Peanuts: nutritional properties, role in the diet and how to use them in the kitchen of R.Borgacci

What are

What are peanuts?

Peanuts - or American peanuts - is the common name of edible seeds (cotyledons wrapped in a fibrous covering) produced by the peanut plant ( Arachis hypogaea ), herbaceous legume of South American origin (Fabaceae family).

There are many varieties, of which the most important from the commercial point of view are American: Spanish, Runner, Virginia, Valencia, Tennessee Red and Tennessee White.

Despite being edible even raw, the peanuts are marketed mainly cooked and roasted in various formats: still inside the whole fruit (pod), shelled and peeled, natural or salted. More recently, the consumption of boiled peanuts is increasing.

Like beans, peas, broad beans, chickpeas and lentils, peanuts are also legumes. However, unlike the latter, they have a totally different chemical profile. From a nutritional point of view, they are not included in the IV fundamental group of foods and are instead classified as oilseeds or dried fruit.

Peanuts are high-calorie foods, rich in fats - basically polyunsaturated - proteins with a medium biological value, fibers, minerals and vitamins of various kinds, but poor in water. Savory ones have a high sodium content. They are known for their excellent polyphenol content with antioxidant action.

For various reasons, peanuts are no longer considered useful foods for clinical nutrition; the main reasons are:

• They are too caloric and do not lend themselves to the diet against overweight and obesity
• While containing a high level of omega 6 polyunsaturated fatty acids, useful in food therapy against hypercholesterolemia, these are mainly made up of arachidonic acid, a semi-essential fatty acid with a strong predisposition to increase the serum levels of pro-inflammatory eicosanoids - involved in increasing cardiovascular risk
• Those salted cannot be included in nutritional therapy against primary sodium sensitive hypertension
• They have a very high allergic power, which can trigger a different symptomatology depending on the degree of hypersensitivity, and in some cases so serious as to induce anaphylactic shock.

Synonyms

The names commonly used as a synonym of peanuts are: peanuts, peanuts or peanut seeds, spagnolette, bagige or bagigie, gagigi, calacavisi scacchetti, cecini, gallette, marchesini, scaccaglie and giapponi.

Peanuts are eaten mostly alone, as an aperitif or snack snack, but they can also be included in some more elaborate recipes. A classic example is chicken or turkey fillets in peanut-grain crust.

From the commercial point of view, the peanut derivatives are considered almost more important than the raw material itself. We are mainly talking about peanut oil, also popular in Europe, which boasts an excellent application in frying - it has a high smoke point - and peanut butter, most famous in the USA, used as a spread on bread and similar. There is also a flour, called peanut flour, obtained from the crushed oil residues suitably ground and used as a gluten-free food in case of celiac disease.

Did you know that ...

Peanuts have a multitude of industrial uses: paint, lubricating oil, skin conceives, furniture polishers, insecticides and nitroglycerine are some examples. Soap is made from saponified peanut oil and many cosmetics contain peanut oil and its derivatives. The protein portion, on the other hand, is often used as biological animal feed, both for livestock and for chickens, or in the manufacture of some textile fibers. The shells are used in the synthesis of plastics, cladding panels, abrasives, fuels, cellulose and glue.

Nutritional Properties

Peanut nutritional properties

Peanuts are foods that belong to the group of nuts or oil seeds. In Italy they do not find a real nutritional application, since the Mediterranean culinary tradition uses extra virgin olive oil as the primary lipid source.

Peanuts have a very high caloric intake, supplied mainly by fats, followed by proteins and finally by carbohydrates; especially in toasted food, the water is very poor. Lipids have a prevalence of unsaturated polyunsaturated fatty acids, with a notable concentration of arachidonic acid - semi-essential omega 6 - proteins have a medium biological value and non-soluble or partially soluble glucides (starch and maltodextrin). Although the peanuts contain proteins with incomplete biological value, they are distinguished by the considerable contribution of lysine, glutamine and arginine; the latter is an amino acid precursor of nitric oxide, important for the immune system and widely used in food supplementation.

Peanuts have a high concentration of dietary fiber, represented almost entirely by insoluble molecules. Cholesterol is absent, as is lactose and gluten. They are considered among the foods in acquitted more rich in amino acid phenylalanine; the purine content is medium. They do not bring considerable levels of histamine and, unlike other oil seeds, they are not among the histamine-lowering foods. However, it should be remembered that peanuts have a high allergenic incidence.

From the mineral point of view, peanuts can be considered rich in: calcium, iron, magnesium, manganese, phosphorus, potassium and zinc; however, their actual bioavailability should be considered, but above all the overall impact of their recommended portion - very low. As far as vitamins are concerned, peanuts have a high concentration of water-soluble molecules of the B group - thiamine (vit B1), riboflavin (vit B2), niacin (vit PP), pantothenic acid (vit B5), pyridoxine (vit B6), folate - but also of the fat-soluble vitamin E (alpha-tocopherol).

Not to be forgotten is the considerable concentration of polyphenols, antioxidant molecules that seem to increase considerably after roasting peanuts.

Peanut oil composition - peanut oil

Peanut or peanut oil is a cooking oil used in the United States and the United Kingdom both as a condiment for raw vegetables, as a salad, and as a cooking base; in Italy instead, it is mainly used for frying.

Peanut oil contains:

• 46% monounsaturated fat - mainly omega 9 oleic acid
• 32% of polyunsaturated fats - mainly omega 6 linoleic acid
• 17% saturated fat - mainly palmitic acid.

Peanut oil is obtained from whole seeds, through a simple method, which involves mixing with water and subsequent centrifugation.

American peanut oil is being studied in NASA's "Advanced Life Support" program for use in future long-term human space missions.

Did you know that ...

Peanuts are used to fight malnutrition. "Plumpy Nut", "MANA Nutrition" and "Medika Mamba" are peanut-based pastes with high protein, high energy and high nutrient content, developed as a therapeutic food to help people in famine. LOMS, UNICEF, the "Peanut Butter" project and "Doctors Without Borders" have used these products to help save malnourished children in developing countries.

Peanuts can be used as legumes and cereals to create a lactose-free, milk-like beverage called peanut milk, which is promoted in Africa as a means of reducing malnutrition among children.

Diet

Peanuts in the diet

Peanuts are rather fatty and protein-rich foods; they do not have a marked digestibility, although this depends very much on the portion of consumption. Generally, if not alone and in very small quantities, they are eliminated from the food therapy of those suffering from digestive diseases.

Peanuts should be excluded from the hypocaloric and normolipidic diet for weight loss against obesity and overweight. In the right portions they would not give any problem, but we must not forget that these are foods normally used as snacks or aperitifs, which generally favors abuse.

Due to the significant intake of omega 6 polyunsaturated fats, peanuts could play a positive role in food therapy against hypercholesterolemia and primary arterial hypertension. However, it is possible that an excess of arachidonic acid - abundant essential omega 6 in peanuts - can increase the level of pro-inflammatory eicosanoids in the blood, involved in increasing cardiovascular risk. For this reason, also due to the hypothetical positive effects on certain blood parameters, it is better not to overdo the amount of peanuts. Moreover, the most widespread commercial form of peanuts is salt, rich in salt and therefore sodium, a mineral involved in the worsening of sodium-sensitive arterial hypertension.

Peanuts have a remarkable protein concentration, but with an incomplete biological value, which is why they cannot replace food of animal origin alone.

The abundant amount of dietary fiber in peanuts would seem to make it a good preventive and curative food for constipation or constipation. However, the medium portion is always rather limited, which is why the intake of fibers made from peanuts is rather moderate. Moreover, these tend to be insoluble, and do not have a modulating effect on intestinal absorption; also the prebiotic function is of minor entity compared to the soluble ones.

Did you know that ...

The skin of peanuts contains resveratrol, a pigment normally associated with black grapes and red wine, which is currently under preliminary investigation for its potential beneficial effects on humans.

Peanuts lend themselves to the diet of celiac, lactose intolerant and histamine. They are instead to be taken with moderation in hyperuricemia and to be avoided in the case of phenylketonuria. They should logically be avoided in food allergy, even if the symptoms can range from the most severe such as anaphylactic shock, to less severe ones such as watery eyes.

Did you know that ...

According to the so-called "Hygiene Hypotesis", the lack of exposure during early infancy to symbiotic agents, especially the intestinal bacterial flora, but also infectious or weed type, such as bacteria, viruses and parasites, could be responsible for the increase in the incidence of food allergy. This would be due to an oppression of the natural development of the immune system, in particular, it is believed that this lack of exposure leads to defects in the establishment of immune tolerance.

Hygiene Hypotesis has also been called "biome depletion theory" and "lost friends theory".

(William Parker (2010-10-13). " Reconstituting the depleted biome to prevent immune disorders ". The Evolution & Medicine Review. Retrieved 2014-03-31).

Due to the high content of vitamin E (tocopherols) and polyphenols, peanuts have an excellent antioxidant power. Moreover, being very rich in water-soluble B vitamins - which mostly play a coenzyme function - they participate in the support of various intrinsic processes in the cellular metabolism of all body tissues.

Toasted peanuts lend themselves to vegetarian and vegan diets; those not thermally treated also in the raw food diet. No type has religious contraindications.

In Italy, the average recommended portion of peanuts - dried fruit or oilseeds - is about 30 g (raw, 170 kcal), as long as it does not alter the percentage of energy macronutrients or the contribution of total calories. In the USA the Food and Drug Administration (FDA) recommends 1.5 ounces (about 42 g).

Allergy

Peanut allergy

Peanuts have a high allergenic power. This is due to the content of protein allergens: Ara h1, Ara h2, Ara h3. These resist firing and definitely over-sensitize 0.6% of the American population, with a certain variability linked to ethnicity and local diagnostic capacity.

Refined peanut oil does not cause allergic reactions in most people with peanut allergies. However, raw peanut oils - unrefined - have been shown to contain proteins that can cause allergic reactions. In a double-blind, randomized crossover study, 60 people with a proven peanut allergy were exposed to both a raw and a refined peanut oil. The authors concluded: "Raw peanut oil has caused allergic reactions in 10% of the allergic subjects studied and should be avoided." They also stated: "Refined peanut oil does not seem to pose a risk to most people with peanut allergies". However, they point out that refined peanut oil may still pose a risk to peanut-allergic individuals if oil that was previously used to cook peanut-containing foods is reused (Hourihane JO, Bedwani SJ, Dean TP, Warner JO (1997) " Randomized, double blind, crossover challenge study of allergenicity of peanut oils in subjects allergic to peanuts ". BMJ. 314 (7087): 1084–8. Doi: 10.1136 / bmj.314.7087.1084. PMC 2126478. PMID 9133891).

According to the so-called "Hygiene Hypotesis", the lack of exposure during early infancy to symbiotic agents, especially the intestinal bacterial flora, but also of infectious or pest type, such as bacteria, viruses and parasites, could be responsible for the increase in the incidence of food allergy. This would be due to an oppression of the natural development of the immune system; in particular, it is believed that this lack of exposure leads to defects in the establishment of immune tolerance. Hygiene Hypotesis has also been called "biome depletion theory" and "lost friends theory" [William Parker (2010-10-13). " Reconstituting the depleted biome to prevent immune disorders ". The Evolution & Medicine Review. Retrieved 2014-03-31].

Comparative studies on the age of introduction of peanuts into the diet in Britain and Israel have shown that delaying peanut exposure during infancy can greatly increase the risk of developing peanut allergies.

It is hypothesized that in children, peanut allergy may also be triggered by the use of skin products containing peanut oil, but scientific evidence is not conclusive. Peanut allergies have also been associated with family history and intake of soy products.

Some school districts in the United States have banned peanuts. However, the effectiveness of school bans on reducing allergic reactions is uncertain. A recent study in Canada has shown that there is no difference in the percentage of accidental exposures that occur in peanut-banning schools and in schools that allow them.

Hygiene

Hygienic safety of peanuts

Peanuts are generally considered safe. Only one type of hygienic risk is known, specifically linked to the presence of aflatoxins. In the past there have been cases of proliferation of Aspergillus flavus in peanuts, with a relative increase in the toxic agent.

This can happen if the peanut plants are subjected to severe drought during the formation of the pods, or if the pods are not stored properly. Lower quality peanuts, particularly where mold is evident, are more likely to be contaminated. The "United States Department of Agriculture" deals with verifying each load of raw peanuts; any lot containing aflatoxin levels greater than 15 parts per billion is destroyed. The peanut industry has implemented specific manufacturing measures to ensure that all peanuts are inspected.

Kitchen

Peanuts in the kitchen

Peanuts are an integral part of the cuisine of many countries, but not of the Italian one. Let's look at some examples:

Peanuts in North American cuisine

In Canada and the United States, peanuts are used in sweet snacks, cakes, biscuits and other desserts. Individually, they are eaten dry roasted with or without salt. 95% of Canadians eat peanuts or peanut butter, with an average consumption of 3 kg per person per year, and 79% consume peanut butter weekly. In the United States, peanuts and peanut butter are essential for ordinary food practices and are generally considered "comfort" foods. Peanut butter is a common food and represents half of the total American peanut consumption; it has a commercial importance of 850 million dollars a year. Peanut soup is found in restaurant menus in southeastern states. In some southern parts of the USA, peanuts are boiled for several hours until they become soft and moist. Peanuts can be fried, even with their shell. Per person, Americans eat 2.7 kg of peanut products each year, spending a total of about $ 2 billion in total retail purchases.

Peanuts in Latin American cuisine

Peanuts are particularly common in Peruvian and Mexican cuisine, marrying indigenous and European ingredients. For example, in Peru, the "picante de cuy" is prepared, a roasted guinea pig served in ground peanut sauce - ingredients originating from South America - with roasted onions and garlic - ingredients of European cuisine. In the Peruvian city of Arequipa a sauce called "ocopa" is prepared, based on roasted peanuts and hot peppers - both originating in the region - with roasted onions, garlic and oil, poured on meat or potatoes. Another example is the "ajíes", based on sautéed seafood or boiled chicken chopped with peanuts. In Mexico, peanuts are used to prepare various traditional dishes, such as chicken in peanut sauce (encacahuatado) and are used as the main ingredient for the preparation of other famous dishes such as "pipián rosso", "mole poblano" and la " taupe oaxacan negro ".

During the colonial period in Peru, the Spaniards used peanuts to replace oily seeds not available locally, but widely used in Spanish cuisine, such as almonds and pine nuts, usually ground or mixed with rice, meat and vegetables for dishes such as the rice Pilaf.

Throughout the region, many candies and snacks are peanut based. In Mexico, it is common to find them in different preparations such as: salted peanuts, "Japanese" peaunuts, pralines, enchilados or in the form of a very nutritious traditional dessert made with peanuts and honey called "palanqueta", and even as peanut marzipan.

Peanuts in Israeli cuisine

The peanuts wrapped in a crunchy cover called in Hebrew "kabukim" represent a very popular Israeli snack, sold by hand or packaged. The coating is based on flour, salt, starch, lecithin and sometimes sesame seeds. The "bamba puffs" are just as popular and have a similar shape to the "Cheez Doodles".

Peanuts in the South East Asian cuisine

Peanuts are widely used in Southeast Asian cuisine, in Malaysia, Vietnam and Indonesia, where they are typically turned into spicy sauce. Originally, these legumes were imported from Mexico thanks to Spanish colonization. A Filipino dish based on peanuts is the "kare-kare", a mixture of meat and peanut butter.

Traditional Indonesian peanut dishes include: "gado-gado", "pecel", "karedok" and "ketoprak", mixed vegetable salads with peanut sauce and "satay".

Peanuts in the South Asian cuisine

In the Indian subcontinent, peanuts are a light snack, usually toasted or boiled and salted - sometimes with added chilli powder. They are also transformed into desserts or sweet snacks with sugar and "jaggery". Indian cuisine uses roasted and crushed peanuts to give salads a crunchy tone; they are whole added without pods to various types of green leafy vegetable stew. Another common use is in the form of peanut oil for cooking. In southern India, the "peanut chutney" is eaten with "dosa" and "idli" at breakfast.

Peanuts in West African cuisine

Peanuts grow well in southern Mali and in neighboring regions of the Ivory Coast, Burkina Faso, Ghana, Nigeria and Senegal; the peanuts are similar to the fruit of the Vigna subterranea native to the place, and the Africans of the West have gradually adopted them to replace it. Here you also prepare a peanut sauce with onions, garlic, peanut butter / pasta and vegetables such as carrots, cabbage and cauliflower, in a vegetarian version or with chicken.

Peanuts are used in Malaysian meat stew. In Ghana, peanut butter is used for "nkate nkwan" peanut butter soup. Crushed peanuts can also be used for the "nkate" and "kuli-kuli" cake, as well as other local foods such as "oto". Peanut butter is an ingredient of the "African salad" of Nigeria. Peanut powder is an important ingredient in the spicy kebab coating in Nigeria and Ghana.

Peanuts in East African cuisine

Peanuts are a common ingredient of different types of condiments - accompanying or "nshima" - consumed in Malawi and in the eastern part of Zambia. In Uganda, dense peanut sauces are used to season rice and other starchy foods. Peanut stew, locally called "ebinyebwa", is obtained by boiling peanut flour with other ingredients, such as cabbage, mushrooms, dried fish, meat or other vegetables. Throughout East Africa, roasted peanuts, often in newspaper cones, are offered by street vendors.

Botany

Notes on peanut botany

The peanut, a plant of the peanuts of the genus Arachis and a hypogaea species, is an annual herbaceous plant that grows up to 30-50 cm. As a legume it belongs to the Fabaceae botanical family and contains symbiotic bacteria that help to fix nitrogen in the vicinity of root nodules.

The leaves of the American peanut plant are opposite and pinnate with four leaflets - two opposite pairs, no terminal leaves. Each leaf is 1 to 7 cm long and 1 to 3 cm wide. Like many other legumes, the leaves tend to close at night.

The flowers of the peanuts have dimensions from 1.0 to 1.5 cm, of yellowish orange color with reddish veins. They are organized in axillary clusters positioned on the stems out of the earth and last a day. The ovary is at the base of what appears to be the stem of the flower, but in reality it is a very elongated floral cup.

Peanut pods develop underground, an unusual feature known as geocarpy. After fertilization, a small stem at the base of the ovary, called a pedicel, extends to form a thread-like structure called "peg". This grows in the soil and the tip, which contains the ovary, develops into a mature pod. The pods are 3 to 7 cm long and normally contain from one to four seeds.