X-ray μCT analysis to characterize cork spot disorder in Chinese pear ‘Chili’ (Pyrus bretschneideri)

High-Resolution Microstructure Analysis of Cork Spot Disordered Pear Fruit “Akizuki” (Pyrus pyrifolia Nakai) Using X-Ray CT

“…Even though cork spot rarely localized at the inner mesocarp (i.e., tissues surrounding the fruit core) in "Akizuki, " such as what was observed in the study of "Chili" (Duan et al, 2020), the core of cork spotted fruit was deformed with a highly branched pore channel when compared with healthy fruit (Figure 6). This result was accordant with what was observed in cork spotted "Chili" (Duan et al, 2020) despite the major morphological differences between "Akizuki" and "Chili." To our knowledge, this study was the first to digitize and reconstruct a fruit core 3D model (Figures 6B,F) and to use the X-ray CT scanning data to analyze the structure and network skeleton.…”

“…X-ray CT scanning, which is notably a non-destructive method, has long been developed and validated for the analysis of agricultural food texture during both preharvest and postharvest periods (Wang et al, 2018). However, the application of Xray CT scanning for the diagnosis and analysis of pear fruit physiological disorders is quite limited (Lammertyn et al, 2003;Muziri et al, 2016;Duan et al, 2020). This study is the first to systematically analyze the cork spot distribution, porous characteristics, network skeleton of different areas, and fruit core integrity and structure in both healthy and cork spotted pear fruit using the high-resolution X-ray CT scanning to explore the causal factors of cork spot disorder in pear.…”

“…To facilitate segmentation, the global thresholds of the grayscale limit were defined to separate pores (i.e., low X-ray attenuation, resulting in lower grayscale values) and flesh tissues (i.e., higher X-ray attenuation, resulting in higher grayscale values). A threshold of 69.7 and 54.8 for cork spotted fruit and healthy fruit, respectively, was used as a discriminative value for the separation of pores and flesh tissue according to the obvious deep valley in the histogram of gray level frequencies (Duan et al, 2020). The 3D stacks of 8-bit grayscale images were then generated after segmentation.…”

“…Knowledge of pear fruit microstructure changes in a quantitative and qualitative 3D view is important for a better understanding of the occurrence of cork spot disorder. Recent research (Duan et al, 2020) first attempted to non-destructively distinguish between healthy and cork spot disordered pear "Chili" (P. bretschneideri) and to preliminarily analyze the porous differences between them using X-ray CT. However, more information and investigation on the microstructure changes in cork spotted pear fruit are still needed to explore the mechanism of the development of cork spot disorder.…”

Review of fruit cork spot disorder of Asian pear (Pyrus spp.)

“…Application of X-ray computed tomography (X-ray CT) scanning to analyze the threedimensional (3D) pore structure of 'Akizuki' fruit revealed that the porosity of cork-spotted fruit (9.37%) was significantly higher than that of non-affected fruit (3.52%). In addition, the pore channels of cork-spotted fruit were highly branched and the degree of pore connectivity was much higher than that of nonaffected fruit (Duan et al, 2020;Cui et al, 2021a). These findings indicate that the flesh tissue structure is changed significantly, the cell space and porosity of the flesh tissue are increased, and the overall flesh exhibits a loose texture and ultimately assumes a more highly porous microstructure in cork-spotted fruit, as summarized in Figure 3.…”