Drying of Coconut
|Drying for copra making||
Copra is produced after drying the coconut kernel. Copra and the coconut oil
as well as the cake derived from it are a major source of foreign exchange
for many coconut growing countries in Asia, the Pacific, and Africa.
The quality of copra and copra cake is influenced by the method and the manner of drying the coconut kernel. Improperly dried copra gives rise to certain moulds, the most harmful of which is the yellow green mould called Aspergillus flavus and other aflatoxin related moulds. Aflatoxin is harmful both for man and animals.
It is therefore extremely important that the coconut kernel be properly dried to prevent the attack of aflatoxin related moulds. Processing of mature nuts to copra has several problems. Improper processing results in low oil yield and incidence of aflatoxin. Proper post-harvest practices, as well as proper drying and storage can increase the oil yield to about 20 percent. Proper drying of coconut results in copra with lower moisture content and lower incidence of aflatoxin.
Copra is mainly produced by small coconut holders using sun drying or smoke-kiln methods. Hot-air dryers are also used to a limited extent.
Copra making involves different steps between harvesting and marketing of the produce. Of these, drying the coconut kernel or reducing its moisture content from 50 percent to 6 percent most influences the quality of the product.
The following are ten guidelines for producing aflatoxin-free copra:
1) Harvest only fully matured (brown) nuts. These are the 12-month old or older nuts;
2) Do not pay the harvester for immature (green) nuts; instead penalise them for picking green nuts;
3) For producers selling husked nuts to desiccated coconut factories, segregate the "fouls" for processing into copra. Never mix the "regular copra" with the copra from "foul" nuts. They tend to have high mould growth;
4) When preparing copra, split the nuts and expose the meat only when certain that drying can start immediately or within four hours from splitting (exposure) to prevent mould formation. When there is the threat of bad weather, defer nut splitting;
5) If the weather suddenly turns bad during the sun-drying period and is expected to remain so for some time, use of mould inhibitors is recommended;
6) For producers practising sun drying, maintain cleanliness in the drying area. Clean pavement or floors before spreading fresh coconut meat. Make sure that soil and other extraneous matters are not mixed with the meat. Plastic sheeting may be used under the coconut meat to avoid direct contact with the ground;
7) Have on hand a portable cover (plastic sheeting) to protect coconut meat from rain and dew. These are shaped like roofing (inverted Vs) to allow aeration. On extended downpours, heat and dry the copra within 24 hours;
8) Continuous sun drying for four to five days (in good sunlight) shall achieve 6 percent moisture content;
9) For producers using smoke, kiln dryers, and other types of dryers, a drying temperature of 35oC to 50oC should be maintained for the first 16 hours of drying followed by 50oC during the next phase until a final moisture content of 6 percent if reached. It is important that drying should begin four hours after the nuts are split to prevent mould contamination;
10) Pressing the copra between the thumb and forefinger, the thumb against the whitemeat is a quick test for 6 percent moisture content. If the copra kernel (white portion) does not stick to the thumb, and readily drops when released, the 6 percent (approximately) moisture level has been achieved.
|References||Kerala Agricultural University. 2011. Package of Practices Recommendations: Crops. 14th edition. Kerala Agricultural University, Thrissur- 360 p.|