Frédéric Depypere

Quantification of microparticle coating quality by confocal laser scanning microscopy (CLSM).

In this work, a novel protocol was developed for determining film coating thickness and coating quality of microparticles, based on the use of confocal laser scanning microscopy (CLSM). CLSM was found to be an adequate non-destructive technique for the quantification of the coating thickness and coating quality of individual thin-coated small particles. Combined with image analysis, it was possible to derive with high accuracy the coating thickness distribution of a representative number of microparticles. The performance of the novel methodology was assessed by the quantification of the coating thickness and coating quality of protein-coated microparticles produced by fluidized bed coating. It was found that the CLSM data on coating layer thickness were generally in good agreement with the results from chemical analysis, down to a thickness of 1-1.5 microm. Using CLSM the importance of setting up the appropriate distance between the coating nozzle and the powder bed with respect to microparticle coating quality in fluidized bed processing was illustrated. Coating quality was found to decrease with increasing distance the coating droplets have to travel before impinging onto the core particles as a result of spray-drying of the coating droplets. Also, coating quality decreased with increasing viscosity of the coating droplets, resulting in reduced spreading on the cores.

Processing of waxy starch/xanthan gum mixtures within the gelatinization temperature range.

Pasting experiments of waxy potato and waxy maize starch systems were set up in which temperatures close to the gelatinization temperature were selected (67.5, 70 and 72.5°C). DSC measurements showed that under these conditions small fractions of the starches remained ungelatinized. During the pasting process two different shear rates were imposed (50s(-1) and 150s(-1)) to investigate the shear stability of the different starch containing systems. Swelling of the granules occurred in a more controlled manner and granule breakdown during pasting could be limited. As a result of these heating conditions more swollen granules are present, as confirmed by laser light diffraction. This positive effect was clearly noticeable in the flow curves of the cooled pastes. Xanthan gum addition could further reduce breakdown either by restricting the swelling or by stabilizing the granules. At higher starch contents the former is most likely dominating.

Dark chocolate’s compositional effects revealed by oscillatory rheology

In this study, two types of oscillatory shear rheology are applied on dark chocolate with varying volume fraction, particle size distribution, and soy lecithin concentration. The first, a conventional strain sweep, allows for the separation of the elastic and viscous properties during the yielding. The second, a constant strain rate sweep, where the strain rate amplitude is fixed as the frequency is varied, is analyzed to obtain Lissajous curves, dissipated energy, and higher order nonlinear contributions. It is shown that chocolate exhibits complex nonlinear behavior, namely shear thinning, shear thickening, and strain stiffening. The effects on this behavior related to volume fraction, particle size distribution, and lecithin concentration are investigated, and comparison with simple monodisperse hard-sphere suspensions is made.

Influence of xanthan transition on the rheological properties of waxy starches.

The effects of xanthan gum on the properties of waxy starch systems were investigated with a particular focus on the conformational transition of xanthan. Different types of starches were used in this setup: maize, potato, chemically modified maize and rice. Under dilute conditions, xanthan gum and its transition did not affect the gelatinization of the starches. However, significant effects on the pasting behavior were observed, where the xanthan transition caused a significant reduction of the viscosity. It was demonstrated that xanthan can limit the breakdown of sensitive starch granules and that this effect might be enhanced by the xanthan transition. Flow curves of the cooled pastes showed that granule integrity is a prerequisite for optimal xanthan functionality, but the granule stabilizing effect of xanthan was too limited under these pasting conditions to significantly influence the flow behavior.

Water-Soluble Cellulose Derivatives as Coating Agents in Fluidized Bed Processing

The quality of a particle coating is strongly affected by both the parameters of the fluidized bed process and the properties of coating materials. Within this research, the effect of solution properties (viscosity of the coating solution, coating solution droplet size) on the quality of coatings obtained from three water-soluble cellulose derivatives (methylcellulose, carboxymethylcellulose, and hydroxypropylcellulose) was investigated. Coating quality was quantified using confocal laser scanning microscopy (CLSM). The results showed a pronounced effect of viscosity on the quality of methylcellulose and carboxymethylcellulose coatings. The best results for methylcellulose coatings were obtained when the least concentrated and at the same time least viscous solution was sprayed onto the fluidized particles. In the case of carboxymethylcellulose the best results were obtained using an intermediate (5 w/v %) concentrated coating solution. The quality of the hydroxypropylcellulose coatings was not influenced by the coating solution viscosity and presented very similar values after performing all fluid bed experiments. For the materials covered in this work, the best coating quality was obtained for hydroxypropylcellulose. The least uniform coatings with the highest number of coating deficiencies and highest degree of agglomeration of coated beads were found for carboxymethylcellulose.

Do anticipated emotions influence behavioural intention and behaviour to consume filled chocolates

Purpose The purpose of this paper is to examine the influence of anticipated emotions (AE) on behavioural intention and behaviour to consume filled chocolates and to give an indication on the possible differences in consumer behaviour between two countries. Design/methodology/approach The theory of planned behaviour (TPB) was used to explain the consumption of chocolate. In this study, TPB is extended with a construct for AE. Findings A total of 859 consumers in Belgium and Hungary participated in the study and results showed that including AE increases the predicted variance of the TPB. Moreover, AE have a positive effect on the intention and the actual behaviour of consumers. Next, the study suggests that Belgian consumers are more influenced by their emotional and control beliefs and that Hungarian consumers are also driven by opinion of family and friends and some behavioural beliefs. Practical implications Overall, TPB can contribute to the understanding of behavioural intention and behaviour towards eating filled chocolate. Moreover, it can help to develop a marketing plan for specific consumer segments as it can identify influencing factors and consumer beliefs towards a product. Originality/value This is the first study that compares the fit of the TPB model with and without the construct of AE. The work contributes to the growing literature on emotions as it does not focus on emotions elicited during or after consumption, but explores if the AE also play a significant role in behaviour.

Processing of Food Powders

The development of formulation engineering concepts in food manufacturing and the demand for diversity in food products has driven a substantial market increase for food ingredients. Most ingredien ...

Computational study of the multiphase flow in the fluidised bed equipment

Although the fluid bed technology has been successfully applied in the coating of particulate solids, some problems like agglomeration and spray-drying still remain unresolved. In order to understand the fluidisation hydrodynamics of a specific fluid bed operation, it is essential to assess the distribution of fluidising air and particles in the fluid bed. In this research, CFD was used to model the airflow and particle trajectories inside a Glatt GPCG-1 fluidised bed coater. The multiphase Eulerian model was used to predict the flow behaviour of the particles and the momentum exchange coefficients were calculated by means of the models of Syamlal-O’Brien, Wen and Yu, and Gidaspow. Good agreement could be observed between simulation and experimental PEPT results.