STUDY ON DRYING OF KRATOM LEAVES USING FLUIDIZED BED METHOD

Abstract

Kratom leaves are used to treat intestinal infections, diarrhea, muscle pain, and to reduce fever. In 2021, the Thai government lifted the restriction on using kratom in food, allowing it to be legally incorporated into food products. At present, kratom is processed into dried leaves and powder, which are used in various products such as kratom-infused beverages and instant tea. This research studied the drying process of green-stem kratom leaves (Tangkwa variety) using a fluidized bed dryer. The system consists of a blower fan that pushes hot air through a heater into the drying chamber at a flow rate of 38 cubic feet per minute (CFM). Kratom leaves weighing 1 kilograms, 2 kilograms, and 3 kilograms were cut into pieces of 3–5 centimeters in size. The experiments were conducted at temperatures of 40°C, 50°C, 60°C, and 70°C, with moisture content recorded every 10 minutes to determine the effects of temperature and leaf weight on moisture ratio, specific energy consumption, and mitragynine content. The results showed that moisture was reduced more quickly at higher temperatures, while drying time increased with greater weight of kratom leaves. Specific energy consumption decreased by up to 9.10% as the drying temperature increased. The mitragynine content in kratom leaves decreased linearly with increasing drying temperature, with the lowest level of 25.93% observed at 70°C. Based on the experimental results, considering energy use and drying time, a drying temperature of 60°C was found to be the most appropriate for this study. However, if retaining the highest mitragynine content is the priority, drying should be conducted at 40°C. The findings from this research can be applied to the development of food and beverage products from kratom leaves, adding value to agricultural products, recommending appropriate drying temperatures to reduce energy consumption, and supporting the production of Thai traditional herbal medicines with controlled active compounds.