Effect of vacuum treatment on the microstructure and properties of onion epidermis

A miniaturized and visual experimental setup was developed for real time observation of structural changes at the cellular level related to vacuum treatment of onion epidermis. The ultrastructure and changes of mass, conductivity and mechanical properties were studied to analyze the microstructure modifications induced by vacuum treatment. The results show that the color in the intracellular region, surface morphology as well as spaces between the cell membrane and the cell wall change with time because of the microstresses due to water transfer and pressure changes. The tensile strength of the onion epidermis is decreased, and the conductivity is increased.