Comparative Assessment of Drying Technologies to Minimize Postharvest Losses in Turmeric

Thinley Gyeltshen, Tenzin Rabgay, Tshering Penjor, Pema Yangdon, Tshering Pem, Domang, Kinzang Thinley, Kinley Sithup & Kinley Wangmo

Turmeric, a valuable spice with high medicinal value, is highly perishable due to its high moisture content (70-80%), necessitating the need for efficient postharvest technologies to minimize losses. Drying is a proven method to extend shelf life and reduce losses, but no comprehensive studies on turmeric drying have been conducted in Bhutan. This study, conducted at the Agriculture Research and Development Centre, Wengkhar, evaluated three drying methods; Open Sun Drying (control), a Fabricated Electric Dryer, and a Solar Dryer integrated with IoT technology, to determine their efficacy in reducing turmeric postharvest losses. Using stratified and random sampling, 450 turmeric rhizomes were sliced and dried across treatments. Significant differences were observed in weight loss and water activity between the methods at a 5% significance level. Although, the Electric Dryer had the shortest drying duration (7.76 hours), it retained higher water activity (58.05), increasing the risk of microorganism growth. In contrast, the IoT-based Solar Dryer required the longest drying time (71.05 hours) but achieved the lowest water activity (39.7) and superior product quality in texture and color. Therefore, given its ability to handle larger volumes, the IoT-based Solar Dryer is recommended for commercial operations. Future research should focus on biochemical composition, particularly curcumin content, and the economic viability of different drying methods.

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