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Wilson Poon: The Physics of Conching Chocolate: Taking rheology from the lab to the factory

Seminarium

Tid: 2019-09-16 14:15 till: 15:00
Plats: Kemicentrum, Lecture hall F
Kontakt: antara [dot] pal [at] fkem1 [dot] lu [dot] se
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A Physical Chemistry seminar by Wilson Poon, Professor of Natural Philosophy, School of Physics & Astronomy, The University of Edinburgh, Edinburgh, U.K.

 

Abstract

The mixing of a powder of 10- to 50-μm primary particles into a liquid to form a dispersion with the highest possible solid content is a common industrial operation. Building on recent advances in the rheology of such “granular dispersions,” we study a paradigmatic example of such powder incorporation: the conching of chocolate, in which a homogeneous, flowing suspension is prepared from an inhomogeneous mixture of particulates, triglyceride oil, and dispersants. Studying the rheology of a simplified formulation, we find that the input of mechanical energy and staged addition of surfactants combine to effect a considerable shift in the jamming volume fraction of the system, thus increasing the maximum flowable solid content. We discuss the possible microscopic origins of this shift, and suggest that chocolate conching exemplifies a ubiquitous class of powder-liquid mixing.