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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    Bolus matters : the influence of food oral breakdown on dynamic texture perception
    Devezeaux de Lavergne, Marine ; Velde, Fred van de; Stieger, Markus - \ 2017
    Food & Function 8 (2017). - ISSN 2042-6496 - p. 464 - 480.

    This review article focuses on design of food structure, characterisation of oral processing by boli characterisation and dynamic texture perception. Knowledge of the food properties governing bolus formation and bolus properties determining temporal changes in texture perception is of major importance. Such knowledge allows academia to better understand the mechanisms underlying texture perception and food industry to improve product texture. For instance, such knowledge can be used for developing foods with desired texture perception that fit in a healthy diet or that are customized to specific consumer groups. The end point of oral processing is the formation of a safe-to-swallow bolus. The transitions of solid and soft solid foods into bolus are accompanied by tremendous modifications of food properties. The review discusses dynamic changes in bolus properties resulting in dynamic changes of texture perception during oral processing. Studies monitoring chewing behaviour are discussed to complement the relationships between bolus properties and dynamic texture perception. We conclude that texture perception evolves over mastication time and depends on food properties, such as mechanical properties, mainly in the beginning of oral processing. Towards the middle and end of oral processing, bolus properties depend on food properties and explain texture perception better than food properties.

    Investigation of oral gels breakdown using image analysis
    Tournier, Carole ; Devezeaux de Lavergne, Marine ; Velde, Fred van de; Stieger, Markus ; Salles, Christian ; Bertrand, Dominique - \ 2017
    Food Hydrocolloids 63 (2017). - ISSN 0268-005X - p. 67 - 76.
    Emulsion-filled gels - Food bolus - Image texture analysis - Mastication - Mathematical morphology

    Characterizing the dynamics of food oral breakdown is of interest to understand the temporal perception of food products. The present work aimed at studying the possible contribution of artificial vision for studying bolus formation. Four emulsion-filled gels were prepared from two concentrations of agar and gelatin. By combining two different layers of these gels, four samples of homogeneous composition and 6 samples of heterogeneous composition were prepared. The layers were colored independently in order to study their breakdown and mixing during oral processing. Images of spat out boluses were collected at different stages of the chewing process and studied by different image analysis methods: gray-level histograms, histogram of shape area, mathematical morphology and gray level co-occurrence matrix. Methods were compared for their ability in discriminating boluses as function of homogeneous gel composition and mastication time. Three methods were found to be relevant and mathematical morphology provided the best results. Using this method, we further analyzed the impact of heterogeneous gels composition on the evolution of boluses properties. Results showed that when two gel layers of different composition were combined, the agar layer dominated bolus properties and that the presence of gelatin impacted the dynamics of gel breakdown. The results were in agreement with results obtained previously when characterizing the physical properties of the boluses. This study showed that artificial vision provides reliable tools for evaluating the dynamics of bolus formation, which is complementary to the methods commonly used in literature while avoiding extensive manipulation of boluses.

    Uncoupling the Impact of Fracture Properties and Composition on Sensory Perception of Emulsion-Filled Gels
    Devezeaux de Lavergne, Marine ; Strijbosch, V.M.G. ; Broek, A.W.M. Van den; Velde, Fred Van de; Stieger, Markus - \ 2016
    Journal of Texture Studies (2016). - ISSN 0022-4901 - p. 92 - 111.
    Bolus - Emulsion-filled gels - Fracture properties - Melting - Oral processing - Serum release - Texture

    The aim of the study is to investigate the effect of fracture properties and composition of emulsion-filled gels on dynamic texture perception. Twelve emulsion-filled gels varying in fracture stress (High/Low) and strain (High/Low) were prepared from three binary gel mixtures. Mechanical properties, syneresis, friction properties, microstructure, melting behavior, oral breakdown and texture perception of the gels were determined. Gels varying in composition but exhibiting similar fracture properties were obtained. Serum release, melting in mouth and friction varied between gels differing in composition. Fracture properties and melting of gels impacted oral breakdown. Fracture properties impacted perception of texture attributes at first bite and during chew down. Melting and syneresis impacted chew down perception of gels. We conclude that fracture stress mainly impacted texture perception at first bite, whereas fracture strain impacted perception of chew down texture attributes with high fracture strain gels being perceived creamy. The composition of gels impacted properties such as melting and serum release, which accounted for high variations in perception of moistness and creaminess between samples. Practical Applications: Fracture properties of food are known to impact the perception of first bite texture attributes. Moreover, they are known to control breakdown of food during oral processing. However, little is known about the impact of fracture properties on perception of chew down texture attributes. The current study highlights the impact of fracture properties on chew down texture perception. It identifies other gel properties depending on gels composition that account for variation in perception between gels. The use of emulsion-filled gels enabled the investigation of sensory attributes related to fat perception. Such knowledge can be used for food reformulation, for instance formulation of low fat soft solid foods. This study indicates which mechanical properties should be controlled to obtain a desired texture profile of soft solid foods.

    Dynamic texture perception, oral processing behaviour and bolus properties of emulsion-filled gels with and without contrasting mechanical properties
    Devezeaux de Lavergne, M.S.M. ; Tournier, C. ; Bertrand, D. ; Salles, C. ; Velde, F. van de; Stieger, M.A. - \ 2016
    Food Hydrocolloids 52 (2016). - ISSN 0268-005X - p. 648 - 660.
    Many highly palatable foods are composed of multiple components which can have considerably different mechanical properties leading to contrasting texture sensations. The aim of this study was to better understand the impact of contrasting mechanical properties in semi-solid gels on oral processing behaviour and dynamic texture perception. Four reference emulsion-filled gels without mechanical contrast were prepared using agar (1 or 2 wt%) or gelatine (2.5 or 5.5% wt). Six emulsion-filled gels with contrasting mechanical properties were obtained by combining two different gel layers. Agar reference gels displaying low fracture strain produced boli with many small particles and were perceived as grainy. Gelatine reference gels displaying high fracture strain produced boli with few large particles which melted in mouth and were perceived as creamy. Reference gels with large fracture stress were masticated for long times with a high chewing muscle activity and perceived as firm and grainy. Bolus properties, oral processing behaviour and dynamic sensory perception of the 6 contrasting gels were compared to the 4 reference gels using Principal Component Analysis. The presence of an agar layer in contrasting gels dominated bolus properties which contained many small particles and did not mix readily in mouth. The temporal sensory profiles and sensory trajectories of contrasting gels fell between the temporal sensory profiles and sensory trajectories of the two gel layers which they were composed of. We conclude that distinct features of dynamic texture perception in emulsion-filled gels with mechanical contrast are perceived separately in mouth.
    Dynamic texture perception and oral processing of semi-solid food gels: Part 2: Impact of breakdown behaviour on bolus properties and dynamic texture perception
    Devezeaux de Lavergne, M.S.M. ; Velde, F. van de; Boekel, M.A.J.S. van; Stieger, M.A. - \ 2015
    Food Hydrocolloids 49 (2015). - ISSN 0268-005X - p. 61 - 72.
    Food texture perception depends on food structure and oral processing behaviour. The aim of this study was to explain dynamic texture perception of emulsion-filled, semi-solid gels by properties of the boli formed during three stages of oral processing. Texture perception of emulsion-filled gels varying in fracture stress and strain was found to be a dynamic process. Specific texture attributes were perceived as dominant sensations in the beginning (firm), middle (moist, refreshing, elastic, sticky) and end of oral processing (grainy, melting, creamy). In the beginning of oral processing mechanical properties of the boli, such as first penetration peak force and flowability, were correlated to sensory firmness. In the middle of oral processing, correlations between boli properties and texture perception were more complex. Perception of moist and refreshing was related to mechanical properties of the boli, such as flowability, rather than to the amount of saliva incorporated into the boli. Perception of elastic and sticky was related to the mechanical bolus properties resilience and adhesiveness. In the end of oral processing, emulsion-filled gels were perceived either as creamy or grainy. Gels perceived as creamy revealed a high bolus flowability while gels perceived as grainy consisted of boli with a high number of broken down particles. We conclude that bolus formation and changes in the properties of the bolus underlay the changes in texture perception during oral processing.
    Bolus matters: impact of food oral breakdown on dynamic texture perception
    Devezeaux de Lavergne, M.S.M. - \ 2015
    Wageningen University. Promotor(en): Tiny van Boekel, co-promotor(en): Markus Stieger; F. van de Velde. - Wageningen : Wageningen University - ISBN 9789462574496 - 227
    textuuranalyse - textuur - voedsel - structuur - eigenschappen - perceptie - spijsvertering - gels - elektromyografie - masticatie - kwalitatieve analyse - worstjes - texture analysis - texture - food - structure - properties - perception - digestion - gels - electromyography - mastication - qualitative analysis - sausages

    Background and aims:

    Texture is an important, yet complex, quality attribute of food. Food structure and properties can be linked to texture perception during the first bite. However, the perception of attributes during chew down is more difficult to explain, as food requires to be broken down to be swallowed safely. Food oral processing, which is a recent discipline connecting food science to the physiology of the eating process, is considered to be the key for understanding dynamic food texture perception. The aim of this thesis is to understand the link between food properties and texture perception by investigating oral food breakdown, in simple model foods.


    Gels were used as a model for soft solid foods. Several properties of the gels were controlled by modifying the composition of gels, including fracture stress and fracture strain, oil droplets binding to the gels matrix, melting, serum release and mechanical contrast. The texture perception of the gels was measured using several sensory methods. Qualitative descriptive analysis (QDA), progressive profiling and temporal dominance of sensations (TDS) were compared in the assessment of dynamic texture perception. In order to link gel properties to texture perception, the oral processing of gels was measured through analyses on the gel bolus and measurements of chewing behaviour. Gel boli were expectorated at various stages of oral processing and were analysed for gel fragments size and number, mechanical properties and saliva incorporation. These analyses were used to quantify the degree of breakdown of gels and to relate bolus properties to changes in texture perception. Chewing behaviour was measured using Electromyography (EMG) to understand the role of oral processing behaviour in bolus formation and dynamic texture perception.


    Dynamic texture perception of gels could be measured by QDA, progressive profiling and TDS which were complementary methods. Fracture properties of gels could predict the perception of first bite texture attributes. Fracture stress and fracture strain were correlated to first bite firmness and brittleness respectively. During chew down, the link between gel properties and texture perception became less clear. Nonetheless, fracture properties and other gels properties, such as melting and serum release, related to chew down perception. Bolus properties depended on gel properties, but related better to chew down texture perception than gel properties. Mainly changes in mechanical properties and fragmentation of the bolus could explained the perception of complex texture attributes, such as creaminess and graininess respectively. Chewing behaviour depended on products properties. In addition, chewing behaviour impacted the formation of the bolus and could result in differences in dynamic texture perception between groups of individuals.


    The oral breakdown of food is a valuable input to understand the perception of complex chew down texture attributes. Such an input could be used to design foods with a desired texture sensory profile for reformulation of foods fitting in a healthier diet or foods for target consumer groups.

    Eating behaviour explains differences between individuals in dynamic texture perception of sausages
    Devezeaux de Lavergne, M.S.M. ; Derks, J.A.M. ; Ketel, E.C. ; Wijk, R.A. de; Stieger, M.A. - \ 2015
    Food Quality and Preference 41 (2015). - ISSN 0950-3293 - p. 189 - 200.
    swallowing threshold - food texture - bite size - age - bolus - patterns - young - gels
    Texture perception of foods has been demonstrated to be influenced by age, dental health and oral processing behaviour. Eating duration is a significant factor contributing to and determining food oral processing behaviour. The influence of eating duration on dynamic texture perception, oral processing behaviour and properties of the food bolus have not been investigated extensively. The aims of this study are (i) to determine the influence of naturally preferred eating duration on dynamic texture perception of sausages and (ii) to explain differences in dynamic texture perception between short and long duration eaters by chewing behaviour and bolus properties. Two groups of subjects were selected based on their natural eating duration for a controlled portion size of two sausages. The group of “long duration eaters” (n = 11) took on average twice as long to consume a piece of sausage compared to the group of “short duration eaters” (n = 12). Independent of eating duration, short and long eating duration subjects chewed sausages with the same chewing frequency (p = 0.57) and muscle effort rate (p = 0.15) during oral processing. Total muscle effort and total number of chews were significantly higher (p <0.05 for both) for long duration eaters mainly due to the longer eating time compared to short duration eaters. Bolus properties showed that short duration eaters did not break down the boli as much as long duration eaters resulting in fewer (p <0.001) and larger (p <0.05) sausage bolus fragments, firmer (p <0.001) and less adhesive (p <0.001) boli with lower fat content (p <0.05) and less saliva incorporation (p <0.001) at swallow compared to the bolus properties of long duration eaters. These differences in bolus properties influenced dynamic texture perception of the sausages as the bolus of short duration eaters revealed different properties than the bolus of long duration eaters. Temporal dominance of sensations (TDS) showed that short and long duration eaters perceived the same sausage similarly in the early stages of oral processing, but started to perceive the texture of the same sausage differently from the middle of oral processing towards the end. We conclude that short duration eaters did not compensate for their shorter eating duration by chewing more efficiently but were comfortable swallowing a less broken down bolus than long duration eaters. Moreover, we conclude that differences in eating behaviour between subjects can lead to differences in bolus properties of sausages causing differences in dynamic texture perception of the same sausage.
    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.
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