Modern Chemistry & Applications

Abstract

The Effects of Blanching, Harvest Time and Location (with a Minor Look at Postharvest Blighting) on Oleoresin Yields, Percent Curcuminoids and Levels of Antioxidant Activity of Turmeric (Curcuma longa) Rhizomes Grown in Jamaica

Cheryl E Green and Sylvia A Mitchell

Turmeric (Curcuma longa) grown in Jamaica was studied for its naturally occurring linear diarylheptanoid compounds namely curcumin, Bis-Demethoxy Curcumin (BDMC), Demethoxy Curucmin(DMC) and for its antioxidant activity. Evaluations were conducted on the basis of whether or not there were any potential effects of blanching, harvest time and location of growth on the quantity and quality of turmeric oleoresins. The highest antioxidant activity of 92.86% was obtained from turmeric rhizomes grown in the parish of Hanover while the highest turmeric oleoresin yields of 14.87% were obtained from the 15 minute blanched-treated turmeric rhizomes. With a new analog-selective RP-HPLC method, the curcumin, DMC, and BDMC were qualified and quantified. It was found that the highest yield of curcumin content of 22.69% was obtained from the 15 minute ‘blanched’ samples grown in the parish of Hanover from the first harvest period for the study. An analytical method validation with linear equations and correlation of regressions of R2=0.9991, R2=0.999.3, R2=0.9998 and R2=0.9992 for inter-day precision analyses were performed to validate the HPLC method.