Cashew, Anarcadium occidentals, a flowering plant belonging to family Anacardiaceae is allied with mango pistachio, poison-ivy and poison oak. The family contains 73 genera and about 600 species. Anacardium contains 8 species of which the cashew is by far the most important economically. Cashew is native to Brazil, where it is called by its Portuguese name Caju or Cajuiro. it is now widely grown in tropical climate for its nuts and apples. Originally spread from Brazil by the Portuguese, cashew tree today can be found in all regions with a sufficiently warm and humid climate.
- Uses of Cashew:
- Cashew wine
- Cashew Nut Shell Liquid (CNSL) for industrial applications
- Cashew nut, apple, shell liquid and juice are used in the treatment of diarrhea, asthma, colds, skin infections, burns sore throat, cancerous ulcers, malaria, syphilitic ulcers, leprosy and elephantiasis.
- Soil and Climatic Conditions Required for Cashew Production
The best soils for cashew are deep, friable, well-drained, sandy loam soils without hardpan, but with phreatic water level at a depth of 5 to 10 meters. On the other hand cashew cannot withstand badly drained, floody soils, heavy soil layers, hard-panned soils and compacted subsoils. Research work at the Cocoa Research Institute of Nigeria (CRIN) has shown that cashew is the only tree crop that is grown from the coast to the Sahel Savannah areas. This wide spread indicates that cashew grows on a variety of soil types, implying that cashew grows on soils of varied physico-chemical characteristics and fertility levels. There are however, optimum soil properties for economic growth of cashew.
Cashew is a tropical plant that grows well between 15° south and 15° north of the equator, and thrives with a wide range of temperature from 15°C and 40°C; and equally wide range of rainfall of 500 – 200mm. While cashew is tolerant to drought, there is a strong relationship between the performances of cashew and the availability of water in the soil. Well-defined dry season of at least four months and preferably longer, favours high productivity of cashew. With sufficient water supply, cashew withstands low relative humidity but extremely dry air during harmattan may wither flowers and hence loss in yield. Extremely humid climate is also unfavorable for cashew production as it favours attack by pests and diseases.
- Planting Materials
One important reason for low and varying yield on many cashew fields is the poor material need for planting. To ensure high returns from the field, select plant materials only from trees, which have all the desired qualities (high yield and resistance to diseases). As cashew is a perennial tree living up to 30-40 years, any mistake made in the early stages will have a long (life) lasting effect on the plantation. One of the most important points for consideration in raising a good field is to select seeds from regular cropping, high yielding healthy trees bearing medium size nuts. The selection of the “best tree” should be the guiding principle and not the outward appearance of the nut.
- Cashew Varieties
So far, the only officially released variety of cashew bred at CRIN by the trio of Sanwo Faluyi and Badaru is called the G Series with a National Code of NGAO -99-1. It is of the Eruwa and Iwo origin. The specific attributes of this cashew type are its high yield – 188,000 nuts/hectare/ye coupled with an intensive and extensive branching system. The G-Series, adapted to both tl Forest and Derived Savanna zones, was released in 1982 but officially registered in 1999.
Apart from the G Series, breeding activities at CRIN has resulted in the development of some extremely higher yielding materials, which are presently being processed for official release. The processing notwithstanding, these materials mostly of the medium-sized nuts (Table 1) have been introduced to farmers through the Institute’s extension programmes. The yield advantage over the Brazilian Jumbo and Brazilian Extra Large accessions range from 300% to 400%.
Outstanding Cashew Varieties Developed by CRIN
|Genotype||Nut Size (g)||Yield Potential (T/Ha)|
|Large (Brazilian Accession)||10.0-12.9||1.80|
|Extra Large (” “)||13.0-15.9||1.00|
|Jumbo 5 (” “)||> 16.0||0.72|
- Cashew Processing
Cashew can be processed into the following products:
- Cashew apple used in the production of jam, chutney or various beverages, wine and juice.
- Cashew Nutshell Liquid (CNSL) used as resin modifier, and as filler in brake lining, and manufacture of paints.
- Cashew Gum processed for pharmaceutical use and as substitute for Gum Arabic.
- Cashew Kernels processed into snacks, edible oil, confectionery etc.
Cashew kernel is the most valuable, and the main objective of processing is to remove the kernel from the shell with as little damage as possible. Technologies used for processing each product are essentially different, as described below:
- Processing of Cashew Apple into Wine
The flow chart for the production of cashew wine and juice is shown below. The washed cashew apples are cut into slices in order to ensure a rapid rate of juice extraction. After slicing, the apples are crushed in the juice press. The fruit juice is sterilized in stainless steel pans at a temperature of 85°C in order to eliminate any wild yeast. The juice is filtered and treated with preservatives. At this stage, the juice can either be pasteurized and packaged as cashew juice, or wine yeast (Saccharomyces cerevisiae) can be added for cashew wine production. Once the yeast has been added, the juice is thoroughly stirred and allowed to ferment for about 7-14 days. The wine is separated from the sediment and clarified by mixing refining agents such as gelatin, pectin or casein. After filtration, the filtered wine is transferred to wooden vats. The wine is pasteurized at 50-60°C. Above 70°C, the alcohol vaporizes. The wine is stored in the wooden vats and subjected to ageing. At least six months should be allowed for ageing. If necessary, the wine should be clarified again before bottling.
Flow Chart for the Production of Cashew Wine and Juice
- Process of Cashew Nut into Cashew Kernels
The processing of cashew nuts into kernels consists of seven main steps:
- Cleaning and sizing
- Roasting and centrifuging.
- Shelling: Removal of the outer shell and CNSL.
- Peeling: Removal of the testa
- Grading: Sorting into different sizes and colours in accordance with standard grading
- Drying or humidifying: To a final moisture content of 5%
- Packing: Pack into an air tight bag or can