Effect of Slice Thickness and Pretreatments on the Quality of Dried Apple Slices (Golden Delicious)

Apple is a perishable fruit due to its higher moisture content, which leads to spoilage and also reduces its shelf life. To improve the storage stability of apples, drying is the most effective and oldest method as it leads to the reduction of water activity. In the present study, dried apple slices were developed from “Golden Delicious” apples. The suggested methodology involves the use of dried apple slices with skin and a thickness of 4.5 mm, pretreated with 1% salt solution for 15 min. The drying process takes place at a temperature of 50°C for 3 h, followed by a temperature of 90°C for 2 h. The water activity of salt- and KMS-pretreated dried apple slices was 0.422 ± 0.00 and 0.438 ± 0.01, respectively, whereas a higher value 0.473 ± 0.01 of water activity was observed in untreated dried apple slices, demonstrating better stability. Also, compared to the control sample, the pretreated slices showed 13% lesser shrinkage due to drying, thereby retaining its shape. The total phenolic content was the lowest in the control sample (101.52 ± 0.37 mg GAE/100 g), while a significant increase was observed in KMS-pretreated (115.44 ± 4.08 mg/100 g) and salt-pretreated (131.55 ± 0.58 mg/100 g) dried apple slices. Moreover, antioxidant activity also was higher in salt-pretreated dried apple slices. Texture profile analysis revealed that the developed apple slices had better crispiness than nonpretreated ones. Thus, pretreatment before drying is of great significance to improve the appearance and quality of products.