| Title: | Exploring the link between coffee matrix microstructure and flow properties using combined X-ray microtomography and smoothed particle hydrodynamics simulations |
| Author(s): | Mo C; Johnston R; Navarini L; Liverani FS; Ellero M; |
| Address: | "Basque Center for Applied Mathematics (BCAM), Alameda de Mazarredo 14, 48009, Bilbao, Spain. cmo@bcamath.org. Aircraft and Propulsion Laboratory, Ningbo Institute of Technology, Beihang University, Ningbo, 315100, People's Republic of China. cmo@bcamath.org. Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK. Illycaffe S.p.A, Via Flavia 110, 34147, Trieste, Italy. Basque Center for Applied Mathematics (BCAM), Alameda de Mazarredo 14, 48009, Bilbao, Spain. Zienkiewicz Centre for Computational Engineering (ZCCE), Swansea University, Bay Campus, Swansea, SA1 8EN, UK. IKERBASQUE, Basque Foundation for Science, Calle de Maria Diaz de Haro 3, 48013, Bilbao, Spain" |
| DOI: | 10.1038/s41598-023-42380-y |
| ISSN/ISBN: | 2045-2322 (Electronic) 2045-2322 (Linking) |
| Abstract: | "Coffee extraction involves many complex physical and transport processes extremely difficult to model. Among the many factors that will affect the final quality of coffee, the microstructure of the coffee matrix is one of the most critical ones. In this article, we use X-ray micro-computed (microCT) technique to capture the microscopic details of coffee matrices at particle-level and perform fluid dynamics simulation based on the smoothed particle hydrodynamics method (SPH) with the 3D reconstructured data. Information like flow permeability and tortuosity of the matrices can be therefore obtained from our simulation. We found that inertial effects can be quite significant at the normal pressure gradient conditions typical for espresso brewing, and can provide an explanation for the inconsistency of permeability measurements seen in the literature. Several types of coffee powder are further examined, revealing their distinct microscopic details and resulting flow features. By comparing the microCT images of pre- and post-extraction coffee matrices, it is found that a decreasing porosity profile (from the bottom-outlet to the top-inlet) always develops after extraction. This counterintuitive phenomenon can be explained using a pressure-dependent erosion model proposed in our prior work. Our results reveal not only some important hydrodynamic mechanisms of coffee extraction, but also show that microCT scan can provide useful microscopic details for coffee extraction modelling. MicroCT scan establishes the basis for a data-driven numerical framework to explore the link between coffee powder microstructure and extraction dynamics, which is the prerequisite to study the time evolution of both volatile and non-volatile organic compounds and then the flavour profile of coffee brews" |
| Notes: | "PubMed-not-MEDLINEMo, Chaojie Johnston, Richard Navarini, Luciano Liverani, Furio Suggi Ellero, Marco eng 80708/European Social Fund/ EP/M028267/1/Engineering and Physical Sciences Research Council/ CEX2021-001142-S/MICIN/AEI/10.13039/501100011033/Agencia Estatal de Investigacion/ PID2020-117080RB-C55/Basque Center for Applied Mathematics/ England 2023/09/29 Sci Rep. 2023 Sep 29; 13(1):16374. doi: 10.1038/s41598-023-42380-y" |
