PREPARATION OF FRUIT Foreign

LITERATURE

BY
K. G. BITTING, M.S.,

BACTERIOLOGIST,

GLASS CONTAINER ASSOCIATION OF AMERICA

———

THE RESEARCH LABORATORY,
GLASS CONTAINER ASSOCIATION
OF AMERICA,
3344 S. MICHIGAN AVENUE,
CHICAGO, ILL.
Copyright, 1920
Glass Container Association of America

 

OLIVES

Olea europaea L.

There is no tree nor fruit which offers more in interest than the olive tree and its fruit. To obtain anything approaching an idea of its many-sidedness, it is necessary to become acquainted with the life and legends of ancient peoples, in which it entered as sustenance and as symbol; to know something of art, as the olive has furnished the motif for much decoration, both symbolic and purely esthetic; to know something of botany and horticulture, to appreciate its parts and to understand their structure and development; something of chemistry and physics, to understand its various constituents and their intelligent treatment; something of the culinary art, to understand its value and its varied uses as a food and condiment; of medicine, to appreciate the many virtues ascribed to it as a healing agent; and of cosmetics, to believe all that is claimed for it as a cleanser and beautifier. Each phase offers many fascinating possibilities, revealed through the most ancient as well as the most recent literature, for with time the olive has gained both in interest and value.

Origin

The olive according to De Candolle has been cultivated for more than 4,000 years, probably the longest period for any tree. Its early history is known only through ancient literature, and ancient remains in which it served either as decoration or as a constituent. Through these its original home has been traced to Asia Minor, a region originally extending from Syria to Greece. That it grew on Mt. Ararat and was the harbinger to Noah of the recession of the flood is told in Genesis—“and the dove came in to him in the evening, and, lo, in her mouth was an olive leaf pluckt off.”

The ancient Egyptians as a part of the fruit of their conquests obtained the olive during the 19th dynasty. Mummies, dating from the 20th to the 26th dynasty, have been found surrounded by garlands of olive leaves. From Egypt it spread into northern Africa. It is said to have been taken to Greece by Cecrops, the founder of Athens. The legend states that in the reign of Cecrops both Poseidon and Athena contended for the possession of Athens. The gods resolved that whichever of them produced a gift most useful to mortals should have possession. Poseidon struck the ground with his trident and straightway a horse appeared. Athena then planted the olive. The gods gave the city to the goddess from whom it was called Athenae.

Pindar says that all the slopes of Olympus were soon covered with it, and that the Athenians used to crown the victors in the Olympian games with its branches. Later it was used to crown their warriors and wise citizens. The method of oil extraction was also obtained from outside. The Greeks are supposed to have had the wild olive, Oleaster, previously, but the fruit of this is valueless. They are the first European people to have cultivated the olive. Its cultivation spread to the surrounding countries, where the Greeks founded colonies, Sicily, the coast of Italy, and Gaul, these forming nuclei for its spread into the adjacent lands. Pliny states, however, that the olive was not introduced into Italy until 627 B.C., and that it reappeared in Gaul in 600 B.C., being carried to the latter country by the Phenician colony that founded Marseilles.

The olive was carried later by the Romans into the countries in which they settled, Spain being the most notable, but it was also carried into the Iberian peninsula by the Arabs.

The Greeks and the Romans cultivated it on the northern side of the Mediterranean, the Tyrians on the southern side, the Arabs finding it there and carrying it with them into Spain when they settled in that country. The double origin of the olive, Greco-Roman and Semitic, in this latter country is borne out by the names bestowed on the olive. In southern Spain the tree is called aceituno, the olive fruit aceituna, and the oil aceite, the name evidently derived from the Arabic name zeitoun, this in turn being derived from the Hebrew zeit. In northern Spain both Arabic and Latin names are used, the tree is called olivo or oliveira, whereas the fruit and oil have the Arabic derivative names aceituna and aceite respectively, but the oil used in the church and in painting is called oleo. In Portugal similar conditions prevail, the cultivated olive is called by the Greco-Latin name oliveira, whereas the wild olive is called by the Arabic name zambugeiro, the fruit azeitona, and the oil azeite.

Though some botanists claim that the olive is native to the Canary Islands, no word for it is found in the remains of the language of the Guanches, an ancient, but extinct, race of people who inhabited the islands. The available records show the tree to have been introduced there since 1403, and probably by the Phenicians.

The olive was introduced by the Spaniards into Chili, Peru, Mexico, and the United States. From Mexico it was brought by Jesuit missionaries into Lower California, the first settlement being at Loreto, in 1697. The Jesuits founded fifteen missions, but were superseded by Franciscans in 1768. These latter proceeded northward to extend their work, the first of their missions being founded in 1769, at San Diego. The secular head of the mission, representing the King of Spain, had the foresight to carry the seeds of flowers, fruits, grains, and vegetables, so that flourishing gardens were soon brought into existence. When the missions went into secular hands in 1843, the gardens in many cases were neglected and many of the fruit trees died. The olive was one of the trees that withstood the neglect and was afterwards used for cuttings by the emigrants from the eastern states who came in 1849. From this time on the olive has received considerable attention, many experiments being made in its culture, and in recent years the plantings have increased to an enormous extent, due to the favor accorded to both the oil and the fruit. It has spread around San Diego and Los Angeles east into the San Joaquin Valley and north into the Sacramento Valley in California, and also into Arizona. In the latter state its cultivation is comparatively recent, so that only about 5 per cent of American olives are produced there.

At the present time the olive is cultivated more or less extensively in the countries surrounding the Mediterranean—Asia Minor, Turkey, Greece, Italy, Austria, France, Spain, Portugal, Tunis, and Algeria. In the Western Hemisphere the main source is California, though the olive is cultivated in some of the countries of S. America.

Duration

The olive tree is of slow growth, but if allowed to grow naturally, it persists for centuries and attains a great size. De Candolle describes one tree 23 feet in circumference, its age supposed to be over 700 years. Tournefort found fruitful old olive trees between Ephesus and Smyrna which must have been planted before the Mussulman invasion, as Turks had not planted olives, not esteeming them. The Mount of Olives on the east side of Jerusalem was among the places best cultivated. Near its foot was the grove called Gethsemane (Gath-Semen, oil press) because of the olives with which it was covered and those of the slopes above where an abundance of oil was pressed out. In the Garden of Gethsemane there remain only eight of these olive trees that are supposed to have existed at the beginning of the Christian era. Chateaubriand, writing in the early part of the nineteenth century of these olive trees, said, “one sees there eight olive trees in extreme decrepitude.” An article written recently by J. D. Whiting, American Vice-Consul at Jerusalem, had an interesting statement relative to one of these trees. “El Butini, the most famous of the Garden of Gethsemane’s eight olive trees, under which the Savior is supposed to have walked during the night of agony, has recently collapsed. The great tree was weakened by the locust plague during the spring and summer of 1915. When El Butini falls, then falls the Turk, runs the legend.”

Throughout Europe and Asia are many old olive trees, some of them producing abundantly, their origin, however, lost in remote centuries. The olive is very tenacious of life, but the methods of cultivation, which tend to increase production, reduce resistance and diminish its duration of life.

Etymology

The generic name Olea is from the Greek elaia, derived from the Celtic or Gothic olew, oil, on account of the abundance of oil in the fruit. The specific name europaea is given to the species cultivated throughout Europe.

The olive has been given fanciful names by the early peoples. It was known as the “tree of wisdom,” “Minerva’s tree,” the “Gift of Heaven,” etc. The Greeks consecrated the tree to Minerva, and made it the symbol of wisdom, abundance, and peace.

Description

The olive is an evergreen tree about 20 to 30 feet high, much branched and spreading. It forms a symmetrical head, having angular branches and opposite leaves. The leaves are dry and leathery in texture, lanceolate, entire, deep green above, and light hoary beneath. The flowers are small, star-shaped, creamy white with yellow centers, have a faint pleasing odor, and are axillary in compact racemes. The fruit, a fleshy pendulous drupe, is very abundant. It is oval, obovate, or globular in shape, about the size of a pigeon’s egg, dull greenish yellow even when full size but unripe, then gradually becomes yellow, red, and finally turns a glossy purplish black or black when ripe. In ripening, the side exposed to the sun reddens, then gradually the whole fruit changes from red to purple, then black. As fruit of all degrees of ripeness are developed at the same time, the tree furnishes an extremely beautiful combination of colors, the various greens of the leaf and fruits forming a background for the splotches of red, purple, and black formed by the ripening fruit. The fruit is peculiar in two respects, first, in that it contains in addition to the ordinary constituents of fruits an abundance of edible oil, consequently making it a valuable food; second in that it contains a bitter substance which does not disappear on maturity, so that the fruit cannot be eaten at any stage in its development without preliminary treatment for the elimination of this substance. The stone is two-celled, many times only one seed developing.

Climatic Requirements

The olive requires rather warm temperature, light humidity, and absence of heavy frosts. It can withstand temperatures of -7 to -8 degrees C. or even lower if not too prolonged, and if the change to higher temperature be gradual. Moist cold is more unfavorable than dry. The altitude at which it will grow depends on the local climate. The climate of the countries bordering on the Mediterranean and that of California are particularly favorable.

Varieties

The wild olive Oleaster is said to have been the original form, called by Linnaeus Olea europaea sylvestris, later by De Candolle Olea europaea oleaster and the cultivated form Olea europaea sativa. The reason for this belief is said to be the oleaster seeds reproduce trees true to type, whereas the seeds of sativa produce trees having the characteristics of oleaster but, though oleaster under cultivation becomes modified in various ways, it does not produce fruit like sativa. Whichever form was the original, the subjection to cultivation for over 4,000 years, under the varying conditions of soil, climate, and methods of cultivation, has produced many varieties. Many of these doubtless are the result of accidental modifications, more or less fixed by successive cultivations. At the present time there are certain well-defined varieties which are cultivated, and of which the characteristics are well known, so that varieties may be selected according to the purpose desired, whether for the preservation of the fruit green, half ripe, or ripe, or for extraction of oil.

Of the large number of varieties introduced into California, Wickson reports analyses made by the State university on 57 varieties. Of these only a comparatively few were retained as worthy of cultivation, chief among these being the Mission olive, the one planted originally in California in the old mission gardens. Wickson states there are several sub-varieties of this form.

Propagation

The olive is propagated by means of seeds, cuttings, grafting, and budding. Propagation by seeds is seldom done in this country, as it is so much slower and more troublesome than by cuttings, aside from the fact that the desired variety may not result. The pulp has to be removed, which is done usually by allowing the fruit to rot or by softening with an alkali. Unless removed from the stone, the seed may not develop for two years, otherwise the seed usually sprouts the first year.

Propagation by cuttings is the commonest and easiest method, as the cuttings root readily, and either old or new wood may be used so that the cuttings may be large or small. Cuttings sent from Europe are usually in the form of truncheons, and these may be cut into pieces like firewood and will root.

The story is told of a grove in Morocco in which the trees exhibited a peculiar arrangement. The reason given for this was that a king and his army on the way to the Sudan had encamped for the night, and stakes or pickets to tie the horses had been cut from a grove near by. The pickets were left and had developed into trees. This seems probable enough when it is considered that pieces of branches are taken, one end whittled to a sharp point and driven into the ground, and that these pieces will take root and develop. An olive company in California has recently transferred 3000 trees, 26 years old, from San Joaquin County to Oroville and Marysville. The trunks were sawed off about 18 inches above the ground, and the roots 12 inches from the stump. In a planting made 6 years previously the same method was used and resulted successfully.

Where trees are found undesirable for some reason, resort is had to budding or grafting. By these means the undesirable trees are not a complete loss, and results are obtained sooner. Many times varieties are obtained from Europe which on developing are not found suited to the conditions in this country; these plants may be used as stock for desirable varieties or some desirable variety is obtained which may be propagated rapidly by these means.

The pruning must be done by persons of understanding, as the fruit is borne only on the two-year portion of the branches, and provision must be made

to cut excessive growth in the season of too heavy development and stimulate in the season of poor development. The pruning thus regulates the growth of the branches which two years later will control the production of the fruit.

Pruning of very large branches is sometimes done to admit more light and heat to the darker, cooler parts of the tree. The small branches thus provided in turn furnish nursery stock. Pruning is done in late winter and early spring. From March to October no pruning is done, but the trees are carefully tended through cultivation, irrigation, and fertilization.

In California the young stock is set out in the groves in April, and about 35 feet apart. During the non-bearing period, the land between, which like all California groves, is kept in good cultivation and free from weeds, is utilized frequently for other crops.

Though numerous stories are written of the remarkable ability of the olive tree to grow and bear in exposed situations, and with only small amounts of soil and water, the olive, like all other fruit trees, requires both cultivation and an adequate amount of water if a constant and abundant harvest be desired. As the groves are irrigated, the proper amount of water may be supplied at all times. The water is conducted through a system of underground pipes, which are provided with outlets at the end of each row of trees. From these outlets the water is directed into furrows to water the trees. As the irrigation is conducted by underground pipes, the groves are easily cultivated.

Products

It would seem that the olive is rightly and appropriately called the “Tree of Abundance,” for all parts of it have been used, and to the ancients, even with their limited cuisine as compared with that of today, it was a symbol of plenty, witness the apostrophe of King Sennacherib, made centuries before the Christian era, who called Assyria “A land of corn and wine; a land of bread and vineyards; a land of oil, olives, and honey.”

FLOWERS

In ancient medicine the blossoms of the olive were highly esteemed, but are not mentioned in the medicine of today. They were used as poultices to alleviate pain, sometimes alone, sometimes mixed with other substances.

LEAVES

The leaves were also used in medicine, a decoction made from them being said to stop bleeding, and on account of their astringency to reduce inflammation. The leaves and bark have an acrid and bitter taste, and have been prescribed as substitutes for cinchona. In France an extract of the leaves is used as a febrifuge, and has also been found valuable in preventing hectic paroxysms.

From time immemorial the leaf and branch have been employed as a symbol of peace, and have appeared in sculpture and painting. No more beautiful emblem than the olive branch can be selected or devised to symbolize both peace and victory, and as such has been known through all the ages. Egyptian mummies, dating from the 20th to the 26th dynasty, have been found surrounded by garlands of olive leaves, and the tomb of the hero of today will oftentimes have its sculptured olive branch, telling its story and making its appeal stronger than could be made by words.

Besides serving for esthetic purposes, the leaves, in spite of their astringency, are eaten by animals as forage, so that the trees have to be protected from them. It is curious that with all the ravages made by animals on the olive trees in the neglected mission gardens in California, after the missionaries had gone, some of these same trees furnished scions for many of the olive groves of today.

WOOD

The wood of the olive tree is much prized for certain purposes. It is very close, fine-grained, yellow to yellowish brown with irregular wavy brown to black lines and mottlings, especially near the root. It has no distinguishable annual rings or pith rays, and has evenly distributed vessels. It takes a beautiful polish. At present it is employed chiefly in lathe-work and carving for small fancy articles, and for cabinet work.

In ancient times it seems to have had a much wider application, due no doubt to the size of the trees, which were larger as a result of not being subjected to the rigorous cultivation and pruning which they receive today. The Bible states that olive wood was used in the Temple. In the time of Pliny it furnished material for construction of ships, for wagon spokes, wedges, columns, pedestals, statues, and furniture. The Romans used both the wild and cultivated trees. The wood industry was developed in the vicinity of Nice in both France and Italy, and still flourishes. A considerable amount has been exported to England in recent years for the manufacture of walking sticks. The poorer quality is used for firewood, is inflammable, and produces great heat.

BARK

The bark contains a large amount of tannin. For medicinal purposes it is reduced to powder and acts as an astringent, a tonic, and a febrifuge. In warm climates a resin is exuded from it which solidifies in the air. It is called Lecca gum, as it was first found near Lecca. It contains some benzoic acid among other constituents and in ancient times was prescribed in medicine, but is not at present, and the gum is considered valueless.

FRUIT

The fruit has been considered a choice food at all times. It has appeared at the feasts of epicures, both ancient and modern, as a relish, and to be eaten at the end of the repast as part of the dessert, and at all times it has also furnished a staple food for the poor in the Orient and in Greek and Latin countries. Those who were well provided were admonished to have care for those less fortunate: “When thou beatest thine olive tree, thou shalt not go over the boughs again; it shall be for the stranger, for the fatherless, and for the widow.” (Deuteronomy XXIV., 20.) The people obliged to live frugally have found it a great resource, particularly in Lent and for those at a distance from the sea unable to obtain fresh fish. It is said that Plato preferred olives to all other foods, and often made a meal on them alone.

Though olives are known and consumed throughout the civilized world, comparatively few persons, aside from those living in the regions of their cultivation, know that olives have to undergo certain treatment before they can be eaten. It is a common practise in olive regions to encourage the visitor to taste the fruit directly from the tree. The fruit, both green and black, looks so fine and tempting, that the disgust on tasting is correspondingly great. It is claimed that some of the older varieties could be eaten without preparation, that they dried naturally, and were sweet like raisins.

The olive contains a bitter and acrid substance or substances which must be removed before the olives are edible. It is referred to in most of the literature as a “bitter principle”, and has been called an acid, a tannin, and more recently a glucoside. Cruess has repeated the work of the various investigators, who claimed these different substances, and as a result has come to the conclusion that it is a glucoside, that is, a combination of glucose with another compound.

In immature fleshy fruits there is usually an accumulation of acids, tannins, and sometimes starch. As ripening proceeds, carbohydrates and aromatic substances are formed, and the bitter, acrid, or astringent taste disappears. In the olive there is no starch found at any stage of maturity. Glucose has been found in all stages, and is supposed to be the substance from which the oil is formed. The oil is in very minute quantities in the fruit up to the time when the pit is formed, from then on it increases gradually up to its maximum when the fruit is not quite mature. In the plant economy the fat or oil is one of the most important food reserves of plants. All parts of the fruit—rind, flesh, stone, and seed—contain oil, the fleshy part, forming about 80% of the fruit, containing the largest amount.

Contrary to the condition existing in most fruits, the bitterness remains through all stages of development in the olive. A substance of glucosidic nature, given the name “oleuropeine”, has been isolated, and found to be of extreme bitterness. This may be the substance or one of the substances which cause the inedibility of the untreated olive.

The oil is the most important constituent of the fruit on account of its high food value and its use in the industries. It is used to a large extent in cold countries and also in dry countries where there are few cattle, the oil taking in the various culinary operations, the place of butter and other fats.

Among the ancient Jews the oil was considered indispensable and as necessary as bread. An abundance of oil was looked upon as a blessing from God. Vast public storehouses were constructed to hold it for the scarce years. To the Greeks the three indispensable foods were oil, grains, and wine, the oil entering into most of their dishes. The Romans had a large trade in the oil, and it was also used, to a large extent, in their domestic cooking. In Italy and Spain street vendors fry fritters in the oil and sell them while hot. It has considerable use in conserving fish, particularly sardines. The higher grades of French, Spanish, Norwegian, and American sardines are packed in olive oil. This use has been extended in recent years to the packing of tuna fish.

Olive oil occupies a high position as a vegetable fat. Many others have been prepared and offered as substitutes, and if judged by chemical composition alone, give practically equal food value, but are lacking in the delicious flavor which makes olive oil distinctive and gives it a superiority over all other oils.

The oil is a large factor in the industries; it serves as an extractive of perfumes, as a constituent of fine, smooth soaps, and as a lubricant in watch factories. Formerly the lower grades were used commonly for lubricating purposes, but with improved methods of clarifying and the greater expense attendant on its use, it has been superseded by cheaper lubricants.

An enormous quantity has been and is still used in religious ceremonies, in the ordinations of the clergy and rulers, and anointing in the sacraments, besides by old world peoples generally in the lamps in the churches and temples, many of which are kept burning continually. An idea of the vast amount consumed for this purpose can be obtained from the fact that in one mosque alone there are 1,200 lamps burning constantly, and requiring about 25,000 kilos of oil annually.

In medicine it has been and is still used extensively. The ancients rubbed it on their bodies to make the muscles supple and to cleanse and protect the skin, particularly after bathing, and it still functions for these purposes. It was used to heal wounds, in liniments, and as a mild laxative. At present it is a constituent of liniments, ointments, cerates, and plasters. The people who are habitual patrons of the olive and its oil are noted for their smooth, beautiful complexions. It is said “the warm rosy complexion of the Italian and Sicilian women is due to the free use of olive oil as much as to the air and climate of their country.”

The residue or marc which remains after the oil is extracted is used as a food for sheep and hogs, for fertilizer, and for fuel, and there is obtained from it a clear, illuminating gas.