Frictional behaviour of molten chocolate as a function of fat content.

Show simple item record Rodrigues, Sophia A Shewan, Heather M Xu, Yuan Selway, Nichola Stokes, Jason R
dc.coverage.spatial England 2021-07-19T04:07:32Z 2021-07-19T04:07:32Z 2021-3
dc.identifier.issn 2042-6496
dc.description.abstract Soft tribology is used to probe the lubrication behaviour of molten chocolate between soft contacts, analogous to in-mouth interactions between the tongue and palate. Molten chocolate is a concentrated suspension of solid particles (sugar, cocoa and milk solids) in cocoa butter. We hypothesise that the complex frictional behaviour of molten chocolate depends on its particulate nature and thus solid volume fraction (sugar & cocoa solids/fat content). In this work, we assess the properties of molten chocolate as a function of fat content by diluting milk chocolate containing 26, 27 and 29% fat with cocoa butter. The tribological behaviour of molten chocolate deviates notably from the typical Stribeck curve of Newtonian fluids. Additional transitions are observed in mixed and elastohydrodynamic lubrication which are respectively attributed to the effect of shear-thinning rheology (i.e. breakdown of aggregates) and the selective entrainment or exclusion of particles depending on interfacial gap height. These transitions are more pronounced in chocolate of high solid fraction, and correlate with the influence of particle aggregation on rheology. In addition, we assess oral lubrication by preparing model chocolate boluses with aqueous buffer, which produces a ternary system of oil droplets and insoluble cocoa solids dispersed within a continuous aqueous phase. The frictional behaviour of chocolate boluses is determined by the viscosity ratio between cocoa butter and aqueous phase, in agreement with previous findings for oil-in-water emulsions. We provide a conceptual model to interpret how fat content influences the oral lubrication and mouthfeel of chocolate during consumption.
dc.format.medium Print-Electronic
dc.language eng
dc.publisher Royal Society of Chemistry (RSC)
dc.relation.ispartofseries Food & function
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.
dc.subject Cacao
dc.subject Chocolate
dc.subject Friction
dc.subject Humans
dc.subject Lubrication
dc.subject Models, Chemical
dc.subject Plant Oils
dc.subject Saliva
dc.subject Viscosity
dc.subject Science & Technology
dc.subject Life Sciences & Biomedicine
dc.subject Biochemistry & Molecular Biology
dc.subject Food Science & Technology
dc.subject 0908 Food Sciences
dc.title Frictional behaviour of molten chocolate as a function of fat content.
dc.type Journal Article
dc.identifier.doi 10.1039/d0fo03378b
pubs.issue 6
pubs.begin-page 2457
pubs.volume 12 2021-06-10T19:37:34Z
dc.rights.holder Copyright: The author en
pubs.end-page 2467
pubs.publication-status Published
dc.rights.accessrights en
pubs.subtype Journal Article
pubs.elements-id 842101
dc.identifier.eissn 2042-650X 2021

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