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 thaii 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.

Structural changes, chemical composition and antioxidant activity of cherry tomato fruits (cv. Micro‐Tom) stored under optimal and chilling conditions

“…The same has been described for standard cultivars of tomato, where reducing sugars (percent fresh weight or per fruit) increased markedly between the mature green and green‐yellow stages. However, fruits with ‘blotchy’ areas, as occurs when they are exposed to chilling injury, contained less glucose and fructose than normal mature green fruits 22…”

Quality attributes of processed tomato products: A review

“…In the initial stages of development, glucose is present in higher concentrations than fructose (glucoserfructose ratio = 1.8). During growth and ripening, the sugar content increases significantly and the glucoserfructose ratio gradually decreases, depending upon variety, to around 1 (5,10). Singh and Saini (11) reported an increase in reducing sugars during the concentration of tomato juice into paste.…”

“…Reducing sugars constitute nearly 50% of the dry matter. Glucose and fructose are the main sugars present, though minute quantities of other sugars have been reported, such as raffinose, arabinose, xylose, galactose; and sugar alcohol, myoinositol (1,(4)(5)(6)(7)(8)(9). Sucrose is also found but its concentration rarely exceeds 0.1% of fresh fruit mass (5).…”

Fruit-specific V-ATPase suppression in antisense-transgenic tomato reduces fruit growth and seed formation

“…5d). Sucrose unloaded in tomato fruit is converted to hexose or its derivatives (Davies and Kempton 1975) and the key enzymes for this reaction are the invertase isoforms. Especially, the activity of vacuolar invertase (soluble acid invertase) is highest in tomato fruit and is correlated to the hexose-sucrose ratio (Nguyen-Quoc and Foyer 2001).…”