Synchrotron radiation microtomography was used as a non-destructive 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 characterise 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 analysed to determine the pore size and its distribution in different regions of the coffee beans by selecting Volumes of Interest. 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.
Evaluation of microstructural properties of coffee beans by synchrotron x-ray microtomography: a methodological approach
PITTIA, Paola;SACCHETTI, Giampiero;
2011-01-01
Abstract
Synchrotron radiation microtomography was used as a non-destructive 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 characterise 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 analysed to determine the pore size and its distribution in different regions of the coffee beans by selecting Volumes of Interest. 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
