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Popcorn or popping corn is a type of maize which explodes from the kernel and puffs up when it is heated in oil or by dry heat. Special varieties of corn are grown to give improved popping yield. Some wild types will pop, but the cultivated strain is Zea mays subsp. mays, which is a special kind of flint corn. Popcorn was first formally developed by Native Americans thousands of years ago.

History

Ears and kernels of an early corn variety capable of being popped were found in 1948 in an archaeological dig in a New Mexico rock shelter known as "Bat Cave". These finds are widely reported as being the oldest ears of popcorn ever found; such reports often say they are dated to be 4000–5000 years old, or more. The actual facts about the Bat Cave corn are less clear. While initial reports dated the corn to be 4000–5000 years old, in 1967 the same researchers revealed data from more specifically targeted dating: a sample consisting only of cobs was dated to be 1,752 years old, and a sample of cobs and nearby wood 2,249 years. These dates have been called into question as well: Michael S. Berry, after a study of the Bat Cave procedures, wrote it "was a poorly excavated site that can be interpreted nearly any way one pleases by juggling the data."

Health risks/benefits of eating popcorn

Popcorn is naturally high in fiber, low in calories, contains no sodium, and is sugar and fat free.

To get health benefits from popcorn, one must choose a low-fat or zero-fat method of preparation, such as by air popping or using a minimal amount of oil for kettle-cooking, and by serving it plain, i.e., without extra ingredients such as butter, salt or sugar.

Healthy varieties of pre-made popcorn are commercially available and can typically be found in grocery stores and food shops. One must take special care to check the product's nutritional facts as different brands may contain different amounts of sodium and fat.

Popcorn is included on the list of foods the American Academy of Pediatrics recommends not serving to children under four, due to a choking risk.

How popcorn pops

As with all cereal grains, each kernel of popcorn contains a certain amount of moisture in its starchy endosperm. Unlike most other grains, the outer hull, or pericarp, of the popcorn kernel is both strong and impervious to moisture, and the starch inside consists almost entirely of a hard, dense type.

As the kernel is heated past the boiling point, water in the kernel turns to superheated, pressurized steam, contained within the moisture-proof hull. Under these conditions, the starch inside the kernel gelatinizes, softening and becoming pliable. The pressure continues to increase until it reaches the breaking point of the hull: a pressure of about 135 psi, or 9.1 atmospheres. The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into an airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff.

Expansion and yield

Popping results are sensitive to the rate at which the kernels are heated. If heated too quickly, the steam in the outer layers of the kernel can reach high pressures and rupture the hull before the starch in the center of the kernel can fully gelatinize, leading to partially popped kernels with hard centers. Heating too slowly leads to entirely unpopped kernels: the tip of the kernel, where it attached to the cob, is not entirely moisture-proof, and when heated slowly, the steam can leak out the tip fast enough to keep the pressure from rising sufficiently to break the hull and cause the pop.

Producers and sellers of popcorn consider two major factors in evaluating the quality of popcorn: what percentage of the kernels will pop, and how much each popped kernel expands. Expansion is an important factor to both the consumer and vendor. For the consumer, larger pieces of popcorn tend to be more tender and are associated with higher quality. For the grower, distributor, and vendor, expansion is closely correlated with profit: vendors such as theaters buy popcorn by weight and sell it by volume. For both these reasons, higher-expansion popcorn fetches a higher price per unit weight.

Popcorn will pop when freshly harvested, but not well: its high moisture content leads to poor expansion and chewy pieces of popcorn. Kernels with a high moisture content are also susceptible to mold when stored. For these reasons, popcorn growers and distributors dry the kernels until they reach the moisture level at which they expand the most. This differs by variety and conditions, but is generally in the range of 14–15% moisture by weight. If the kernels are over-dried, the expansion rate will suffer and the percentage of kernels that pop at all will decline. Over-dried popcorn can be rehydrated by introducing some water into the storage environment (consumers can do this at home as well), but the expansion rate will still be below that it would be had they not been over-dried to begin with.

Two explanations exist for kernels which do not pop at proper temperatures, known in the popcorn industry as "old maids". The first is that unpopped kernels do not have enough moisture to create enough steam for an explosion. The second explanation, according to research led by Dr. Bruce Hamaker of Purdue University, is that the unpopped kernel may have a leaky hull.

Types

Popcorn varieties are broadly categorized by the shape of the kernels, the color of the kernels, or the shape of the popped corn. (Varieties of every color produce a white result when popped: only the pericarp is colored.) "Rice" type popcorns have a long kernel pointed at both ends; "pearl" type kernels are rounded at the top. Commercial popcorn production has moved mostly to pearl types. Historically, pearl popcorns were usually yellow and rice popcorns usually white. Today both shapes are available in both colors, as well as others including black, red, and variegated. Commercial production is dominated by white and yellow.

In popcorn jargon, a popped kernel of corn is known as a "flake". Two shapes of flakes are commercially important. "Butterfly" flakes are irregular in shape and have a number of protruding "wings". "Mushroom" flakes are largely ball-shaped, with few wings. Butterfly flakes are regarded as having better mouthfeel, with greater tenderness and less noticeable hulls. Mushroom flakes are less fragile than butterfly flakes and are therefore often used for packaged popcorn or confectionery. The kernels from a single cob of popcorn may form both butterfly and mushroom flakes; hybrids that produce 100% butterfly flakes or 100% mushroom flakes exist, the latter developed only as recently as 1998. Growing conditions and popping environment can also affect the butterfly-to-mushroom ratio.

Trivia

• Indiana produces more popcorn than any other state in the US.
• Popcorn has been served in cinemas since 1912.
• In North America, it is traditionally served salted; in Asia, sweet or salted is equally preferred.
• The average popping temperature for popcorn is around 175°C (347°F).
• The commercial popcorn machine was invented in Chicago, Illinois xccvfl;kjghwertlhjsrt;kjwher;tkjwnert;jkwhedr;tjkhdsr;ltiwje Charles Cretors in 1885.
• Popcorn is used as a wall or Christmas tree decoration in some parts of North America.
• At least four localities claim to be the "Popcorn Capital of the World": Marion, Ohio; Ridgway, Illinois; Schaller, Iowa; and North Loup, Nebraska.
• Popcorn is the official state snack of Illinois.
• The world's largest popcorn ball was unveiled in October 2006 in Lake Forest, Illinois. It weighed 3,415 pounds and had a circumference of 24.5 feet.
• The Boy Scouts of America sell popcorn door-to-door as a primary fund-raiser, similar to Girl Scout cookies.
• American popcorn promoter and guru Orville Redenbacher was first seen on national T.V. in 1971, long before his signature commercial appearances as himself promoting his gourmet kernels. Redenbacher appeared on an episode of the popular game show, To Tell The Truth, and he stumped the panelists including Kitty Carlisle, Bill Cullen, Joe Garagiola, and Peggy Cass, all of whom were shown munching on and enjoying samples of Redenbacher's then-"new" novelty popcorn flavors including "chili," and "bar-b-que."

See also

• Kettle corn
• Caramel corn
• Popcorn bag
• Popcorn brands
• Popcorn lung

Notes

1. Popcorn History
2. ^ Smith p. 10.
3. "Prevent Your Child From Choking". FDA Consumer Magazine Sep–Oct 2005 issue. URL retrieved Jan 6 2007.
4. ^ Lusas & Rooney p. 388.
5. Lusas & Rooney pp. 388–389.
6. Halauer p. 213.
7. ^ Halauer p. 214.
8. http://abclocal.go.com/wls/story?section=News&id=404205
9. http://www.thepopcornfactory.com/popcorn/jump/landingball.asp

References

• Halauer, Arnel R. (2001). Specialty Corns. CRC Press. ISBN 0849323770.
• Lusas, Edmund W.; Rooney, Lloyd W. (2001). Snack Foods Processing. CRC press. ISBN 1566769329.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Smith, Andrew F. (1999). Popped Culture: The Social History of Popcorn in America. University of South Carolina Press. ISBN 1570033005.

External links

• Popcorn Board (U.S.)
• Wyandot Popcorn Museum, Marion, OH

• Cereals
• Popcorn
• Snack foods