The fruit is then pressed between two boards to a thickness of approximately 1.5 cm. This
removes much of the moisture as a juice and also makes small holes in the skin which allows
quicker penetration of the sugar syrup used in later stages of the process. The squashed fruit is
then simmered in a strong hot sugar syrup (75lb sugar per 1000 pieces of fruit with enough water
to cover) for two hours. (The syrup can only be used a limited number of times and is financially a
key raw material. Any alterative use of the syrups, for example in the production of wine, vinegar
or sweets, could markedly improve the overall profitability of the enterprise.) Finally, the fruit is
removed from the syrup with tongs, placed on mesh trays and dried in small Brace-type solar
driers (8ft x 4ft). After two to three days drying, the fruit is removed with tongs to avoid handling,
and packaged in heat sealed cellophane bags of average net weight 4oz.
Solar drying improves on open-air drying by protecting the products from rain, insects, other
animals and dust which may contain faecal material. Faster drying reduces the likelihood of
mould growth, and higher drying temperatures mean that more complete drying is possible which
may allow much longer storage times.
The more valuable the crop to be dried, the higher the financial risks involved if the producer has
to accept spoilage rates from open-air drying, and the more often the solar drier would be used.
Initially, the solar driers were not well liked by the women at Pueblo a Pueblo; the polythene
darkened with the sunlight and was easily damaged. Intermediate Technology assisted by
providing a sample of an ultra violet sunlight resistant film (ICI Melinex) which proved most
acceptable, being strong and long lasting. The NGO purchased 100m of this film which lasted six
years. A solar roof inclination of 9° was used, later increased to 15° to improve efficiency.
In 1986, 40 women were involved in the production of cashew fruit caramel. Each team of 10
women could produce 800 dry fruits per day. The women were earning 4 Lempira (US$ = 2L) per
day, which was more than the average man's earnings of 3L. The market in the USA was paying
$2 per pound and was buying 5,000 lb each year.
By 1990, the size of the group had increased to between 60 and 70, and 40 solar driers were in
use. Sales to the USA had reached 9,000 lb per year and Pueblo a Pueblo expect to increase the
size of the project for the 1991 season to meet growing demand. A total of five more women's
groups with 50 members is planned.
It is clear that this is an example of a viable, sustainable income-generating project. It is also one
of the very few examples of the successful commercial application of small solar driers.
• Cashew Nut Processing D C Russell, FAO Agricultural Services Bulletin No 6, FAO, Rome
• The Processing of a Date-like Caramel from Cashew Apple A J Ortiz, R D Cooke, R A
Quires. Tropical Science 1982, 24(1)
• The Biochemistry of Fruits and Their Products Mazliak P (1970) Vol 1. A D Hulme (ed)
pp 209-238 London and New York