The quality of discharged coconut meat or copra is influenced by the method and the manner in which the coconut kernel is discharged. If the coconut kernel is not properly discharged, it gives rise to harmful molds. The mould (yellow-green in color) is called Aspergillus flavus , which produces aflatoxin, a type of mycotoxin. Aflatoxin is harmful to both man and animals.
The coconut kernel should be properly treated to prevent the attack of aflatoxin related molds. Processing of quality mature coconuts to copra has several problems. If it is not properly processed, it will result in low oil yield. By following proper post-harvest practices while drying and storage can increase the oil yield. If the coconut kernel is not properly discharged then there will be less moisture content, and this will result in lower incidence of aflatoxin.
Copra making involves different steps
Between harvesting and marketing of the produce, coconuts go through different processes.
- First, the mature coconuts are discharged using sun drying or smoke-kiln methods. Hot-air dryers are also used at times. Mature coconuts have a higher percentage of meat and are thicker and denser with higher level of fat content. Mature coconut meat contains abundance of oil.
- Foul nuts tend to have high mold growth, so they are best avoided. Only matured (brown) nuts that are 12-month-old or older are used to make dried coconut meat.
- The most important process is drying the coconut kernel or reducing its moisture content from 50 percent to 6 percent. This effects the quality of the product.
- To prepare copra, the nuts are split and the meat exposed and the drying is started immediately or within four hours from splitting. If the drying time is delayed after splitting then mold formation will start. If the weather is not suitable for drying then nut splitting is deferred.
- If the weather suddenly turns bad during the sun-drying period, mold inhibitors are used.
- Cleanliness is maintained in the drying area during sun-drying. Soil and other extraterrestrial matters should not get mixed with the meat. Coir mats or plastic sheets are used under the coconut meat to avoid direct contact with the ground.
- Plastic sheeting is used to protect coconut meat from rain and dew. On extended downpours, the copra is heated and discharged within 24 hours.
- Coconut kernels are sun dried for four to five days (in good sunlight) to attain 6% moisture level.
- If the coconut kernel is used using kiln dryers, a drying temperature of 35 o C to 50 o C is maintained for the first 16 hours of drying. In the next phase, 50 o C is maintained until a final moisture content of 6 percent is reached.
- Pressing the copra between the thumb and forefinger, the thumb against the white meat, is a quick test for 6 percent moisture content. If the copra kernel (white portion) does not stick to the thumb, and when drops are released, the 6 percent (approximately) moisture level has been achieved.