A general feature of tomato fruit containing genetically reduced levels of polygalacmronase activity is decreased deterioration and cracking, particularly when handled at the ripe and over ripe stages. As fully ripe fruit are metabolically compromised and very prone to mechanical injuries, we investigated the influence of impact bruising on electrolyte leakage, pectin solubility, and depolymerization in ripening tomato fruit.
`Sunny' tomato fruit harvested at the mature-green, turning, and ripe stages of development and subjected to controlled impact injury exhibited elevated ethylene production at all developmental stages. Subsequent analyses were performed on discs prepared from bruised and uninjured pericarp tissue. Discs from bruised tissues exhibited enhanced electrolyte leakage and, in bruised tissues from ripe fruit, enhanced pectin efflux. Levels of soluble pectins derived from ethanol-insoluble powders were unaffected by bruising; however, pectins from bruised ripe fruit exhibited mol wt downshifts relative to those from nonbruised tissues.