Firmness
Fruit firmness was measured by compression of individual apple cubes with an Instron Universal Testing
Instrument. A 100 Newton (N) load cell was used and the crosshead speed was 10 mm/min. A 5 cm diameter flat plate was used. This test measured apple firmness based on the resistance of the flesh of an individual apple cube to
deformation by the plate . Three replicates of 10 apple cubes were used for each storage time. Results
were expressed as the maximum force (Newton) required for a compression of 5 mm.