X-ray CT applications to reveal physical defects of onion during storage

Abstract

Inappropriate conditions of storage may result in physical defects that are sometimes visually undetectable. X-ray CT is a non-destructive instrument that has been widely implemented to identify sound and/or defect structures of many products, but only a little used for onion. In this study, the structure change of local onion during storage were imaged and characterized. To see the X-ray CT utilization, Onion harvested from a local farm was, for the first step, stored in an extreme condition potentially causing physiologically structure damage. X-ray CT scanning of intact onion was performed at low resolution to see the structure difference at the preand post-storage condition. Image processing was conducted to observe the change of the physical parameters. From the result, X-ray CT depicted spatially structural deformation of onion after a short-term storage period. Onion generally underwent shrinkage marked by the decrease in the cross-section area and the increase in air spaces between the fleshy leaves. This result was also in line with the decrease in weight and moisture content with respect to the storage conditions. This study concludes that X-ray CT has a high potential to reveal the physical defects of local onion affected by inappropriate storage conditions.