Potato
White potatoes are edible tubers that grow at the end of underground stems of the plant Solanum tuberosum, a member of the Nightshade family
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Updated On: 10/4/2007Print

Potato is the term which applies either to the starchy tuberous root vegetable crop from the perennial plant Solanum tuberosum of the Solanaceae, or nightshade, family, or to the plant itself. Potato is the world's most widely grown tuber crop, and the fourth largest food crop in terms of fresh produce — after rice, wheat, and maize (corn).

The potato originated in the area of contemporary Peru and Bolivia, identified more specifically in research published by David Spooner in 2005 as an area of southern Peru, just north of Lake Titicaca. The potato was introduced to Europe around 1700, and subsequently by European mariners to territories and ports throughout the world. Thousands of varieties persist in the Andes, where over 100 varieties might be found in a single valley, and a dozen or more might be maintained by a single agricultural household.

Potato plants grow high to the ground and bear yellow to silver flowers with yellow stamens.

Potatoes are cross-pollinated mostly by bumblebees that carry pollen from other potato plants, but a substantial amount of self-fertilizing occurs as well. Any potato variety can also be propagated vegetatively by planting tubers, pieces of tubers, cut to include at least one or two eyes, or also by cuttings, a practice used in greenhouses for the production of healthy seed tubers.

Some commercial potato varieties do not produce seeds at all (they bear imperfect flowers) and are propagated only from tuber pieces. Confusingly, these tubers or tuber pieces are called "seed potatoes".

After potato plants flower, some varieties will produce small green fruits that resemble green cherry tomatoes. Each fruit can contain up to 300 true seeds. One can separate seeds from the fruits by putting them in a blender on a slow speed with some water, then leaving them in water for a day so that the seeds will sink and the rest of the fruit will float. All new potato varieties are grown from seeds, also called "true seed" or "botanical seed" to distinguish it from seed tubers. Potato fruit contains large amounts of the toxic alkaloid solanine, and is therefore unsuitable for consumption.

Nutritionally, potatoes are best known for their carbohydrate content (approximately 26 grams in a medium potato). Starch is the predominant form of carbohydrate found in potatoes. A small but significant portion of the starch in potatoes is resistant to enzymatic digestion in the stomach and small intestine and, thus, reaches the large intestine essentially intact. This resistant starch is considered to have similar physiological effects and health benefits of fiber (e.g., provide bulk, offer protection against colon cancer, improve glucose tolerance and insulin sensitivity, lower plasma cholesterol and triglyceride concentrations, increase satiety, and possibly even reduce fat storage) (Cummings et al. 1996; Hylla et al 1998; Raban et al. 1994). The amount of resistant starch found in potatoes is highly dependent upon preparation methods. Cooking and then cooling potatoes significantly increases resistant starch. For example, cooked potato starch contains about 7% resistant starch, which increases to about 13% upon cooling (Englyst et al. 1992).

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