|Fig. 56: The marble-like emblic (Phyllanthus emblica), hard and sour, is valued in Asia as a thirst-quencher and for its ascorbic acid content.|
The tree is a graceful ornamental, normally reaching a height of 60 ft (18 m) and, in rare instances, 100 ft (30 m). Its fairly smooth bark is a pale grayish-brown and peels off in thin flakes like that of the guava. While actually deciduous, shedding its branchlets as well as its leaves, it is seldom entirely bare and is therefore often cited as an evergreen. The miniature, oblong leaves, only 1/8 in (3 mm) wide and 1/2 to 3/4 in (1.25-2 cm) long, distichously disposed on very slender branchlets, give a misleading impression of finely pinnate foliage. Small, inconspicuous, greenish-yellow flowers are borne in compact clusters in the axils of the lower leaves. Usually, male flowers occur at the lower end of a growing branchlet, with the female flowers above them, but occasional trees are dioecious.
The nearly stemless fruit is round or oblate, indented at the base, and smooth, though 6 to 8 pale lines, sometimes faintly evident as ridges, extending from the base to the apex, give it the appearance of being divided into segments or lobes. Light-green at first, the fruit becomes whitish or a dull, greenish-yellow, or, more rarely, brick-red as it matures. It is hard and unyielding to the touch. The skin is thin, translucent and adherent to the very crisp, juicy, concolorous flesh. Tightly embedded in the center of the flesh is a slightly hexagonal stone containing 6 small seeds. Fruits collected in South Florida vary from 1 to 1 1/4 in (2.5-3.2 cm) in diameter but choice types in India approach 2 in (5 cm) in width. Ripe fruits are astringent, extremely acid, and some are distinctly bitter.
Origin and Distribution
The emblic tree is native to tropical southeastern Asia, particularly in central and southern India, Pakistan, Bangladesh, Ceylon, Malaya, southern China and the Mascarene Islands. It is commonly cultivated in home gardens throughout India and grown commercially in Uttar Pradesh. Many trees have been planted in southern Malaya, Singapore, and throughout Malaysia. In India, and to a lesser extent in Malaya, the emblic is important and esteemed, raw as well as preserved, and it is prominent in folk medicine. Fruits from both wild and dooryard trees and from orchards are gathered for home use and for market. In southern Thailand, fruits from wild trees are gathered for marketing.
In 1901, the United States Department of Agriculture received seeds from the Reasoner Brothers, noted nurserymen and plant importers of Oneco, Florida. Seeds were distributed to early settlers in Florida and to public gardens and experimental stations in Bermuda, Cuba, Puerto Rico, Trinidad, Panama, Hawaii and the Philippines. The fruits of these seedlings aroused no enthusiasm until 1945 when Mr. Claud Horn of the Office of Foreign Agricultural Relations in Washington, D.C., inspired by Indian ratings of the emblic as the "richest known natural source of vitamin C", asked that analyses be made in Puerto Rico. A high level of ascorbic acid was found and confirmed in Florida but interest quickly switched to the Barbados cherry (q.v.) which was casually assayed and found to be as rich or richer when underripe. The emblic was soon forgotten. Some old trees still exist in southern Florida; others have been removed in favor of housing or other developments. In 1954, the Campbell Soup Company in Camden, New Jersey, requested 5 lbs (2.25 kg) of the fruits for study. They were sent, but no further interest was evidenced. In 1982, several individuals asked for and were given seeds for planting in Australia. They did not reveal whether the tree was desired for its own sake or for its fruits.
In India there are 3 named cultivars grown commercially:
'Banarsi'originated in Banarsi district of Uttar Pradesh; medium to large, the 6 segments paired, giving the appearance of only 3; 1 1/2 in (4 cm) long, 1 3/4 in (4.5 cm) wide; skin thin and translucent, light-green, turning whitish as the fruit ripens; flesh slightly fibrous, medium juicy, moderately astringent. Earliest in season. Tree is semi-spreading; not a heavy cropper; tends to alternate bearing unless interplanted.
'Chakaiya'flattened at base and apex; may have 6, 7, or 8 segments; of medium size, 1 1/4 in (3.2 cm) long, 3 1/4 in (8.25 cm) wide; flesh fibrous. Tree is spreading; prolific. This cultivar is now preferred over the others because of its yield.
'Francis' ('Hathijhool')rounded-oval, bulged at the apex; has 6 segments; large, 1 5/8 in (4.3 cm) long and 2 in (5 cm) wide. The tree is a regular producer of good crops, but prone to fruit necrosis.
The ordinary small fruits5/8 to 1 in (1.5-2.5 cm) wide, with reddish skin, rarely grown commercially, are mainly used for medicinal purposes.
Cross-pollination is desirable. 'Banarsi' bears better when interplanted with other varieties. Growers in India are beginning to scatter a few seedling trees around in their groves. Honeybees work the flowers in the morning and late evening. It is now known that lack of pollination is the cause of up to 70% shedding of flowers in the first 3 weeks after onset of blooming.
The emblic is subtropical rather than strictly tropical. In India, it flourishes from sea-level up to an altitude of 5,000 ft (1,800 m). Seeds were planted at the Agricultural Research and Education Center in Homestead, Florida, in 1955 and the seedlings were set out in the field in 1956. They survived unusually cold weather in the winter of 1957-58. That freeze damaged a tree with a trunk 1 ft (30 cm) thick at Laurel, Florida. It was set back again by cold in December 1962. It put out many shoots which, by October 2, 1963 were 10 ft (3 m) high, showing a remarkable ability to recover from cold injury. On the other hand, it is intolerant of excessive heat. In India, mature trees can stand temperatures up to 115º F (46º C) in the summer but young plants must be shaded.
The emblic seems to grow equally well under both and and humid conditions. It is noted for being able to thrive in regions too dry and soil too poor for most other fruit crops. For maximum productivity, the tree requires deep soil ranging from sandy loam to clay, light or heavy, slightly acidic to slightly alkaline. At high pH (as much as 8.0), nutritional deficiencies are evident. Limestone is considered unsuitable but the large, old trees in southern Florida are all in oolitic limestone. Good drainage is essential. A low degree of salinity seems to be fairly well tolerated.
The tree is often propagated by seeds taken from overripe fruits sun-dried to facilitate removal of the stone, or cut in half right through the stone. The extracted seeds are given the float test and 100% of those that sink will germinate. In 4 months, seedlings will have a stem diameter of 1/3 in (8 mm) and can be budded or grafted from June to September and in February and March in India. The Forkert and patch techniques have given 85% to 100% success. Chip-budding, using seedlings 1 1/2 years old as rootstocks, is easier and 60% to 80% successful in September and October and February and March. Inarching is sometimes practiced in India but survival rate may be only 25% to 30% after separation from the stock and further losses may occur in the field. At the Experimental Farm of the University of Miami in 1955, air-layers and cuttings were unsuccessful but root sprouts grew well.
Emblic trees bearing fruits of inferior quality may be top-worked by cutting back to a height of 4 ft (1.2 m) and applying coal tar to the cut surfaces. Trials at Saharanpur showed that this is best done in March when the trees are not in active growth. Budding of the new shoots can be done successfully any time from June to September.
While the emblic has long been established as an important and remunerative crop in India, the systematic culture of high-quality fruit is a modern development actively promoted by the Indian Government. It is recommended that the trees be spaced 30 to 40 ft (9-12 m) apart and planted in well-prepared holes enriched with a composted manure and soil mixture, and well-watered. Thereafter, watering is done only in the dry season. Seedlings in Florida have attained 8 to 9 ft (2.4-2.7 m) in height in 5 years. They usually begin to bear when 5 to 6 years old and normally bear for about 50 years.
There are no standard practices for fertilizing the emblic but 1 to 1 1/2 oz (28-42 g) of nitrogen per tree for each year of age up to 10 years has been suggested. After 10 years the nitrogen is increased and potash and superphosphate are added. Half of the fertilizer should be given after fruit-set and the other half 4 months later.
The branches are brittle and judicious pruning to develop a strong framework is advocated to avoid branch breakage from heavy loads of fruit.
Season and Harvesting
The emblic is sensitive to day-length. In northern India, flowering takes place from March to May. In Madras, the tree blooms in June-July and again in February-March, the second flowering producing only a small crop. In Florida flowering occurs during the summer months, the main crop maturing during the winter and early spring. A few fruits developed from late blooms are found in summer and fall.
In India, people shake down the fruits that are ready to fall and gather from the ground those that have already fallen, and take them to market. They stand handling well. The yield varies a great deal as many young fruits are shed throughout the period of fruit development, and there is considerable difference in the productivity of seedlings and cultivars. P.N. Bajpai, in a study of the fruiting habits of four 15-year-old emblic trees, found an average yield of 415 fruits, which weighed approximately 24 1/2 lbs (11 kg). 'Banarsi' trees 10 years old have yielded 35.2 lbs (16 kg). 'Chakaiya' trees of the same age have yielded 39.6 lbs (18 kg). Mature 'Chakaiya' trees may bear 55 lbs (25 kg) per year.
Pests and Diseases
The chief pest of this tree in India is the bark-eating caterpillar, Indarbela sp., which tunnels into the branches and trunk. A secondary enemy produces shoot galls. A non-pathogenic problem, especially in 'Francis', is called "fruit necrosis" in India. It is evidenced by internal browning which gradually extends to the surface where dark spots become corky and gummy. It can be overcome by bi-monthly sprays of borax in September and October. There are few serious diseases but the fungi, Bestonea stylophora, Phakospora phyllanthi and Ravenelia emblicae, cause ring rust, leaf rust and fruit rot.
Fresh emblics on the market or in storage are subject to blue mold and rotting caused by Penicillium islandicum. Rinsing with very dilute borax or sodium chloride solutions helps retard such spoilage. Emblic preserves on the market have been found contaminated with yeasts, molds and bacteria. Pre-processing treatment with 0.01% sulfur dioxide or sodium benzoate prolongs keeping quality.
|Fig. 57: Emblics, heavily sugared, are sold in the native markets of Southeast Asia.|
Rural folk in India claim that the highly acid, fresh, raw fruit, followed by water, produces a sweet and refreshing aftertaste. Wood-cutters in Southeast Asia eat the emblic to avoid thirst, as the fruit stimulates the flow of saliva. This is the one tree left standing when forests are clear-cut in Thailand, and busses stop along highways to let thirsty travelers run to the tree to get the fruits. The emblic is regarded as sacred by many Hindus and the Hindu religion prescribes that ripe fruits be eaten for 40 days after a fast in order to restore health and vitality. It is a common practice in Indian homes to cook the fruits whole with sugar and saffron and give one or two to a child every morning.
Fresh emblics are baked in tarts, added to other foods as seasoning during cooking, and the juice is used to flavor vinegar. Both ripe and half-ripe fruits are candied whole and also made into jam and other preserves, sweetmeats, pickles and relishes. They are combined with other fruits in making chutney. In Indonesia, emblics; are added to impart acidity to many dishes, often as a substitute for tamarinds.
When necessary, bitterness is overcome by soaking the fruits in a salt solution or by adding citrus fruit, unripe mango or tamarind. In preserving emblics; whole, the fruit is first brined, washed and pricked, blanched in an alum solution, layered with sugar until a sirup is formed, and then boiled. It is finally packed in enameled cans or crystallized as a confection. In India, a sauce is made from the dried, chipped flesh. In its preparation, the chips are cooked in water, mashed in a mortar with caraway seeds, and further seasoned with salt and yogurt. This, also, is commonly eaten after fasting. During World War II, emblic powder, tablets and candies were issued to Indian military personnel as vitamin C rations. Drs. Rama Rao, Balakushnan and Rajagopalan, of the Institute of Science at Bangalore, describe a method of spray-drying emblic juice to produce a special powder for fortifying salt as a means of increasing vitamin C intake.
In Thailand, where the tree is common in the forests, the fruits are favored by deer, especially the tiny barking deer.
|Food Value Per 100 g of Edible Portion*|
|Ascorbic Acid**||625 mg|
*As reported by the Finlay Institute Laboratory, Havana.
**The ascorbic acid ratings vary immensely. Analyses in Puerto Rico, showed 625 mg; fruits from one tree in Avon Park, Florida, showed only 467 mg, while 2 adjacent trees in Homestead, Florida, showed 1,130 and 1,325 mg; and Dr. Margaret Mustard reported an average of 1,561.0 and a high of 1,814 mg in 7 samples analyzed.
The ascorbic acid in the emblic is considered highly stable, apparently protected by tannins (or leucoanthocyanins) which retard oxidation. Biochemical studies at the Central Drug Research Institute, Lucknow, India, show 13 tannins plus 3 or 4 colloidal complexes. In juice extracted from the fresh fruit, the ascorbic acid is stable for at least a week. Fresh juice stored at 35.6º F (2º C) loses only 14% ascorbic acid after 45 days. Only 30% is lost in evaporation over open flame at 149º F (65º C), but the product loses 40% during a week in a refrigerator and 100% in 20 days.
Efforts in India to prepare a stable ascorbic acid concentrate from the dried fruit have been frustrating because sun-drying loses 65% ascorbic acid. Artificial drying at 185º F (85º C) loses 34%; and at 212º F (100º C), 72%. Once dried, there is negligible loss. However, vacuum-drying (27 in. Hg) at 140-176º F (60-80º C) retains the original ascorbic acid levels, the dried product containing 2,000 to 3,500 mg per 100 g, depending on the content of the fresh fruit. Even after 14 months of refrigerated storage, there is a loss of only 15 to 20%.
Separation of tannins from expressed juice by precipitation with neutral lead acetate and ion exchange chromatographic purification has yielded crystalline ascorbic acid amounting to 70-72% of that in the juice.
The dry, powdered fruit contains 6.3% phyllembic acid, 6% fatty matter, 5% gallic acid, ellagic acid, emblicol (a crystalline phenolic product) and other constituents. Phyllemblin (ethyl gallate) isolated from dried fruit, acts as a mild CNS depressant and has spasmolytic activity.
Other uses of the fruit and parts of the tree are numerous:
Fruit: The dried fruit yields ink and hair-dye and, having detergent properties, is sometimes used as a shampoo. A fixed oil derived from the fruit allegedly acts as a hair-restorer and is used in shampoos in India. This oil is the main ingredient in an "Amla Conditioner" currently sold by Shikai Products of Santa Rosa, California, by mail and through "health food" stores and other "natural" product outlets. A most curious custom is the making of simulated pottery jars from a paste of the boiled fruit, the surface being decorated with impressed colored seeds. Dyes from the fruit and leaves impart an appealing light-brown or yellow-brown hue to silk and wool. When sulfate of iron is added as a mordant, the color becomes black.
Bark: The tannin-rich bark, as well as the fruit and leaves, is highly valued and widely employed in conjunction with other so-called myrobalans, especially fruits of various species of Terminalia. The twig bark is particularly esteemed for tanning leather and is often used with leaves of Carissa spinarum A. DC. and Anogeissus latifolia Wall.
Leaves: The foliage furnishes fodder for cattle and branches are lopped for green manure. They are said to correct excessively alkaline soils.
Wood: The hard but flexible red wood, though highly subject to warping and splitting, is used for minor construction, furniture, implements, gunstocks, hookas and ordinary pipes. Durable when submerged and believed to clarify water, it is utilized for crude aqueducts and inner braces for wells, and branches and chips of the wood are thrown into muddy streams for clarification and to impart a pleasant flavor. The wood serves also as fuel and a source of charcoal.
Medicinal Uses: The emblic is of great importance in Asiatic medicine, not only as an antiscorbutic, but in the treatment of diverse ailments, especially those associated with the digestive organs. For such use, the fruit juice is prepared in the form of a sherbet or is fermented. In the latter state, it is prescribed in jaundice, dyspepsia and coughs. The dried chips of flesh are dispensed by apothecaries and often are mixed with grape juice and honey for dosage. The fruit is considered diuretic and laxative. Triphala, a decoction of emblic with Terminalia chebula Retz. and T. bellerica Roxb. is given for chronic dysentery, biliousness, hemorrhoids, enlarged liver, and other disorders. A powder prepared from the dried fruit is an effective expectorant as it stimulates the bronchial glands. The juice that exudes when the fruit is scored while still on the tree is valued as an eyewash and an application for inflamed eyes. An infusion made by steeping dried fruit overnight in water also serves as an eyewash, as does an infusion of the seeds. A liquor made from the fermented fruits is prescribed as a treatment for indigestion, anemia, jaundice, some cardiac problems, nasal congestion and retention of urine.
Emblic leaves, too, are taken internally for indigestion and diarrhea or dysentery, especially in combination with buttermilk, sour milk or fenugreek. The milky sap of the tree is applied on foul sores. The plant is considered an effective antiseptic in cleaning wounds, and it is also one of the many plant palliatives for snakebite and scorpion stings. A decoction of the leaves is used as a mouthwash and as a lotion for sore eyes.
The flowers, considered refrigerant and aperient, and roots, emetic, are also variously employed. The root bark, mixed with honey, is applied to inflammations of the mouth. The bark is strongly astringent and used in the treatment of diarrhea and as a stomachic for elephants. The juice of the fresh bark is mixed with honey and turmeric and given in cases of gonorrhea. It is clear that the majority of the applications of the fruit and other parts are based on the astringent action of the tannins they contain. The short-term effects of tannins appear beneficial, but habitual indulgence can be highly detrimental, inasmuch as tannin is antinutrient and carcinogenic.
An ointment made from the burnt seeds and oil is applied to skin afflictions. The seeds are used in treating asthma, bronchitis, diabetes and fevers. They contain proteolytic and lipolytic enzymes, phosphatides and a small amount of essential oil. Approximately 16% consists of a brownish-yellow fixed oil.