Introduction
Ethylene is a naturally occurring hydrocarbon gas, although it can also result in combustion of large chained hydrocarbons. Additionally, it is the simplest gaseous organic compound of the alkene group. Statistically, it is the most commercially manufactured gas globally since it has several industrial applications. The gas is odorless, and climacteric fruits do produces the gas as they begin to ripe, for instance, apples. During the fruit ripening process, the gas is responsible for color changing, softening of the fruit as well as the change in texture in addition to other processes too (Abeles et al., 2012 n.p).
Respiration versus ripening
Ripening is mostly applied on fruits to provide a description of a transition from physiological maturity towards senescence stage or else to age as well as the death of plant tissues. It is a transitional stage which comprises reproduction facilitation thus preparing as a seed-bearing organ for dispassion from the plant. Therefore, ripening is the initial stage of significant biochemical as well as physiological changes which includes, internal softening of the flesh, changes in fruit’s skin color, development of aroma as well as sweetening (Abeles et al., 2012 n.p). The process of ripening typically commences after the fruit has reached its maximum size as well as its physiological maturity. From the research, it has been seen that at the physiological stage, the fruit must be in a position to accumulate complicated molecules in the form of proteins, lipids, carbohydrates as well as organic acids. Consequently, once the fruit is harvested from its plant, it progress as a living organism although it can no longer draw on nutrients as well as water from the plant so as to supply its needs for energy to help complete the ripening process. Therefore, the fruit remains active metabolically, and respiration relies entirely on the complex molecules which were accumulated (Abeles et al., 2012 n.p). On the other hand, respiration is a continuous process of oxidative breakdown of complicated molecules into simpler molecules to produce water, energy, carbon dioxide in addition to simpler molecules necessary for various cellular biochemical reaction needs for ripening process.
Chemical structure of ethylene
Ethylene contains double bonds of carbon thus making it be unsaturated. It is mostly written as H2C=CH2 but structurally it can be written as;
H H
C=C
H H
During the fruit ripening process, a process known as biosynthesis takes place and it involves the following stages; the first stage is the conversion of S-adenosyl-L-methionine to 1-aminocylepropane-1-carboxylic acid. The final step includes the conversion of ACC into ethylene, HCN as well as carbon dioxide (Villarreal et al., 2010 683-689). This process is catalyzed by ACC oxidase. During this process, the production rate of ethylene can easily be regulated through a process known as autocatalytic biosynthesis.
Chemical equations and reactions of ethylene in fruit ripening.
Some of the reaction in fruit ripening process entail the production of ethylene gas for example, CH2CH2C=COONH CH2CH2 +CO2 +HCN
Another consideration is the other processes of formation of ethylene like catalytic cracking;
C2H5OH C2H4 + H2O + Heat
All these reactions leads to the production of ethylene gas which is significant in the fruit production process. The gas can be produced artificially through different methods such as thermo-cracking of large chain carbons as well as industrial distillation (Villarreal et al., 2010 683-689).
Conclusion
In conclusion, ethylene is paramount in accelerating the ripening of climacteric fruits such as bananas, tomatoes, apples and others by altering the complex molecules reactions in these fruits. Hence, it is very significant to understand its chemical structures as well as reaction processes as discussed above.
Work cited
Abeles, Frederick B., Page W. Morgan, and Mikal E. Saltveit Jr. Ethylene in plant biology. Academic press, 2012.
Villarreal, Natalia M., et al. "Effect of ethylene and 1‐MCP treatments on strawberry fruit ripening." Journal of the Science of Food and Agriculture 90.4 (2010): 683-689.
