Effects of Variety and Curing and Drying Methods on Quality Attributes of Turmeric (Curcuma domestica) Powder

Variety and the method used for curing and drying affect the quality and marketability of processed turmeric (Curcuma domestica) powder. This study was conducted to determine the effects of Variety (Bonga51/71, HT3/2002, and Dame), Curing method (conventional curing (CCM) and improved curing (ICM)), and Drying method (open-air drying (OSD), solar tunnel dryer (STD), and greenhouse solar dryer (GSD)) on the quality attributes (moisture content, total ash, acid-insoluble ash, curcumin, oleoresin, essential oil, and color rating) of turmeric powder using a 3x2x3 factorial design. The results revealed that moisture content was reduced substantially to 7.67% and 6.5% for HT3/2002 variety cured with CCM and ICM but dried with STD, respectively; and to 6.67% and 6.42% for Dame variety cured/dried/ with ICM/GSD and CCM/STD, respectively. Dame variety cured with ICM and dried with GSD resulted in the lowest total ash (6.67%); but it gave the lowest acid-insoluble ash when cured with CCM and dried with OSD (0.993%) and GSD (0.997%). The highest curcumin retention (6.99%) and oleoresin yield (13.88%) were obtained from Bonga51/71 variety cured with CCM and dried with STD, and Dame variety cured with ICM and dried with OSD, respectively. On the other hand, the highest (6.52%) essential oil yield was obtained from Bonga51/71 variety cured with CCM and dried with OSD. In summary, OSD provides the lowest total and acid-insoluble ashes (pharmacognostic parameters of turmeric for different medicinal uses) and the highest oleoresin (contains color, pungency, and flavor constituents of turmeric) in CCM and ICM curing methods, respectively.