ONION

Family: Liliaceae, Allium species

Source: Simon, J.E., A.F. Chadwick and L.E. Craker. 1984. Herbs: An Indexed Bibliography. 1971-1980. The Scientific Literature on Selected Herbs, and Aromatic and Medicinal Plants of the Temperate Zone. Archon Books, 770 pp., Hamden, CT.

Onion is the general name for herbs of the genus Allium and includes chives, Allium schoenoprasum L., garlic, Allium sativum L., and shallots, Allium cepa var. aggregatum. Chives, native to Eurasia, have light green, hollow, cylindrical leaves that reach a height of 0.3 meters. Dense clumps of bulbs are clustered on a very small rhizome and the plant has purple, lavender, or rose flowers and small gray fruit with fertile black seeds. Garlic, formerly classified as Allium controversum Schrad., Allium sativum var. controversum (Schrad.) Regel and Allium sativum var. ophioscorodon (Link) Doll, has flat leaves that reach a height of 1 meter. Its ovoid bulbs are usually divided into several cloves, that bear bulblets, and terminal umbels, that have bulbils. The plant has white flowers, that later abscise. Shallots, formerly classified as Allium ascalonicum L., have hollow cylindrical leaves that reach a height of 0.3 meters, flowers that are colored from pink to purple and are generally sterile, and cloves of bulbs produced from a parent bulb. Chives are usually produced in window boxes, gardens, and pots for consumption and decorative purposes. Garlic plants are grown commercially in the western United States, Egypt, Italy, Bulgaria, Hungary, and Taiwan (11.1-128). Shallots are traditionally produced in the southern United States.

The reported life zone for Allium species is 6 to 27 degrees centigrade with an annual precipitation of 0.3 to 4.0 meters and a soil pH of 4.5 to 8.3 (4.1-31). Bulbs are produced in response to warm temperatures and long days of spring. Chives, hardy plants adapted to most soils, require full sunlight for best growth. They can be harvested several times each year. Garlic, a hardy perennial, grows best in fertile, well-drained clay loams.

For production, garlic cloves are separated from underground parent bulbs or from bulbils of the inflorescences and then planted in the spring or from autumn to mid-winter in the western United States. The underground bulbs are harvested when the leaves wither. Traditionally, early emerging garlic has cloves that are enclosed in white scales of the parent bulb while late garlic has cloves that are enclosed in pinkish scales of the parent bulb. Shallot culture is similar to that of garlic with lateral bulbs or shoots generally used to establish plantings. Artificial drying of harvested material is preferred, as this results in smaller losses of allyl sulfide, total sulfur, antibacterial activity, and aroma (11.1-126).

The volatile oils of Allium include disulfides and trisulfides (1.1-53). Garlic oil includes alliin, s-methyl-L-cysteine sulfoxide, s-propyl-L-cysteine sulfoxide, alliinase, mucilage, albumin, and other compounds (2.3-236, 14.1-11, 14.1-35). The characteristic flavor, aroma, and active principle in garlic are found only upon rupture of the cell membranes, which allows the enzyme alliinase to produce the disulfide of the characteristic garlic odor.

Chives are grown for their delicate, mild, onion-flavored leaves. Available fresh, dried, and freeze-dried, they are used in soups, stews, egg dishes, salads, cheese, cream cheese and garnishes. Chive bulbs are sometimes pickled. The chive plant is grown as an ornamental, especially a long garden borders. Garlic bulbs are available fresh or dried and as cloves, powdered, crushed, dehydrated, or as an ingredient in table salt. The oil and the oleoresin from garlic are used extensively in the food industry as a flavoring in soups, stews, sauces, breads, cheeses, vinegars, pickles, processed foods, meats, sausages, and other dishes. Shallots are used in salads, sauces, soups, stews, and vinegars.

Medicinally, chives have traditionally been considered a digestive and used to improve the appetite (11.1 -101). Garlic has been traditionally considered an antiseptic, anthelmintic, antispasmodic, carminative, cholagogue, diaphoretic, digestive, diuretic, expectorant, febrifuge, and insect repellent. The plant has also been used as a folk remedy against asthma, colds, coughs, ulcers, high blood pressure, poor circulation, tumors, and leprosy (11.1-126, 14.1-17). The plant is reported to have strong microbial activity, to reduce blood sugar, and to affect cholesterol levels and arteriosclerosis (7.6-17, 7.6-21, 7.5-24, 7.6-88, 7.5-90, 7.6-91, 11.1-126). Raw extracts of garlic are reported to be anthelmintic (7.6-40). Allicin, the active chemotherapeutic compound, may be an important neoplastic drug (11.1-96). Contact with garlic can cause dermatitis, and garlic preparations have been fatal to children (11.1-136).

Chinese chives, garlic chives, and oriental chives are Allium tuberosum Rottl. ex K. Spreng., native to southeast Asia; the leaves and flower stalks of these are used as vegetables. Elephant or great-headed garlic, Allium ampeloprasum L. Ampeloprasum Group, is a mild novelty-type, large-bulbed garlic used as a seasoning.

[Note: References listed above in parentheses can be found in full in the original reference].

Last modified 6-Dec-1997