Effect of Different Pretreatments on Drying Characteristics and Physicochemical Properties of Apricot (<i>Prunus armeniaca</i> L.)

ABSTRACT In this study, apricot samples were dried by using different drying methods (tray drying, microwave drying, and freeze drying). Moreover, different pretreatments (infrared, ultrasound, and treatment with dipping green tea extract) were also applied to the samples. The effect of process conditions on physical and chemical quality of dried apricot samples were investigated. It was aimed to come of age of these technologies as an alternative to conventional pretreatments. Among all drying techniques, the shortest processing time was achieved by microwave drying at 270 W. Midilli was found to be the best model that fits the moisture ratio values among 10 thin layer models. Freeze dried samples had the lowest water activity which ranged from 0.2260 to 0.4868 and rehydration capacity of dried samples were found to be between 2.40 and 3.09. Besides, it was found that the total phenolic content of dried apricots varied between 99.24 and 512.60 mg GAE/100 g dry matter. In addition, the maximum antioxidant activity values for microwave drying (270 W) were obtained in the green tea extract pretreated samples and calculated to be 1.85 ± 0.01 mg TE/g dry matter. NMR and SEM analysis were also applied to the samples. To sum up, it can be declared that microwave technology and green tea extract pretreatments were superior and had beneficial impacts on the end product's quality.