In Situ ESEM Examination of Microstructural Changes of an Apple Tissue Sample Undergoing Low-Pressure Air-Drying Followed by Wetting

Low-pressure drying of apple tissue has been visualized in situ using an environmental scanning electron microscope (ESEM). Both freshly cut and pre-boiled sample tissues were tested for drying and followed by wetting processes and the differences between the two types of samples noted. Bubble formation was observed when drying the freshly cut sample and were found to form only around the intact cells (intracellular spaces or channels). Boiling produced a more uniform surface and no bubble formation could be observed. Air-drying of the two tissue samples was conducted as a complementary investigation so that the effect of boiling can be better ascertained.