Effects of Convective Drying of Quince Fruit (Cydonia oblonga) on Color, Antioxidant Activity and Phenolic Compounds under Various Fruit Juice Dipping Pre-Treatments

Abstract

In this study, 3 mm thick quince slices were dipped in bitter orange (BO), tangerine (Citrus deliciosa Mediterranean) (CDM), orange (O), tangerine (Citrus reticulata Owari) (CRO), pomegranate (P) juices and a non-pre-treatment (control) dried at an air temperature of 70 °C and air velocity of 1.5 m/s. According to the results of the pre-treatment trials, drying time was found to be a minimum of 121 min in pomegranate at 5 min dipping time to reach a safe moisture content of 10% (w.b.). The lowest total color change (∆E) values were observed in orange juice dipped samples (10.19). We found the highest total phenolics (TP) (16.77 mg GAE/g d.w.) in CDM, Trolox equivalent antioxidant capacity (TEAC) (32.49 µmol TE/g d.w.) in P and total flavonoid (TF) (2018.15 mg GAE/kg d.w.) in BO for 5 min dipping time values. As a result, pomegranate juice pre-treatment in all dipping times improved the biocompounds for quince slices.