2019 ASHS Annual Conference

This study examined the drying behavior of fermented cacao (Theobroma cacao) beans subjected to three different drying systems: sun drying, mechanical oven drying, and dehumidification drying. Multiple treatments that included factors such as location, drying intervals, and temperature were conducted within these systems. Sun drying treatments were conducted at four different sites on Hawaii Island to represent the diverse range of environmental conditions. Sites included: Papaikou, and Pepeekeo, which characterize areas with high rainfall and relative humidity, as well as in Kainaliu, and Kawaihae, which receive lower rainfall and relative humidity. Mechanical oven drying, and dehumidification drying were both done indoors in Hilo. Treatments for each drying system included both constant and intermittent cycles. For sun drying, this entailed subjecting one sample to full sunlight all day, and another sample to a standard drying protocol (3 hours of drying the first day, 4 hours the second day, 6 hours the third day, and full sun everyday thereafter until the beans reached a moisture value of 7-7.5% wb. Treatments for oven drying were done at 57°C, and included three separate intervals: 1) constant drying, 2) standard drying, and 3) using an oven drying protocol developed in Trinidad (drying for 2 hours with a rest period of 22 hours). Dehumidification drying was done at a constant rate (drying at 30% relative humidity) and using a step-down approach (drying at a starting point of 65% RH, and decreasing in 10% increments every 24 hr. until beans reached 7-7.5 % wb). Moisture content was measured twice daily throughout the drying period. Color attributes, and pH were measured before and after drying. Bean samples from each treatment were sent to Dandelion Chocolate Company, Guittard Chocolate, and Seguine Cacao Cocoa & Chocolate Advisors to be processed into chocolate and subjected to sensory evaluation. There were significant differences in average drying rates between treatments, with sun drying in Papaikou taking the longest amount of time to dry, and oven drying constant, which took the least amount of time, at rates of 17.9 and 2.9 days respectively. Initial moisture content of beans averaged at 54.9% wb. Average starting pH for testa and cotyledon were 4.54 and 4.7. Average end pH for testa and cotyledon differed significantly between treatments. Results from sensory evaluations of both liquor and chocolate showed differences between treatments, with oven drying standard scoring the highest in terms of overall flavor.