Quantitative Study of Tomatoes using MRI

The study of vegetables using Magnetic Resonance Imaging (MRI) is advantageous as the process is non-invasive and allows the produce to still be consumed afterwards. With approximately $100 million of tomatoes produced annually in Canada, preventing the spread of rot benefits farmers, the economy and the environment. Developing innovative ways to reduce produce waste fosters a sustainable food industry. Some fungus varieties can infect tomatoes long before symptoms of rot appear. Differences in internal structure or quantitative values may be used to identify non-infected and infected tomatoes, so the latter may be removed before rot spreads. A quantitative study was performed on post-harvest tomatoes to provide data for future experimentation. MRI uses magnetic fields to produce signals from the hydrogen nuclei contained in the water molecules of a tomato. The lifetime of the signal was used to parameterize three different regions of the tomato. The signal lifetime varies due to differences in the structural and chemical environments around the hydrogen nuclei. Signal lifetimes are more sensitive in detecting subtle changes compared to a qualitative image or observation. These signal lifetimes were used directly to obtain information about the tomatoes and were also used to provide contrast on images. The contrast of an image was manipulated simply by changing the weighting of the signal lifetimes. This allows the image to be optimized for best visualization of certain tomato structures and/or abnormalities. The methodology developed in this work is general and can be applied to other organic systems