Cashew nut trees, though originally native to Brazil, have spread throughout the tropical world and now, the major producers of cashew include Nigeria, India, Vietnam and the Ivory Coast. The key differentiator about the cashew nut is the fact that the nut appears outside the fruit. The cashew fruit is also known as as cashew apple and the nut appears beyond the fruit. The cashew nut is the seed and this is surrounded by a double shell. So as to finally reach the seed, that’s the cashew nut, these shells have to be removed and this involves systematic processing.
Initially, the raw nuts are cleaned and dirt, sand, rocks and some other particles and foreign matter are removed.
After cleaning, the nuts are dried in the open sun, in order to eliminate the moisture. In order to ensure that the nuts are dried on both the sides, they have to be rolled over on a regular basis. The drying process occurs under the sun, usually in an open lawn.
The outer shell of the cashew is extremely hard and should be softened. This is done by means of the roasting process. Here, the cashews are roasted at a cooker, which is supplied with steam from a boiler. The roasting time depends on the nature of the cashew and is judged based on experience.
When the outer shell is softened, it is cut. The cutting process can be manual as well as automatic. In the event of automatic operation, you will find special machines that do the task. However, the blade setting is highly critical, to make sure that inner kernel isn’t affected. The manual method requires the use of either hand or leg operated machines. There is a greater control in this process and a higher percentage of kernels come out undamaged. However, great care needs to be taken, since the shell contains an allergic resin. This can be dangerous, if not properly handled.
Drying in a hot room
Even though the outer shell of the cashew was cut, there is an adhering seed coat or testa. This needs to be removed. Since this seed coating is tightly held on to the seed, the only way to remove this is by drying in a hot chamber. Normally, the cashews are stored in trays and hot air from a blower is passed over them. The temperature maintained is generally about 75 to 80 degrees Celsius. When the testa is softened, further processing is simple.
In this stage, the testa is peeled. Although previously, the manual method of peeling was used, this has been mechanized. The most commonly used method is to blow the testa away by way of high pressure atmosphere. This will guarantee testa removal without any damage to the kernels. Other methods employed include freezing, suction, passing the kernels via rubber rollers, etc..
Grading and Packing
Lastly, the kernels are graded. The broken pieces are sorted and the whole kernels also sorted according to their shape, color and other parameters. Packing of different grades is done in a hygienic environment and the cashews are prepared to hit the market for consumption.