Ethylene gas, sourced from various external means like ethylene gas cylinders, compressed ethylene gas, is commonly used to induce ripening in fruits. However, direct contact between ethylene gas and fruits is strictly prohibited. Ethylene accelerates the ripening process, leading to faster and more uniform ripening, which, in turn, reduces the time between harvest and consumption. This shorter interval can enhance both the quality and nutritional value of the fruit. Nevertheless, some fruits are sensitive to ethylene and may experience premature decay if exposed to it. Additionally, fruits ripened with ethylene may lack the distinctive flavor and aroma of naturally ripened counterparts. Furthermore, continuous respiration and ethylene emission contribute to a decline in both nutritional and sensory qualities, along with a decrease in postharvest shelf life.

2.2.1. Calcium Carbide

Calcium carbide (CaC2) is a versatile chemical compound widely used in various industries. It exists as a colorless solid in its pure form but is commercially available as a grey or brown technical grade. CaC2 is widely employed ripening agent in the developing countries, releases acetylene gas which is an analog of ethylene, but is often contaminated with harmful impurities such as arsenic, phosphorus, calcium phosphide and silicon carbide (Danish et al. 2015; Gasik et al. 2013). Nevertheless, the use of calcium carbide to ripen fruits is a major health hazard because the acetylene gas produced by the hydrolysis of calcium carbide contains traces of arsenic and phosphorus, both of which may lead to various health problems. Furthermore, most fruits ripened with these methods have lower in firmness, taste and poor shelf life (Islam et al. 2016; Siddiqui and Dhua, 2010).

various health hazards such as liver and kidney damage (Bhadoria et al. 2018). In addition to the

food industry, ethephon is used as a plant growth regulator, as it has been known to increase fruit

size, promote color development and precocious flowering, and causes flower abscission (Ali &

Baidya, 2021; Bhadoria et al. 2018). Therefore, ethephon has a wide range of applications in

agriculture and horticulture, making it an essential chemical compound in the agriculture sector.

Nonetheless, its efficacy depends on the environmental conditions and surrounding stimuli such

as light, humidity and temperature. In comparison to Calcium carbide, ethephon is often seen as

preferable for fruit ripening, as it requires less time to ripe the fruits such as banana, tomato, and

pineapple. However, the choice between Ethephon and calcium carbide may depend on various

factors, including the specific type of fruit, environmental conditions, and regulatory guidelines.

Ethylene glycol, a colorless, odorless, and sweet-tasting liquid used primarily as an industrial coolant and antifreeze formulations, have been identified as a fruit ripening agent (Hassan, 2016).

This ripening agent when diluted with water, speed up the ripening of fruits such as Banana, tomato, apple quicker than their regular ripening rate, mainly in colder climatic situations. The

fruits are treated with an Ethylene glycol solution, that produces ethylene gas as it breaks down,

prompting the ripening process. Compared to other ripening agents it ripens fruits faster in cold

conditions (Maduwanthi & Marapana, 2019). While the use of ethylene glycol for fruit ripening

has shown promising results, it is crucial to exercise caution as the compound is highly toxic to

humans and animals cause damage to kidney and liver when ingested (Goonatilake, 2008).

Methyl jasmonate, a naturally occurring plant hormone, contributing to improved fruit quality without reported toxicity for human consumptions (Concha et al., 2013; Wang et al., 2018). The limited use of methyl jasmonate in fruit ripening compared to calcium carbide and ethephon is primarily due to regulatory considerations, differences in effectiveness, specific applications, cost

and consumer perception. Efforts in research and agriculture continue to explore the potential

benefits of methyl jasmonate while addressing its limitations (Baek et al., 2021; García-Pastor et al., 2020).

fruits such as bananas, mangoes, and papayas. (Nura et al. 2018). Additionally, propylene, another

colorless gas, is also used in the food industry as a ripening agent. It is primarily used to ripen

tomatoes and melons, but the activity of propylene is only 1% of that of ethylene (Awhor, 2021). Methanol, a poisonous alcohol, is used in small quantities to accelerate the ripening of some fruits, including bananas and tomatoes (Islam et al. 2018). Potassium permanganate is a powerful

oxidizing agent that can be used as a ripening agent for bananas and tomatoes (Alvarez-Hernandez et al. 2019). It is important to be aware of the potential health and safety risks associated with the use of these agents and to ensure that they are used in a safe and responsible manner. However, due to toxic in nature such chemicals should not be used for ripening purposes.