Applicability of confocal raman microscopy to observe microstructural modifications of cream cheeses as influenced by freezing

Marcello Alinovi*, Germano Mucchetti, Ulf Andersen, Tijs A.M. Rovers, Betina Mikkelsen, Lars Wiking, Milena Corredig

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

Confocal Raman microscopy is a promising technique to derive information about microstructure, with minimal sample disruption. Raman emission bands are highly specific to molecular structure and with Raman spectroscopy it is thus possible to observe different classes of molecules in situ, in complex food matrices, without employing fluorescent dyes. In this work confocal Raman microscopy was employed to observe microstructural changes occurring after freezing and thawing in high-moisture cheeses, and the observations were compared to those obtained with confocal laser scanning microscopy. Two commercially available cream cheese products were imaged with both microscopy techniques. The lower resolution (1 μm/pixel) of confocal Raman microscopy prevented the observation of particles smaller than 1 μmthat may be part of the structure (e.g., sugars). With confocal Raman microscopy it was possible to identify and map the large water domains formed during freezing and thawing in high-moisture cream cheese. The results were supported also by low resolution NMR analysis. NMR and Raman microscopy are complementary techniques that can be employed to distinguish between the two different commercial formulations, and different destabilization levels.

Original languageEnglish
Article number679
JournalFoods
Volume9
Issue5
Number of pages14
ISSN2304-8158
DOIs
Publication statusPublished - May 2020

Keywords

  • Cheese freezing
  • Confocal laser scanning microscopy
  • Cream cheese
  • Cryoprotectants
  • Microstructure
  • NMR spectroscopy
  • Raman spectroscopy

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