dc.description.abstract |
Cocoa (Theobroma cacao) is a commercial plantation crop in India. It is the
main raw material in the production of chocolates, cosmetics, health drinks,
pharmaceuticals etc. 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 sickle which is a labour intensive method. 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 continuous cocoa pod breaker. 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 continuous cocoa pod breaker consists of hopper, metal rollers, chute,
rotating cylindrical strainers, frame, prime mover and pulleys. Cocoa fruit was fed
manually in to breaker unit through hopper. Gap between the rollers was set so as the
cocoa kernels were not damage during the pod breaking process. Tangential force of
the roller pushed the cocoa pod towards the gap resulted in breakage. Cocoa pod,
kernels and placenta then discharged to strainer through chute. Rotation of strainer
separated the cocoa kernels from cocoa pod and placenta, and passed through the
pores of the strainer. It was then collected and could be directly send for fermentation
process. The broken pods were remained above the strainer and got separated.Performance of the machine was evaluated in terms of capacity, energy
requirement, percent bean damage, per cent bean recovery, shelling efficiency and
machine efficiency. The average capacity and breaking efficiency of cocoa pod
breaker was 550.5 kg/h and 95-98 percent, respectively. Bean damage percentage was
0.5 per cent. The shelling efficiency and beans separation efficiency of the strainer at
inclination, 45° 96.42 and 86.5 per cent, respectively. The performance of the
developed cocoa pod breaker was compared with traditional method of pod breaking,
the total time required to break 100 kg cocoa pods and collect the beans for
mechanical and manual method was 10.44 and 50.17 minute, respectively.
The field evaluation of the developed machine was done with two cocoa
varieties viz., Criollo and Forastero. The performance of the machine was evaluated
based on its capacity, per cent bean damage, efficiency of cocoa pod breaker and
energy requirement. From the field trail it is understood that, the efficiency of the
machine is higher for Criollo variety as compared to Forastero variety.
The fermentation studies were conducted in artificial fermentation chamber,
poly house and ambient condition and it was compared with three different
environmental conditions (ambient, poly house and fermentation chamber). The
effects of treatments on dependent variables like temperature, pH, moisture content
and microorganisms during fermentation process were studied. In this study,
fermentation of cocoa beans on all methods in the artificial fermentation chamber
found the best among the other treatments for the production of good quality cocoa.
Similarly, the box method was found the best among the other treatments for the
production of good quality cocoa.
The cost of operation of cocoa pod breaker of 550 kg/h capacity was
estimated as Rs.74.42 /- |
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