Ripening

Veraison Cabernet Sauvignon

Methylcyclopropene

2017-10-26 Ripening lemons on a tree, Albufeira (2)

Grape tomato cluster partially ripened

Honeycrisp apples

Kupine dozrijevaju na stabljici (Croatia).3

Ripening is the process through which fruits and some vegetables undergo physical and chemical changes to reach their optimal edibility, flavor, color, and texture. This process is critical in the agricultural sector, food industry, and for consumers seeking the highest quality produce. Ripening is influenced by a variety of factors including genetics, environmental conditions, and the application of certain chemicals.

Overview

During ripening, fruits and vegetables undergo several noticeable changes. These include the conversion of starches into sugars, resulting in a sweeter taste; a change in color due to the breakdown of green chlorophyll and the unmasking or synthesis of other pigments; and a softening of the texture as pectin (the substance that holds the cell walls together) breaks down. The process is naturally regulated by the plant hormones ethylene, abscisic acid, and others, with ethylene being the most significant in most fruits.

Types of Fruits

Fruits can be classified based on their ripening behavior into two main categories: climacteric and non-climacteric.

• Climacteric fruits are those that can ripen after being harvested. They experience a significant increase in ethylene production and respiration rate during ripening. Examples include apples, bananas, and tomatoes.
• Non-climacteric fruits do not continue to ripen once removed from the plant. These fruits do not show a significant increase in ethylene production or respiration rate after harvest. Examples include grapes, citrus fruits, and strawberries.

Ripening Agents

Artificial ripening agents, such as exogenous ethylene, calcium carbide, and others, are sometimes used to initiate or accelerate the ripening process, especially for climacteric fruits. While ethylene is a natural plant hormone and safe, the use of calcium carbide has raised health concerns due to its potential to leave behind residues of arsenic and phosphorus.

Storage and Transportation

Proper storage and transportation are crucial in managing the ripening process, especially for climacteric fruits that continue to ripen after harvest. Controlled atmosphere storage, which involves adjusting the levels of oxygen, carbon dioxide, and nitrogen, along with temperature and humidity control, can slow down the ripening process and extend the shelf life of produce.

Ethical and Environmental Considerations

The use of artificial ripening agents and the energy required for controlled atmosphere storage raise ethical and environmental concerns. There is a growing demand for organic produce and sustainable practices in the food industry, which includes minimizing the use of chemicals and reducing energy consumption in the storage and transportation of fruits and vegetables.

Conclusion

Ripening is a complex process that plays a vital role in the agricultural and food industries. Understanding the science behind it and the factors that influence it can help in producing high-quality, flavorful, and nutritious fruits and vegetables. As consumer awareness and concern for health and the environment grow, there is an increasing emphasis on natural ripening processes and sustainable practices.