Selected apples of uniform size and colour were manually washed, cored, and sliced longitudinally using a manual corer-slicer (Tchibo GmbH Hamburg, Germany). For each extract, three apple slices
(thickness of inner cutting edge 9 mm, width 25 – 35 mm) were soaked in dipping solution at ambient temperature for 2 min. The excess liquid was removed and the samples were stored at room
temperature for 4 h.