GINGER

Zingiber officinale Rosc

Family : Zingiberaceae

Description

Ginger is one of the earliest known oriental spices and is being cultivated in India both as a fresh vegetable and as a dried spice since time immemorial. Ginger is obtained from the rhizomes of Zingiber officinale. The ginger family is a tropical group especially abundant in Indo-Malaysia, consisting of more 1200 plant species in 53 genera. The genus Zingiber includes about 85 species of aromatic herbs from East Asia and tropical Australia. The word ginger is derived from a Sanskrit word singabera meaning 'shaped like a deer's antlers (horn)'. Ginger is not known in a wild state and has been cultivated for so long in both China and India that its exact origin is unclear. It is believed to be a native of Southern Asia.

Distribution

Ginger has a long respected history as a spice. It reached the West at least two thousand years ago, recorded as a subject of a Roman tax in the second century after being imported via the Red Sea to Alexandria. Tariff duties appear in the records of Marseilles in 1228 and in Paris by 1296. Rosengarten (1969) recorded that ginger was mentioned by the Chinese philosopher Confucius (551-479 BC). Its medicinal properties are mentioned by Dioscorides (1 century A.D) in his D. Materia Medica. It was introduced to Germany and France in the ninth century and to England in the tenth century. Ginger is known in England before the Norman Conquest, as it is commonly found in the 11th century Anglo-Saxon leech books. Ginger is detailed in a 13th century work, "Physicians of Myddvai," a collection of recipes and prescriptions written by a physician, Rhiwallon, and his three sons, by mandate of Rhys Gryg, prince of South Wales (who died in 1233). By the 13th and 14th centuries it was familiar to English palates, and next to pepper, was the most popular spice. Ginger, as a product of the Far East, was indelibly imprinted on the taste buds of Westerners before potatoes, tomatoes, and corn were even known to exist by Europeans. Arabs took it from India to East Africa (13th century). The Portugese Mendoja, introduced ginger into Mexico soon after the discovery of that country. They in turn introduced in Jamaica. Since the ginger rhizomes can be easily transported in a living state, the plant has been introduced to several tropical and sub-tropical countries. Ginger is now commercially cultivated in nearly every tropical and subtropical country in the world with arable land for export crops. The major production is in India, Jamaica, Nigeria, Sierra Leone, Brazil, China, Japan, Indonesia, Taiwan and Australia. Jamaica and India produce the best quality ginger. In India, about 70% of the total ginger production is confined to Kerala. Other states which grow ginger are Assam, Andhra Pradesh, Himachal Pradesh, West Bengal and Sikkim.

Botany

Ginger is a slender herbaceous perennial herb belonging to Zingiberaceae family. It forms a spreading, tuberous, underground stem or rhizome. The plant produces erect, tall and dark green leafy shoots (pseudostems) 30-100 cm of high. The aerial pseudostems ususally bear 8-12 distichous leaves. Leaves are alternate, lanceolate or linear-lanceolate, acute, smooth and with subsessile sheathing. They are 5-25 cm long and 1-3 cm wide. There is a broad, thin, glabrous ligule (about 5mm long) and slightly bilobed. Flowers are borne in a bracteal, imbricated spike, terminating in a leafless stem reaching to about 15-25 cm in height. They are situated in the axils of large, greenish - yellow obtuse bracts. They are small, fraile, short lived, very a few, and usually arising one or two at a time. The evanoscent flowers are yellowish and speckled with a purplish lip. Calyx is thin, tubular, spathaceous, 1-1.2 cm long and is three-toothed. Corolla tube is 2-2.5 cm long with three lobes. The dorsal lobe is 1.5-2.5 cm long, 8 mm wide and is curved over the anther and narrowed to the tip. The labellum or lip corresponds to three stamens, is nearly circular, dull purple with cream blotches at base. The perfect stamen has a short filament; the anther is cream coloured and is prolonged into a beak-like appendage. The rhizome, protruding just below the apex of the appendage, has a circular apical aperture surrounded by stiff hairs. There are two slender free styloids. The inferior ovary is trilocular with several ovules per locule on axile placentation. Fruit is an oblong, thin walled, three - valved capsule but is rarely produced. The seeds are small, black and arillate. Rhizomes are fleshy sympodial, hard and thick, laterally compressed, often palmately branched with about 1.5-2.5 cm in diameter. The inner core is usually pale yellow while the outer is light yellow. They are covered with small distichous scales with an encircling insertion and fine fibrous roots in the top layer.

Cultivation

Though a perennial plant, ginger is usually grown as an annual for harvesting as a spice. Ginger requires a warm and humid climate. It is cultivated from almost sea level to an altitude of 1500 m above MSL either under heavy rainfall conditions (150-300 cm/year) or under irrigation. The crops thrive well in sandy or clayey loam, red loam or laterite loam soils having good drainage and humus content. Ginger does the best in partial to complete shade. It can be grown as a pure crop as well as an inter-crop in coconut, coffee and orange plantations. Ginger is propagated vegetatively through rhizomes. The size of the planting material varies from place to place and variety to variety. Seed rhizomes are treated with fungicides and insecticides to avoid any seed-borne diseases and scales. Planting is done during April - May with the receipt of pre-monsoon showers. When the crop is raised under rainfed conditions, seed rhizomes are planted in raised beds. In irrigated crop, it is done on ridges. After planting, the beds are mulched with green leaves thrice at intervals of one month. Adequate weed control, earthing up and plant protection measures against shoot borer (Conogethes punctiferalis) and soft rot disease caused by Pythium aphanidermatum should be carried out as and when needed. Incidence of rhizome scales (Aspidiella hartii), plant parasitic nematodes (Meloidogyne spp., Pratylenchus spp. and Radopholus similis) and bacterial wilt caused by Ralstonia solanacearum can be managed by selecting healthy seed rhizomes.

Ginger is harvested by digging out rhizomes when the tops have died down. The harvesting and processing of dried ginger varies in different countries. The rhizomes are lifted from the earth, cleared of all adhering matter by washing, blanched and then sun-dried. A few of farmers scald the rhizomes in hot water before drying in the sun. Others scald and then peel or scape them to remove before drying. In Jamaica, the rhizomes are peeled, washed and sun dried. It requires about 6-8 days to dry the rhizomes. If the ginger is for vegetable purpose or for preparation of candied ginger, salted ginger or for soft drinks, pickles, etc. the harvesting should be done at 4-5 months of planting, when these rhizomes are still immature, tender, succulent and mild in pungency. The ginger of commerce consists of the thick scaly rhizomes (underground stems) of the plant. They branch with thick thumb-like protrusions, thus individual divisions of the rhizome are known as "hands."

Aroma and flavour

Ginger contains 1.5-3.0% volatile oil. The volatile oil is composed mainly of sesquiterpene hydrocarbons. Oxygenated sesquiterpenes are present up to 17% and the remainder is composed of monoterpene hydrocarbons and oxygenated monoterpenes. Of the sesquiterpene hydrocarbons, about 20-30% is (-) a -zingeberene, up to 12% (-) - b -bisabolene, up to 19% (+)-ar-curcumene and up to 10% farnasene. The volatile oil possesses the aromatic odour and flavour but not the pungent flavour of the spice. Studies have shown that b-sesquiphellendrene and ar-curcumine were the major contributors to the 'ginger' flavour whereas a-terpenol and citral contributed a lemony flavour. The pungent components of ginger are three compounds: gingerol, shogoal and zingerone. Gingerols are a series of compounds with the general structure, 1-(4'- hydroxy -3' methoxyphenyl) -5-hydroxyalkan - 3 ones. They are mainly condensation products of zingerone. The presence of zingerone and shogoals in fresh extract is non existant. They are formed during the drying process.

Culinary use

Ginger, being a major spice, has many uses in food, flavouring and medicinal products. The aroma of ginger is pleasant and spicy and flavour penetrating, pungent and slightly biting. It is a common ingredient in Asian cooking and it flavours several products like confectionary, gingerole, curry powders, pickles, several soft drinks and alcoholic beverages. It is also essential in Western baking like in taditional gingerbreads, cakes, biscuits etc. It is available fresh and preserved in brine or syrup. Besides these, ginger oils and oleoresins also have a variety of uses. The essential oil is used in commercial flavourings.

Medicinal and other use

Ginger has several medicinal properties. It is carminative, diaphoretic and spasmolytic. Ginger is truly a world domestic remedy. Asian cultures have used it for centuries. Experimental data developed by Chinese scientists verifies the ability of ginger to "strengthen," the stomach while acting as a mild stomach and intestinal stimulant. It has also been shown to inhibit vomiting. Animal experiments have also shown analgesic and anti-inflammatory activity. Even in modern China, while an essential ingredient in almost any meal, it is also one of the most widely consumed drugs. Both fresh and dried roots are official drugs of the modern Chinese pharmacopoeia, as is a liquid extract and tincture of ginger. Ginger is used in dozens of traditional Chinese prescriptions as a "guide drug" to "mediate" the effects of potentially toxic ingredients. In fact, in modern China, Ginger is believed to be used in half of all herbal prescriptions. Several of its pharmaceutical uses are mentioned in Ayurveda. Like the ancient Chinese, in India the fresh and dried roots were considered distinct medicinal products. Fresh ginger has been used for cold-induced disease, nausea, asthma, cough, colic, heart palpitation, swellings, dyspepsia, loss of appetite, and rheumatism. Ginger is as popular a home remedy in India today, as it was 2,000 years ago. Studies by Japanese researchers indicate that ginger has a tonic effect on the heart, and may lower blood pressure by restricting blood flow in peripheral areas of the body. Further studies show that ginger can lower cholesterol levels by reducing cholesterol absorption in the blood and liver.

Ginger extracts have been extensively studied for a broad range of biological activities including antibacterial, anticonvulsant, analgesic, antiulcer, gastric antisecretory, antitumor, antifungal, antispasmodic, antiallergenic, and other activities. Gingerols have been shown to be inhibitors of prostaglandin biosynthesis. Other scientific studies show that gingerol, one of the primary pungent principles of ginger, helps counter liver toxicity by increasing bile secretion. Ginger has potent anti-microbial and anti-oxidant (food preservative) qualities as well. A recent study, furthering ginger's reputation as a stomachic, shows that acetone and methanol extracts of ginger strongly inhibits gastric ulceration. Several studies published in the last two decades have confirmed the traditional claims for use as an anti-vomiting or anti-motion sickness agent.

Ginger is valued the world over, as a culinary herb, condiment, spice, home remedy, and medicinal agent. It is likely that ginger will be enjoyed and valued for the next millennium, and new research will undoubtedly reveal new value for this ancient herb.