An ancient proverb recites “A march apple ruins all basket“And, in fact, it is a common experience to observe how some fruits, if arranged in a apple baskettend to mature fasteruntil it rot. But there is one scientific explanation Who underlies this popular wisdom? The answer lies in theethylenea vegetable hormone produced by some fruits, called climactericwhich regulates the process of maturation. The rotten apples release large quantities of this hormone, which over time accelerates the maturation of the nearby apples, risking that they also rot. For its ability to encourage the maturation of immature fruit, ethylene is used in the agri -food industry to ensure a daily availability of mature bananas in supermarkets around the world.
What is the ethylene, the vegetable hormone of maturation
Have you ever included an immature fruit in a basket of apple basket, like fishing? If yes, you will probably have noticed how, within a couple of days, the fishing has become perfectly matureready to be consumed. This phenomenon has a scientific response, which lies in the release by the apples of a gaseous vegetable hormone called ethylene which, for some plants, acts as a real “conductor” of maturation process. This compound, in fact, once produced is linked to specific cell receptors and triggers a cascade of genetic and biochemical modifications that transform theI waitthe consistencyThe taste and thearoma of the fruit.
In particular, Etilene favors the degradation of cell wallsthat is, the rigid external coating of plant cells, making the consistency softer. It also stimulates the conversion of the pulp of the pulp into simple sugars – as fructose, glucose and sucrose – which give the fruit a sweeter taste. At the same time, it promotes the degradation of chlorophyllthe green pigment typical of immature fruits, and the synthesis of pigments like anthocyanins, responsible for the bright colors of ripe fruits, as well as of volatile aromas typical of ripe fruit.
In short, it is thanks to the trainee whether a fishing or a tomato go from being green, hard and aciduli to become sweet, soft and of a bright color that invites the tasting.
Not all fruits are sensitive to the stone
The fruits whose ripening is regulated by the production of ethylene – Like apples, bananas, peaches, pears, kiwis, persimmons, melons, figs, apricots, avocado, mango and tomatoes – are said climacteric. Their distinctive feature is the ability to continue to mature even after the collectionprecisely because their maturation depends on the self-production of ethylene, which acts as a real independent trigger of the maturation process.
On the contrary, there are fruits – such as grapes, raspberries, cucumbers, citrus fruits, cherries, strawberries and pineapple – whose maturation depends on Other physiological mechanisms And it is not significantly influenced by the ethylene. These fruits are called non -climactericand have the particularity of do not mature once detached from the plant. As a result, if collected too early, they will remain unripe and do not fully develop their flavor. However, precisely because of the absence of a post-branch maturation mechanism, they tend to keep longer.
Ethylene can be used to shorten fruit maturation times
Fruits like apple And pear release large quantities of ethylene. For this reason, if you want to prevent fruit that mature too quickly, it is better Do not keep it together in the same basket. But ethylene can also be an excellent ally! If you buy the fruit still unripe – especially fruits climacteric as kiwi, avocado, bananas, persimmons, melon and peaches – Just put it next to an apple for accelerate its maturation naturally. In these cases, however, it is important frequently check the state of the fruitsbecause ethylene is a very powerful hormone and prolonged exposure can make them mature too quickly and bring them to rot in a short time.
In the non -climacteric fruitson the other hand, the ethylene does not directly stimulate the maturation, but it can still influence the color of the peel. For example, if you put an apple next to an still green orange, you can observe a turn of the color towards the orange, even if the pulp will remain immature.
Mature bananas at any time of the year thanks to thehythlene
Ethylene is also extremely important in thefood industry. For example, we consider one of the most consumed fruits in the world and also loved by us Italians: the bananas. Bananas are tropical fruits, which grow only in specific locations in the world, including India, Brazil and Philippines (except for some cultivars, however not very productive, capable of growing and fruiting in other countries, including Italy).
Those we find on the shelves of our supermarkets come mainly from South America and they arrive in Italy after walking around 9000 km and almost a month of travel by sea. Yet, regardless of the period of the year, we can find bananas at daily daily right degree of maturationor still ready to eat in a maximum of one or two days. But how is it possible to get a constant supply of bananas, perfectly perfect and to the exact degree of maturation, Despite having to face such a long journey? The secret lies precisely in one artificial maturation obtained thanks toethylene.
To facilitate transport and prevent the development of mold and imperfections, in fact, bananas are collected in their countries of origin still very immature and transported to Europe in large quantities on special ships (call bananiere) within refrigerated containers in conditions such as slow down its maturation.
Only once they arrive at their destination the bananas to be sold are gradually transferred to Maturation cells – that is, environments with conditions of ventilation, controlled temperature and humidity – in which it is generally added ethylene in the form of gas. Thanks to this “turbot chemical“The bananas quickly complete the maturation process And they arrive on the shelves of our supermarkets ready to be consumedserved in different degrees of maturation: from those still green for those who prefer them more unripe to the intense yellow ones for those who love the sweetest and most mature ones.
The use of storage to stimulate fruit maturation has actually historical origins. For example, the Ancient Chinese they burned incense to make the pears mature, while the Ancient Egyptians They engraved figs to accelerate the maturation process. Although these practices were based on empirical observations, today we know that both are effective precisely because they stimulate the production of ethylene. In a nutshell, with simple and rudimentary methods, our ancestors exploited the same physiological principles that we use today consciously in the industrial field to control fruit maturation.
