Potato Slices Drying: Pretreatment Affects the Three-Dimensional Appearance and Quality Attributes

Abstract

In the current study, the effects of steam blanching, saline immersion, and ultrasound pretreatment on the drying time, three-dimensional (3D) appearance, quality characteristics, and microstructure of potato slices were investigated. All the pretreatment methods enhanced the drying kinetics relative to the untreated potato slices. The 3D appearance was evaluated by reconstructed 3D images, shrinkage, and curling degree. The reconstructed images could well reproduce the appearance changes in the potato slices during drying. All the three pretreatment methods reduced the shrinkage during the drying process relative to the untreated potatoes. The curling degree was evaluated by the height standard deviation (HSD) of the material surface. The results showed that saline immersion inhibited the curling of the potato slices during the drying process, while ultrasound aggravated the curling of the potato slices. The potatoes treated by blanching obtained a lower total color difference (ΔE), higher total polyphenol content, and antioxidant capacity compared with the samples treated with saline immersion and ultrasound pretreatments. The observation of the microstructure by scanning electron microscope (SEM) verified the effects of the pretreatments on the drying time and appearance deformation. Therefore, it is of great significance to regulate the 3D appearance and quality characteristics of agricultural products during the drying process by an appropriate pretreatment.