Starch and sugar conversion in Dioscorea esculenta tubers and Curcuma longa rhizomes during storage.

Abstract

An investigation was carried out to reveal the changes in the concentration of soluble carbohydrates under tuber dormancy in food yam (Dioscorea esculenta) tubers and in an economically important spice cum medicinal plant turmeric (Curcuma longa) rhizomes under storage. Harvested, fully matured tubers of yam and rhizomes of turmeric were stored in wooden boxes under the conditions of 28±2°C temperature and 65 to 75% relative humidity in dark. The moisture content, dry weight, starch, sugars, organic acids and respiration were studied in the tubers during 1 to 7 weeks after storage individually. This investigation revealed that the moisture content, dry weight and starch levels decreased gradually with a concomitant increase in sugar content under different stages of dormancy.