Oil and oleoresin of turmeric.

Abstract

12 tumeric cultivars which are commonly grown in India were analysed in order to determine their suitability for the extraction of oil and oleoresin. Their volatile oil content ranged from 2.5 to 7.2% and their curcumin content from 1.8 to 5.4%. The release of oil during distillation was slow because of the presence of high-boiling sesquiterpene derivatives. The bright yellow colour of tumeric was found, by TLC to be due to curcumin and to 2 other related pigments with the same absorption max. (425 nm) in the visible region. Acetone, alcohol and ethylene dichloride were found to be suitable for extracting the oleoresin from tumeric. Both the Soxhlet and the cold percolation extraction methods gave good yield of oleoresin, with a good recovery of curcumin ( greater than 85%), when finely ground spice ( greater than 60 mesh) was used. Bench-scale extractions, by stainless steel columns and a distillation unit, gave tumeric oleoresin which conformed to specifications of the Essential Oil Association, USA.