A new cryo-STEM method for imaging food colloids in the scanning electron microscope.

Scanning

Food Processing & Functionality Department, Moorepark Food Research Centre, Teagasc, Fermoy, Co. Cork, Ireland.

Published: January 2011

A new cryo-scanning transmission electron microscopy (cryo-STEM) technique for imaging casein micelles in a field emission scanning electron microscope is presented. Thin films of micellar casein suspensions on lacey carbon grids were prepared using a modified sample holder developed by Gatan UK. Bright and dark field images were obtained at -135°C showing casein micelles in their frozen hydrated state and in the size range 30-500 nm. Results were compared favorably with published images of casein micelles obtained with conventional cryo-transmission electron microscopy, suggesting that cryo-STEM is a useful alternative technique for visualizing food colloids close to their native state.

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http://dx.doi.org/10.1002/sca.20190DOI Listing

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