Delicious, crunchy, and nutty peanuts are one of the popular oilseeds known to humankind since centuries. The kernels 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 nuts such as pistachio, almonds, etc.
Botanically, they are small sized, underground fruit pods of a 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 oilseeds and established principal 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 underground, from where the fruits develop into peanut pods we know.
To harvest, the entire plant including roots dug out of the soil. Each plant may hold 10-150 fruit pods. The pods have a thick, wrinkled outer shell with 2-3 constrictions as in bean pods. Each peanut kernel is covered with a papery thin, brown layer and can be split into two halves as in any other legumes.
Bambara groundnuts (Vigna subterranea L. Verdc) are different from American peanuts (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 monounsaturated 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 the Mediterranean diet which is rich in monounsaturated fatty acids help prevent coronary artery disease and stroke risk by favoring healthy serum lipid profile.
Peanut kernels are a 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 polyphenolic antioxidants, primarily p-coumaric acid. This compound has been thought to reduce the risk of stomach cancer by limiting the formation of carcinogenic nitrosamines in the stomach.
Peanuts are an excellent source of resveratrol, another polyphenolic antioxidant. Resveratrol has been found to have a 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 bioavailability 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(α -tocopherol); containing about 8 g per100 g. vitamin E is a powerful lipid soluble antioxidant which helps maintain the integrity of mucosa 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 contributes to health and blood flow to the brain.
The nuts are a rich source of minerals like copper, manganese, potassium, calcium, iron, magnesium, zinc, and selenium.
Just a handful of peanuts per day provide enough recommended levels of phenolic antioxidants, minerals, vitamins, and protein.
Peanuts can be available in the markets year around. In the stores, different forms; shelled, unshelled, salted, and sweetened can be found for purchase. Try to buy unshelled (intact outer shell) nuts instead of processed ones. They are generally available in airtight packs and 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 a cool, dry place for many months, whereas shelled (without the shell) nuts should be placed inside airtight container and kept in 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 prepared from roasted nuts, with or without the addition of oil. It is popular throughout the world and commonly used as dip/spread. Peanut milk is also a favorite lactose-free 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 manifest 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 easily susceptible to fungal (mold) infection, especially by Aspergillus flavus which produces aflatoxin. Aflatoxin is a potent 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.