Zingiber
officinale Roscoe
Standardized Common
Name: Ginger
Family: Zingiberaceae
Taxonomy: Zingiber is
native to warmer parts of Asia; estimates of the number of species range from
80 to 135. Zingiber officinale exists only in cultivation, and its
country of origin is unknown; it is widely cultivated in tropical areas.
Description: Rhizomatous perennial
herb. Rhizome 3–16 cm long, to 3–4 cm broad and 2 cm thick, laterally
flattened, irregularly branching, pale yellowish brown, bearing leaves reduced
to scales. Roots numerous, fleshy, yellow, brittle. Stems unbranching, to 1.5 m
high. Leaves basal or cauline in 2 vertical ranks, linear, 5–30 cm long; base
sheathing, apex acuminate. Inflorescence a spike, borne on peduncle 15–25(–35)
cm high, the fertile portion 4–5 cm long, 1.5–2 cm thick, few-flowered, with
flowers subtended by bracts. Calyx tubular, cleft on one side, ca. 1–1.2 cm
long. Corolla tubular below with tube 2–2.5 cm long, 3-lobed with lobes 1.6–1.8
cm long, yellow to orangish or greenish yellow, the dorsal lobe partly purple
with cream patches. Stamens 6, purple; only 1 stamen fertile, the anther cream;
anterior staminode petaloid, 3-lobed. Ovary inferior, trilocular; fruit a red
capsule.
Parts
in Commerce:
Rhizome
Identification: Ginger has
customarily been sold by reference to the region of its cultivation (Jamaican
and African ginger being commonly used in the United States; see Evans for
details of the characteristics of ginger from different regions). Processors in
certain regions often engage in traditional methods of processing the rhizome
that include peeling or scraping off the cork, either in whole or just on the
flattened sides, followed by drying. Since unpeeled fresh ginger is a common
vegetable and is easily recognized, only peeled ginger, which looks rather
different, is described.
- Irregularly
branched, usually 7–16 cm long, with short branches curving in the
direction of the main rhizome axis, 1–3 cm long, all produced more or less
in one plane
- Laterally
flattened; branches of fresh material up to 3–4 cm broad and ca. 2 cm
thick, those of peeled and dried material reduced to as little as 1 cm
broad
- When peeled,
exposed layer is usually pale, yellowish-gray to pale brown or orangish,
finely striated (sometimes gray to blackish in certain varieties); cork
remains are usually yellowish to grayish brown or brown
- Fracture short,
often mealy, but variable; ends of vascular bundles often protrude
slightly from surface
- Interior yellow
to yellowish or orange-brown, not bright orange
- In
cross-section, contains (in the absence of outer cork layers) a
comparatively thin ring of starchy cortex containing yellowish secretory
cells and (towards the inside) grayish vascular bundles; light brown
endodermis; large parenchymatous central stele containing numerous
scattered vascular bundles, with yellow oil cells and yellow to reddish or
dark brown resin cells plentiful throughout
- Odor aromatic,
pleasant
- Taste
characteristic, aromatic and pungent
Adulterants: Since ginger is
always cultivated, virtually no confusion with other species occurs. Several
other species of Zingiber have been substituted for Z. officinale
in the past. Though some of these are also used medicinally, they may generally
be distinguished from Z. officinale by their comparatively unpleasant
taste and aroma, sometimes resembling camphor. They may also vary in other
ways, such as:
- Much larger or smaller than typical rhizomes
- Epidermis (if present) without wrinkles or lacking developed scale
leaves
- Bright orange rather than yellowish inside
- Yellow oil cells sparsely distributed
Whitening by dusting with lime has been reported as
a deliberate adulteration. A simple chemical test for this adulteration,
according to Wichtl, is that dilute acetic acid (aka vinegar) in contact with
lime will cause bubbling due to production of carbon dioxide.
References:
Evans WC. Trease and Evans’ Pharmacognosy, 14th ed. London: WB Saunders
Company Ltd.; 1996:281–284.
Greenish HG. Materia Medica. Jodhpur: Scientific Publishers (India); 1920
reprinted 1999:37–379.
Roy SC, Roy K. Morphological and anatomical studies
of rhizome of Zingiber officinale Rosc. and its adulterant Zingiber
cassumunar Roxb. (Zingiberaceae). J Econ Tax Bot. 1982 [publ.
1983];3: 919–921.
Theilade I. A synopsis of the genus Zingiber
(Zingiberaceae) in Thailand. Nordic J Bot. 1999;19:389–410.
Wichtl M, ed. Herbal Drugs and
Phytopharmaceuticals, 3rd English
ed. Stuttgart: medpharm Scientific Publishers and Boca Raton, FL: CRC Press;
2004:653–656.
World Health
Organization. WHO Monographs on Selected Medicinal Plants. Vol. 1 Geneva: World Health Organization;
1999–2002:277–287.
Wu D, Larsen K. Zingiberaceae. In: Wu Z, Raven PH,
eds. Flora of China, vol. 24. Flagellariaceae through Marantaceae.
Beijing: Science Press and St. Louis, MO: Missouri Botanical Garden Press;
2000:322–377.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:212–218.
