2.9. Moisture content and water activity The moisture content (X) of the fresh and treated apples was determined gravimetrically, using the equation below, by drying at 105 1 C until constant weight was achieved. Here, md is the weight of the apple slice after the drying processes and m is the weight of the apple slice. The water activity (aW) of fresh,impregnated and dried samples was measured at 25 C using a Novasina aW Sprint TH-500 instrument (Pf?ffikon, Switzerland).