Effect of curing methods on quality and drying characteristics of turmeric

Abstract

Turmeric rhizomes of Suranjana cultivar were cured by traditional and microwave methods in water and sodium bicarbonate solution and dried in hot air dryer. Effect of curing methods on moisture content, hardness, colour, curcumin content, essential oil content, total phenolic content and drying rate were investigated. Curing methods did not have significant effect on moisture content of cured rhizomes. Hardness of turmeric rhizomes decreased as curing duration increased. Microwave curing in sodium bicarbonate solution for 6 min resulted in maximum value of the colour indices, highest curcumin content (5.20%) and essential oil content (4.38%) in turmeric powder and highest dry recovery (24.20%). Curing caused significant reduction in drying time. Minimum drying time (20.84 h) was required in microwave curing in water for 8 min, whereas, uncured samples took longest time (29 h) for drying. Drying of all the turmeric rhizomes cured by different methods occurred in falling rate period.