Fruit Growth, Ripening and Post-Harvest Physiology

Description

Fruit evolved as vehicles for production and dispersal of seeds. Humans then imposed further selection pressures to develop products for our use. Such development has accelerated over the past century. Our concept of a fruit as a sweet and fleshy object for eating is really quite recent in evolutionary terms. As fruit grow, proportions of cell wall, carbohydrate, organic acid, lipid, phospholipid and volatile (aroma) compounds change dramatically; and within each of those groups there are changes in the proportion of individual group members. Several processes take place as fruit ripen and become edible, and then senesce. These changes may take place while fruit are still attached to the plant or after harvest. Tomato, banana and avocado are examples of fruit that at harvest can be at a mature green but unripe stage and are inedible until subsequent ripening processes have occurred. During the twentieth century, additional selection pressures have been applied to temperate fruit species in a drive for cultivars that are well suited to postharvest handling and storage. This has not been true for most tropical fruit, which have had less selection for such characteristics and which still present challenging problems for postharvest researchers and breeders. Accordingly, fruits account for a substantial fraction of the world’s agricultural output, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings. Ripening is a process in fruits that causes them to become more palatable. In general, a fruit becomes sweeter, less green, and softer as it ripens.