Dynamic Mechanical Properties of the Apple Cortex in Relation to Sample Location and Ripening

Compressive complex moduli were determined for two cultivars of apples at two ripeness stages by subjecting cylindrical tissues from various locations within the apple to sinusoidal stress. The complex moduli varied within sampling regions and with regional sampling depths. They also varied with the degree of ripeness, but only at certain storage temperatures and in certain sampling regions of the fruit. The data analysis showed that the sinusoidally varying stress and strain test and the Magness Taylor pressure test did not measure the same mechanical properties and that apparently the complex modulus was influenced by changes in the cellular structure of the fruit tissues.