The rheology and foamability of crystal-melt suspensions composed of triacylglycerols


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Date

2022-02-14

Publication Type

Journal Article

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Abstract

The rheology of triacylglycerol (TAG) crystal-melt suspensions (CMSs) consisting of anhydrous milk fat (AMF), cocoa butter (CB), and palm kernel oil (PKO) as function of crystallization shear rate (gamma) over dot(cryst) and crystal volume fraction Phi(SFC) is investigated by in-line ultrasound velocity profiling - pressure difference (UVP-PD) rheometry. Measurements up to Phi(SFC) = 8.8% are presented. Below the percolation threshold Phi(c), no yield stress tau(0) is observed and the viscosity eta scales linearly with Phi(SFC). Above Phi(c), a non-linear dependency of both tau(0) and eta as function of Phi(SFC) is apparent. For AMF and CB, the increase in (gamma) over dot(cryst) leads to a decrease in eta and tau(0) as function of Phi(SFC), whereas for PKO based CMSs the opposite is the case. Scanning electron microscopy (SEM) and polarized light microscopy (PLM) relate these rheological findings to the microstructure of the investigated CMSs by taking the effective aspect ratio a(eff )and the concept of the effective crystal volume fraction Phi(eff )(SFC)into account. Foam formation by dynamically enhanced membrane foaming (DEMF) is performed directly after crystallization and reveals that depending on the CMS rheology and crystallite-, crystallite cluster- and crystal floc microstructure, a wide range of gas volume fractions between 0.05-0.6 are achievable.

Publication status

published

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Book title

Journal / series

Volume

18 (6)

Pages / Article No.

1183 - 1193

Publisher

Royal Society of Chemistry

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Edition / version

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Organisational unit

03345 - Windhab, Erich Josef (emeritus) / Windhab, Erich Josef (emeritus) check_circle
08821 - Fischer, Peter (Tit.-Prof.) check_circle

Notes

Funding

180971 - Industrially relevant Synchronous Multiscale 3D-Printing Process (SYMUS-PD3) for the fast manufacture of tailored texturized and sensory/nutrition-functionalized food systems (SNF)

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