Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Effect of gelatinisation on textural properties of complex starch gels: combining microscopy and water distribution to quantify gelatinisation degree
    Lyu, Zhihong ; Sala, G. ; Scholten, E. - \ 2019
    Gelatinization degree - Water distribution - textural properties - starch gel - microstructure
    Numerous foods contain starch as thickener or gelling agent, providing specific textural properties that vary based on type of starch (botanical source and chemical modifications) and different processing parameters (amount of water, heating temperature and heating time). A specific amount of water is required to fully gelatinize the starch granules at temperatures that are starch type dependent. Other water-binding ingredients will affect the gelatinisation degree
    of the starch, affecting the final structure of the system. The water distribution is therefore an important parameter that should be quantified in order to interpret the contribution of starch to the properties of the end product. In the present work, we studied the gelatinisation degree of two types of starch by observing the evolution of granule morphology by microscopy, that of size distribution by dynamic light scattering and by quantifying changes in the distribution of water (bound vs free) in time by centrifugation techniques. This made possible to estimate the gelatinisation degree of starch granules and the microstructure of starch gels. At low gelatinisation degree, the starch swelled a few times the original size and formed a compact particle gel, while at high gelatinisation degree, the starch granules totally collapsed, leaching amylose into the continuous aqueous phase and forming a polymer gel. The final gel type
    influenced the properties of the starch gel. The characterization of textural properties showed that the particle gels in which the starch granules were still recognizable were quite hard and brittle, while gels of the polymer type were soft and elastic. The possibility of linking gelatinisation degree, microstructure and textural properties of starch gels allows us to study the role of this ingredient in the functional and sensory properties of more complex systems
    and, ultimately, to modulate these properties for several types of foods.
    Composite Gels Containing Whey Protein Fibrils and Bacterial Cellulose Microfibrils
    Peng, Jinfeng ; Calabrese, Vincenzo ; Geurtz, Julia ; Velikov, Krassimir P. ; Venema, Paul ; Linden, Erik van der - \ 2019
    Journal of Food Science 84 (2019)5. - ISSN 0022-1147 - p. 1094 - 1103.
    bacterial cellulose microfibrils - fibrillar gel - microstructure - protein fibrils - whey protein isolate

    In this study, we investigated the gelation of WPI fibrils in the presence of bacterial cellulose (BC) microfibrils at pH 2 upon prolonged heating. Rheology and microstructure were investigated as a function of BC microfibril concentration. The presence of BC microfibrils did not influence the gelation dynamics and resulting overall structure of the WPI fibrillar gel. The storage modulus and loss modulus of the mixed WPI-BC microfibril gels increased with increasing BC microfibril concentration, whereas the ratio between loss modulus and storage modulus remained constant. The WPI fibrils and BC microfibrils independently form two coexisting gel networks. Interestingly, near to the BC microfibrils more aligned WPI fibrils seemed to be formed, with individual WPI fibrils clearly distinguishable. The level of alignment of the WPI fibrils seemed to be dependent on the distance between BC microfibrils and WPI fibrils. This also is in line with our observation that with more BC microfibrils present, WPI fibrils are more aligned than in a WPI fibrillar gel without BC microfibrils. The large deformation response of the gels at different BC microfibril concentration and NaCl concentration is mainly influenced by the concentration of NaCl, which affects the WPI fibrillar gel structures, changing form linear fibrillar to a particulate gel. The WPI fibrillar gel yields the dominant contribution to the gel strength.

    Nonlinear surface rheology and interfacial microstructure imaging of WPI particles and their constituents
    Yang, Jack - \ 2019
    protein pickering stabilizer - air/water interface - microstructure - surface rheology - Lissajous plots - atomic microscopy
    Production of structured soy-based meat analogues using simple shear and heat in a Couette Cell
    Krintiras, G.A. ; Gobel, T.W. ; Goot, A.J. van der; Stefanidis, G.D. - \ 2015
    Journal of Food Engineering 160 (2015). - ISSN 0260-8774 - p. 34 - 41.
    calcium caseinate dispersions - functional-properties - process parameters - extrusion-cooking - fibrous materials - protein isolate - wheat gluten - microstructure - mixtures - system
    A Couette Cell device was employed to provide proof of concept for the production of structured meat analogues by application of simple shear flow and heat to a 31 wt% Soy Protein Isolate (SPI)–Wheat Gluten (WG) dispersion. Three relevant process parameters (temperature, time and rotation rate) were varied over a range of realistic values (90–110 °C, 5–25 min and 5–50 RPM, respectively). Layer- or fibre-structured products with high stress and strain anisotropy indices have been demonstrated. Fibrousness is favoured at temperatures over 90 °C and under 100 °C, whereas the role of process time and rotation rate is not critical. Simultaneous application of simple shear and heat is the key to obtaining structured plant protein-based products. The Couette Cell concept is scalable and can enable continuous operation. On this ground, it appears as a realistic option for production of meat analogues at commercial scale.
    Dynamic texture perception and oral processing of semi-solid food gels: Part 1: Comparison between QDA, progressive profiling and TDS
    Devezeaux de Lavergne, M.S.M. ; Delft, J.M. van; Velde, F. van de; Boekel, M.A.J.S. van; Stieger, M.A. - \ 2015
    Food Hydrocolloids 43 (2015). - ISSN 0268-005X - p. 207 - 217.
    emulsion-filled gels - sensory texture - rheological properties - mechanical-properties - temporal dominance - time - microstructure - sensations
    Texture perception of food is a dynamic phenomenon depending on food properties and oral processing. Several sensory techniques enable to measure texture perception over time. The aim of this study was to compare quantitative descriptive analysis (QDA), temporal dominance of sensation (TDS) and progressive profiling in the assessment of dynamic texture of emulsion filled gels varying in fracture stress (low/high), fracture strain (low/high) and oil release (oil droplets bound/unbound to the gel matrix). The QDA results revealed that the variation of mechanical properties led to significant differences in texture properties perceived at first bite (firmness and brittleness). Texture attributes perceived at later stages of mastication showed significant differences between gels depending on the first bite properties e.g. soft gels were perceived as more melting. Progressive profiling showed that creaminess increased over eating time while firmness decreased. TDS results were in agreement with the other methods and additionally conveyed information on the succession of perceived attributes over time. The TDS sensory trajectories demonstrated that for all gels dynamic perception evolved in a similar fashion but samples with a high or low fracture strain differed at the end of oral processing. We conclude that texture perception of semi-solid gels is dynamic and can be measured by either of the three sensory methods. The mechanical properties of the gels influence the perception of texture attributes at first bite and at later stages of mastication. QDA, TDS and progressive profiling gave matching and complementary results in the assessment of dynamic sensory texture.
    Phase segregation through transient network formation in a binary particle suspension in simple shear: Application to dough
    Opheusden, J.H.J. van; Molenaar, J. - \ 2014
    Physical Review. E, Statistical nonlinear, and soft matter physics 89 (2014). - ISSN 1539-3755 - 8 p.
    brownian dynamics simulations - wheat doughs - flow - microstructure - gluten - deformation - separation - migration
    In this paper we describe a viscoelastic type of phase separation in a simulated binary fluid with a sticky and an inert component, without any external gradients. Phase segregation under simple shear occurs due to transient network formation of the sticky component, expelling the inert particles from the network. When model parameters are adjusted to reduce network formation and rearrangement, the segregation effect is significantly smaller or absent. The behavior is independent of shear rate; segregation increases mainly with shear strain. The model is applied to wheat dough. Recent experiments have shown that prolonged shear flow of wheat dough can even give macroscopic segregation.
    Shear structuring as a new method to make anisotropic structures from soy-gluten blends
    Grabowska, K.J. ; Tekidou, S. ; Boom, R.M. ; Goot, A.J. van der - \ 2014
    Food Research International 64 (2014). - ISSN 0963-9969 - p. 743 - 751.
    starch-zein blends - wheat-flour - electron-microscopy - globular-proteins - extrusion-cooking - behavior - microstructure - dispersions - consumption - mechanism
    The concept of shear-induced structuring was applied to concentrated blends of soy protein isolate (SPI) and wheat gluten (WG) to create novel semi-solid food textures. Concurrent simple shear deformation and heating (95 °C) of the protein blends generated original structures consisting of fibers or layers. The ratio of SPI to vital WG and the final concentration determined the morphology of the structure. It is hypothesized that the spatial distribution of the SPI-rich phase and the WG-rich phase in a blend was altered by the shear flow. When both phases became aligned horizontally in the shear cell, a fibrous structure was formed; when they became aligned vertically in the shear cell, a layered structure was formed. The structures obtained were analyzed visually and using texture analysis and scanning electron microscopy.
    Rehydration kinetics of freeze-dried carrots
    Vergeldt, F.J. ; Dalen, G. van; Duijster, A.J. ; Voda, A. ; Khalloufi, S. ; Vliet, L.J. van; As, H. van; Duynhoven, J.P.M. van; Sman, R.G.M. van der - \ 2014
    Innovative Food Science and Emerging Technologies 24 (2014). - ISSN 1466-8564 - p. 40 - 47.
    fruits - foods - microstructure - vegetables - quality - impact - nmr
    Rehydration kinetics by two modes of imbibition is studied in pieces of freeze-dried winter carrot, after different thermal pre-treatments. Water ingress at room temperature is measured in real time by in situ MRI and NMR relaxometry. Blanched samples rehydrate substantially faster compared to non-blanched samples, independent of their porous microstructure. It is proposed that for non-blanched tissues immobilized sugars result in nearly complete swelling of the solid matrix, hindering the ingress of water through the porous network. Nonblanched carrot pieces frozen at-28 °C rehydrate faster compared to those frozen at-150 °C, due to blocking of smaller pores by swelling. In blanched tissues themobilization of sugars results in amore homogeneous Sugar distribution, leading to less swelling of the solid matrix and allowing fast ingress of water via capillary suction. Industrial relevance: The dried fruits and vegetables that are currently available on the market are a poor compromise between convenience (rehydration kinetics) and sensorial quality. This is a major bottleneck for consumers to “Make the Healthy Choice the Easy Choice” and this also negatively impacts market growth. Currently, rational optimization of drying processes is impeded by lack of insight which structural features determine rehydration kinetics (convenience) and texture (sensorial quality) upon rehydration. We therefore started a program to quantitatively assess and model microstructural features and rehydration behavior of freeze-dried carrots as a model system.
    Origin of Water Loss from Soy Protein Gels
    Urbonaite, V. ; Jongh, H.H.J. de; Linden, E. van der; Pouvreau, L.A.M. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)30. - ISSN 0021-8561 - p. 7550 - 7558.
    blood-plasma gels - holding capacity - isolate gels - gellan gels - microstructure - pressure - behavior - whey - ph
    Water holding (WH) of soy protein gels was investigated to identify which length scales are most contributing to WH when centrifugal forces are applied. More specifically, it was attempted to differentiate between the contributions of submicron and supramicron length scales. MgSO4 and MgCl2 salt specificities on soy protein aggregation (submicron contribution) were used to create different gel morphologies (supramicron contribution). Obtained results showed that the micrometer length scale is the most important contribution to WH of gels under the applied deformation forces. WH of soy protein gels correlated negatively with Young?s modulus and positively with recoverable energy. The occurrence of rupture events had only a limited impact on WH. The ease by which water may be removed from the gel, but not the total amount, seemed to be related to the initial building block size. These insights could be exploited in product development to predict and tune oral perception properties of (new) products.
    Whey protein particles modulate mechanical properties of gels at high protein concentrations
    Saglam, D. ; Venema, P. ; Vries, R.J. de; Berg, L. van den; Linden, E. van der - \ 2014
    Food Hydrocolloids 38 (2014). - ISSN 0268-005X - p. 163 - 171.
    stabilized emulsion gels - beta-lactoglobulin - viscoelastic properties - rheological properties - isolate gels - mixed gels - microstructure - behavior - gelation - ph
    We have studied the influence of dense whey protein particles on the mechanical properties of whey protein isolate (WPI) gels at high protein concentrations (16–22% (w/w)). Incorporation of dense whey protein particles in the gel, while keeping the total protein concentration constant, leads to a considerably lower storage modulus. By adding protein particles, the total protein concentration of the WPI gels could be increased by 25–55% (w/w), without increasing the storage modulus of the gel. The large deformation properties of the WPI gels were also influenced by the presence of dense protein particles. Gels containing protein particles fractured at a lower strain than pure WPI gels at the same protein concentration. We conclude that protein particles can be used to modulate mechanical properties of WPI gels and are promising candidates for the development of high protein foods with improved textural properties.
    Translational and rotational diffusion of flexible PEG and rigid dendrimer probes in sodium caseinate dispersions and acid gels
    Salami, S. ; Rondeau-Mouro, C. ; Barhoum, M. ; Duynhoven, J.P.M. van; Mariette, F. - \ 2014
    Biopolymers 101 (2014)9. - ISSN 0006-3525 - p. 959 - 965.
    glucono-delta-lactone - hydrodynamic transport-properties - nuclear-magnetic-resonance - polystyrene latex spheres - aqueous polymer-solutions - light-scattering - nmr - suspensions - gelation - microstructure
    The dynamics of rigid dendrimer and flexible PEG probes in sodium caseinate dispersions and acid gels, including both translational diffusion and rotational diffusion, were studied by NMR. Above the onset of the close-packing limit (C ~ 10 g/100 g H2O), translational diffusion of the probe depended on its flexibility and on the fluctuations of the matrix chains. The PEG probe diffused more rapidly than the spherical dendrimer probe of corresponding hydrodynamic radius. The greater conformational flexibility of PEG facilitated its motion through the crowded casein matrix. Rotational diffusion was, however, substantially less hindered than the translational diffusion and depended on the local protein–probe friction which became high when the casein concentration increased. The coagulation of the matrix led to the formation of large voids, which resulted in an increase in the translational diffusion of the probes, whereas the rotational diffusion of the probes was retarded in the gel, which could be attributed to the immobilized environment surrounding the probe. Quantitative information from PFG-NMR and SEM micrographs have been combined for characterizing microstructural details in SC acid gels.
    Ice crystal interspacing in frozen foods
    Sman, R.G.M. van der; Voda, A. ; Dalen, G. van; Duijster, A. - \ 2013
    Journal of Food Engineering 116 (2013)2. - ISSN 0260-8774 - p. 622 - 626.
    directional-solidification - apple tissue - part ii - texture - growth - cream - crystallization - transport - model - microstructure
    In this paper we show that the ice crystal growth in food and biomaterials is a function of the freezing rate. Our experimental data and literature data on other biomaterials collapse to a single curve, if plotted against the freezing rate. The fitted correlation is compared to scaling rules developed for dendrite interspacing during directional solidification of alloys. We argue that the food freezing process is reasonably comparable to the solidification process in alloys, as is apparent in the comparable exponent in our fitted scaling rule with the one commonly used in alloy solidification. (C) 2013 Elsevier Ltd. All rights reserved.
    Hydrodynamic Interactions between Two Equally Sized Spheres in Viscoelastic Fluids in Shear Flow
    Snijkers, F. ; Pasquino, R. ; Vermant, J. - \ 2013
    Langmuir 29 (2013)19. - ISSN 0743-7463 - p. 5701 - 5713.
    spherical-particles - boger fluids - suspensions - rheology - alignment - microstructure - aggregation - evolution - liquid
    The effect of using a viscoelastic suspending medium, on the;in-plane hydrodynamic interaction between two equally sized spheres in shear flow is studied experimentally to understand flow-induced assembly behavior (i.e., string formation). A counterrotating device equipped with a Couette geometry is used together with quantitative videomicroscopy. To evaluate the effects of differences in rheological properties of the suspending media, fluids have been selected that highlight specific constitutive feature's. These include a reference Newtonian fluid (N), a,constant-viscosity, high-elasticity Boger fluid (BF), a wormlike micellar surfactant solution with a, single dominant relaxation time (WMS), and a broad spectrum shear-thinning elastic polymer solution (ST). As expected, the trajectories are symmetric in the Newtonian fluid. In the BF, the midpoints. of the spheres are observed to remain in the same plane before and after,the interaction, as in the Newtonian fluid, although the path lines are in this case no longer symmetric. Interactions in the, ST and WMS are highly asymmetric. Two, fundamentally different kinds of path lines are Observed in the WMS and ST: reversing and Open trajectories: The type of trajectory depends on the initial Configuration of the spheres with respect to:each,other and on the shear rate. On the basis of the obtained results, shear-thinning of the viscosity seems to be the key rheological parameter that determines the overall nature of, the interactions rather than the relative magnitude of the normal stress differences.
    Preload-responsive adhesion: effects of aspect ratio, tip shape and alignment
    Paretkar, D. ; Kamperman, M.M.G. ; Martina, D. ; Zhao, J. ; Creton, C. ; Lindner, A. ; Jagota, A. ; McMeeking, R. ; Arzt, E. - \ 2013
    Journal of the Royal Society, Interface 10 (2013)83. - ISSN 1742-5689 - 13 p.
    fibrillar interfaces - switchable adhesion - contact - surfaces - microstructure - design
    We tested the adhesive response of polymer surfaces structured with arrays of cylindrical fibrils having diameters of 10–20 µm and aspect ratios 1–2.4. Fibrils had two different tip shapes of end-flaps and round edges. A preload-induced mechanical buckling instability of the fibrils was used to switch between the states of adhesion and non-adhesion. Non-adhesion in fibrils with round edges was reached at preloads that caused fibril buckling, whereas fibrils with end-flaps showed adhesion loss only at very high preloads. The round edge acted as a circumferential flaw prohibiting smooth tip contact recovery leading to an adhesion loss. In situ observations showed that, after reversal of buckling, the end-flaps unfold and re-form contact under prevailing compressive stress, retaining adhesion in spite of buckling. At very high preloads, however, end-flaps are unable to re-form contact resulting in adhesion loss. Additionally, the end-flaps showed varying contact adaptability as a function of the fibril–probe alignment, which further affects the preload for adhesion loss. The combined influence of preload, tip shape and alignment on adhesion can be used to switch adhesion in bioinspired fibrillar arrays
    Wheat gluten in extruded fish feed: Effects on morphology and on physical and functional properties
    Draganovic, V. ; Goot, A.J. van der; Boom, R.M. ; Jonkers, J. - \ 2013
    Aquaculture Nutrition 19 (2013)6. - ISSN 1353-5773 - p. 845 - 859.
    structural characteristics - lysine supplementation - salmonid feeds - rainbow-trout - oil uptake - products - protein - meal - microstructure - digestibility
    This article focuses on understanding the role of vital wheat gluten on the structural parameters of extruded fish feed and its correlation to the physical and functional properties. Gluten–soy protein concentrate blends with five gluten concentrations (0–200 g kg-1) were produced. An abrupt reduction in oil uptake was observed with the 200 g gluten kg-1 blend. Inclusion of gluten from 100 to 200 g kg-1 resulted in unacceptable product properties. Sinking of feed pellets with 0 and 50 g gluten kg-1 was 100%, whereas only 36% of pellets with 200 g gluten kg-1 sank. We suspect that this is due to a relationship between morphological structure and oil impregnation during coating of feeds. The addition of gluten at 200 g kg-1 gave a smoother and non-porous outer surface. Pellets without gluten had a larger number of cells that were smaller than 200 µm (P <0.05) compared with pellets with 100 and 200 g gluten kg-1. More spherical cell shapes (P <0.01) and a compact structure were favoured in the presence of gluten. The closed porosity increased (P <0.05), whereas interconnectivity between pores decreased (P <0.01), with increasing gluten content from 0 to 200 g kg-1. The effects of the addition of gluten are probably related to the film-forming properties of gluten.
    Protein micro-structuring as a tool to texturize protein foods
    Purwanti, N. ; Peters, J.P.C.M. ; Goot, A.J. van der - \ 2013
    Food & Function 4 (2013)2. - ISSN 2042-6496 - p. 277 - 282.
    amino-acids - dietary-protein - rheological properties - statistical-mechanics - high-carbohydrate - elderly people - whey - requirements - muscle - microstructure
    Structuring protein foods to control the textural properties receives growing attention nowadays. It requires decoupling of the product properties such as water holding capacity and the mechanical properties from the actual protein concentration in the product. From an application point of view, both increasing and lowering the protein content in the food are interesting. Foods enriched with proteins are important due to their reported health benefits, but increasing the protein content in food products generally leads to products that are firmer and have a more rubbery mouth-feel than the regular products, making them less attractive. A reduced protein content, for example in meat- or cheese-analogues, is relevant because it leads to a lower caloric intake per serving and it enhances its economic potential. Decoupling of the protein concentration and product properties can be obtained by changing the internal structure of those food products. This paper outlines the use of protein aggregates and particles in a protein matrix as a tool to obtain different textural properties of a model protein product. Whey protein isolate (WPI) was taken as a model protein. However, further investigation of WPI microparticles should focus on a better understanding of their swelling behaviour in the protein matrix to fully use the potential of those protein particles as a tool to decouple product properties and actual protein concentration.
    The influence of pH and ionic strength on the swelling of dense protein particles
    Saglam, D. ; Venema, P. ; Vries, R.J. de; Linden, E. van der - \ 2013
    Soft Matter 9 (2013). - ISSN 1744-683X - p. 4598 - 4606.
    whey-protein - drug-delivery - beta-lactoglobulin - sensitive hydrogels - mesh size - gels - gelation - isolate - concentrate - microstructure
    We have studied swelling properties and stability of protein particles prepared through emulsification and heat-induced gelation of whey proteins under different conditions. The protein particles themselves are stable over a wide pH range, but around pH 5 aggregation was observed, presumably because of a weakened electrostatic repulsion close to the protein iso-electric point. Protein leakage from the particles was found not to be higher than 8% (w/w) in most of the pH range, but increased significantly at alkaline pH. The pore size of the particles is in the range of 4 to 20 nm at neutral pH and the particles show a pH- and salt-responsive swelling, due to their polyampholytic character, as shown by confocal scanning electron microscopy analysis. These results indicate that these whey protein particles could be used as targeted delivery vehicles. The pH sensitive swelling of the particles may also result in significant changes in the volume of the particles, thereby influencing the rheological properties of dispersions made out of these particles, especially in concentrated systems.
    Stiffening in gels containing whey protein isolate
    Purwanti, N. ; Veen, E. van der; Goot, A.J. van der; Boom, R.M. - \ 2013
    International Dairy Journal 28 (2013)2. - ISSN 0958-6946 - p. 62 - 69.
    physicochemical changes - body-composition - filled gels - aggregation - stability - matrix - bars - microstructure - storage - muscle
    Gels made only from whey protein isolate (WPI) stiffened over the first few days of storage, after which the textural properties remained nearly constant. However, protein gels containing WPI microparticles, at the same total protein content, stiffened over a longer period than those without microparticles. This stiffening was suggested to be the result of rearrangement of crosslinks in the gel. Addition of particles induces additional effects leading to water distribution between the protein particles and continuous phase. The stiffness change over time was different for gels made from a mixture of locust bean gum and xanthan gum containing microparticles. The stiffness of matrix gel and of gels containing 20% (w/w) microparticles was rather stable over time; microscopy analysis of these gels showed that particle size was constant after 72 h storage. Nevertheless, changes were observed in small deformation; this might be the consequence of slow rearrangements within the protein particles.
    Relation between Gelation Conditions and the Physical Properties of Whey Protein Particles
    Saglam, D. ; Venema, P. ; Vries, R.J. de; Aelst, A.C. van; Linden, E. van der - \ 2012
    Langmuir 28 (2012)16. - ISSN 0743-7463 - p. 6551 - 6560.
    beta-lactoglobulin - isolate gels - structural-properties - particulate gels - water emulsions - ph - emulsification - microstructure - microscopy - rheology
    We have developed a robust procedure for preparing protein micro-particles with a high internal protein content ([small tilde]20 % w/w). Such protein micro-particles, having controlled size, protein content, and surface composition can be useful in the development of novel food products with high protein content. Protein particles were formed through emulsification of a WPI (whey protein isolate) solution (25% w/w) in sunflower oil containing 2.5 % (w/w) PGPR (Polyglycerol Polyricinoleate) as an oil-soluble emulsifier. The emulsion (w/o) was heated to induce gelation of the protein inside the emulsion droplets. Oil was removed through successive centrifugation and washing steps. This resulted in micron-sized protein particles dispersed in an aqueous phase. The average diameter of the particles was in the order of a few [mu]m, depending on the mixing speeds applied in the primary emulsification step. CLSM (Confocal laser scanning microscopy) analysis of protein particles indicated that there is oil associated with the particles, either surrounding the particles and/or distributed throughout the particles. NMR analysis showed that this amount of oil does not exceed 1.8% (w/w).
    Inhomogeneous distribution of fat enhances the perception of fat-related sensory attributes in gelled foods
    Mosca, A.C. ; Rocha, J.L. ; Sala, G. ; Velde, F. van de; Stieger, M.A. - \ 2012
    Food Hydrocolloids 27 (2012)2. - ISSN 0268-005X - p. 448 - 455.
    emulsion-filled gels - oil droplet - custard desserts - texture - microstructure - deformation - fracture - cheese
    This study investigated the effect of the spatial distribution of fat on the perception of fat-related sensory attributes using a model system that consisted of layered agar/gelatin gels containing oil-in-water (O/W) emulsion droplets dispersed in the gel matrix. Four layers of gel varying in the amount of emulsion droplets were combined to prepare samples with homogeneous and inhomogeneous distributions of fat (emulsion droplets). The composition of the gels was optimized to obtain samples with comparable mechanical properties. A significant enhancement of mouthfeel attributes such as spreadable and melting was observed in samples with inhomogeneous distributions of fat in a Quantitative Descriptive Analysis (QDA) panel. Inhomogeneous samples with large differences in fat content between layers were perceived more spreadable and melting than the sample in which fat was homogeneously distributed. Creaminess ratings tended to increase as the difference in fat content between layers increased in the inhomogeneous samples. Additionally, the position of the high-fat layers in the sample affected the perception of fat-related attributes. The sample with high-fat layers on the outside had the highest ratings for all mouthfeel and afterfeel attributes. The enhancement of fat-related attributes by an inhomogeneous distribution of fat depended on the overall fat content. The enhancement at 15 wt% fat was larger than that at 5 wt% fat. We suggest that the modulation of the spatial distribution of fat can be used to reduce the fat content of food products without causing undesirable changes in the sensory properties
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