Fall Harvest: Jerusalem Artichokes/Sunchokes

October 6, 2013 at 9:16 AM | Posted in vegetables | 7 Comments
Tags: Artichoke, Asteraceae, Florida, Jerusalem, Jerusalem artichoke, John Goodyer, North Dakota, Tuber

Jerusalem artichokes/Sunchokes are brown nubs, that look a bit like small pieces of fresh ginger. Look for firm tubers with smooth, tan skins in fall and winter.

 

 

Stem with flowers

The Jerusalem artichoke (Helianthus tuberosus), also called sunroot, sunchoke, earth apple or topinambour, is a species of sunflower native to eastern North America, and found from eastern Canada and Maine west to North Dakota, and south to northern Florida and Texas. It is also cultivated widely across the temperate zone for its tuber, which is used as a root vegetable.

 

 

It is a herbaceous perennial plant growing to 1.5–3 meters (4 ft 10 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 and the larger leaves on the lower stem are broad ovoid-acute and can be up to 30 centimeters (12 in) long, and the higher leaves smaller and narrower.
The flowers are yellow and produced in capitate flowerheads, which are 5–10 centimeters (2.0–3.9 in) in diameter, with 10–20 ray florets.
The tubers are elongated and uneven, typically 7.5–10 centimetres (3.0–3.9 in) long and 3–5 centimetres (1.2–2.0 in) thick, and vaguely resembling ginger root, with a crisp texture when raw. They vary in color from pale brown to white, red, or purple.
The artichoke contains about 10% protein, no oil, and a surprising lack of starch. However, it is rich in the carbohydrate inulin (76%), which is a polymer of the monosaccharide fructose. Tubers that are stored for any length of time will digest 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 sweeter than sucrose.
Jerusalem artichokes have also been promoted as a healthy choice for diabetics. This is because fructose is better tolerated by people that are diabetic. 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 has been shown to make less inulin than when it is in a warmer region.

 

Jerusalem artichokes

 

Unlike most tubers, but in common with other members of the Asteraceae (including the artichoke), the tubers store the carbohydrate inulin (not to be confused with insulin) instead of starch. For this reason, Jerusalem artichoke tubers are an important source of inulin used as a dietary fiber in food manufacturing.
Crop yields are high, typically 16–20 tonnes/ha for tubers, and 18–28 tonnes/ha green weight for foliage. Jerusalem artichoke also has potential for production of ethanol fuel, using inulin-adapted strains of yeast for fermentation.
Jerusalem artichokes are easy to cultivate, which tempts gardeners to simply leave them completely alone to grow. However, the quality of the edible tubers degrades unless the plants are dug up and replanted in fertile soil. This can be a chore, as even a small piece of tuber will grow if left in the ground, making the hardy plant a potential weed. In fact, the plant can be pernicious. It can ruin gardens by smothering or overshadowing nearby plants and can overtake huge areas if left untamed. Commercial fields growing sunchoke which then change to other vegetables or crops often must be eradicated with glyphosate (sometimes twice, with attendant side effects of these potent toxins) to stop the spread of the sunchokes. Each sunchoke root can make an additional 75 to as many as 200 tubers by fall end.

The tubers are sometimes used as a substitute for potatoes: they have a similar consistency, and in their raw form have a similar texture, but a sweeter, nuttier flavor; raw and sliced thinly, they are fit for a salad. The carbohydrates give the tubers a tendency to become soft and mushy if boiled, but they retain their texture better when steamed. The inulin cannot be broken down by the human digestive system, which can cause flatulence and, in some cases, gastric pain. Gerard’s Herbal, printed in 1621, quotes the English planter John Goodyer on Jerusalem artichokes:
“which way soever they be dressed and eaten, they stir and cause a filthy loathsome stinking wind within the body, thereby causing the belly to be pained and tormented, and are a meat more fit for swine than men.”
Jerusalem artichokes have 650 mg potassium per 1 cup (150g) serving. They are also high in iron, and contain 10-12% of the US RDA of fiber, niacin, thiamine, phosphorus and copper.
Jerusalem artichokes can be used as animal feed, and, while they must be washed before being fed to most animals, pigs forage and safely eat them directly from the ground. The stalks and leaves can be harvested and used for silage, though cutting the tops greatly reduces the harvest of the roots.