Changes in the individual sugars of tomato fruit during ripening

Abstract
Changes in the concentrations of the individual sugars of the walls and locular contents of tomato fruit during ripening have been studied. The major sugars were glucose and fructose together with much smaller amounts of sucrose and myoinositol. During the initial stages of development the fruit contained approximately twice as much glucose as fructose, but with approaching maturity and the onset of ripening the glucose/fructose ratio declined to less than unity. On a per fruit basis the distribution of the major sugars between the walls and locular contents was about 3 : 1 at the green stage, falling to 2 : 1 as the fruit ripened. Total reducing sugars (% fresh weight or per fruit) increased markedly between the mature green and green‐yellow stages with a tendency to decrease with subsequent ripening. These changes were predominantly influenced by changes in fructose content, with glucose changing little. The concentrations of sucrose and myoinositol, both less than 0.05% fresh weight, declined with ripening. The green areas of the outer walls of “blotchy” fruit contained much less glucose and fructose than did the walls of normal mature green fruit, while the red areas contained amounts similar to those encountered in normally ripened red fruit.