Optimisation of the temperature and drying time of kaffir lime leaves (Citrus hystrix DC.) using Response Surface Methodology

This study optimised the drying process of kaffir lime leaves (Citrus hystrix DC.) to extend the shelf life and preserve the quality by reducing the moisture content. A Central Composite Design (CCD) under the Response Surface Methodology (RSM) framework was employed, with the temperature (55 °C, 60 °C, 65 °C) and drying time (5, 5.5, 6 h) as the variables. Experiments were conducted with a mechanical food dehydrator, and the parameters evaluated included the water content and drying yields. The optimal condition was identified as 60 °C for 5 h, resulting in a drying yield of 33.3% and a final moisture content of 7.153 (% w.b.), which meets the quality standards for dried products. The novelty of this research lies in the application of RSM to determine effective drying conditions for kaffir lime leaves, which are not widely used, but have good economic potential. The research proved that drying with the right conditions can greatly improve the quality and stability of dried kaffir lime leaves.