Potential of microwave drying technology for increase drying rate and physical quality of kaffir lime (Citrus hystrix DC) leaves

Abstract

The effects of microwave power on microwave drying rates and the physical quality of kaffir lime leaves were studied. Three power levels were used in this study, high (723 watts), medium (537 watts), and low (420 watts). The moisture content, drying rate, color (L, a, b), and organoleptic parameters of each power level will be compared with the oven drying method (60°C). The result shows that the final moisture content of the high, medium, and low power of microwave drying are 6.06, 4.26%, and 6.16%db respectively, which is lower than oven drying, 16.62%db. Besides, the drying rate of microwave drying is 26.39-48.71%db/minute, higher than oven drying 0.32%db/minute. Dried kaffir lime leaves with medium level power (537 watt) has the lowest color difference (ΔE = 1.0 ± 0.29) compared to fresh leaves. While, the color and aromatic preference test dried kaffir lime leaves by microwave drying was preferable than oven drying.