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Study of the porous structure of white chocolate by confocal Raman microscopy

Dahlenborg, Hanna LU ; Millqvist-Fureby, Anna; Brandner, Birgit D. and Bergenståhl, Björn LU (2012) In European Journal of Lipid Science and Technology 114(8). p.919-926
Abstract
Confocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10 mu m into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a... (More)
Confocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10 mu m into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a pressure driven convective flow of liquid fat from within the chocolate matrix that, depending on temperature, moves up to the surface or goes back into the matrix, leaving an empty pore with a shell of fat at the surface, which in some cases collapse and leaves a hollow pore and channel. Therefore, these findings support that the protrusions could be connected to oil migration in chocolate and, thus, further to fat bloom development. Practical applications: Confocal Raman microscopy can be used to investigate the local distribution of different components in white chocolate. This technique offers the possibility to acquire the local distribution of different components within the sample, with a resolution down to the optical diffraction limit. Further, the analysis can be performed at ambient conditions, without requiring any special sample preparation or marker molecules. The results obtained by using this technique suggest that specific surface imperfections on chocolate could be part of a network of pore structures at and beneath the chocolate surface, which could be related to oil migration and thus, to fat bloom formation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chocolate, Cocoa butter, Raman microscopy, Spectroscopy, Surface, structure
in
European Journal of Lipid Science and Technology
volume
114
issue
8
pages
919 - 926
publisher
John Wiley & Sons
external identifiers
  • wos:000307727400011
  • scopus:84865287012
ISSN
1438-7697
DOI
10.1002/ejlt.201200006
language
English
LU publication?
yes
id
c2121c88-e51e-4b8f-ab62-d5881113fde8 (old id 3059671)
date added to LUP
2012-09-26 09:50:04
date last changed
2017-10-01 03:02:37
@article{c2121c88-e51e-4b8f-ab62-d5881113fde8,
  abstract     = {Confocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10 mu m into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a pressure driven convective flow of liquid fat from within the chocolate matrix that, depending on temperature, moves up to the surface or goes back into the matrix, leaving an empty pore with a shell of fat at the surface, which in some cases collapse and leaves a hollow pore and channel. Therefore, these findings support that the protrusions could be connected to oil migration in chocolate and, thus, further to fat bloom development. Practical applications: Confocal Raman microscopy can be used to investigate the local distribution of different components in white chocolate. This technique offers the possibility to acquire the local distribution of different components within the sample, with a resolution down to the optical diffraction limit. Further, the analysis can be performed at ambient conditions, without requiring any special sample preparation or marker molecules. The results obtained by using this technique suggest that specific surface imperfections on chocolate could be part of a network of pore structures at and beneath the chocolate surface, which could be related to oil migration and thus, to fat bloom formation.},
  author       = {Dahlenborg, Hanna and Millqvist-Fureby, Anna and Brandner, Birgit D. and Bergenståhl, Björn},
  issn         = {1438-7697},
  keyword      = {Chocolate,Cocoa butter,Raman microscopy,Spectroscopy,Surface,structure},
  language     = {eng},
  number       = {8},
  pages        = {919--926},
  publisher    = {John Wiley & Sons},
  series       = {European Journal of Lipid Science and Technology},
  title        = {Study of the porous structure of white chocolate by confocal Raman microscopy},
  url          = {http://dx.doi.org/10.1002/ejlt.201200006},
  volume       = {114},
  year         = {2012},
}