The objective of this research was to investigate suitable condition for drying kaffir lime leaves
with heat pump and heater at temperature of 45, 50 and 55?C. The changes of physical properties
including moisture content, water activity, rehydration ratio, color and chemical properties including
?-carotene, total phenolic content and antioxidant activity of kaffir lime leaves were determined. The
results showed that the moisture content and drying time to reach the final moisture content below 12%
wb. decreased with higher drying temperature. Water activity of dried samples were in the range of
0.397-0.522. Drying temperatures did not give significant effects on total color difference value and
rehydration ratio of dried samples. Moreover, it was found that the drying at 50 and 55?C exhibited the
higher content of ?-carotene, total phenolic and antioxidant activity than 45?C. Overall, our findings
suggest that drying of kaffir lime leaves with heat pump and heater at 55?C for 270 and 240 min are the
best condition, respectively.