The effect of ultrasound pretreatment on quality attributes of freeze-dried quince slices: Physical properties and bioactive compounds

The study was conducted to examine the effect of ultrasound (US) pretreatment on physical and chemical/nutritional attributes of freeze-dried quince slices. The quince fruits were washed, hand-peeled and cut with a dimension of 1 cm (L) x 0.2 (W) cm x 1 cm (H). The quince samples were treated in an ultrasonic bath in three different times which were 10, 20, and 30 min. Untreated and ultrasonically pretreated quince samples were dried in a freeze dryer. Freeze-dried samples were analyzed in terms of physical properties such as shrinkage, rehydration, color, water activity, and hardness and bioactive compounds including total phenols, ascorbic acid, and antioxidant capacity. A significant difference was observed among untreated and ultrasonically pretreated quince samples. The freeze-dried quince slices treated with a US (especially 20 min-treatment) showed a higher preservation of bioactive compounds in addition to improved physical properties compared to the untreated quince samples. In overall, US pretreatment is a promising process as demonstrated in current research by its capability to better retain freeze-dried quince quality in terms of physical and chemical properties. Practical Applications The freeze drying of quince fruit with the aid of US pretreatment was investigated. A significant development in the quality preservation of freeze-dried of quince slices with an US-pretreatment was accomplished. This research will contribute a useful technique to produce freeze-dried quinces with a significantly enhanced product quality. Drying of quince samples with a freeze drying in addition to US-pretreatment might be applied to get a high-quality fruit with an improved bioactive compounds and physical property.