International journal of food science and technology vol:31 issue:3 pages:267-276
The purpose of this research was to use destructive and non-destructive measurement methods to evaluate Granny Smith apple quality changes under room storage conditions (20 degrees C, 65% relative humidity) and to relate it to internal structure changes as observed using light microscopy. The Granny Smith apple firmness was non-destructively measured with forced vibration and acoustic impulse techniques. At the determined time intervals, compression and tensile tests were carried out to determine apple flesh mechanical properties. The cell-wall rupture was examined with light microscopy. The pH value, internal air space (IAS), soluble solids concentration (SSC), colour changes and weight losses of the apples were also monitored during storage. Apple firmness measured with forced vibration correlated well with the impulse test. The acoustic impulse measurement had less deviation compared with the vibration test. The pH value and IAS increased during storage at room temperature. The Granny Smith apple has a long storage life and the criteria for the mealiness are suggested from compression and tensile tests.