Synchrotron tomography applications in agriculture and food science research
A 5-minute read
In this article, synchrotron X-ray imaging's properties and uses in agricultural and food science research are introduced. The agriculture and food sector is a huge industry that includes natural resources like water, fertilizers, and organic matter in addition to plants, animals, food, and their products. These things differ from one another in terms of varieties, species, grades, and types due to distinctive internal characteristics, compositions, and structures.
Figure 1. Schematic diagram of how X-rays pass through object. Dashed line shows X-ray wave without an object. Upper curves: cross section corresponding to X-ray phase shift. Lower curves: cross section corresponding to X-ray absorption ( Yashiro et al., 2021)
In order to improve the use, conservation, and productivity of plants, seeds, soil, and food, scientists can quickly and non-destructively analyze the internal properties and compositions of these resources using synchrotron imaging techniques utilizing a bright and tuneable technique, as shown in the imaging setup in Fig. 1. Synchrotron phase ‑contrast imaging, or microtomography, is very similar to SR-absorption based CT imaging; the only difference is that Fresnel fringes are produced because the detector is placed at a variable distance from the sample rather than being placed close to it as in SR-absorbtion CT-based imaging. Low-density materials can also be imaged because of the technique's utilization of X-ray refraction by the sample, which draws attention to the sample's edges and internal boundaries even if the material does not absorb adequate X-rays to provide a clear abs X-ray image.
Figure 2. Sychrotron X-ray image slices of different layers showing voids and cracks in chocolate samples (Reinke et al., 2021)
Roasting stands out as a prevalent unit operation within food processing, involving the application of heat. In the context of coffee processing, roasting holds particular significance, as it entails subjecting green beans to temperatures reaching up to 250 °C to achieve the desired level of roast. The ensuing heat-triggered reactions induce notable changes in the chemical, physical, and structural attributes of the raw beans, consequently impacting the sensory and textural qualities of the resulting coffee. Pittia et al. utilized SR-μCT (as listed in Table 1) to examine the morphology and internal microstructural features of coffee beans, along with the effects of roasting. Their findings revealed that roasted coffee beans exhibited a higher and more uniformly distributed porosity, approximately 40%, compared to the 6% found in green beans. This avenue of research presents opportunities to explore the influence of process parameters on porosity evolution during roasting and to establish correlations with findings from conventional and non-destructive imaging techniques. Similarly, the removal of heat in unit operations such as freezing can also impact the structural characteristics of foods, particularly evident in dairy products. The textural properties of ice cream products, for instance, are closely linked to their internal structure, which may undergo alterations during cooling cycles due to crystal formation.
References
[1] Yashiro, W., Voegeli, W., & Kudo, H. (2021). Exploring frontiers of 4D X-ray tomography. Applied Sciences (Switzerland) , 11 (19), 1–16. https:// doi.org/10.3390/app11198868
[2] Reinke SK, Wilde F, Kozhar S, Beckmann F, Vieira J, Heinrich S, et al. Synchrotron X-Ray microtomography reveals interior microstructure of multicomponent food materials such as chocolate. J Food Eng 2016;174:37–46. https://doi.org/10.1016/j.jfoodeng.2015.11.012.