For physicochemical analysis, the apples were washed with
distilled water and peeled. The firmness of the fruit flesh was
measured with an Effegi penetrometer (Alfonsine, Italy) fitted with
an 11.1 mm tip. The soluble solid concentration (SCC) was determined
using a hand-held refractometer (Model HRT 32, Krüss
Optronic, Hamburg, Germany) at 20 C. Afterward, the apple core
was removed with a core borer and the apples were parted in 6mm
slices. The used Braeburn apple slices had an average initial surface
area of 39.9 cm2.