Experimental investigation on rapid filling of a large-scale pipeline

This study presents the results from detailed experiments of the two-phase pressurized flow behavior during the rapid filling of a large-scale pipeline. The physical scale of this experiment is close to the practical situation in many industrial plants. Pressure transducers, water-level meters, thermometers, void fraction meters, and flow meters...

Modulation of the adsorption properties at air-water interfaces of complexes of egg white ovalbumin with pectin by the dielectric constant

The possibility of modulating the mesoscopic properties of food colloidal systems by the dielectric constant is studied by determining the impact of small amounts of ethanol (10%) on the adsorption of egg white ovalbumin onto the air-water interface in the absence and presence of pectin. The adsorption kinetics was monitored using tensiometry....

The adsorption and unfolding kinetics determines the folding state of proteins at the air-water interface and thereby the equation of state

Unfolding of proteins has often been mentioned as an important factor during the adsorption process at air-water interfaces and in the increase of surface pressure at later stages of the adsorption process. This work focuses on the question whether the folding state of the adsorbed protein depends on the rate of adsorption to the interface,...

Importance of physical vs. chemical interactions in surface shear rheology

The stability of adsorbed protein layers against deformation has in literature been attributed to the formation of a continuous gel-like network. This hypothesis is mostly based on measurements of the increase of the surface shear elasticity with time. For several proteins this increase has been attributed to the formation of intermolecular...

Use of polysaccharides to control protein adsorption to the air-water interface

In order to understand foaming behaviour of mixed protein/anionic polysaccharide solutions, we investigated the effect of β-lactoglobulin/pectin interaction in the bulk on β-lactoglobulin adsorption to the air-water interface. Adsorption kinetics were evaluated by following surface pressure development in time of several pure protein solutions...

Assessing the extent of protein intermolecular interactions at air-water interfaces using spectroscopic techniques

There is an ongoing debate about whether a protein surface film at an air-water interface can be regarded as a gelled layer. There is literature reporting that such films show macroscopic fracture behavior and a rheology comparable to three-dimensional protein bulk-networks. If this is the case, a complete description of the formation of...

Reversible self-association of ovalbumin at air-water interfaces and the consequences for the exerted surface pressure

In this study the relation between the ability of protein self-association and the surface properties at air-water interfaces is investigated using a combination of spectroscopic techniques. Three forms of chicken egg ovalbumin were obtained with different self-associating behavior: native ovalbumin, heat-treated ovalbumin-being a cluster of 12...

Correlation between mechanical behavior of protein films at the air/water interface and intrinsic stability of protein molecules

The relation between mechanical film properties of various adsorbed protein layers at the air/water interface and intrinsic stability of the corresponding proteins is discussed. Mechanical film properties were determined by surface deformation in shear and dilation. In shear, fracture stress, σf, and fracture strain, γf, were determined, as well...

Quantitative description of the relation between protein net charge and protein adsorption to air-water interfaces

In this study a set of chemically engineered variants of ovalbumin was produced to study the effects of electrostatic charge on the adsorption kinetics and resulting surface pressure at the air-water interface. The modification itself was based on the coupling of succinic anhydride to lysine residues on the protein surface. After purification of...

Protein Adsorption at Air-Water Interfaces: A Combination of Details

Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air-water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure, external reflection circular dichroism, infrared,...

Spreading of oil from protein stabilised emulsions at air/water interfaces

Spreading of a drop of an emulsion made with milk proteins on air/water interfaces was studied. From an unheated emulsion, all oil molecules could spread onto the air/water interface, indicating that the protein layers around the oil globules in the emulsion droplet were not coherent enough to withstand the forces involved in spreading. Heat...

Interfacial rheological properties and conformational aspects of soy glycinin at the air/water interface

Interfacial (rheological) properties of soy glycinin were studied at different pH. At acidic and high alkaline pH glycinin (11S form, Mw ∼ 350 kDa) dissociates into smaller subunits, the so called 3S form (Mw ∼ 44 kDa) and 7S form (Mw ∼ 175 kDa). This dissociation behaviour is expected to affect the interfacial rheological properties of glycinin...