Jerusalem artichoke

The Jerusalem artichoke (Helianthus tuberosus), also called sunroot, sunchoke, or earth apple, is a species of sunflower native to central North America. It grows wild in eastern and western North America but is considered an introduced species. It is also cultivated widely across the temperate zone for its tuber, which is used as a root vegetable. Helianthus tuberosus is a herbaceous perennial plant growing to 1.5–3 m (4 ft 11 in–9 ft 10 in) tall with opposite leaves on the upper part of the stem but alternate below. The leaves have a rough, hairy texture. Larger leaves on the lower stem are broad ovoid-acute and can be up to 30 cm (12 in) long. Leaves higher on the stem are smaller and narrower. The flowers are yellow and produced in capitate flowerheads, which are 5–10 cm (2.0–3.9 in) in diameter, with 10–20 ray florets and 60 or more small disc florets. The tubers are often elongated and uneven, typically 7.5–10 cm (3.0–3.9 in) long and 3–5 cm (1.2–2.0 in) thick, and vaguely resembling a ginger root in appearance, with a crisp and crunchy texture when raw. They vary in colour from pale brown to white, red, or purple. Before the arrival of Europeans, Native Americans cultivated H. tuberosus as a food source. The tubers persist for years after being planted, so that the species expanded its range from central North America to the eastern and western regions. Early European colonists learned of this, and sent tubers back to Europe, where it became a popular crop and naturalized there. It later gradually fell into obscurity in North America, but attempts to market it commercially have been successful in the late 1900s and early 2000s. The tuber contains about 2% protein, no oil, and little starch. It is rich in the carbohydrate inulin (8 to 13%), which is a polymer of the monosaccharide fructose. Tubers stored for any length of time convert their inulin into its component fructose. Jerusalem artichokes have an underlying sweet taste because of the fructose, which is about one and a half times as sweet as sucrose. It has also been reported as a folk remedy for diabetes. Temperature variances have been shown to affect the amount of inulin the Jerusalem artichoke can produce. When not in tropical regions, it makes less inulin than when it is in a warmer region. Despite one of its names, the Jerusalem artichoke has no relationship to Jerusalem, and it is not a type of artichoke, though the two are distantly related as members of the daisy family. The origin of the 'Jerusalem' part of the name is uncertain. Italian settlers in the United States called the plant girasole, the Italian word for sunflower, because of its familial relationship to the garden sunflower (both plants are members of the genus Helianthus). Over time, the name girasole (pronounced closer to in southern Italian dialects) may have been changed to Jerusalem. In other words, English speakers would have corrupted 'girasole artichoke' (meaning, 'sunflower artichoke') to Jerusalem artichoke. Another explanation for the name is that the Puritans, when they came to the New World, named the plant with regard to the 'New Jerusalem' they believed they were creating in the wilderness. Also, various other names have been applied to the plant, such as the French or Canada potato, topinambour, and lambchoke. Sunchoke, a name by which it is still known today, was invented in the 1960s by Frieda Caplan, a produce wholesaler who was trying to revive the plant's appeal.