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Why do apples, pears, and bananas soften as they ripen?

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lime processing — fruit processing Limes being prepared for processing into juice, Tecoman, Mexico.

Apples, pears, and bananas soften as they ripen primarily due to the degradation of cell wall substances.1

This process is driven by the activity of specific enzymes that act as biological catalysts. As fruits transition from a mature to a ripe state, these enzymes facilitate the breakdown of structural components within the fruit tissue, leading to a loss of firmness.1

In many fruits, this ripening process is signaled and accelerated by ethylene, an airborne hormone. As the fruit reacts to ethylene, acids begin to break down and the internal structure softens, contributing to the fruit's final edible texture. While this enzymatic activity is a natural part of the fruit's life cycle, it also renders the fruit highly perishable, as the same processes that create a desirable, soft texture eventually lead to the gradual deterioration of the fruit tissue.21