Enzymes Involved in Fruit Softening

Softening of the flesh is one of the most dramatic changes accompanying the ripening of many fruits. Although other parameters of quality are important, the peak of fruit ripeness is usually associated with a fairly narrow range of firmness. Furthermore, texture that is considered optimal for fruit consumed fresh may not be best for fruit that is processed. Softening undoubtedly reflects changes in cell walls of fruit tissues as the fruit progresses through ripening into senescence. Once the process is initiated in mature fruit, the period of acceptable texture may be short, even with refrigeration and controlled atmosphere storage. A prerequisite to improved methods of controlling softening, whether to initiate and accelerate it or to prevent softening beyond the optimum stage, is an understanding of cell wall structure, its changes, and the enzymes involved in its degradation. I. Histology of Fleshy Fruits. Appreciation of the biochemical aspects of fruit softening