THE DRYING KINETICS AND POLYPHENOL DEGRADATION OF COCOA BEANS

摘要

This study investigated the kinetics of drying and polyphenol degradation duringrnhot air and sun drying of cocoa beans. Hot air drying was carried out using a constantrnhumidity-controlled (50% relative humidity) oven at temperature range ofrn60–80C, and sun drying was carried out by exposing the beans under direct sunlight.rnSeveral semi-theoretical models were used to model the kinetics of moisturerndiffusion and it was found that the Page and Logarithmic models were able tornprovide good prediction. A first-order reaction kinetics was used to predict thernpolyphenol degradation process with rate constants ranging from 0.011/h torn0.052/h. Activation energy for polyphenol degradation was determined at 8.97 kJ/rnmol using the Arrhenius equation. Effective diffusivity during drying was foundrnwithin the order of magnitude (10~(-12)–10~(−10) m_2/s) reported in most dryingrnliteratures.