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Evaluation of Microstructural Properties of Coffee Beans by Synchrotron X‐Ray Microtomography: A Methodological Approach
Author(s) -
Pittia Paola,
Sacchetti Giampiero,
Mancini Lucia,
Voltolini Marco,
Sodini Nicola,
Tromba Giuliana,
Zanini Franco
Publication year - 2011
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2010.02009.x
Subject(s) - x ray microtomography , synchrotron radiation , materials science , roasting , synchrotron , coffee bean , microstructure , porosity , biological system , composite material , optics , chemistry , physics , food science , metallurgy , biology
Synchrotron radiation microtomography was used as a nondestructive imaging technique to investigate the microstructural properties of green and roasted coffee beans. After image acquisition, 2D images have been reconstructed and 3D images of the beans have been then obtained. Qualitative and quantitative analysis of the images allow to fully characterize the morphological and structural features of the coffee beans. Roasting causes meaningful changes in the microstructure of the coffee bean tissue with the development in the entire bean of a porous structure with pores of different shape and size depending on the zone of the bean and cracks occurring mainly in the more external regions and between parenchyma and mucilage. The highly contrasted X‐ray images have been analyzed to determine the pore size and its distribution in different regions of the coffee beans by selecting Volume‐of‐Interest (VoI). The use of phase‐contrast hard X‐rays imaging techniques represents an interesting tool of investigation of the internal structure, morphology, as well as the quality of whole coffee beans. Moreover, the high potentiality of 3D X‐ray imaging and the approach used in this study could be applied in understanding the effects of roasting process conditions on the evolution of microstructural properties of the bean that may affect the stability as well the grinding and brewing performances. Practical Application: Synchrotron radiation microtomography is an elegant nondestructive imaging technique to investigate the microstructural properties of porous cellular matrices like the green and roasted coffee beans. The quantitative analysis of the resulting 2D and 3D images allows a more comprehensive and objective characterization of the sample under investigation as a whole or of extracted Volumes‐of‐Interest in the bean. This imaging technique could have a major role in understanding the effects of roasting process conditions on the microstructural properties of the bean.