Any of six species of annual climbing vines, also called vegetable sponge or sponge gourd, that make up the genus Luffa in the gourd family, native to the Old World tropics. Two species cultivated in temperate areas (L. acutangula and L. aegyptiaca) produce 1-ft (30-cm) cucumber-shaped fruits. Edible and greenish when young, these fruits become straw-coloured with age. On removal of the skin, pulp, and seeds, there remains a complex of closely netted vascular bundles (food- and water-carrying tubes) that resembles a sponge in texture. This spongelike product is used for bathing, for washing dishes, and as an industrial fibre.
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Flower of goatsbeard (Tragopogon pratensis)
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In the broadest sense, all plant life and plant products (vegetable matter); in common, narrow usage, the fresh edible portion of herbaceous plants (roots, stems, leaves, flowers, or fruit), either eaten fresh or prepared in some way. Almost all current vegetables were cultivated in ancient Old or New World civilizations, though some have been greatly modified. Vegetables are good sources of minerals (especially calcium and iron), vitamins (especially A and C), and dietary fiber. All the amino acids needed to synthesize protein are available in vegetables. Fresh vegetables quickly age and spoil, but their storage life can be extended by such preservation methods as dehydration, canning, freezing, fermenting, and pickling.
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Yam is the common name for some species in the genus Dioscorea (family Dioscoreaceae).These are perennial herbaceous vines cultivated for the consumption of their starchy tubers in Africa, Asia, Latin America and Oceania. There are hundreds of cultivars among the cultivated species.
The sweet potato (Ipomoea batatas) has traditionally been referred to as a "yam" in parts of the southern United States and Canada even though it is not part of the Dioscoreaceae family.
The word yam comes from Portuguese inhame or Spanish ñame, which both ultimately derive from the Wolof word nyam, meaning "to sample" or "taste"; in other African languages it can also mean "to eat", e.g. yamyam and nyama in Hausa.
A Nigerian word for yam is adamwanga meaning "Adamo's food". Adamo was a chief notorious for his ability to consume incredible amounts of food, and was even banned from a neighboring village for his refusal to stop.
Yam tubers can grow up to 2.5 meters in length and weigh up to 70 kg (150 pounds).
The vegetable has a rough skin which is difficult to peel, but which softens after heating. The skins vary in color from dark brown to light pink.
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The majority of the vegetable is composed of a much softer substance known as the "meat". This substance ranges in color from white or yellow to purple or pink in ripe yams.
Yams are a primary agricultural commodity in West Africa and New Guinea. They were first cultivated in Africa and Asia about 8000 B.C. Due to their abundance and consequently, their importance to survival, the yam was highly regarded in Nigerian ceremonial culture and even worshiped.
Yams are still important for survival in these regions. The tubers can be stored up to six months without refrigeration, which makes them a valuable resource for the yearly period of food scarcity at the beginning of the wet season.
Yams may be served fried, boiled or pounded into a fufu dough form.
It is eaten raw and grated, after only a relatively minimal preparation: the whole tubers are briefly soaked in a vinegar-water solution to neutralize irritant oxalate crystals found in their skin. The raw vegetable is starchy and bland, mucilaginous when grated, and may be eaten plain as a side dish, or added to noodles.
A mix of one part rice bran, two parts mashed potato granules and four parts yam powder can be used, or one part mashed potato granules to two parts yam powder.
If the 'easy way' is used, then of course, the glycemic index may not be so low as with pure yam powder. But it will be lower than for mashed potato granules on their own, and will therefore provide correspondingly better protection against diabetes (see under 'Nutritional value').
Men and women, young and old, look forward to this festival because it begins a new season and a New Year. On the last night before the festival, yams from the old year are disposed of. The New Year must begin with tasty, fresh yams. All cooking pots, calabashes and wooden bowls are thoroughly washed, especially the wooden mortar in which yam is pounded.
Pounded Yam and vegetable soup “edikayikor” is the main food in the celebration. So much of it is cooked that, no matter how heavily the family eats or how many friends and relatives they invite from the neighboring villages, there is always a large quantity of food left over at the end of the day.
In many societies yams are so important that one can speak of a 'yam culture'. Growing the tuber is associated with magic; the best ones must be given to the chief or king; there is a series of myths connected to a divine origin; a farmer may gain a lot of prestige by growing the largest or longest yam.
In many cultures the yam is considered the most sensual of the tubers.. Here are some examples of where this applies:
In Tonga, the ancient names of the months of the year, and the names of the days of the moon-month, were all geared towards the growing of yam.
They are large plants; the vines can be as long as 10 to 12 meters (35 to 40 feet). The tubers most often weigh about 2.5 to 5 kg (6 to 12 lbs) each but can weigh as much as 25 kg (60 lbs). After 7 to 12 months growth the tubers are harvested. In Africa most are pounded into a paste to make the traditional dish of "pounded yam" (Kay 1987).
In the Philippines it is known as ube (or ubi) and is used as an ingredient in many sweet desserts. In Vietnam, it is called khoai mỡ and is used mainly as an ingredient for soup. In India, it is known as ratalu or violet yam or the Moraga Surprise. In Hawaii it is known as uhi.
Uhi was brought to Hawaii by the early Polynesian settlers and became a major crop in the 1800's when the tubers were sold to visiting ships as an easily stored food supply for their voyages (White 2003).
It was introduced to Europe in the 1800s when the potato crop there was falling victim to disease, and is still grown in France for the Asian food market.
The tubers are harvested after about 6 months of growth. Some are eaten right after harvesting and some are used as ingredients for other dishes, including noodles, and for traditional medicines (Kay 1987).
Some varieties can be eaten raw while some require soaking or boiling for detoxification before eating. It is not grown much commercially since the flavor of other yams is preferred by most people. However it is popular in home vegetable gardens because it produces a crop after only 4 months of growth and continues producing for the life of the vine, as long as two years. Also the bulbils are easy to harvest and cook (Kay 1987).
In 1905 the air potato was introduced to Florida and has since become an invasive species in much of the state. Its rapid growth crowds out native vegetation and is very difficult to remove since it can grow back from the tubers, and new vines can grow from the bulbils even after being cut down or burned (Schultz 1993).
The tubers are eaten baked, boiled, or fried much like potatoes. Because of the small size of the tubers, mechanical cultivation is possible; which, along with its easy preparation and good flavor, could help the lesser yam to become more popular in the future (Kay 1987).
The wild forms are very toxic and are sometimes used to poison animals when mixed with bait. It is said that they have also been used for criminal purposes (Kay 1987).
Yam products generally have a lower glycemic index than potato products, which means that they will provide a more sustained form of energy, and give better protection against obesity and diabetes.
The word yam or yams is sometimes used as street slang for cocaine.