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Kaysan G, Schork N, Herberger S, Guthausen G, Kind M. Contact-mediated nucleation in melt emulsions investigated by rheo-nuclear magnetic resonance. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:615-627. [PMID: 34700357 DOI: 10.1002/mrc.5228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Increasing the efficiency of disperse phase crystallization is of great interest for melt emulsion production as the fraction of solidified droplets determines product quality and stability. Nucleation events must appear within every single one of the μm-sized droplets for solidification. Therefore, primary crystallization requires high subcooling and is, thus, time and energy consuming. Contact-mediated nucleation is a mechanism for intensifying the crystallization process. It is defined as the successful nucleation of a subcooled liquid droplet induced by contact with an already crystallized droplet. We investigated contact-mediated nucleation under shear flow conditions up to shear rates of 457 s-1 for a quantitative assessment of this mechanism. Rheo-nuclear magnetic resonance was successfully used for the time-resolved determination of the solids fraction of the dispersed phase of melt emulsions upon contact-mediated nucleation events. The measurements were carried out in a dedicated Taylor-Couette cell. The efficiency of contact-mediated nucleation λsec decreased with increasing shear rate, whereas the effective second order kinetic constant kcoll,eff increased approximately linearly at small shear rates and showed a linear decrease for shear rates higher than about 200 s-1 . These findings are in accordance with coalescence theory. Thus, the nucleation rate is optimal at specific flow conditions. There are limitations for successful inoculation at a low shear rate because of rare contact events and at a high shear rate due to too short contact time.
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Affiliation(s)
- Gina Kaysan
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
| | - Nicolas Schork
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
| | | | - Gisela Guthausen
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
- Engler-Bunte Institute, Water Science and Technology, KIT, Karlsruhe, Germany
| | - Matthias Kind
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
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Milc KW, Serial MR, Philippi J, Dijksman JA, van Duynhoven JPM, Terenzi C. Validation of temperature-controlled rheo-MRI measurements in a submillimeter-gap Couette geometry. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:606-614. [PMID: 33788305 DOI: 10.1002/mrc.5157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
A temperature-controlled submillimeter-gap (500 μm) rheo-magnetic resonance imaging (MRI) Couette cell has been developed to measure confined flow of soft structured materials under controlled temperature. The proposed setup enables performing rheo-MRI measurements using (i) a spatially uniform temperature control over the range 15°C to 40°C and (ii) a high spatial resolution up to 10 μm, as a consequence of the improved mechanical stability of the in-house developed rotating elements. Here, we demonstrate the performance of the cell for the rheo-MRI velocimetry study of a thixotropic fat crystal dispersion, a complex fluid commonly used in food manufacturing. The submillimeter-gap geometry and variable temperature capability of the cell enable observing the effects of shear- and temperature-induced fat recrystallization on both wall slip and shear banding under strongly confined flow. Our improved rheo-MRI setup opens new perspectives for the fundamental study of strongly confined flow, cooperative effects, and the underlying interparticle interactions and for ultimately aiding optimization of products involved in spreading/extrusion, such as cosmetics and foods.
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Affiliation(s)
- Klaudia W Milc
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands
| | - Maria R Serial
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands
| | - John Philippi
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands
| | - Joshua A Dijksman
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - John P M van Duynhoven
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands
- Science and Technology, Unilever Foods Innovation Centre Hive, Wageningen, The Netherlands
| | - Camilla Terenzi
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands
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4
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Serial MR, Arnaudov LN, Stoyanov S, Dijksman JA, Terenzi C, van Duynhoven JPM. Non-Invasive Rheo-MRI Study of Egg Yolk-Stabilized Emulsions: Yield Stress Decay and Protein Release. Molecules 2022; 27:molecules27103070. [PMID: 35630546 PMCID: PMC9146701 DOI: 10.3390/molecules27103070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/19/2022] [Accepted: 04/23/2022] [Indexed: 02/04/2023] Open
Abstract
A comprehensive understanding of the time-dependent flow behavior of concentrated oil-in-water emulsions is of considerable industrial importance. Along with conventional rheology measurements, localized flow and structural information are key to gaining insight into the underlying mechanisms causing time variations upon constant shear. In this work, we study the time-dependent flow behavior of concentrated egg-yolk emulsions with (MEY) or without (EY) enzymatic modification and unravel the effects caused by viscous friction during shear. We observe that prolonged shear leads to irreversible and significant loss of apparent viscosity in both emulsion formulations at a mild shear rate. The latter effect is in fact related to a yield stress decay during constant shearing experiments, as indicated by the local flow curve measurements obtained by rheo-MRI. Concurrently, two-dimensional D-T2 NMR measurements revealed a decrease in the T2 NMR relaxation time of the aqueous phase, indicating the release of surface-active proteins from the droplet interface towards the continuous water phase. The combination of an increase in droplet diameter and the concomitant loss of proteins aggregates from the droplet interface leads to a slow decrease in yield stress.
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Affiliation(s)
- Maria R. Serial
- Laboratory of Biophysics, Wageningen University, 6708WE Wageningen, The Netherlands; (M.R.S.); (C.T.)
| | - Luben N. Arnaudov
- Unilever Global Food Innovation Centre, 6708WE Wageningen, The Netherlands; (L.N.A.); (S.S.)
| | - Simeon Stoyanov
- Unilever Global Food Innovation Centre, 6708WE Wageningen, The Netherlands; (L.N.A.); (S.S.)
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708WE Wageningen, The Netherlands;
| | - Joshua A. Dijksman
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708WE Wageningen, The Netherlands;
| | - Camilla Terenzi
- Laboratory of Biophysics, Wageningen University, 6708WE Wageningen, The Netherlands; (M.R.S.); (C.T.)
| | - John P. M. van Duynhoven
- Laboratory of Biophysics, Wageningen University, 6708WE Wageningen, The Netherlands; (M.R.S.); (C.T.)
- Unilever Global Food Innovation Centre, 6708WE Wageningen, The Netherlands; (L.N.A.); (S.S.)
- Correspondence:
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5
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Milc KW, Dijksman JA, van Duynhoven JPM, Terenzi C. Quantifying cooperative flow of fat crystal dispersions. SOFT MATTER 2022; 18:2782-2789. [PMID: 35316311 DOI: 10.1039/d2sm00233g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We quantify the cooperative flow behaviour of fat crystal dispersions (FCDs) upon varying crystallization conditions. The latter enabled altering the multiscale microstructure of the FCDs, from the nanometer-sized platelets, and the dispersed fractal aggregates, up to the strength of the mesoscopic weak-link network. To the goal of characterizing strongly-confined flow in these optically-opaque materials, we acquire high-resolution rheo-magnetic-resonance-imaging (rheo-MRI) velocimetry measurements using an in-house developed 500 μm gap Couette cell (CC). We introduce a numerical fitting method based on the fluidity model, which yields the cooperativity length, ξ, in the narrow-gap CC. FCDs with aggregates sizes smaller than the confinement size by an order of magnitude were found to exhibit cooperativity effects. The respective ξ values diverged at the yield stress, in agreement with the Kinetic Elasto-Plastic (KEP) theory. In contrast, the FCD with aggregates sizes in the order of the gap size did not exhibit any cooperativity effect: we attribute this result to the correspondingly decreased mobility of the aggregates. We foresee that our optimized rheo-MRI measurement and fitting analysis approach will propel further similar studies of flow of other multi-scale and optically-opaque materials.
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Affiliation(s)
- Klaudia W Milc
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands.
| | - Joshua A Dijksman
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - John P M van Duynhoven
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands.
- Unilever Foods Innovation Centre Hive, Wageningen, The Netherlands
| | - Camilla Terenzi
- Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands.
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Nikolaeva T, Vergeldt FJ, Serial R, Dijksman JA, Venema P, Voda A, van Duynhoven J, Van As H. High Field MicroMRI Velocimetric Measurement of Quantitative Local Flow Curves. Anal Chem 2020; 92:4193-4200. [PMID: 32052954 PMCID: PMC7081226 DOI: 10.1021/acs.analchem.9b03216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Performing
rheo-microMRI velocimetry at a high magnetic field with
strong pulsed field gradients has clear advantages in terms of (chemical)
sensitivity and resolution in velocities, time, and space. To benefit
from these advantages, some artifacts need to be minimized. Significant
sources of such artifacts are chemical shift dispersion due to the
high magnetic field, eddy currents caused by the pulsed magnetic field
gradients, and possible mechanical instabilities in concentric cylinder
(CC) rheo-cells. These, in particular, hamper quantitative assessment
of spatially resolved velocity profiles needed to construct local
flow curves (LFCs) in CC geometries with millimeter gap sizes. A major
improvement was achieved by chemical shift selective suppression of
signals that are spectroscopically different from the signal of interest.
By also accounting for imperfections in pulsed field gradients, LFCs
were obtained that were virtually free of artifacts. The approach
to obtain quantitative LFCs in millimeter gap CC rheo-MRI cells was
validated for Newtonian and simple yield stress fluids, which both
showed quantitative agreement between local and global flow curves.
No systematic effects of gap size and rotational velocity on the viscosity
of a Newtonian fluid and yield stress of a complex fluid could be
observed. The acquisition of LFCs during heterogeneous and transient
flow of fat crystal dispersion demonstrated that local constitutive
laws can be assessed by rheo-microMRI at a high magnetic field in
a noninvasive, quantitative, and real-time manner.
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Affiliation(s)
- Tatiana Nikolaeva
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,MAGNEFY, Stippeneng 4, 6708 WE , Wageningen, The Netherlands
| | - Frank J Vergeldt
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,MAGNEFY, Stippeneng 4, 6708 WE , Wageningen, The Netherlands
| | - Raquel Serial
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,MAGNEFY, Stippeneng 4, 6708 WE , Wageningen, The Netherlands
| | - Joshua A Dijksman
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Paul Venema
- Physics and Physical Chemistry of Foods, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Adrian Voda
- Unilever Food Innovation Centre, OBronland 14, 6708 WH , Wageningen, The Netherlands
| | - John van Duynhoven
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,Unilever Food Innovation Centre, OBronland 14, 6708 WH , Wageningen, The Netherlands.,MAGNEFY, Stippeneng 4, 6708 WE , Wageningen, The Netherlands
| | - Henk Van As
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,MAGNEFY, Stippeneng 4, 6708 WE , Wageningen, The Netherlands
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