Avocados build red blood

"Four or five tortillas, an avocado, and a cup of coffee - that's a good meal." So say the Indians of Guatemala. And they're right. The dark-green pear-shaped fruit, the avocado, is a popular food in Central America and an extremely nutritious one. Not to mention appetizing; cheap, and available throughout most of the year.

It contains between 9 and 30 per cent oil similar in composition to olive oil, as well as high quantities of vitamin B. Experiments at the University of California have shown that the digestibility of avocado fat is equal to that of butter fat and not below that of beef fat. Since avocados are rich in oil, they also provide calories, 123 to 387 per 100 grams of avocado pulp.

But they are low in sugar - only about I per cent - which means that the fruit is recommended as a high energy food for diabetics.

The avocado gives a relatively high content (1.0-1.4 per cent) of iron-rich ash. Experiments have demonstrated that anaemic rats formed haemoglobin when fed diets supplemented with 1-5 grams of avocado pulp. Since avocado iron is physiologically available, it should be a valuable dietary factor in the prevention or cure of anaemia.

The total dry matter in the edible portion of the avocado is, at 30 per cent, greater than in any other fresh fruit. (The nearest contender, the banana, contains only 25 per cent.) The avocado also outdoes other fresh fruits in content of mineral matter. Soda, potash, magnesium, and lime account for more than half the ash or mineral matter. For protein and ash, the avocado surpasses any other fruit, and it contains on average fully 50 per cent of the carbohydrates contained in many fresh fruits.

For many Central Americans, the avocado takes the place of meat in the diet. When meat is scarce, the fact that an acre of land will yield a larger amount of food if planted to avocados than it will with any other tree crop assures the continued importance of the avocado industry in Latin American and Caribbean countries. That region's regular suppliers of the international market include the French overseas department of Martinique, Mexico, Guatemala, the Dominican Republic, and Peru. Demand is increasing significantly as a result of the development of new domestic and export markets. In the USA alone, the volume of avocados sold on the domestic market has increased tremendously. In Western Europe, imports of the fruit have also increased remarkably. France is by far the leading importer followed at a long distance by the United Kingdom. The two countries account for about 70 per cent of the total imports and are also largely responsible for the rapid rise in imports in recent years. Other European importers include Belgium, Denmark, Italy, the Netherlands, Finland, Norway, Sweden, Austria, and Switzerland.

The major suppliers to the Western European countries have so far been Israel and the Republic of South Africa. However, future exports from these countries will be facing tough competition not only from the Latin American and Caribbean countries but also from African countries, especially Kenya, Cameroon, and Cd'Ivoire.

Recipes for tasty avocado dishes abound. A purof avocado, lime juice, salad dressing, and salt is suitable for freezing. An avocado salad base can be prepared by blending 100 parts avocado with five parts lemon juice, four parts chopped onion, and one part salt.

In Brazil, where the avocado is regarded more as a dessert than as a staple foodstuff, it is made into a delicious ice cream. Avocado cookbooks have been published in Cuba, and in the avocado-growing states of Florida, California, and Hawaii in the USA.

Avocado trees, broad-leaved evergreens of the family Lauraceae, genus Persea, can be grown in all tropical and subtropical areas. In general they require the same growing conditions as citrus fruit but need more water. There are three recognized races of avocados based on their ecological origin - Mexican, Guatemalan, and West Indian. The Mexican race is native to the mountains of Mexico and Central America. The Guatamalan originated from the highlands of Central America. The West Indian race is native to the lowlands of Central America and northern South America. Many cultivars of commercial importance are hybrids of these three races.

The primary means of transporting avocados to the various markets is by truck within the country of origin and by ship for export. Only a small proportion of the avocados in international trade travel by air. Kenya is one exception that air-freights its avocados, but supplies from most other countries go by sea. For long distance shipments controlled-atmosphere containers are used which allow fruit to arrive in excellent condition, even after long sea voyages.

The fruits are picked and shipped when they are mature but firm and thus require ripening prior to consumption. The temperature at which an avocado is ripened has a pronounced effect on the rate of ripening and the quality of the ripened fruit in terms of flavour, texture, and appearance.

The avocado fruit is unusual in that it need not be picked as soon as it reaches maturity. In California, some cultivars can remain on the tree for six months or longer after maturing. Florida-grown cultivars can remain on the tree for as little as three weeks or for as long as three months after maturing. Generally, fruit of the summer cultivars belonging to the West Indian race remain attached to the tree for shorter periods of time than the later maturing cultivars. Shipping of fruits which have reached maximum maturity is not recommended because their shelf-life is reduced and their large seeds may sprout.

Nick Kesi