Development and Performance Evaluation of a Cocoa pod breaker cum bean extractor

Abstract

Cocoa (Theobroma cacao) is a commercial plantation crop in India. It is mainly cultivated in Kerala, Andhra Pradesh, Karnataka and Tamil Nadu as an intercrop with arecanut or coconut. Cocoa is the main raw material in the production of chocolates, cosmetics, health drinks, pharmaceuticals etc. It contains about 50 per cent fat which is useful in the production of candle, soap, ointments etc. The processing of cocoa involves the breaking of pods, extraction, fermentation, drying, dehulling and winnowing of the beans; and the production of value added products like cocoa butter, beverage and cake. Cocoa pod consists of three main components viz.,crust pod, cocoa bean and placenta. The cocoa beans which are embedded in a mucilaginous pulp inside the pod consist of two parts- seed coat and seed cotyledon. Seed cotyledon is the material in which characteristic flavour and aroma produced during fermentation. At present, cocoa pod breaking and bean extraction from crust pod are done manually by using machete or sickle and need many workers. Manual chopping could increase the number of damage bean which leads to fungal attack. In order to eliminate the drudgery involved in manual cocoa pod breaking, avoid injury to workers, increase efficiency and to ensure high quality products, an attempt was made to develop a cocoa pod breaker cum bean extractor. Before the fabrication of machine, the engineering properties of cocoa viz., physical, mechanical and frictional properties of fresh cocoa pod were determined. Physical properties studied were size, shape, mass and density. The mechanical and frictional properties viz., compression test, angle of repose and co-efficient of friction were determined as per the standard procedures. The developed cocoa pod breaker cum bean extractor had two main parts- 1) Cocoa pod breaker and 2) Cocoa bean extractor. Cocoa pod breaker consists of two rollers in which each roller was reverse rotated. The gap between the rollers was set based on the size of the cocoa pods fed. Bean extractor consists of a rotational strainer which help to separate beans from the broken cocoa pod.Gap between the rollers was adjusted so that the pod should break properly, whereas no damage occurred to cocoa kernels during the process. Cocoa fruit was fed manually in to pod breaker unit through hopper. The tangential force of the roller pushed the cocoa pod towards the gap resulted in breakage. Broken cocoa pod, kernels and placenta then discharged to the strainer through chute. Strainer separated the cocoa kernels from cocoa pod and discharged through strainer outlet. The broken pods were remained above the strainer. Performance of the machine was evaluated in terms of capacity, percent bean damage, percent bean recovery and machine efficiency. The average time required to break 5 cocoa pods using pod breaker was 20 s where as in manual method was 30 sec. Similarly the time required to separate the bean was around 31 s for cocoa pod breaker against 55 sec for manual method. The cocoa pod breaker had a maximum capacity of 327 kg/hr at a motor speed of 350 rpm whereas in manual method the capacity was 216 kg/hr. Similarly the bean damage per cent, bean recovery per cent and overall efficiency of the machine was estimated at 0.4, 75.6 and 87.4 per cent, respectively. The bean damage recorded during testing was less than 1 per cent. The developed cocoa pod breaker cum bean extractor may enhance the quality of cocoa products to a great extent. Also it avoids the risk and danger exposed during the process of splitting the cocoa pods manually.