Raw cashew nut needs proper processing for human consumption. There are several value-added products you can produce from a cashew processing unit. These are cashew nut shell liquid (CNSL), dried and roasted cashew nut.
If you live in a cashew growing area, then you can consider this business. There are two different ways you can initiate the processing plant. One is semi-automatic and another is fully-automatic. Generally, the cashew nut processing involves the recovery of edible kernels from the raw nut by mechanical means. In detail, the process consists of moisture conditioning, roasting, shelling, kernel drying, peeling, grading, and packing.
Establishing a cashew processing plant doesn’t demand a huge investment. Additionally, you can set up the unit in any size depending upon the demand-supply ratio.
Cashew Processing Market Opportunity
Raw cashew nut is not suitable for human consumption. Therefore, it needs proper processing. And manual processing doesn’t provide good quality production. Hence, small cashew farms always look for the mechanizing processing unit. In addition to that, this type of cashew nuts has good export potential in the different countries.
In the local market, raw and roasted cashew is a profitable FMCG product. Almost every grocery stores, supermarkets, malls sell these items regularly. Furthermore, the bakery, confectioneries, hotels, sweetshops, and restaurants are the major bulk consumers of cashew.
Starting a Cashew Processing Plant – Basic Steps
Grading of raw nuts before processing reduces broken kernel. Nuts are conditioned by sprinkling water and allowed to remain moist for 24-48 hours. Generally, you will need to roast the raw nuts to make their shell brittle and to lose the kernel from the shell. Methods of roasting are drum roasting, oil bath roasting, and steam boiling.
In drum roasting, feed the nuts into an inclined rotating drum which is heated initially to such an extent that the exuding oil ignites and burns, thus charring the shell. The drum maintains its temperature due to the burning of CNSL oozing out of the nuts. Roasting takes 3-5 minutes.
Oil bath roasting is a traditional method. In this method, you will need to pass the raw nuts for 1-3 minutes through a bath of CNSL maintained at a temperature of 190-200°C by means of a screw or belt conveyor.
The roasting equipment consists of a rectangular vvessel60-90 cm wide and 90 cm deep with a flat bottom. The whole assembly furnace uses spent cashew shell as fuel. After conditioning, you will need to give the nuts a mild roasting in a closed vessel for 20-25 minutes at 100-120 PSI to lose the kernels from the shell and make its removal easy.
Nuts after roasting are shelled manually in most of the units. Its output is 15-20 kg kernels in 8 hours with 90% whole kernels. Mechanical shelling can also be done where the shell is cut and the kernel is scooped out using a sharp needle. The output of a worker is 14-22 kg of kernels. The main disadvantage is that the kernels are contaminated by the CNSL from the mildly roasted nuts. The varying size of nuts requires careful manipulation during cutting to avoid injury to hands.
First of all, dry the kernels after separation from shells to reduce the moisture content (2-4%) and loosen the adhering testa. The most commonly used is Borma dryer with wire mesh trays loaded into metal chambers heated indirectly by gases from the furnace at the bottom. Frequently, change the trays for uniform heating.
Peeling is the removal of testa from kernels. Kernels after removal from the dryer being brittle are cooled for 24-48 hours for moisture absorption. You can remove the testa using sharp bamboo sticks. The average peeling capacity is 7-10 kg/head.
Grading and Conditioning:
Generally, you need to grade the kernels based on their size and color according to the Government specifications of your area. You will need to condition the kernels before packing to prevent breakage during transport. Additionally, you will need to maintain a moisture content below 5%, otherwise microbial and oxidative spoilage takes place.
Cashew nuts get rancid and quickly go stale, necessitating packaging having a permeability of oxygen and moisture. Generally, you can pack the bulk of cashew nuts in tin containers (metal cans) after evacuating and filling with CO2. Flexible packaging system with N-gas infusion or molded vacuum packaging can considerably reduce the packaging cost. So, you must use the updated and modern packaging machine for cashew packing.
Cashew Apple Processing – Basic Steps
First of all, wash the ripe cashew apples in water. Then extract the juice by using screw press or by hand pressing. You can obtain about 50-60% raw juice with 9-10% soluble solids. Also, you can remove the tannins present in juice by mixing with gelatin (0.5g/kg of juice), or polyvinylpyrrolidone (1.4 g/kg of juice) or rice gruel (1.25 ml/kg of juice), allow to settle and decant the clear juice.
In case of mixing with rice gruel, repeat the process again. You can use the raw juice for making syrup, squash, ready-to-serve beverages, vinegar, wine, and liquor. To prevent spoilage of raw juice, you can mix the sodium benzoate (0.7 g/kg) and citric acid (5 g/kg) along with a clarifying agent.
Cashewnut Shell Liquid Processing
Cashew nut shell liquid (CNSL) is a naturally-occurring phenol. Actually, it contains in the soft honeycomb mesocarp of the shell. CNSL is a viscous, oily or balsam-like substance, pale yellow to dark brown. It has a bitter taste and caustic properties.
Fresh CNSL contains 90% anacardic acid. And you can convert it into cardanol on heating. The rest 10% is cardol which is mainly responsible for the vesicant property. It comes as a by-product from the shell obtained during the processing of nut.
Generally, you can follow different methods such as hot oil bath, expeller, kiln method and solvent extraction. Of these expeller extractions are common.
Generally, you can extract about 7 kg of crude oil from 100 kg shell. The CNSL is a versatile industrial raw material. It is used widely ion the formulation of resins, detergents, insecticides dyes, antioxidants for mineral oils, lubricants, drugs etc.
The major products for industrial application are cashew lacquer, insulating varnishes, electrical windings and electrical conductors impregnated with CNSL and cashew cement (CSNL reacted with formaldehyde).
Actually, starting a small cashew processing unit demands proper strategic planning and distribution strategy. Also, you must consider the quality control seriously. Generally, quality control plays a very important role in the international market.