From Wikipedia, the free encyclopedia
Nut is a general term for the dry seed or fruit of some plants.
While a wide variety of dried seeds and fruits are called nuts, only a
certain number of them are considered by biologists to be true nuts. Nuts are an important source of nutrition for both humans and wildlife.
All nuts are seeds, but not all seeds are nuts. Nuts are both the
seed and the fruit, and cannot be separated. Seeds come from fruit, and
can be removed from the fruit, like almonds, cashews and pistachios, which were once inside fruit.
Botanical definition
A nut in botany is a simple dry fruit with one seed (rarely two) in which the ovary
wall becomes very hard (stony or woody) at maturity, and where the seed
remains unattached or unfused with the ovary wall. Most nuts come from
the pistils with inferior ovaries (see flower) and all are indehiscent (not opening at maturity). True nuts are produced, for example, by some plant families of the order Fagales.
- Order Fagales
Culinary definition and uses
Korean Pine nuts — unshelled, and shell, above; shelled, below
A nut in cuisine
is a much less restrictive (but vital) category than a nut in botany,
as the term is applied (from the viewpoint of the cook, not of the
botanist) to many seeds that are not botanically true nuts. Any large, oily kernel
found within a shell and used in food may be regarded as a nut. Because
nuts generally have a high oil content, they are a highly prized food
and energy source. A large number of seeds are edible by humans and
used in cooking, eaten raw, sprouted, or roasted as a snack food, or pressed for oil that is used in cookery and cosmetics.
Nuts (or seeds generally) are also a significant source of nutrition
for wildlife. This is particularly true in temperate climates where
animals such as jays and squirrels store acorns and other nuts during the autumn to keep them from starving during the late autumn, all of winter, and early spring.
Nuts, including both tree nuts and peanuts, are among the most common food allergens.[1]
Some fruits and seeds that are nuts in the culinary sense but not in the botanical sense:
See also: List of edible seeds
Nutritional benefits
A graph detailing the nutritional properties of nuts and oily seeds.
Several epidemiological studies have revealed that people who consume nuts regularly are less likely to suffer from coronary heart disease. Recent clinical trials have found that consumption of various nuts such as almonds and walnuts can lower serum LDL
cholesterol concentrations. Although nuts contain various substances
thought to possess cardioprotective effects, scientists believe that
their fatty acid profile is at least in part responsible for the hypolipidemic response observed in clinical trials.
In addition to possessing cardioprotective effects, nuts generally have a very low glycemic index (GI).[2] Consequently, dietitians frequently recommend nuts be included in diets prescribed for patients with insulin resistance problems such as diabetes mellitus type 2.
One study found that people who eat nuts live two to three years
longer than those who do not. However, this may be because people who
eat nuts tend to eat less junk food. [3]
Other uses
The "nut" of the horse-chestnut (Aesculus hippocastanum), is also known as a conker. Conkers are inedible, due to the presence of the toxic glucoside aesculin, but are collected and used in an old children's game, also known as conkers,
in which a nut is threaded onto a strong cord and then each child
attempts to break their opponent's conker by hitting it with their own.
A related species, Aesculus californica, was formerly eaten by the Native Americans of California in times of famine. It must be leached to remove the toxic constituents before eating.
References
- ^ "Common Food Allergens". The Food Allergy & Anaphylaxis Network. Retrieved on 2007-06-24.
- ^ David Mendosa (2002). "Revised International Table of Glycemic Index (GI) and Glycemic Load (GL) Values". Retrieved on 2007-11-23.
- ^ "ABC News: The Places Where People Live Longest". URL accessed January 18, 2007.
Kellogg, John H. "Nuts May Save the Race." The Itinerary of Breakfast. New York: Funk & Wagnalls Company, 1920. 165–203.
External links
Classical
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