The content of active constituents of stored sliced and powdered preparations of turmeric rhizomes and zedoary (bulb and finger) rhizomes

Abstract

The stability of active constituents (curcuminoids and volatile oil) in turmeric (Curcuma longa Linn.) rhizomes and zedoary [Curcuma zedoaria (Berg.) Roscoe] bulb and finger rhizomes during storage have been investigated. They were prepared as sliced and powdered and separately packed, either in black polyethylene bags or in paper bags, and stored at room temperature (28-31oC). Samples at initial and three monthly intervals were examined over 12-15 months storage to determine the contents of curcuminoids, volatile oil and moisture. The results showed that storage of rhizomes in black polyethylene bags could prevent samples from taking up moisture better than those stored in paper bags. The sliced and powderedturmeric rhizomes exhibited no decrease in curcuminoids content after 15 months of storage irrespective of the nature of the packing material. However, the slices of zedoary (bulb and finger) rhizomes lost curcuminoids to a lesser extent than powdered rhizomes during storage period. Volatile oil content of turmeric rhizomes, zedoary (bulb and finger) rhizomes decreased slower when stored as slices rather than as powders. The result from the present study suggested that in order to maintain the quality of turmeric and zedoary rhizomes as raw material for food and medicinal uses, they should be prepared in sliced form and stored in black polyethylene bags in order to maintain their content of active constituents during storage period.

Keywords

• turmeric
• zedoary
• curcuminoids
• volatile oil
• stability
• storage conditions