Potato is a tuber coming from South America, belonging to the family of Solanaceae, its name derives from “batata”, a word used for referring to sweet potato. South American people use this tuber since more than 4000 years, they learned how to select a huge number of varieties, virtually suited for every climate. Known all over the world, potato is today the most important vegetable of the earth for human nutrition. «Indians harvest papas and then dry them under the sun, they use them for making what they call chuno, which can be kept for many days and which is used as a bread and in this land are widely traded in the mines of Potosì. They also eat raw, boiled or roasted papas… There is a considerable trading of chuno (dried potatoes) which is mainly done in the mines of Potosì». This is how Josè de Acosta described in 1589 potatoes in his “Historia moral y natural de las Indias Occidentales” (Moral and natural history of Western Indies).

Potatoes are the most common vegetable in the world and the most important ones for human nutrition

 Potatoes are very common in Mexico and South America since more than 4000 years; in Europe were introduced by Spaniards in 1570 and spread in the other countries, in particular Germany and Austria. In the beginning of 1600s it was imported in England, where it soon became the main food for poor people. In 1719 arrived in the United States introduced from Ireland. Potatoes saved whole generations of people during the wars which tormented Europe from 1600 on. The army of Napoleon was used to set on fire crops in order to put the people to be conquered on famine. Peasants were then forced to replace cultivation of wheat with potatoes, as they did not burn, could be kept and hidden underground, under the sand or in cellars, for a long time and safely.

 Potato was one of the cause for the immigration of Europeans overseas. Famine of the last half of the nineteenth century forced hundreds of thousands of Irish, German, English and Dutch peasants to find better life conditions in America. Potato is currently found everywhere in the world and it probably is the most important vegetable of the earth. The cultivation of potato is done in all the continents from the 70° latitude north to the tropics, adapting itself to very different climates. The main producer of potatoes is China that with its 67 millions of tons covers 21% of worldwide production.

 In Italian patata, in French pomme de terre, in German kartoffeln, in Spanish patata. Potato, (Solanum tuberosum), coming from Mexico and South America, is a herbaceous plant with a green trunk, the edible part is made of the extremities of the underground runner, which gives origin to the potato. Leaves are opaque green, rough and slightly hairy in the lower side, flowers are white or violet, grouped in clusters, fruits are pulpy and round berries containing many small and flat seeds. Potato requires a tempered climate and fresh soils, rich in humus, the multiplication is done by tubers, which can be planted whole or in pieces, provided every piece has at least two sprouts. The sectioning of potatoes must be done at least eight days in advance in order to allow the tuber to form cicatrices, therefore eliminating the possibility of infections.

 The sowing is done during the months of March or April (for early potatoes it is done in December), by planting the tubers at about 5-10 centimeters deep, in order to have 5-6 plants for square meter. In August (for early potatoes in April), when the stems gets dried, it is proceeded with harvesting. Tubers must be kept in rooms shielded from light, with a temperature from 0 to 8° C (32-46° F) in order to avoid germination, a cellar would be the best place. It is good to check the potatoes out from time to time and to remove the sprouts which begin to develop. Potatoes must not be kept together with fruits, in particular with apples who accelerates the germination process. Industrial processing of potatoes avoids germination by using specific chemical products. It should also be avoided the keeping of potatoes in plastic bags, as this would prevent tubers to “breathe”.

 According to a cultural point of view, by considering the same area, potatoes produce a richer crop than cereals and it is more easy to cultivate and to harvest. For this reason the cultivation of potatoes rapidly spread all over the world. There are many varieties of potatoes, however they can be classified in the following generic categories, all of them usually found in green groceries:

• Yellow pulp potatoes - (Dutch) the color derives from the presence of carotenes, the pulp is compact and are appreciated for being baked and for frying, both industrially and at home, as well as for the preparation of salads
• White pulp potatoes - have a pale and floury pulp which crumbles during cooking, ideal for the preparation of dumplings and puree. They are not suited for frying because they are too dry and tend to absorb too much oil and fats
• New potatoes - are being harvested when the ripening process is not complete and can be recognized because of their thin skin. It is best to eat them after having been boiled. Because their qualities tend to get lost with time, they are not suited for keeping and must be consumed as soon as possible
• Red skin potatoes - (King Edwards) characterized by a firm pulp, they are indicated for intense cooking, such as in foil, oven and fried. The taste of red skin potatoes largely depends on the quality of the soil in which they have been cultivated
• American potatoes - also known as “sweet potato” or “batata”, with a red, violet or white skin and with the typical sweetish taste

 Potatoes are used both for human and animal nutrition, they are also a precious resource for the cosmetic industry. Yellow pulp potatoes, are suited for being boiled, roasted, fried, cooked in the oven or steamed. White floury pulp potatoes are suited for the preparation of puré, puddings, dumplings and soufflé. Scientific studies done in Greece have defined the perfect “formula” for the preparation of fried potatoes, a study which required, it seems, one year. The result of this study suggest to peel and cut potatoes in sticks one centimeter large and four long, which are then put in the microwave oven at maximum power for two minutes. Then the oil is heated (which must be of vegetal origin) at a temperature of 170° C (338° F). Finally, the potatoes are fried for 12 minutes and 30 seconds.

 Potatoes are characterized by a high content in starch and a moderate content in proteins. It is important to pay attention to green stains which can be found on the skin, as they signal the presence of solanine, a toxic alkaloid. Solanine is found in the skin and however in the external part and in sprouts. When the presence of these stains is found, or when potatoes are characterized by a bitter taste, it is recommended to eliminate the part by deeply peel them or even - for safety reasons - to discard them. The intake of solanine for more than 400mg is responsible for headaches, vomit, cramps to the stomach and diarrhea. In potatoes the content of solanine is lower than 100mg per kilogram, however it should be considered the cooking of potatoes in water reduces the initial content of about 40-50%. Despite the presence of solanine, it is very improbable to get intoxicated with potatoes: one should eat 4 kilograms of raw potatoes or 8 kilograms of boiled potatoes. Solanine disappears after a prolonged cooking at 170° C (frying or baking).

 The nutritional properties of potatoes are very interesting, in fact for many people they still make the base food of their nutrition, they are very rich in vitamin C, starches and mineral substances such as phosphor, iron and magnesium. Many believe potatoes are very caloric, however this is not true. One hundred grams of potatoes provide about 80 calories while giving, at the same time, a sense of satiety. Two hundreds grams of potatoes correspond to about 50 grams of pasta or to 75 grams of bread. Because of its properties, potatoes are an easily digestible food, suited for diabetics, anyone being overweight, to the ones suffering kidney insufficiency, gout and hypertension, thanks to its low content in sodium. What makes potatoes caloric and less digestible are condiments, because of the high capacity of absorbing fats used during cooking. As an example, boiled potatoes with a little of salt can replace bread in the diet, however fried potatoes, as they tend to absorb fats and oils during cooking, are absolutely forbidden to anyone being on a ipocaloric diet.

 One hundred grams of raw potatoes contains: 83% of edible part, 78.5g of water, 2.1g of proteins, 1g of fats, 18.9g of carbohydrates, 15.9g of starch, 0.4g of soluble sugar, 1.6g of fibers, 7mg of sodium, 570mg of potassium, 0.6mg of iron, 10mg of calcium, 54mg of phosphor, 0.10mg of vitamin B1, 0.04mg of vitamin B2, 2.5mg of vitamin PP, 3µg of vitamin A, 15mg of vitamin C. the most simple way to cook potatoes is boiling. There are two school of thought about this subject: some support the idea potatoes must be boiled with the skin, others prefer to peel them. In case it is preferred to boil potatoes without skin, they must be peeled, any bruise should be removed and then soaked in salted water. Then it is brought water to full boil, by considering lesser quantities of water ensure a lower loss of substances and mineral elements from the tubers. As the water boils, potatoes are poured and allowed too cook for 20 minutes. To check whether potatoes are cooked, it is enough to dig the blade of a knife or a fork: when no hard parts are encountered inside the tuber, the potato is cooked. In case it is preferred to boil potatoes with the skin, they should be carefully washed before proceeding with cooking. When purchasing potatoes, particular attention must be paid on the skin, which must be whole, with no stains, sprouts or clefts.