EXPERIMENTAL STUDY ON DRYING BLACK SOLDIER FLY LARVAE USED IN PRODUCTION OF FISH AND POULTRY FEED

Larvae for fish or chicken feed must be dried to a moisture content of 8% to 10% to meet the requirements for feed milling and storage. The purpose of this study was to determine the drying kinetics of larvae under hot air drying methods. Three different drying temperatures (60, 70 and 80 °C) were used to dry larvae arranged in thin layers. Then, one batch of larvae drying was tested using a reversible air flatbed dryer coupled with an indirect wood furnace at a drying temperature of 70 °C. Opened sun drying was used as the control. Three drying equations were generated; these included one per drying temperature, and regression coefficients were greater than 0.97. Using a reversible air flatbed dryer at a drying temperature of 70 °C, the drying time was 12.8 hours to reduce the moisture content of larvae from 73.0% to 8.6%; the drying cost was US$56.7/ton. Meanwhile, sun drying took five days to reduce the moisture content from 63.6% (moisture content of larvae after it was shocked by hot air) to 8.9% with the average solar radiation intensity and the variation of 388  221.4 W/m2. Nutrient components were tested with the percentage of protein from 48.6% to 50.1% and with no difference between the drying methods.