The kidney shaped edible Nuts are called kernels and are obtained from the fruit or the raw nut after removal of the outer leathery covering which surrounds it, using different processing methods – dried well, steaming, shelled, peeled, graded, roasted, quality inspection, quality control and packing. Cashew processing actually includes the various steps and the processing methodology used varies from region to region. In Brazil, mechanical processing is done, while in India, processing is highly labour oriented. Even inside India, there are differences in the processing methods used in different regions. In Karnataka & Tamil Nadu steam boiling method is followed while in parts of Kerala, Orissa and Andhra Pradesh, drum roasting method is followed.
The different steps involved in Cashew processing using Steam boiling :
a) Steaming – The in-shell cashews are steamed under pressure to soften the shell. This causes the cashews inside to become loose and easier to remove in time.
b) Shelling – Each cashew shell is split open longitudinally and the cashew inside is immediately taken out by hand.
c) Drying – The skin on cashews is dried in an oven at low heat for a few hours to loosen the skin.
d) Peeling – The skin of each cashew is removed by hand and the cashew is simultaneously visually graded according to quality.
e) Grading – The whole cashew kernels are individually graded by hand according to count per pound. Cashews are graded on how white they are and how broken the kernel is. There are four color grades, four styles of break on the kernel and six sizes (or maximum number of kernels per pound). Nowadays grading machines are used for grading.
f) Quality Inspection – The cashews of each grade are inspected according to the present quality standards for that grade.
g) Quality Control – The Cashew kernels are then put through a set of quality assurance measures like heating in an oven, metal detection, dust aspiration and handpicking conveyor.
h) Packing – The Cashew Kernels are packed in 50-pound (22.68 kg) multilayer barrier pouches in a modified atmosphere of low oxygen and high carbon dioxide and nitrogen. These pouches are placed one each in a carton.
The Cashew Nut Kernels are graded according to their size, shape and colour, as Wholes, Splits, Brokens, Butts, Scorched butts etc. Wholes are again classified as W180, W240, W320, W450 etc., according to the number of whole kernels per pound (0.45 kg). The edible cashew nuts are available in around 26 – 33 different grades. The Wholes are sold as snack food while the split nuts are generally used as ingredients in other foodstuff.
India stands first in processing. India processes around 1.59 million tons of cashew nuts every year though it produces only around half of the quantity that it processes. Due to the large processing capacity in India, the country imports raw cashew nuts from African countries, Indonesia & Cambodia. Vietnam processes around 0.90 million tons of cashews nuts every year and while Brazil processes around 0.30 million tons. India has emerged as a largest market for cashew where the demand of cashew for consumption has been steadily increasing over the years. On an average 150 to 160 thousand Metric Tonnes of Cashew Kernels produced in India get absorbed in Indian markets itself.