Fruit: list, properties, nutritional values

Fruit is a food with high nutritive density and low caloric density, rich in important nutrients. With important mineralizing and vitaminizing functions, it also has laxative properties and stimulates digestion. Let's find out better.

What is fruit

The fruit forms a food group that is more homogeneous than that of vegetables and vegetables. However, there are differences in its nutritional value and in its preservation possibilities; these concern the conformation (the peel is often less fragile than the thin peel), the color (the colored fruit is much richer in vitamin A and C) and the diversity of the genetic selection.

It is at full maturity that the fruit reaches its maximum nutritional and gustatory qualities but the ripe fruit is not always carried well and the good fruit is not always beautiful: the selected varieties have been chosen more for their good attitude to transport and good looks for taste or vitamin value.

Very often there are discrepancies between the botanical concept of fruit - intended as a transformation product of the ovary of the flower after fertilization - which also includes some vegetables such as aubergines, tomatoes, pumpkins, etc. and the meaning that is correctly attributed to it, namely that of food that usually serves to conclude a meal. For the botanist, therefore, there is no difference between fruit and vegetables: an aubergine is a real fruit as much as a peach, even if it is not sweet!

Still from a botanical point of view, the function of the fruit is to protect and accompany the development of the seeds and embryos they contain, also favoring dissemination, useful for the plant for the diffusion of the species and to reduce the phenomena of competition to the inside the same species that we would have if the new plants were born at the foot of the mother plant.

How the fruit is made up and how it is classified

In general, in the fruit we distinguish three layers: exocarp, mesocarp and endocarp which together form the pericarp that surrounds the seed or seeds. Sometimes these three layers are very evident, for example in peach they correspond to peel, pulp and kernel containing the seed. Many other times, however, these layers are much less distinguishable, for example in grapes.

A first classification of fruits is between real fruits and false fruits or apples. In the first case the fruit derives only from the ovary of the flower, in the second also from the receptacle surrounding the ovary (for example in an apple or a pear: the part we eat derives from the receptacle, the part that contains the seeds and that we discard derives from the ovary).

A second distinction is between fleshy fruits and dried fruits . For the distinction it is necessary to observe the fruit at maturity, that is when the seeds are completely developed and ready for dissemination. If at this point the fruit is still more or less pulpy and hydrated, it is a fleshy fruit (apples, watermelons, lemons), but if all the cells of the fruit are dehydrated and therefore dead and alive there are only the seeds contained in it, then it is a dry fruit (hazelnut, legume, caryopsis).

For botany, these "dried fruits" are something completely different from "dried fruit": for example, almond and peach produce the same type of fleshy fruit, the drupe, only we eat what we throw out of a peach, that is the seed contained in the core.

Given the extreme variety of nutritive principles in the different fruits, the need to divide the fruit into:

acidulous-sugary : apples, pears, peaches, plums, grapes, apricots, cherries, strawberries, raspberries;
acidulous : contains about 15% of sugars, providing a maximum caloric intake of about 60Kcal (citrus);
sugar : contains more than 15% of sugars, providing a caloric intake of more than 70 Kcal (figs, bananas, pineapples);
floury : chestnuts;
oily : it contains a high quantity of lipids (50-65%) and proteins (10-20%) in addition to a fair amount of carbohydrates (15-20%). The caloric intake is about 600 Kcal (peanuts, walnuts, hazelnuts, almonds, pine nuts, pistachios).

The fruit-based diet: all the pros and cons of fruiting

Properties of fruit

Fruit, with the exception of oil, is a food with high nutritive density and low caloric density characterized by a whole series of nutritive principles:

high water content (from 80 to 96% of the weight; the maximum we find in the watermelon)
high content of vitamins A and C
mineral salts such as K, Mg, Fe, Ca which are assured by fruit and vegetables, in industrialized countries, for about 1/5 of the recommended quantities
dietary fiber (cellulose, hemicellulose and pectin)
irrelevant protein and lipid content
good sugar content ( sucrose and fructose ) present above all in pulpy and sugary fruit.

We must remember that in fruit there are also potentially toxic substances (cyanogenic glucosides, nitrates, oxalates, antithyroid agents, solanine).

Fruit, ally of

The protective role of the nutrients contained in fruits and vegetables is now known. However, these numerous principles, chemically isolated, purified and administered, do not have the same positive effects as when they are in the fruit because their action is a synergy that occurs with all the other vegetable components (essential oils, tannins, pectins, etc.) present in the fruit. same.

The main functions of fruits and vegetables are:

vitaminizing action thanks to the high intake of vitamins;
mineralizing action exerted above all by calcium, iron, copper, cobalt, manganese and zinc salts;
diuretic and detoxifying action thanks to the prevalence of potassium which facilitates the elimination of nitrogen metabolism products and excess chlorides;
alkalizing action useful for protein foods (acid-formers);
laxative action exerted by the fiber that stimulates intestinal peristalsis (although some fruits contain high amounts of tannins with astringent properties, eg in quince, medlar, raspberry);
stimulating action digestion determined by organic acids (citric, ascorbic, etc.) that stimulate the production of digestive juices.

How to choose it

In order to optimally use the nutrient content, fruit should be consumed after harvest - many vitamins are reduced over time - raw - vitamins A, B, C and E are deactivated by heat - and not excessively washed - vitamins B and C are water-soluble as well as mineral salts.

For the first point it is possible to avoid the consumption of local products on a seasonal basis which guarantees:

ripening on the plant
the best taste
the greater supply of nutrients
the guarantee of freshness
the reduced presence of preservatives
known cultivation practices (EU)
savings
a naturally varied diet.

In general it can be said that the more the productions are distant from the region of consumption, the less are the guarantees of quality and freshness.

To overcome the problem of not washing the fruit excessively, it must be emphasized first of all that washing is essential to remove all those chemical pollutants used in modern agriculture and that therefore preferring fruit from organic or biodynamic agriculture, can be a good compromise.