Optimization of Total Phenolic Content from Gynura Procumbens Leaves Under Oven and Microwave Drying

The optimization of the process variable; temperature, power, and drying time, under oven and microwave drying were studied for total phenolic content of Gynura procumbens leaves. The optimization conducted using response surface methodology central composite design of experiment. The optimum drying condition was obtained at 65.61°C at 10 hours with 201.78 mgGAE/g of TPC yield for oven drying while, for microwave drying was 436.19 Watt at 8.37 minutes with 12.24 mgGAE/g of TPC yield. The response surface methodology used in this study was able to predict the optimum drying condition for total phenolic content via linear and interaction mathematical model with higher adjusted coefficient determination , for both oven and microwave drying, 0.9383 and 0.7785, respectively. Hence, the models gave good prediction of the total phenolic content obtained from Gynura procumbens leaves under the experimental conditions used in this study. In addition, these outcomes are also expected to contribute to the production of shelf stable Gynura procumbens leaves which can be used for pharmacological purposes.