Advances in Colloid and Interface Science (v.219, #C)

Towards predicting the stability of protein-stabilized emulsions by Roy J.B.M. Delahaije; Harry Gruppen; Marco L.F. Giuseppin; Peter A. Wierenga (1-9).
The protein concentration is known to determine the stability against coalescence during formation of emulsions. Recently, it was observed that the protein concentration also influences the stability of formed emulsions against flocculation as a result of changes in the ionic strength. In both cases, the stability was postulated to be the result of a complete (i.e. saturated) coverage of the interface. By combining the current views on emulsion stability against coalescence and flocculation with new experimental data, an empiric model is established to predict emulsion stability based on protein molecular properties such as exposed hydrophobicity and charge. It was shown that besides protein concentration, the adsorbed layer (i.e. maximum adsorbed amount and interfacial area) dominates emulsion stability against coalescence and flocculation. Surprisingly, the emulsion stability was also affected by the adsorption rate. From these observations, it was concluded that a completely covered interface indeed ensures the stability of an emulsion against coalescence and flocculation. The contribution of adsorption rate and adsorbed amount on the stability of emulsions was combined in a surface coverage model. For this model, the adsorbed amount was predicted from the protein radius, surface charge and ionic strength. Moreover, the adsorption rate, which depends on the protein charge and exposed hydrophobicity, was approximated by the relative exposed hydrophobicity (QH). The model in the current state already showed good correspondence with the experimental data, and was furthermore shown to be applicable to describe data obtained from literature.Display Omitted
Keywords: Coalescence; Flocculation; Model; Adsorption rate; Adsorbed amount; Surface coverage;

C. elegans as a tool for in vivo nanoparticle assessment by L. Gonzalez-Moragas; A. Roig; A. Laromaine (10-26).
Characterization of the in vivo behavior of nanomaterials aims to optimize their design, to determine their biological effects, and to validate their application. The characteristics of the model organism Caenorhabditis elegans (C. elegans) advocate this 1 mm long nematode as an ideal living system for the primary screening of engineered nanoparticles in a standard synthetic laboratory. This review describes some practicalities and advantages of working with C. elegans that will be of interest for chemists and materials scientists who would like to enter the “worm” community, anticipates some drawbacks, and offers relevant examples of nanoparticle assessment by using C. elegans.Display Omitted
Keywords: Caenorhabditis elegans; Nanoparticles; Nanoscience and nano-bio interfaces; Model organism;

There have been major advances in the development of edible colloidal delivery systems for hydrophobic bioactives in recent years. However, there are still many challenges associated with the development of effective delivery systems for hydrophilic bioactives. This review highlights the major challenges associated with developing colloidal delivery systems for hydrophilic bioactive components that can be utilized in foods, pharmaceuticals, and other products intended for oral ingestion. Special emphasis is given to the fundamental physicochemical phenomena associated with encapsulation, stabilization, and release of these bioactive components, such as solubility, partitioning, barriers, and mass transport processes. Delivery systems suitable for encapsulating hydrophilic bioactive components are then reviewed, including liposomes, multiple emulsions, solid fat particles, multiple emulsions, biopolymer particles, cubosomes, and biologically-derived systems. The advantages and limitations of each of these delivery systems are highlighted. This information should facilitate the rational selection of the most appropriate colloidal delivery systems for particular applications in the food and other industries.Display Omitted
Keywords: Delivery systems; Hydrophilic actives; Biopolymers; Nutraceuticals; Microparticles; Nanoparticles;