Cashew - Anacardium occidentale
The Cashew,
Anacardium occidentale L., is a member of the Anacardiaceae family, along with mango,
pistachio, poison ivy and poison oak. The family contains 73 genera and
about 600 species. Anacardium
contains 8 species, native to tropical America, of which the cashew is
by far the most important economically.
Cultivars
Cashews are one of the few fruit crops normally
grown from seed, and few improved cultivars exist, at least in
commercial production.
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ORIGIN, HISTORY OF CULTIVATION
Cashew is native to northeastern Brazil, in the area
between the Atlantic rain forest and the Amazon rainforest. The Portuguese introduced cashew to the west coast
of India and east Africa in the 16th century, shortly after its
discovery in 1578. It was planted in India initially to reduce erosion,
and uses for the nut and pseudofruit, the cashew apple, were developed
much later. Nut domestication predated the arrival of
Europeans to Brazil, although international nut trade did not occur
until the 1920s. India developed more refined methods for removing
the caustic shell oil, and this country is given credit for developing
the modern nut industry.
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World (2004
FAO) - 2,082,101 MT, or 4.6 billion lbs. Produced commercially in 32
countries on over 7.5 million acres. Cashew is now the #1 tree nut crop in the world, since its production
surpassed that of almond in 2003. Average yields worldwide are about 600 lbs/acre.
Top 10 countries
(% of world production) |
1. Viet Nam (28)
|
6. Indonesia (4) |
| 2. India (25) |
7. Guinea-Bissau
(4)
|
| 3. Nigeria (10) |
8. Cote D'Ivoire (4) |
| 4. Brazil (8) |
9. Mozambique (3) |
| 5. Tanzania (6) |
10. Benin (2) |
Cashews produce 2 additional products of commercial
value from their fruit: cashew apples and cashew nut shell liquid. The
cashew apple is the juicy, swollen peduncle of the fruit.
United States
- Cashews are not produced commercially in the USA. The USA imported 102,000 MT of cashew in 2003, valued at $398 million.
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Plant
A small to medium tree, generally single-trunked and
spreading in habit, up to 40' in height but generally 10-20' in
cultivation (Figure 9.3). In older trees, spread may be greater than
height, with lower limbs bending to touch the ground. Leaves are thick,
prominently veined, oval to spatulate in shape, with blunt tips and
entire margins. New foliage contains reddish pigment.
Flowers
Flowering is similar to the close relative mango:
both male and perfect flowers are borne in the same inflorescence
(polygamous). Individual flowers are 1/4" across, with crimson petals,
often striped longitudinally and reflexed. They are borne terminally on
panicles, generally at the beginning of the dry season.
Flowering may occur over several weeks.
Pollination
Trees are at least partially self-fruitful, as lone
trees can bear many fruit. Various insects, even flies and ants provide
pollination.
Fruit
The true botanical fruit is a nut, about 1" long,
shaped like a small boxing glove, hanging below a fleshy, swollen
peduncle called the cashew apple or pseudofruit. Fruit are borne singly or in small clusters, and
mature in 60-90 days.
The nut shell has an inner and outer wall, separated
by a honeycomb tissue infused with caustic oil. Cracking the nuts fresh
results in the oil contaminating the kernel, so nuts are roasted to
drive off oils before they are shelled. The nuts are about 22-30%
kernel by weight, and kernels are difficult to extract whole compared
to other tree nuts.
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Soils and Climate
Tolerant of sandy, poor soils, Soil pH 4.5-6.5,
intolerant of poor
soil drainage
Drought tolerant if soils are deep, and can grow in
areas receiving
only 30-50" of rain per year
High rainfall and
humidity favor diseases that destroy the flowers and reduce fruit set
No cold tolerance
Propagation
Propagation is most often by seed, planted directly
in the field where the tree is to be sited.
Rootstocks
- generally none, but cashew seedlings can be used for rootstocks for
grafted trees.
Planting Design,
Training, Pruning
Planting Design: 20-35 ft between trees and
rows
Cashews form open, spreading canopies naturally, and
very little information on pruning exists.
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HARVEST, POSTHARVEST HANDLING
Maturity
The cashew apple and nut abscise from trees
naturally when ripe. Maturation occurs over a period of several weeks
during the dry season.
Harvest Method
Nuts are collected from the ground by hand. Frequent
passes though the planting must be made if apples are to be utilized,
as they are highly perishable. Rain at harvest may increase rot and
stimulate nut germination.
Postharvest Handling
The presence of caustic cashew nut shell liquid
(CNSL) in the shells makes cashew processing more difficult and
hazardous than for other nut crops. After harvest, the nuts are dried
in the sun or in simple tray driers and stored for processing later.
Dried nuts can be stored for about 2 years at room temperature after
reaching water contents of 5-10%. Nuts are re-hydrated partially by
soaking or storing in high humidity since this facilitates extraction
of whole kernels and CNSL. Nuts are separated by size before roasting
to ensure uniformity of the roasting process. After roasting, nuts are
shelled either by hand or
in machines.
Storage
Vacuum packed, roasted nuts can be stored for up to
one year, and carbon dioxide packing extends life an additional year.
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The cashew apple may be consumed fresh, but contains
high quantities of tannins yielding a bitter taste and dry mouth feel.
It is more often cooked, partially dried, or candied, as in the
Dominican Republic and India. The alcoholic drink, Feni, is made from
fermented cashew apple juice in India. The wine made from the juice is
said to be the finest made from tropical fruits. Per capita consumption of cashew is 0.8 lbs/year in the USA.
Dietary value, per 100 gram edible portion
|
Cashew nut
|
Cashew apple |
| Water (%) |
3-7
|
86
|
| Calories |
578
|
---
|
| Protein (%) |
18-22
|
0.1
|
Fat (%)
|
46
|
0.3
|
Carbohydrates (%)
|
27
|
9-15
|
Crude Fiber (%)
|
1.1
|
0.75
|
|
% of US RDA* |
| Vitamin A |
0
|
0
|
| Thiamin, B1 |
45
|
---
|
Riboflavin, B2
|
12
|
---
|
| Niacin |
12
|
---
|
| Vitamin C |
0
|
200-600
|
| Calcium |
0.2
|
0.5
|
Phosphorus
|
5.8
|
2
|
| Iron |
50
|
5
|
| Sodium |
4.6
|
<0.1
|
| Potassium |
12
|
0.1
|
* Percent of recommended daily allowance set by FDA, assuming a 154 lb
male adult, 2700 calories per day.
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