Ethylene (CH₂ = CH₂) is an unsaturated hydrocarbon (alkene) that acts naturally as a plant hormone.

Ethylene gas is the main ripening agent produced naturally within fruits and it starts the ripening process. Not only that, in plants it also promotes the opening of the flowers, the shedding of the leaves and, in aquatic and semi-aquatic species, it favors the rapid elongation of the stems or leaves.

A very small concentration of ethylene in the air is sufficient to promote the ripening process. However, the fruit distribution chain implies in many cases that ripening is artificially induced by the application of various agents.

The main agents of artificial fruit ripening that are commercialized in the world market today are mainly ethylene, ethephon and calcium carbide.

The use of CaC₂ in fruit ripening is still common in many countries due to its high availability and very low prices. Calcium carbide reacts with moisture to produce acetylene gas, which mimics the action of ethylene and is used as an artificial ripening agent.

However, acetylene is not as effective as ethylene (much more quantity must be used for the same effectiveness). In addition, small concentrations of arsenic, phosphorus and lead are released during this process which are highly toxic to humans. Several studies have been carried out in recent years that prove the dangerousness of the minerals released in the reaction of calcium carbide with moisture to produce acetylene. These components may affect the different body organs and cause various health problems like headache, dizziness, mood disturbances, sleepiness, mental confusion, memory loss, cerebral edema, seizures and prolonged hypoxia.

Consuming calcium carbide-ripened fruits can cause serious health problems. Therefore, its use is illegal in most countries. GRIT, within the specialty chemicals business unit, promotes the introduction in these regions of ethylene gas as an effective fruit ripening agent and not harmful to human health.

GRIT, at its Avinyó plant in Spain, has a cryogenic tank of more than 50 m3 to store ethylene and that allows it to package this gas in various formats depending on the customer’s needs. Normally this gas is mixed with nitrogen (N₂) to later be applied in fruit ripening chambers. To promote the disuse of calcium carbide for the artificial ripening of fruits in countries that is still common, GRIT is already in contact with the main associations of fruit producers and importers to promote change and thus improve the health of the consumers.