Foodstuffs can be defined as organisms (or parts thereof), whether of plant or animal origin, which when ingested provide the human body with energy and nutrients. They can be classified into foods of plant origin and foods of animal origin.

Foods of vegetable origin

Foods of plant origin are spontaneously produced by the earth or are the fruit of its cultivation.

Cereals and their by-products

For most of the world’s populations, cereals are the main source of energy and especially protein. They are plants belonging to the grass family, of which the inner part of the caryopsis (i.e. the fruit of the plant) is generally consumed. This portion is consumed either as such, for example in the case of rice, or in the form of flour. Flour, in fact, is the main ingredient of most foods made from cereals, such as pasta or bread.

Cereals

The structure of the cereal caryopsis is common among all species. It consists of three layers, from the outer to the innermost, called pericarp, aleurone layer (or aleurone) and endosperm. At the base of the caryopsis, separated from the endosperm by a very thin membrane called the scutellum, is the germ, also known as the embryo. The pericarp and the aleurone layer are rich in cellulose, a special organic compound with a supporting function for the structure of the plant tissue. Also highly represented in these parts of the caryopsis are lignin, which is an organic polymer from which the bran originates, as well as pentosans (special carbohydrates), lipids, proteins, phosphorus, magnesium, zinc, vitamins B1, B2 and PP. The endosperm, on the other hand, consists mainly of starch, but also protein, calcium and sodium. The germ is the part richest in nutrients, especially vitamins (B1 and E) and lipids, but also sucrose, raffinose, protein and minerals. It is therefore unfortunate that this, like the aleurone layer, is removed during processing. Whole grains are also known to be rich in food enzymes, i.e. enzymes necessary for the digestion of the food containing them. It is also unfortunate that cereals contain several so-called anti-nutritional factors, i.e. constituents that prevent the proper utilisation of nutrients in the food. Among these factors are phytic acid and its derivatives (phytates), which constitute a very strong binding substrate from which nutrients are unlikely to be released for absorption in the gastrointestinal tract. The presence of phytic acid in cereals conspicuously limits the absorption of iron, calcium, magnesium and zinc. There are also molecules in cereals that inhibit digestive enzymes: for example, in maize there is an antivitamin that combines with vitamin PP, preventing its absorption, and in rye there are inhibitors of the enzymes involved in protein digestion. Another characteristic of these foods is their tendency to be digested slowly, resulting in fermentation and the production of gas. Cereals include wheat (corn), rice, maize, barley, oats, rye, sorghum and millet. The most widely consumed cereal in the world is wheat, followed by rice and maize. All other cereals are defined as minor, but not because of characteristics related to the nutrients they contain, but rather because they are consumed to a lesser extent by mankind. With regard to rice, this food requires a more in-depth discussion, which will be given the appropriate space below. Well, rice, apart from its varieties (e.g. carnaroli, vialone nano, arborio, basmati, pilaf, etc.), can be classified according to the technological treatment it undergoes before being offered on the market, although in all cases the product is usually consumed as a whole caryopsis. For this classification there are polished rice and brown rice. The former, compared to the latter, has the characteristic of having undergone a partial or total refining process. Both polished rice and brown rice also exist in the so-called parboiled variant, which implies a further treatment prior to marketing. As far as brown rice is concerned, the processing steps are as follows:

threshing: this produces caryopses covered with glumes (a sort of ‘first skin’ of the rice grains), also known as paddy, paddy or dressed rice;
husking, which is followed by the production of caryopses stripped of their husks. It is at the end of this process that the finished brown rice is obtained.

On the other hand, polished rice, in addition to the above-mentioned two phases, presupposes others to follow, namely:

bleaching, which results in the formation of caryopses with traces of pericarp and aleurone layer. Depending on the level of refining, rice can be classified into semi-refined (4th quality), refined 3rd quality, refined 2nd quality and refined 1st quality;
brushing, the purpose of which is to remove residues from the caryopsis (waste);
polishing, usually carried out with seed or vaseline oil. At the end, camolino rice is obtained;
polishing, a process that involves treating the rice with talcum powder and glucose.

During the whitening process, polished rice is depleted of many of the minerals it contains, especially calcium, iron and sodium. This loss, more specifically, affects between 40% and 75%. During milling, rice also loses much of the thiamine it contains. These deprivations obviously do not affect brown rice, as it is neither whitened nor polished. As far as parboiled rice is concerned, it essentially consists of a water and steam treatment to which the rice is subjected immediately after threshing (and immediately before husking). More specifically, the paddy rice is soaked for two days in water and then subjected to steam under pressure for thirty minutes. This treatment favours the migration of water-soluble substances towards the inside of the caryopses and a gelatinisation of the surface. This is the reason why parboiled rice, even if subsequently polished, contains a higher amount of thiamine than its counterpart that does not undergo the water and steam treatment. As a result of this process, the food also takes on a slightly amber colour, hence the epithet ‘ivory’ that is sometimes associated with parboiled rice. Finally, it should be noted that rice can also be classified according to the size of the caryopsis and the different percentage of starch present in it.

Flour

The term flour refers to wheat that has undergone a process of milling, sifting (i.e. sieving, refining) and filtering out impurities and foreign matter. It can be classified according to the genome of the plant from which it is derived into:

wheat flour (or simply flour);
durum wheat semolina (or simply semolina). It is a granular, sharp-edged product;
durum wheat semolina (or simply semolina). This is what remains after the semolina has been extracted from durum wheat.

Bread

Bread is the product of mixing water, yeast and flour from some kind of cereal, such as rye or wheat, capable of producing gluten (i.e. a particular food compound that is mainly protein). The resulting product is left to rise for a suitable period and then baked. The law states that the water content (moisture content) must be 29% for sizes up to 70g, rising to 41% for sizes over 1kg in weight.

Pasta

Pasta is a particular product that is obtained by processing durum wheat semolinaor semolato. For the production of pasta with a high moisture content (so-called fresh pasta), flour can be used instead of semolina or bran. The production of pasta involves different steps:

kneading: flour, semolina or wheat flour is mixed with water;
drawing or rolling: drawing is the process by which the previously produced dough is passed through a special machine, called a drawing die, in which the pasta is given the desired shape (e.g. spaghetti, macaroni, fusilli, etc.). During drawing, the dough is compressed, heated and extruded. In contrast, rolling requires the dough to be compressed manually between two rollers. While the latter process has undoubted advantages from a purely nutritional point of view, it requires more time and money on the part of the producer. More specifically, the heating of the dough that takes place during the drawing process causes the destruction of the gluten contained therein, which constitutes the chemically supporting structure of the entire food. This process, on the other hand, is extremely rapid, so much so that a single passage of the dough through the drawing die is enough for it to be ready for the subsequent treatment. Rolling, on the other hand, involves several passes through the rollers, each of which takes longer than drawing, but does not involve an increase in the temperature of the dough, so the structure of the food is not damaged as much as it is in the drawing process. Wire-drawing is often performed with Teflon machines, but in relatively recent times, bronze wire-drawing has started to become popular, which is an effective compromise between Teflon-drawing and rolling. Although bronze-drawn pasta has a higher production cost than Teflon-drawn pasta, it is compatible with an industrial production process; on the other hand, it exposes the foodstuff to lower temperatures than those to which it is exposed in Teflon-drawn pasta. Structural damage in bronze drawing is therefore reduced.
Drying and cooling: the amount of water contained in the pasta varies between 12.5% for dry pasta and 30% for fresh pasta. During the drying phase, an attempt is made to obtain the desired degree of humidity. Since water allows a greater proliferation of potentially pathogenic microorganisms, the shelf life of fresh pasta is much shorter than that of dry pasta.

There are also pastas prepared with eggs (four whole hen eggs weighing no less than 200 g per kilogram of semolina) and special pastas, enriched with various other ingredients.

Leguminous and oilseed crops

The term legumes refers to seeds with edible characteristics that belong to the legume species (papilionaceae). They can be eaten fresh or dried (but also frozen or preserved).

Dried legumes

Fresh pulses, however, unlike dried ones, being immature seeds with a high water content, have similar nutritional characteristics to vegetables. For this reason, when referring to pulses in daily life, only dried ones are specifically meant. Some examples of dried legumes are beans, peas, broad beans, lentils, chickpeas, lupins and chickling peas. Legumes are a very rich source of protein, albeit of low biological value, but the main reason why their intake is recommended is their good lecithin content, a substance that can significantly lower cholesterolaemia.

Oilseeds

Oilseeds are considered as a subgroup of dried leguminous plants, but are treated separately because they sometimes have different nutritional values from the others. They are those particular leguminous plants from which oil can be extracted. These include peanuts and soybeans.

Vegetables

Vegetables have a practically negligible protein and fat content and a very low carbohydrate content as well. In fact, they are overwhelmingly made up of water (average water content is 89%, with extremes between black truffles, which contain 76%, and lettuce and radishes, which contain 96%). The reason why the intake of these foods is highly recommended lies in:

in the high content of alkalising minerals (such as magnesium and potassium), which decrease the acidity of blood and urine by bringing their pH values closer to a physiological standard, acting in conjunction with organic acids contained in other foods;
in the interesting dietary fibre content;
in the important content, only in some of them, of vitamin C (found in peppers, turnip leaves, Brussels sprouts, broccoli, cabbage, cauliflower, lettuce and spinach) and provitamin A, i.e. carotenes (in which carrots, green radicchio, spinach, yellow squash, ripe tomatoes, peppers, agretti, chard, lettuce are rich);
the interesting content of food enzyme.g.

Potatoes

Potatoes, like tubers in general, provide a rather modest caloric intake compared to all other foods, but, if we want to make a comparison solely with other foods belonging to the vegetable and vegetable category, they provide considerably more energy. The higher energy intake of potatoes is especially related to the higher amount of starch present in them. For the rest, potatoes have the same nutritional characteristics as all vegetables and greens, with the added bonus of a modest intake of vitamin B, which is usually underrepresented in this food category.

Sprouts

Sprouts are particularly rich in enzymes, minerals and vitamins, but also in readily absorbable amino acids. Other interesting properties of sprouts are their ability to strengthen the immune system, consequently giving more energy available for training, and their anti-inflammatory effect. They are also easy and quick to grow (in 4-6 days they are ready for consumption) even at home. The properties of some sprouts are listed below (Ceriani, 2011):

soy: they are rich in protein and vitamins with high biological value;
alpha alpha (alfalfa): contain plenty of vitamin C and essential amino acids;
oats: provide large amounts of calcium, magnesium and iron (of great support during training);
broccoli: rich in selenium, iron, vitamin C and vitamin A;
quinoa: provides many minerals, vitamins and enzymes.

Seeds

Pumpkin, sesame and sunflower seeds are one of the best sources of zinc. They also contain interesting amounts of sterols and sterolins, substances that not only improve endocrine functionbut also help lower cholesterol. In addition to this, pumpkin seeds contain important amounts of oils and flavones. All edible seeds are very rich in fats (even more than oily nuts, which will be discussed shortly).

Fruit

Fruit represents a more homogenous food group than vegetables and greens, but nevertheless a classification is still possible. Fruit reaches the peak of its nutritional and organoleptic characteristics at the end of the ripening process. However, ripe fruit does not keep for too long, and it is therefore unlikely that one will be able to consume fruit that is exactly at the peak of its ripeness.

The pulpy fruit

Fleshy fruit is the one most consumed by Italians. Like vegetables and greens, it too has a low energy content (except in a few cases, such as avocados), although the concentration of sugars (mostly simple) is higher than that of vegetables and greens. Here, too, the amount of water is decidedly abundant (ranging from 80% to 95%). The reason why the consumption of pulpy fruit is recommended is therefore not in the amount of carbohydrates, proteins or lipids it contains, but in:

a good content of certain vitamins, especially some carotenes and vitamin C, although both are rarely present in the same fruit. Fruits rich in carotenes include yellow peaches and apricots. Fruits rich in vitamin C include strawberries, cherries, pineapples, kiwis and all citrus fruits. Both vitamins are found in melons and persimmons;
a significant mineral content;
an interesting dietary fibre content;
the presence of food enzymes within it (e.g. significant amounts of lipase within the avocado).

It is also remarkable that some fruits contain some peculiar substances that are highly beneficial to the human organism. This is the case with the avocado, which contains certain fats that act by inhibiting the activity of cytokines, molecules with a pro-inflammatory action, and resulting in the synthesis of new collagen. The effect on joints is clearly positive. Another case is that of grapefruit, whose content of a special compound called naringin (as well as L-tyrosine) enhances the thermogenic effect of certain compounds, such as caffeine. Pulpy fruit can be divided into three sub-categories according to its composition and nutritional characteristics. In detail:

sour fruit: to this category belong all those fruits which, when fully ripe, have a considerable content of organic acids. These acids, as well as giving the characteristic flavour, contribute to the preservation of the food. Acidulous fruits certainly include all citrus fruits;
Sour-sugary fruit: this category is characterised not only by a good content of organic acids, but also by a good percentage of simple sugars. Acid-sugar fruits include apples, pears, grapes, apricots, peaches, plums and berries;
sugary fruits: sugary fruits are characterised by a relatively high content of simple sugars (15% to 22%). Figs, bananas, dates and persimmons belong to the sugary fruit category.

Oily fruit

Oily fruit has the same nutritional characteristics as pulpy fruit. It also has a high thiamine, calcium, iron, potassium and phosphorous content, but above all, it has a much higher energy value, since it is rich in protein and lipids (especially unsaturated). It is particularly rich in the enzyme lipase.

Floury fruit

Fleshy fruit has similar characteristics to pulpy fruit. It is characterised by a high carbohydrate content.

Starchy fruit

Starchy fruit has the characteristic of being relatively rich in starch. It is essentially represented by the chestnut.

Vegetable fats

Some foods consist essentially of pure fat isolated from its source. Normally, although there are exceptions to this rule, fats of vegetable origin are in liquid form and are therefore called oils. Vegetable oils consist of two fractions depending on whether or not they can undergo the chemical process known as saponification, the details of which we will not go into here. There is therefore a saponifiable fraction, which is around 98-99%, and an unsaponifiable fraction. The former is composed of esters, especially triglycerides, but also, in appreciable quantities, diacylglycerols and monoacylglycerols. This composition is roughly constant for all oils of vegetable origin, but what distinguishes olive oil from seed oils is the different fatty acid composition: in olive oil, monounsaturated fatty acids prevail, while in seed oils, polyunsaturated fatty acids are the most represented. As for the unsaponifiable fraction, although it is much smaller in quantity than the saponifiable fraction, it is of great nutritional importance. Within the unsaponifiable fraction of vegetable oils are present:

aliphatic alcohols, important for the excretion of bile acids and the elimination of cholesterol;
phenolic compounds, which prevent oxidation of the oil by preventing it from going rancid. These compounds are mainly represented in olive oil. This is the reason why olive oil has a longer shelf life than seed oil;
phytosterols, which, by competing for intestinal absorption with cholesterol, reduce its presence in the blood stream;
phospholipids, components of cell membranes;
chlorophyll;
aromatic compounds;
tocopherols (especially α-tocopherol);
antioxidant substances, which prevent the peroxidation of cell membranes by free radicals.

Olive oil

Of all vegetable fats for seasoning, olive oil certainly deserves special mention. In fact, it is certainly the most genuine, as it possesses numerous properties that promote the maintenance of good health and, to a certain extent, the creation of new muscle tissue as a result of training (via an indirect, testosterone-mediated mechanism). The following characteristics make olive oil the most wholesome and healthy fat for seasoning:

By virtue of its tocopherols/polyunsaturated fat ratio, it is able to protect membrane lipids better than any other oil;
is able to decrease total cholesterolaemia and LDL-cholesterol, while leaving HDL levels (and triglycerides) unchanged;
Due to its high oleic acid content, it can protect lipoproteins (including LDL) from membrane peroxidation, decreasing their atherogenicity (i.e. their ability to form potentially lethal obstructions, called atheromas, within blood vessels);
promotes the production of the eicosanoid prostacyclins;
stimulates the production of special gastric enzymes called enterogastrins and thus reduces acid production in the stomach;
coats the stomach in a very fine oily emulsion, protecting it from mechanical trauma;
exerts an indirect protective action by inhibiting gastric secretion mediated by other gastrointestinal hormones and stimulating alkaline secretion of cells in the pyloric antrum and stomach fundus;
promotes bile secretion and the release of cholecystokinin. This hormone causes the release of bile from the gallbladder and the release of pancreatic digestive enzymes. It also stimulates insulin secretion and, by affecting the vagus nerve, determines the sense of satiety;
stimulates exocrine secretion of digestive enzymes by the pancreas;
prevents diseases such as gastritis and ulcers.

Olive oil retains these characteristics best when consumed raw. Nevertheless, when frying or otherwise cooking food, olive oil remains the most suitable fat, as it resists oxidative stress better than seed oil and other condiment fats. When buying olive oil, it is important to pay attention to the type of process used to produce it. There are in fact several methods to produce olive oil, but they can all be classified into three categories:

mechanical methods;
chemical methods;
physico-chemical methods.

Merchologically speaking, oils produced by mechanical methods are those that result in the so-called ‘virgin’ product. The other methods, on the other hand, have characteristics that render the oil extracted from the olives impure and contaminated, if only slightly. When olive oil is extracted using mechanical methods, the temperature of the freshly extracted oil is around 27°C. In this case we speak of cold pressing. In the case of pressing methods that involve raising the temperature of the freshly extracted oil above 27°C (hot pressing), the amount of oil that can be extracted certainly increases, but the organoleptic and nutritional characteristics of the extracted oil also drop considerably. Olive oil can be classified as follows:

extra virgin olive oil: obtained by cold mechanical pressing and containing less than 0.8 per cent acidity;
virgin olive oil: obtained by cold mechanical pressing and containing an acidity of 2% or less;
lampante virgin olive oil: obtained by mechanical pressing, but has nutritional and organoleptic defects;
rectified olive oil: obtained following chemical rectification of lampante virgin oil in order to correct its excessive acidity;
olive oil: a mixture of virgin and refined olive oils with an acidity of 1% or less.

Olive pomace oil

Olive pomace is what remains after the extraction of oil from olives. From it, it is possible to extract other oil, albeit of lower quality (and price). It must, in fact, necessarily be extracted by chemical processes. The resulting oil, called crude olive-pomace oil, is not edible, but will become edible after a refining process (resulting in rectified olive-pomace oil, also not edible) and the addition of a quantity of virgin olive oil.

Seed oil

Other vegetable oils are seed oils. Seed oil can be extracted from various oilseeds, such as rapeseed, sunflower or sesame, but also from pulses, such as soybean and peanut, or from oil fruits, such as coconut (refined and hydrogenated coconut oil is often a component of some chocolates, ice creams and parfaits) or palm. Of these, only maize germ oil and grape seed oil have to undergo certain processing after extraction. Seed oils are usually quite rich in polyunsaturated fatty acids and essential fatty acids such as linoleic acid, linolenic acid and arachidonic acid, while they are depleted in vitamins due to the rectification treatments they undergo. In truth, however, there are several vitamin-enriched seed oils on the market. There is also so-called miscellaneous seed oil on the market, i.e. a product consisting of a mixture of many different seed oils. Since it is not possible for the consumer to know the amount of each oil in this mixture, it is also not possible to obtain the so-called smoke point, i.e. the temperature at which the heated oil gives rise to the formation of acrolein, a hepatotoxic substance. It is therefore advisable to avoid using this particular oil for frying. The following table summarises the peculiar characteristics of the various seed oils currently on the market (Moriondo, 2010):

Type of oil	Features
Peanut	Light yellow in colour, slightly sweetish taste. It is used for frying, seasoning and for making margarine. With special treatments, peanut butter can be obtained.
Coconut	It is extracted from the dried pulp of the coconut. It consists mainly of saturated fatty acids and is not suitable for cooking. Subjected to hydrogenation, it is used in confectionery.
Sunflower	It can be extracted either by pressure or solvents. It is one of the most widely used seed oils for seasoning and cooking at low temperatures; it is not suitable for frying. It contains up to 75% linoleic acid.
Corn	Light straw colour, practically tasteless. It is suitable for seasoning and cooking at low temperatures. It is rich in linoleic acid (40-60%) and oleic acid (25-45%).
Palm	It is widely used for the production of margarines. It has a high smoke point and is therefore suitable for frying.
Rapeseed and rapeseed	They are used as components in blends of various seed oils.
Sesame	Yellow-brown in colour. Used in the East for seasoning and cooking, it is also used to make margarines.
Soya	It is unsuitable for cooking at high temperatures because it is rich in polyunsaturated fatty acids.

Margarines

It has been said that there are exceptions to the rule that fats of vegetable origin must be liquid. Well, margarines are just the most well-known exception (although there are also margarines of animal origin). These are solid fats used to season and add flavour to food. They are produced from one or more seed oils, usually the most common and cheapest. During the process of solidifying the seed oils, by means of chemical procedures, numerous modifications occur that make margarines less genuine than butter, another fat similar to margarine and used for the same purposes, but with the difference that butter is always of animal origin. The process of solidifying oils to produce margarines carries with it consequences that are sometimes quite disadvantageous from a nutritional point of view. In particular, some polyunsaturated fatty acids are converted into monounsaturated and saturated fatty acids (cholesterolaemia is obviously adversely affected by this process). In addition, fats in oil are converted from cis to trans form. It is a good idea not to exaggerate with the consumption of these products and, for the athlete who wants to keep fit even as age begins to advance, they should be avoided altogether.

Food of animal origin

Food of animal origin consists of portions of the animal’s own body as well as its products.

Milk and dairy products

Milk is the product of the continuous and uninterrupted milking of the females of certain animals, such as cows, goats or sheep, in good health. Dairy products are the by-products of milk.

Cow’s milk

Of all the types of milk (properly speaking), cow’s milk is widely consumed. This is why a special section will be devoted to it here. The nutritional characteristics of cow’s milk vary considerably depending on the breed and type of feed of the cow, as well as the number of calves calved and its age. Generally, however, it is made up of 87% water, protein is rather low although of high quality, as are lipids (especially in certain types of milk, which will be discussed later), although as many as 57 different fatty acids have been isolated in milk, while the carbohydrate content (especially lactose) averages around 4.5%. Proteins consist of 80 per cent caseins, i.e. proteins with a high biological value (especially rich in the amino acids lysine and methionine), while the remaining 20 per cent consists of whey proteins. Raw milk is generally rich in vitamins A, D, E, B1, B2, B5 and B12, while the heat treatments it undergoes to ensure its preservation significantly deplete its intake. It is also known to be very rich in calcium, while it is almost devoid of iron. Milk can be classified according to the type of treatment it underwent to be made edible and according to its fat content. Regarding the first classification, a preliminary division is between raw milk, pasteurised milk and sterilised milk. The former undergoes a simple process of filtration and refrigeration before being put on the market. Since it may contain various pathogenic microorganisms, it should always be consumed after boiling. As for pasteurised milk, it can in turn be classified into fresh milk and high-temperature pasteurised milk. Both fresh milk and high-temperature pasteurised milk are exposed to heat before being marketed, but whereas fresh milk is subjected to a relatively low temperature for a relatively long time (compulsorily within forty hours of milking), high-temperature pasteurised milk is subjected to much more intense heat, but for a much shorter time (even one second). These heating processes are called pasteurisation. The purpose of pasteurisation is to destroy all forms of pathogenic micro-organisms present in the food. However, spores survive, which can spoil the nutritional and organoleptic characteristics of the food if the milk is stored for too long. Fresh milk can only be marketed as ‘high quality’ if it has the following characteristics:

quantity of total protein not less than 3.2 per cent, with a minimum percentage of undenatured serum protein (i.e. intact, not altered by the heating process) of 15.5 per cent;
amount of total fat not less than 3.5 per cent;
bacterial count not exceeding 100000 germs per millilitre of food;
cytological index (which gives a measure of the cells contained in the milk) at most 300000/ml of feed.

An additional purifying treatment that pasteurised milk can undergo consists of passing the milk through a very fine-meshed ceramic filter, capable of filtering out most of the bacteria present in it. The product thus obtained, called microfiltered milk, can be subjected to a lower pasteurisation temperature without sacrificing its hygienic characteristics. As far as sterilised milk is concerned, it can be distinguished into sterilised milk proper and long-life milk. The former is subjected to relatively low temperatures (but still higher than those used in pasteurisation) for a relatively long time, while the latter is exposed to much more intense heat, but for a shorter period. The latter version of sterilised milk is also called UHT (Ultra High Temperature) because of the extremely high temperatures at which it is heated during the sterilisation process. The sterilisation process exterminates any and all forms of microorganisms in the milk, without exception, not even spores, making the food easier to preserve. The nutritional characteristics of pasteurised and sterilised milk are almost the same (in the latter, the food enzymes mentioned by Howell are destroyed along with the germs), but the organoleptic characteristics can be quite different: sterilised milk generally has a more ‘burnt’ taste and for this reason tastes less appreciable than fresh milk. A significant difference between the types of milk examined here is the shelf life, which is longer the higher the temperature and the longer the process to which the food is subjected. At the two extremes, of course, are fresh milk, which cannot be stored for more than a week (in the refrigerator at 4°C), and UHT milk, which can last up to six months. Regarding the classification of milk according to its fat content, there are three types of milk on the market: whole milk (high-quality fresh pasteurised milk can only be commercially whole), semi-skimmed milk and skimmed milk. The former has the original lipid content; the latter has undergone a process to decrease its lipid content (centrifugation and homogenisation), which in this case is around 1.8%; finally, skimmed milk is depleted of its lipid content to an even greater extent, until it drops to around 0.8%. The latter is the one with the least pleasant taste, while the former has the most pronounced flavour. Many human nutrition specialists recommend the intake of semi-skimmed milk for those who do not have any particular illnesses due to fat accumulation. Milk is generally considered a very nutritious food, but, it has to be said, it has a strong contraindication that affects many people: it is a fact that about 50 per cent of the world’s population is lactose intolerant, since it lacks the specific enzyme for breaking down this sugar (lactase). For these people, there is an adapted product known as delactose milk, which has undergone a treatment to split the lactose molecules into a glucose and a galactose molecule. It is sweeter than ordinary cow’s milk. There are also people who, even though they are able to produce lactase, by not taking milk for a long time, tend to favour the development in the body of a situation whereby the synthesis of the enzyme decreases, even conspicuously. In these cases, wishing to begin the introduction of milk into the diet again, it is advisable to accustom the organism gradually to the intake of this foodstuff, introducing a minimum quantity at first, then gradually increasing the dose. Apart from this shortcoming, milk is generally a very well digestible food (warning: mixing milk with coffee means greatly lowering its digestibility due to the high tannin content in coffee). In addition to the treatments considered so far, milk can also undergo dehydration processes to increase its shelf life. These include:

concentration, often after addition of sucrose syrup. The result is called concentrated milk;
evaporation. The result is milk powder.

In concentrated milk, the percentage of water is less than 27%, while in powdered milk it is between 2 and 4%. Both these types of milk have a shelf life of about six months.

Yoghurt

Yoghurt is obtained by adding bacteria such as lactobacillus bulgaricus and streptococcus thermophilis to cow’s milk. By feeding on lactose, they give the starting food the sour aftertaste that characterises unsweetened yoghurt. As a result of the activity of these bacteria, the lactose content of the food is significantly depleted. For this reason, milk-intolerant individuals can sometimes manage to eat yoghurt without experiencing digestive problems. Yoghurt, usually of a pasty consistency but sometimes also liquid, has roughly the same nutritional characteristics as milk, the difference being that the sugar content in pure yoghurt is slightly lower.

Cheeses

Cheeses are foods that are also obtained, like yoghurt, from milk. The production process involves heating it to a temperature of 35-38°C and then adding a particular product called rennet or, more commonly, rennet. Rennet is an enzyme-type compound that is commonly extracted from the stomachs of infant mammals or, alternatively, can be obtained from the fermentation of mould cultures. The latter type of rennet, called microbial rennet, is also adapted to the particular needs of vegetarians. Finally, again for the needs of the vegetarian consumer, there is also a vegetable version of rennet (although improperly so called). Vegetable rennet is formed from the juices of certain vegetables (mostly thistles and artichokes). The process of adding rennet is called curdling. Rennet has the characteristic of being able to break down the casein present in the milk into various fragments, thus coagulating the particles of fat mass present in the original feed (resulting in the formation of calcium paracaseinate). These particles precipitate to the bottom of the vessel, giving rise to a paste-like mass called curd. In truth, there is a second way to obtain curd: coagulation can also be achieved by acidification from the action of certain bacteria naturally present in milk when it is not pasteurised or sterilised. The curd is then treated in various ways depending on the type of cheese to be produced. More in detail:

can be broken into relatively large fragments, which are then squeezed and subsequently kneaded. These are the fresh cheeses and have the characteristic of having a high water content. Some of the most common examples of fresh cheeses are stracchino, mascarpone (very fatty!) or mozzarella (relatively light);
can be broken into medium-sized fragments, which are then compressed. These are the semi-hard cheeses, including provolone and caciocavallo;
can be broken into very small fragments. These are hard cheeses. Some examples: emmenthal, grana padano, parmesan.

The resulting cheese is then cooked:

at a temperature of between 30 and 35°C for so-called raw cheeses;
at a temperature of between 35 and 50°C for so-called semi-cooked cheeses;
at a temperature of between 50 and 60°C for so-called cooked cheeses. This treatment particularly concerns hard cheeses, which are continuously stirred during the cooking process.

After cooking, the cheese is salted (salt acts as a preservative as well as a flavour enhancing agent) and then left to mature for a period of time that may vary from a few days to several years, as in the case of harder cheeses (e.g. parmesan and grana padano). Regarding the nutritional values of cheeses, the protein content of these foods, which is qualitatively lower than that of milk, ranges between 15% and 35%. They are rich in lactose, whey protein, riboflavin and calcium. The latter, in particular, is in greater quantity than that contained in milk, since during the preparation of cheeses, coagulation to calcium paracaseinate takes place. Cheeses also contain a moderate amount of vitamin D. The following table summarises the classification of cheeses (Moriondo, 2010, modified):

Classification parameter	Type of cheese	Features	Examples
Based on moisture content	Hard cheeses	Water less than 40 per cent	Parmesan cheese, Sicilian pecorino cheese
	Semi-hard cheeses	Water between 40% and 45%.	Emmenthal, fontina cheese
	Soft cheeses	Water above 45%	Taleggio, gorgonzola
Based on fat content (% fat in dry matter)	Fat cheeses	Fat greater than 35%	Caciocavallo, gouda
	Semi-fat or light cheeses	20% to 35% fat	Mozzarella
	Low-fat cheeses	Less than 20 per cent fat	Low-fat mozzarella, light cheese

Ricotta

Ricotta is commercially included in the cheese group, but scientifically it is inaccurate to call it a cheese, although it certainly is a dairy product (i.e. a derivative of milk). Ricotta, in fact, unlike cheese, is made from whey, the liquid part of milk that is separated from the curd. The calcium paracaseinate coagulation process, which takes place during cheese production, takes place at a temperature of around 80-90°C and during this process the ricotta is, as the name of the food itself suggests, cooked twice. During the cooking process, the whey is denatured and floccules emerge on the surface of the container, which, precisely, consist of the ricotta. Often, during industrial processes for the production of this foodstuff, additives are added to improve its flavour characteristics and acidifying substances such as muriatic acid, hydrochloric acid, citric acid, tartaric acid or, more simply, lemon juice. The coagulated flocculi are then drained in special containers (traditionally wicker baskets are used) to remove excess whey. Ricotta can be prepared from the milk of various mammals and depending on the choice of animal, the nutritional values vary, sometimes considerably: for example, the presence of sugars (lactose) varies from 2% to 4%, while the fat content varies from 8% to 24%. As for the protein content, cottage cheese is certainly rich in proteins and they are also of fair quality, better than those found in milk.

Butter

Butter is a fat for seasoning and, like cottage cheese, cheese and fermented milk, is derived from milk. It consists of the fat part of milk, separated from it. Usually, industrial centrifuges are used to extract all the fat from milk. Besides a large amount of saturated fat it also contains essential fats ω-3 and ω-6 in a ratio of 1:1.

Seasoning fats of non-dairy origin

In addition to butter, there are a number of commercially available seasoning fats of animal origin, the best known of which are lard and strutto.

Lard

Lard is the layer of fat that is extracted from the subcutaneous tissue of the neck, back and flanks of pigs and then subjected to salting, flavouring and curing processes. It is particularly rich in sodium.

Strutto

Strutto, also a seasoning fat, is made from all the fatty parts of the pig: these parts are removed from the animal, cut into pieces and cooked over very low heat. In this way, the fat melts and the small amount of water it contains evaporates. During the cooking process, the pieces of fat release what is known as strutto, which is removed and left to rest. Once the strutto thus obtained has cooled, salt, antioxidants and possibly various spices and flavourings are added and it is then pressed.

Meat

Commonly, the term meat refers exclusively to the meat of land animals. More precisely, meat is the muscle tissue of barnyard or slaughter animals or game, including connective tissue, skin, etc. Meat can be classified according to the animal of origin into:

red meat: from animals that possess red or red-tinged muscles, such as pigs or cattle, since they possess a good amount of myoglobin;
white meat: from animals that possess white or tending to white muscle, such as chickens or hens, as they possess a low amount of myoglobin;
black meat: from game. They have red or red-tinged meat, but are nevertheless commercially classified as black meat. They are very rich in myoglobin.

Talking about the nutritional values of meat, the important protein contribution, which is of excellent quality (in some cases, however, it may be deficient in the amino acid lysine), certainly stands out among them. And while carbohydrates are practically absent in this type of food, fats can have a decidedly variable content, depending both on the animal of origin and on the part of it that is consumed. Generally speaking, it should be borne in mind that red meat has a higher fat content than white meat. As for minerals, the most important of all is certainly iron, which is also very bioavailable, since it is found in its hemeic form, included in the animal’s muscle myoglobin. The same vitamins contained in cereals and dried legumes are also present in meat. Going into more detail now, the animals whose meat is consumed on Italian tables can be classified into:

beef: the protein content averages around 20%, while the fat content ranges between 1% and 15%;
horse meat: the term horse meat refers to meat from donkeys and horses. The characteristic feature of this meat is its high iron content (3.2/100g of product), but it also contains a good amount of unsaturated fatty acids and carbohydrates, which give it its particular taste (but also contribute to its deterioration). It has a rather high percentage of protein with a high biological value;
lamb meat: the term lamb is properly understood to mean the animal that has not yet been weaned (20-25 days of age). It has a (relatively) low percentage of protein and is rich in fat;
lamb meat: slang does not differentiate between lamb and suckling lamb, however, to be precise, suckling lamb is the already weaned animal between 100 and 120 days old. It is richer in protein and lower in fat than lamb proper;
kid meat: rich in protein and low in fat;
pork: pork can be classified in turn into heavy pork and light pork. The former is used for the production of cold cuts, while the latter is sold as fresh meat. Light pork is an excellent source of protein, but also of vitamins B1 and B2;
chicken and guinea fowl meat: it is rich in protein and B vitamins, while being rather low in fat. Most of the fat is concentrated on the skin, which makes it easy to eliminate. It is highly digestible;
turkey meat: the characteristics of this meat are very similar to chicken and guinea fowl meat, but it is also relatively richer in iron;
chicken meat: this meat, among those in the white meat group, is the fattest;
cockerel meat: rich in protein and low in fat;
rabbit meat: it is rich in protein, mineral salts (especially, despite being very white, it is rich in iron), vitamins B1, B2 and PP. It is low in fat (especially cholesterol);
game: very rich in protein and low in fat. It is usually rather difficult to digest.

Below is a table summarising the special nutritional characteristics of food meats:

Animal of origin	Significantly represented nutrients
Lamb	Vitamin B2, potassium, cholesterol
Domestic duck	Vitamin A, PP, phosphorus, cholesterol
Lean adult cattle	Iron, phosphorus, potassium
Semi-fat adult cattle	Iron, potassium
Kid	Vitamin B1, phosphorus, cholesterol
Castrato (sheep)	Vitamin A, B2, potassium
Horse	Iron, phosphorus, potassium
Wild boar	Cholesterol
Skinny rabbit	Vitamin B1, potassium
Pheasant	Vitamin B1, B2, PP
Guinea fowl (breast)	Vitamin PP
Hen	Vitamin B1, phosphorus, potassium, cholesterol
Hare	Vitamin B2, iron, phosphorus, potassium
Lean heavy pork	Vitamin B1, potassium
Goose	Vitamin PP, potassium, cholesterol
Pigeon	Vitamin PP, phosphorus, cholesterol
Quail	Vitamin A, PP, phosphorus
Turkey (breast)	Iron, phosphorus
Beef tripe	Cholesterol
Calf	Vitamin PP, B2, phosphorus, potassium
Lean veal	Iron, potassium
Semi-fat veal	Potassium

Offal and sweetbreads

Still referring to food from land animals, we can mention offal, i.e. the internal organs of animals, such as the heart or liver for example, and finally the so-called sweetbreads, i.e. the small glands, such as the thymus, endocrine pancreas or salivary glands. These are mostly used for the purpose of feeding domestic animals, but also play a role in human nutrition. All offal, and in particular the liver and kidneys, have a high nutritional value: they are rich in proteins with a high biological value, vitamins A, D, PP, folic acid and B vitamins (especially B2); minerals such as iron, zinc and copper are also highly represented in them. With the exception of the liver, they are low in fat and carbohydrates. The downsides of offal include its high cholesterol content, but also the fact that organs that are consumed as offal often act as filters for toxic substances that may have accumulated in them. It is therefore not advisable to habitually consume offal such as liver and kidneys; and in any case, as these foods are very perishable, the cold chain should be maintained until consumption, which should take place after as short a storage period as possible. A table summarising the special nutritional characteristics of offal now follows:

Piece and animal of origin	Significantly represented nutrients
Beef heart	Vitamin B1, B2, iron, potassium
Heart of pork	Vitamin B2, calcium, iron, cholesterol
Bovine tongue	Cholesterol
Bovine kidney	Vitamin A, B1, B2, PP, cholesterol, iron
Cattle brains	Vitamin C, PP, phosphorus, cholesterol
Bovine liver	Vitamin B2, C, PP, A, iron, calcium, phosphorus, cholesterol

Fish and seafood

The nutritional role of fish and seafood could be roughly considered the same as that of meat from land animals. Fish can be classified according to two different parameters, namely the type of aquatic environment from which the animal originates and its fat content. With regard to the first classification, as can easily be guessed, fish can be subdivided into:

freshwater fish;
saltwater fish.

In truth, this classification does not have as great an impact on the nutritional values of fish as the classification according to fat content may have:

lean fish: have a fat content of less than 3%;
semi-fatty fish: they have a fat content of between 3% and 5%;
fatty fish: they have a fat content of more than 5% and often exceed 10%.

The carbohydrate content of fish and seafood is extremely low, with a few exceptions (mussels, oysters, clams and other molluscs), while the protein content, which is of high biological value (with exceptions for the amino acid lysine), is on average lower than that of meat, although it is not uncommon to find fish that have a higher protein content than meat. The main reason why many nutritionists recommend the habitual consumption of fish lies in the marked presence of essential fatty acids in this food. Crustaceans, on the other hand, are usually not recommended due to their high cholesterol content.

Eggs

The term eggs, legally speaking, refers exclusively to chicken eggs. In fact, for the marketing of chicken eggs, it is not necessary to specify the animal they come from on the pack, whereas for eggs of all other animals, it is mandatory to indicate the animal of origin on the pack label. Eggs have a rather interesting quality and quantity of protein content, located both in the yolk (egg yolk) and albumen (egg white). As for lipids, they are also in fair quantity, but located almost exclusively in the yolk, which is rich in cholesterol. The abundance of cholesterol is the main reason why these foods are sometimes advised against. In fact, this suggestion is only partially appreciable: eggs are also rich in lecithin, which has significant cholesterol-lowering power, but while lecithin is heat-sensitive and therefore easy to damage during cooking, cholesterol is not. Following the cooking process, therefore, the ratio of lecithin to cholesterol will tilt in favour of the latter. Regarding carbohydrates, these are represented in eggs in rather small quantities. Micronutrients, on the other hand, can be found in the yolk or albumen in very different quantities. Eggs also contain choline and methionine, two substances that have a protective function on the liver cells, since they degrade fatty acid molecules and promote their functionality. Eggs also exert a diluting action on bile, a particular liver secretion through which this organ performs its cleansing activity on the body. Unfortunately, egg whites also contain a known anti-nutrient agent: this is a glycoprotein known as avidin that can prevent the metabolisation of vitamin H. However, avidin can be easily inactivated by cooking. If, therefore, light cooking is desirable for yolks, so as to damage the lecithin as little as possible, it is best to cook the egg whites longer so as to inactivate the avidin. Ox-eye’ eggs and ‘barzotte’ eggs, in which the yolk remains soft while the egg white becomes firm, are therefore the most nutritionally recommendable preparations.

Drinks

Beverages can be classified into two different macrogroups: alcoholic and non-alcoholic. Alcoholic drinks are those that contain ethyl alcohol. Although it cannot rightly be considered a nutrient, it provides 7kcal per gram. The ethyl alcohol content of a drink is usually expressed as a percentage of volume and corresponds to the volumes of alcohol contained in 100 volumes of drink. To convert the alcohol content into grams of alcohol present, multiply the former by 0.8. Much has been written about the deleterious effects of alcoholic beverages, so I feel it would be pointless to discuss this in detail here. However, I would like to point out that people who are heavy drinkers of alcohol tend to put on weight very easily: alcohol is absorbed very quickly and in large quantities (especially if consumed on an empty stomach) and often gives rise to the formation of storage fat. In addition, alcohol interferes with the absorption of proteins and amino acids, so if you are used to consuming alcohol regularly, especially during protein meals, you may find yourself in protein deficit despite taking in an adequate amount of protein for your needs. Alcohol can also fatigue the liver, as the organ responsible for waste disposal, and on some individuals it can have an oestrogenic effect, negatively affecting strength performance, as well as retention and accumulation of muscle mass. In this regard, moreover, alcohol can block the secretion of GH (growth hormone). But alcohol does not only have negative effects on health (although the positive ones are far fewer, both in terms of quality and quantity, than the negative ones): studies by Masquelier and Renaud have shown that drinking three glasses of wine (especially red) a day reduces the cardiovascular risk, since wine contains substances (tannins, flavonoids, anthocyanins and procyanidins) capable of lowering LDL cholesterol and increasing prostacyclin and HDL cholesterol. Wine also has a protective effect against ulcers due to the presence of catechins and procyanidol oligomers. It can also protect against free radical damage and the formation of gallstones. It should be made clear, however, that all these beneficial substances can also be derived just as effectively from foodstuffs proper, the consumption of which does not have all the negative health repercussions that wine does. More specifically, tannins are widely found in the plant world. Some examples of excellent food sources are nerves such as coffee and tea (especially green tea). Cocoa is also an excellent source, as are artichokes, legumes and some fruits such as persimmons, strawberries, walnuts, peanuts, almonds, chestnuts and, of course, that same grape from which wine is made. Flavonoids are highly represented in spinach, blueberries, kiwis, green tea, onions, lettuce and dark chocolate. As for anthocyanins, these are found in all red-coloured vegetables, such as berries, cherries, currants and, again, red grapes. Aubergines are also a good source. Catechins are found in cocoa and green tea, while procyanidols and related substances can be taken in by consuming grapes. Turning now to soft drinks, their calorie content may vary, as do their ingredients. They are often rich in simple sugars and food additives, but there are some products, such as certain fruit juices, that have a very short ingredient list. Nevertheless, these products are often pasteurised (i.e. heated up to a certain temperature) in order to be cleaned of all those pathogens that promote the rapid deterioration of the product. This treatment also has the side effect of destroying many micronutrients, which are sometimes artificially added again at the end of the production process.

Spices and herbs

Spices and herbs are usually used to give flavour to food, to stimulate digestion or by virtue of their healing properties. It should be noted that the flavouring characteristics of these foods can be altered by certain particular types of cooking, so the experienced cook will inquire about the most propitious time to add these ingredients to his or her dish. Below is a summary table of the various spices and herbs, complete with their properties (Moriondo, 2010):

category	name	properties
Spices	Aniseed (green)	Has a beneficial action against intestinal fermentation; aids digestion; promotes milk secretion
	Coriander	Stimulates digestion; has a beneficial action against intestinal fermentation
	Cumin	Stimulates digestion
	Fennel (seeds)	Has a beneficial action against intestinal fermentations
	Juniper (berries)	Stimulates appetite and kidney function
	Chilli	Aids digestion; limits putrefactive phenomena in the intestine
	Cayenne pepper	Its capsaicin content (a special organic compound) gives it an interesting thermogenic (fat-burning) power.
Aromatic herbs	Dill	Promotes milk secretion; combats aerophagy and meteorism
	Basil	Has tonic, antiseptic and calming effects; stimulates digestion
	Borage	The infusion is used to treat coughs and bronchitis; it is used as an adjuvant in liver failure
	Chervil	It has diuretic and blood-purifying effects; its fresh juice, combined with lukewarm milk, soothes coughs
	Watercress	Has depurative, diuretic, restorative and antibacterial effects
	Dandelion	Has diuretic, remineralising, digestive effects; promotes liver function
	Tarragon	Stimulates appetite, facilitates digestion; combats aerophagia and meteorism
	Chives	Has diuretic effects; combats meteorism
	Marjoram	Indicated in cases of nervousness, headaches, intestinal spasms and difficult digestion
	Melissa	Stimulates appetite; aids digestion, conciliates sleep; infusion is useful in earache, toothache and certain nervous syndromes
	Mint	It has digestive, disinfectant, gastrointestinal antispasmodic and anti-allergic effects; it is indicated in cases of meteorism, aerophagia, dizziness and headache
	Oregano	Has antispasmodic effects; limits putrefactive phenomena in the intestine
	Nettle	Has a remineralising effect
	Parsley	Regulates blood circulation; has antispasmodic effect on the walls of the intestine; aids digestion
	Horseradish	Has a purifying action; fights bronchitis; has antiscorbutic properties
	Rosemary	It has diuretic, antiseptic, antispasmodic and nervous system tonic effects; it stimulates the secretion and fluidification of bile, gastric and cardiac function; the infusion is an excellent restorative, also prescribed in cases of migraine and weakness
	Arugula	Has purifying effects, combats weakness
	Sage	Stimulates the digestive and circulatory systems; has disinfectant, anti-infective, antispasmodic functions; acts as a balancer of the nervous system
	Savory	Has antiseptic effects
	Timo	Has antiseptic, antispasmodic, tonic effects; helps fight colds and flu

Functional foods

The term functional food, pharma food or alicament refers to those particular types of food that possess characteristics beneficial to the health of the human organism but which, in most cases, cannot be classified as nutrients. These include:

phytochemical foods: these possess substances useful, for example, in preventing cancer or high blood pressure. These in turn can be classified into:
1. fortified foods: when they are, in fact, fortified with a certain substance already naturally present in them, albeit perhaps in small quantities (e.g. vitamin C);
1. fortified foods: when a substance that does not occur naturally in them is added to them;
probiotic foods: consisting mostly of cheese and various types of fermented milk. They have the characteristic of containing live lactic ferments and can act by rebalancing the intestinal bacterial flora, i.e. by increasing the amount of beneficial bacteria present in the intestine. However, their consumption is only advisable for those suffering from disorders related to intestinal bacterial activity. In other cases, the usefulness of these foods is not relevant;
prebiotic foods: they have the same usefulness and limitations as probiotic foods, with the difference that they do not contain live lactic ferments, but substrates that promote their proliferation in vivo in the intestine;
symbiotic foods: they have the characteristic of containing both live milk enzymes, specific to probiotic foods, and substrates to promote their proliferation, specific to prebiotic foods. They perform the tasks of prebiotic foods and probiotic foods better and in a shorter time;
dietetic foods: these are foods intended for particular classes of consumers characterised by a particular physiological or pathological state that influences their nutritional needs. These foods include those for diabetics, deprived of sugars such as glucose or saccharose and perhaps with added artificial sweeteners (e.g. saccharin), or milk deprived of lactose for those who show intolerance to this sugar.