Lubrication of chocolate during oral processing

Rodrigues, S. A., Selway, N., Morgenstern, M. P., Motoi, L., Stokes, J. R. and James, B. J. (2017) Lubrication of chocolate during oral processing. Food and Function, 8 2: 533-544. doi:10.1039/c6fo00950f


Author Rodrigues, S. A.
Selway, N.
Morgenstern, M. P.
Motoi, L.
Stokes, J. R.
James, B. J.
Title Lubrication of chocolate during oral processing
Journal name Food and Function   Check publisher's open access policy
ISSN 2042-650X
Publication date 2017-02-01
Year available 2016
Sub-type Article (original research)
DOI 10.1039/c6fo00950f
Open Access Status Not yet assessed
Volume 8
Issue 2
Start page 533
End page 544
Total pages 12
Place of publication Cambridge, United Kingdom
Publisher Royal Society of Chemistry
Language eng
Formatted abstract
The structure of chocolate is drastically transformed during oral processing from a composite solid to an oil/water fluid emulsion. Using two commercial dark chocolates varying in cocoa solids content, this study develops a method to identify the factors that govern lubrication in molten chocolate and saliva's contribution to lubrication following oral processing. In addition to chocolate and its individual components, simulated boluses (molten chocolate and phosphate buffered saline), in vitro boluses (molten chocolate and whole human saliva) and ex vivo boluses (chocolate expectorated after chewing till the point of swallow) were tested. The results reveal that the lubrication of molten chocolate is strongly influenced by the presence of solid sugar particles and cocoa solids. The entrainment of particles into the contact zone between the interacting surfaces reduces friction such that the maximum friction coefficient measured for chocolate boluses is much lower than those for single-phase Newtonian fluids. The addition of whole human saliva or a substitute aqueous phase (PBS) to molten chocolate dissolves sugar and decreases the viscosity of molten chocolate so that thinner films are achieved. However, saliva is more lubricating than PBS, which results in lower friction coefficients for chocolate-saliva mixtures when compared to chocolate-PBS mixtures. A comparison of ex vivo and in vitro boluses also suggests that the quantity of saliva added and uniformity of mixing during oral processing affect bolus structure, which leads to differences in measured friction. It is hypothesized that inhomogeneous mixing in the mouth introduces large air bubbles and regions of non-emulsified fat into the ex vivo boluses, which enhance wetting and lubrication.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
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