This work studied the effects of drying temperature on the quality and drying kinetics of betel leaves (Piper betle L.). As the drying process applies heat on the product, this might lead to the degradation and decomposition of valuable phytochemicals within the herbs. In this study, the effect of drying temperature on the quality of dried leaves was studied by analyzing the change of major phytochemicals found in the leaves, which are hydroxychavicol and eugenol. The results indicate that the content of major compounds increased with temperature from 40 to 70°C but underwent decomposition when the leaves dried at 80°C. Besides that, the drying kinetics for different drying temperatures also studied. The kinetics results show that the increase of drying temperature shortened the total drying time. Five thin-layer models were selected in describing the drying process of betel leaves. The logarithmic model was found to be the most suitable one.

This work investigated the effects of extraction temperature on the quality of extract and the kinetics of solid‐liquid extraction of betel leaves. In this study, the effects of extraction temperature on the quality of extract were evaluated by comparing the concentration of its active compounds, including hydroxychavicol (HC) and eugenol (EU). The results indicate that the increase of extraction temperature led to the increase of the concentration of HC. EU concentration was decreased when temperatures higher than 60C were used. The kinetics data show that the extraction process reached equilibrium in a short time – about 40 min. Two models, namely equilibrium‐dependent solid‐liquid extraction (EDSLE) model and diffusion‐dependent solid‐liquid extraction model were applied to describe the extraction process. By comparing the values of correlation coefficients, the EDSLE model was found to be more suitable in describing the extraction process as it provided a better fit to the experimental data. PRACTICAL APPLICATIONS Betel leaves is one of the invaluable medicinal plants that has multiple useful bioactivities found in Malaysia. In this work, the effect of extraction temperature on the quality of the extract of betel leaves was investigated by quantifying the change of two active compounds, namely hydroxychavicol and eugenol. This is because the bioactivities depend on the content of the phytochemicals within the plant. The critical extraction temperature was determined based on the findings. Aside from this, the kinetics of the extraction process was also studied. Two mathematical models including equilibrium‐dependent solid‐liquid extraction (EDSLE) model and diffusion‐dependent solid‐liquid extraction model were used to predict the extraction process. EDSLE, which is simple and easy to be solved, was applicable in simulating the extraction process. The findings from this study are useful in understanding and optimizing the solid‐liquid extraction process of betel leaves.