Contrast enhanced X‐Ray microCT scans of fruit cortex tissue

Improvements in quality control and storage condition of fruit products is increasingly reliant on computer modelling and simulations. Representative 3D models of fruit cortex tissue derived from accurate biological data are thus necessary. Although there are a number of methods that can capture images of fruit tissue, X‐ray micro‐computed tomography (μCT) have demonstrated its value to imaging and modelling studies through its intrinsic ability to capture high resolution data from fruit tissues of interest with high throughput. However, due to the high energy nature of X‐ray beams found in commercial X‐ray systems, materials with similar atomic composition (such as fruit tissue) cannot be distinguished from each other. This limitation results in the inability to determine the boundaries of adjacent tissue structures such as cell clusters and tissue vasculature, which introduces geometric inaccuracies in the subsequently derived 3D models. Although phase contrast synchrotron‐radiation micro‐tomography can somewhat counteract this problem, the availability of synchrotron light sources are extremely limited. Therefore, new methods of contrast enhancement must be developed for use with existing commercial X‐ray systems. One method of achieving boundary separation is via the aid of contrast agents, which are solutions with heavy elements embedded within. However, as contrast solutions are typically utilized in medical applications, its use in plant material and more specifically fruit tissue is limited. This study demonstrates the use of non‐toxic and readily available contrast solutions in combination with a Phoenix Nanotom μCT scanner to achieve enhanced structure boundary separation. 5mm cortex samples from apples and pears were excised and immersed within contrast solutions for up to 2 hours, and were subsequently scanned at 75kV with a 3μm voxel size. Resulting reconstructed images show significantly higher greyscale intensities at cell and vasculature boundaries, and thus enables more accurate 3D models to be generated for use with computational studies.status: publishe