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METHODS article

Front. Food. Sci. Technol.
Sec. Food Characterization
Volume 4 - 2024 | doi: 10.3389/frfst.2024.1464882
This article is part of the Research Topic Advances in Microimaging of Food Structure: Techniques, Applications, and Insights View all articles

Microstructure of confectionery masses revealed by cryo-planing

Provisionally accepted
Jaap Nijsse Jaap Nijsse 1*Adriana Fernanda Cruz Serna Adriana Fernanda Cruz Serna 2Sergey M. Melnikov Sergey M. Melnikov 2
  • 1 Consistence Microstructure Research Laboratory, Barendrecht, Netherlands
  • 2 IFFCO Central R&D, IFFCO Group, Sharjah, United Arab Emirates

The final, formatted version of the article will be published soon.

    Here we present a novel, combined cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) method for imaging of chocolate confectionery product microstructures of several millimeters down to about 100 nanometer. The SEM part of the method is based on cryofixation, cryo-polishing, and scanning electron microscopy, at low vacuum and low temperature using the backscattered electron signal. Starting with cryo-fixation of the chocolate sample in a desired state (cooled, ambient, or melted), the sample is cryo-planed in a cryo-ultramicrotome. Once a polished cut is obtained, the sample is analyzed using a cryo-SEM technique, with the unusual combination of low temperature and low vacuum settings, without heavy metal coating. Imaging is done based on material density contrast. Elemental composition of particles is recorded by energy dispersive x-ray spectroscopy (EDS). The combination of imaging contrast and EDS allows identification and measurement of the four main constituents of chocolate (cocoa solids, fat, sugar, and milk solids). Finally, the same cryo-polished sample sections of solid chocolate products are analyzed using CLSM imaging technique to reveal complementary microstructural details. An obvious application of the method could be the visualization and quantitative analysis of the size, shape, and composition of chocolate confectionery products.

    Keywords: (Compound) Chocolate, CLSM, Cocoa, Confectionery, confocal laser scanning microscopy, Cryo-SEM, Cryo-Polishing, Energy dispersive X-ray spectroscopy

    Received: 15 Jul 2024; Accepted: 16 Oct 2024.

    Copyright: © 2024 Nijsse, Cruz Serna and Melnikov. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Jaap Nijsse, Consistence Microstructure Research Laboratory, Barendrecht, Netherlands

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.