A Study on the Breaking and Winnowing Machine for Cocoa Beans at Small Industrial Scale in Vietnam

Abstract

In the chocolate or cocoa powder processing process, the roasted cocoa beans have to pass to the breaking and winnowing step to obtain the nibs. The quality of chocolate or cocoa powder depends strongly on the amount of shell that is not separated and still mixing on the nibs. Recently, most of the cocoa bean breaking machines are based on the principle of grinding. This leads to some disadvantages as (1) the shells might be not separated from the cocoa kernel after the shattering that results in low efficiency of the cleaning process (<96%); and (2) the nibs are also crushed so much to become smaller so that they are easy to moving out together with the shell in the winnowing step due to the similar density. As a result, the ratio of nibs loss during the cleaning process is very high as around 11.3%. Therefore, the shattering and cleaning process has strongly affected the economic efficiency of cocoa production. One of the new methods for cocoa breaking and winnowing in order to increase the cleanness level and to reduce the nibs loss rate has been developed and studied. The cocoa seeds breaking based on the centrifugal mechanism in combination with the pneumatic cleaning have been conducted to manufacturing breaking and winnowing machine with a capacity of about 80 kg/hour. The experimental results indicate that the efficiency of the cleaning process rises to more than 99% and the ratio of nibs loss reduces to 1.6% only which leads to increase the economic efficiency of the cocoa processing process.