Abstract
The frequency of second resonance and the elasticity index (a relative value of the shear modulus measured by the vibration response technique) of fruit during ripening in ‘Le Lectier’ pears were monitored by a new nondestructive measurement device. In addition, the changes in fresh weight, flesh firmness and soluble solid concentration were determined, and the relationship between elasticity index and those characteristics was demonstrated. The elasticity indices in fruits at harvest time ranged from 48 to 65 (×106), and those indices decreased during ripening. The decreasing patterns of elasticity indices differed with the type of fruit, and those indices ranged from 18 to 25 (×106) when fruits reached the edible ripe stage 40 days after treatment (DAT). Changes in the physical properties of various fruit could be continuously traced by the elasticity index, and it was suggested that the differences in fruit quality at harvest time and softening patterns during ripening were attributed to the dispersion of differences in ripeness at the time when fully ripe (40 DAT). The fresh weight and flesh firmness decreased during ripening, although the soluble solid concentration was increased, and those characteristics correlated with the elasticity index. These findings suggest that the edible ripe stage of ‘Le Lectier’ pears during ripening can be estimated by the elasticity index, which was affected by both water concentration and soluble solid concentration.
