Fruit ripening is accompanied by a number of biochemical events, including changes in color, sugar, acidity, texture, and aroma volatiles that are crucial for the sensory quality.
Carbohydrates play a major role in the ripening process, by way of depolymerization leading to decreased molecular size with concomitant increase in the levels of ripening inducing specific enzymes, whose target differ from fruit to fruit.
Soft fruits undergo an enzymatic degradation of the cell-wall polysaccharides during ripening. In many fruits, such as peaches and tomatoes, the softening is attributed to pectinolytic enzymes, but cellulose may be important in the ripening of avocadoes.
Increased solubility of pectic polysaccharides is one of the most universal features of ripening fleshy fruits. Pectin depolymerization during fruit ripening has been shown to be largely due to pectinolytic enzymes, including polygalacturonases and pectinmethylesterases.
All biochemical and physiological changes that take place during fruit ripening are driven by the coordinated expression of fruit ripening-related genes. These genes encode enzymes that participate directly in biochemical and physiological changes. They also encode regulatory proteins that participate in the signaling pathways, and in the transcriptional machinery that regulate gene expression and set in motion the ripening developmental program.
Biochemical changes when fruit ripens
