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Plum
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Apricots, cherries, plums, peaches and almonds are names with different etymologies; but the genus name Prunus, given by Linnaeus, is common to all these trees that produce some of the most prized types of fruits. Although in Roman times Prunus probably indicated only the plum tree, with the passing of time it became usual to include in the same genus many species found mostly in temperate regions. Some representatives of this genus also grow in South America in the Andes. Today the plum is cultivated to some extent everywhere in Europe and in the United States. The biggest producers are the east European countries. Among the thousands of cultivars throughout the world are found the characteristic mirabelles with very small fruits; the Florentia and the Shiro, both juicy and sweet, but with slightly tart skin; the good Reine Claude (or "greengage") and the Santa Rosa. There are many American varieties such as Damson Beauty, Italian Prune, Burbank, Sugar, and Stanley. Plums are eaten fresh or dried (prunes), but a large part of the harvest is used by the canning industry for preserves, jams and sweet pickles. Some varieties are also distilled to make brandy such as the Balkan slivovitz. Plums are harvested when their characteristic fragrance is strongest; the first fruits to be collected are those that are going to be preserved or candied. The late varieties are used for drying: the fruits are laid in the sun and then baked in special ovens at a particular temperature. The skins acquire the beautiful brownish color and sheen which make them so valued commercially. The laxative action of prunes is well known. Culpeper, the great seventeenth-century English herbalist, spoke highly of plums as fruits belonging to Venus. As well as recommending the fruits "both in health and sickness, to relish the mouth and stomach. . ." he also wrote that "plum-tree leaves boiled in wine, are good to wash and gargle the mouth and throat" and that the leaves boiled in vinegar would also cure ringworm! Taken in excess, however, the versatile plum could cause colic. Because of the organic acids in plums, they have been recommended for those with gout and uricemia. They are high in carbohydrates but their vitamin content is negligible. Each species of Prunus contains a large number of cultivars. Throughout the centuries, man has always placed great importance on the nutritional and commercial value of plants, and has also succeeded in obtaining particular varieties valued for their flowers or leaves and therefore used as outdoor ornamentals. Early in their cultivation it was probably almost exclusively the sugar content of the ripe fruit that led gardeners to think of its high energy value. But when man began to analyze chemically the various components of the single species, he discovered numerous mineral salts and, more recently, vitamins. This discovery brought both hope and dissension. Today, science tries to show each kind of food, including fruit, in an impartial light, emphasizing the calorific or mineral or vitamin properties, which can be present at various levels simultaneously. It is impossible to discuss in a general way the precise composition of fruit. The sugar content of a cherry differs considerably, for example, from that of a peach. But a fairly accurate average can be obtained. It can be seen that fresh fruit contains more water than anything else, 80 - 90%; the amount of assimilable carbohydrates is also high, about 12%. Mineral salts, protein and lipids have approximately the same values, 1% or less. The rest of the weight is made up of nonassimilable substances (2 - 3%) and various vitamins which, however, are not always present. With the exception of a few very rich fruits, they are not generally found in great quantity. The vitamins of the B complex are often scarce or even absent, while a satisfying amount can be provided of the groups A and C. Contrary to general belief it is not true that fruit is an inexhaustible source of vitamins. Mineral salts which are present in small amounts cannot be compared in quantity with those provided by, for example, milk, meat and cheese. Fruit does, however, have a beneficial effect on the human body, because of its assimilable sugars and the number of calories produced. Another important factor is the presence in fresh fruit of some organic acids, such as tartaric, citric, and oxalic. Fresh fruit is considered by some to be useful for cases of acidosis and rheumatic disturbances. [Bianchini, Francesco, Corbetta, Francesco, Pistoia, Marilena, The Complete Book of Fruits and Vegetables, United States Translation: Crown Publishers, New York, 1976; Originally published in Italy as I Frutti della Terra, Arnoldo Mondadori Publisher, Italy, 1973]