Design and Performance Evaluation of a Screw Press-Type Cocoa Butter Extractor for Small-Scale Cocoa Entrepreneurs

This study aimed to develop a screw press-type cocoa butter extractor optimized for small and marginal cocoa entrepreneurs and to evaluate the quality of the extracted cocoa butter. The screw press features a tapered screw shaft with diameters of 27 mm at the inlet and 35 mm at the outlet, an expelling chamber measuring 32.7 × 294 mm, and a hopper with a pyramidal frustum-shaped design with 365 × 360 mm at the top and 82 × 34 mm at the narrow end. The heating unit consists of four 550 W coils, providing a temperature range of 50°C–200°C, along with other control mechanisms. Cocoa butter was extracted from cocoa nibs through the combined effects of heat and pressure generated within the barrel. The extractor's performance was assessed based on cocoa butter yield, extraction efficiency, material discharge efficiency, and extraction loss. At 120°C and a screw speed of 50 rpm, the system yielded 44% cocoa butter, with an extraction efficiency of 81.4%, material discharge efficiency of 89%, and extraction loss of 11%. The quality parameters of the extracted cocoa butter, including free fatty acid content (1.27%), iodine number (33.18), peroxide value (1.68), moisture content (0.14% w.b.), and water activity (0.428), were within acceptable limits. The machine's rated capacity was 10 kg/h, with a power requirement of 0.9 kWh. Overall, the developed cocoa butter extractor proved to be economically feasible for small-scale production under optimized conditions and holds commercial potential.