the level of valerenic acids in fresh whole roots held at ambient conditions for 10 days but a considerable decrease in water content. Hence valerian growers can separate or soak roots prior to washing and can store fresh roots before drying without concern over loss of valerenic acids. However, drying at the lowest feasible temperature is recommended. (c) 2005 Society of Chemical Industry.