Delicious, crunchy, and nutty peanuts are one of the popular oil seeds known to humankind since centuries. The kernels are enriched with many noteworthy health-benefiting nutrients essential for optimum health and wellness. They are actually legumes but carry almost all the qualities of other popular edible kernels such as pistachio, almonds, etc.
Botanically, they are small sized, underground fruit pods of plant belonging to the Fabaceae family, in the genus, Arachis. Some of the common names are groundnut, earthnuts, etc.
Scientific name: Arachis hypogaea.
|Peanut kernels in a bowl.||Peanut pods.|
Peanut is a small annual dicotyledon herb growing up to a foot above the ground. It is thought to have originated in the Central Americas and from where it spread to rest of the world through Spanish explorers. Today, it is one of the widely cultivated oil-seed and established prime commercial crop in China, India, African nations, and the United States of America.
Peanut plant takes approximately 120 to 150 days to produce the crop after sowing its seed. The process of peanut development is quite interesting! Its yellow flowers, after self-pollination, develop into "ovaries" called pedicels, which elongate rapidly to turn downward to bury several inches deep under the ground surface, from where the fruits develop into peanut pods we know.
To harvest, the entire plant including roots, is dug out of the soil. Each plant may bear 10-150 fruit pods. The pods have rough, wrinkled outer shells with 2-3 constrictions as in bean pods. Each peanut kernel is covered with thin brown layer and can be split into two equal halves as in any other legumes.
Bambara groundnuts (Vigna subterranea L. Verdc) are different from American groundnuts (Arachis hypogaea) in that they appear somewhat like round cowpeas. Bambara groundnuts are indeed one of the popular legume crops in many African regions, providing much-needed protein, fat and other essential nutrients of vegetable origin.
Peanuts are rich in energy (567 calories per 100 g) and contain health benefiting nutrients, minerals, antioxidants and vitamins that are essential for optimum health.
They compose sufficient levels of mono-unsaturated fatty acids (MUFA), especially oleic acid. MUFA helps lower LDL or "bad cholesterol" and increaseS HDL or "good cholesterol” level in the blood. Research studies suggest that Mediterranean diet which is rich in monounsaturated fatty acids help to prevent coronary artery disease and stroke risk by favoring healthy blood lipid profile.
Peanut kernels are good source of dietary protein; compose fine quality amino acids that are essential for growth and development.
Research studies have shown that peanuts contain high concentrations of poly-phenolic antioxidants, primarily p-coumaric acid. This compound has been thought to reduce the risk of stomach cancer by limiting formation of carcinogenic nitrosamines in the stomach.
Peanuts are an excellent source of resveratrol, another polyphenolic antioxidant. Resveratrol has been found to have protective function against cancers, heart disease, degenerative nerve disease, Alzheimer's disease, and viral/fungal infections.
Furthermore, studies suggest that resveratrol may reduce stroke risk through altering molecular mechanisms in the blood vessels (reducing susceptibility to vascular damage through decreased activity of angiotensin, a systemic hormone responsible for blood vessel constriction that would elevate blood pressure), and by increasing production of vasodilator hormone, nitric oxide.
Recent research studies suggest that roasting/boiling enhances antioxidant bio-availability in the peanuts. It has been found that boiled peanuts have two and four-fold increase in isoflavone antioxidants biochanin-A and genistein content, respectively. (Journal of agricultural and food chemistry).
The kernels are an excellent source of vitamin E (a-tocopherol); containing about 8 g per100 g. vitamin E is a powerful lipid soluble antioxidant which helps maintain the integrity of cell membrane of mucus membranes and skin by protecting from harmful oxygen free radicals.
The nuts are packed with many important B-complex groups of vitamins such as riboflavin, niacin, thiamin, pantothenic acid, vitamin B-6, and folates. 100 g of peanuts provide about 85% of RDI of niacin, which contribute to brain health and blood flow to brain.
The nuts are rich source of minerals like copper, manganese, potassium, calcium, iron, magnesium, zinc, and selenium.
Just a handful of peanuts per day provides enough recommended levels of phenolic anti-oxidants, minerals, vitamins, and protein.
Peanuts can be available in the markets year around. In the stores, different forms; shelled, unshelled, salted, sweetened etc can be found for purchase. Try to buy unshelled (intact outer shell) nuts instead of processed ones. They generally available in the airtight packs as well as in bulk bins. The pods should feature compact, off white color healthy-looking shell, uniform in size, and feel heavy in hand. They should be free from cracks, mold, and spots and free of rancid smell.
Unshelled groundnuts can be placed in cool dry place for many months, whereas shelled (without the shell) nuts should be placed inside airtight container and kept inside the refrigerator to avoid them turn rancid.
Peanut kernels usually eaten as is, by cracking them with firm pressure between fingers or using clippers, or nutcracker machine. The nuts can also be enjoyed roasted, boiled, salted, or sweetened.
They are nutty, yet pleasantly sweet in taste. Roasting enhances taste, augments antioxidants levels like p-coumaric acid, and helps remove toxic aflatoxin.
Roasted and crushed kernels often sprinkled over salads, desserts, particularly sundaes and other dairy based preparations.
Boiled peanuts possess unique flavor and taste. Boiling, in fact, enriches their nutritional and antioxidants profile.
Peanut butter is a food-paste made of ground-roasted nuts, with or without addition of oil. It is popular throughout the world and commonly used as dip/spread. Peanut-milk is also a popular lactose-free milk like healthy drink.
Peanut allergy is a type of hypersensitivity response in some people to food substances prepared using these nuts. The resultant over-reaction of the immune system may manifet as severe physical symptoms like vomiting, stomach-pain, swelling of lips and throat leading to breathing difficulty, chest congestion, and sometimes death. It is, therefore, advised to avoid any food preparations that contain peanut products in these individuals.
Peanuts are one of the crops that are susceptible to fungal (mold) infection, especially by aspergillus flavus which produces aflatoxin. Aflatoxin is a very powerful and dangerous known carcinogen that may cause liver cirrhosis and cancer. Roasting helps reduce toxin levels in these nuts and thus offers some protection against aflatoxin. (Medical disclaimer).
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1. Refer Stanford Medicine cancer center information page-Nutrition to reduce cancer risk.