Evaluation of quality during storage of apple leather

Fruit leathers, a dehydrated snack, have the potential to increase fruit solids consumption especially in the young. Two apple puree formulations containing sugar and citric acid and one containing potassium metabisulphite (100 mg SO2/kg final product) were prepared by hot-air drying at 60 °C to a water activity of 0.7 (moisture content = 25 kg water/100 kg of final product). The fruit leathers were then subjected to a storage trial and remained stable for a period of 7 months at 20 °C. Changes in organoleptic and nutritional parameters such as Browning Index (BI) and antioxidant activity (AA), respectively, were evaluated. The effect of temperature was studied by accelerated storage tests at 30 °C. Using the kinetic constants at both temperatures, a Q10 coefficient was calculated as 2.55 for BI and 16.26 for AA, leading to estimated activation energies of 68.9 and 206.1 kJ mol−1, respectively.

► This research studied the quality changes of dehydrated apple leathers during storage. ► The relevant quality indices were browning index (BI) and antioxidant activity (AA). ► Storage was studied at 20 °C (ambient temperature) and 30 °C (accelerated test). ► Kinetic models were fitted to quality data as a function of time at both temperatures. ► Storage was limited by BI at low temperatures and by AA at high values.