Encapsulation

Use Cases 

Can a model that describes the shape relaxation of capsules be established?

Reference: Tregouët, C.; Salez, T.; Monteux, C.; Reyssat, M., Microfluidic probing of the complex interfacial rheology of multilayer capsules. Soft matter 2019, 15 (13), 2782-2790.

Knowing the mechanical properties of a membrane is of great interest. These properties control the transport and release of the droplet content in food industry, drug delivery, material science, cosmetics, etc.

In this paper, the automated drop tensiometer TRACKER™  was used to highlight the capsule formation at a dodecane/water interface

After a deformation, a competition starts between the viscous forces deforming the droplets and the interfacial tension force restoring its shape. The authors establish a universal model based on a capillary relaxation model that includes the surface tension measurements and an elastic relaxation model that includes the viscoelastic modulus.

 

TECLIS product: TRACKER™  automatic drop tensiometer

Key words: capillary relaxation model, polymer capsule, liquid to solid transition

Can plant proteins be used for

encapsulation systems ?

Reference: Li, X., Erni, P., Van Der Gucht, J., & De Vries, R. (2020). Encapsulation using plant proteins: Thermodynamics and kinetics of wetting for simple zein coacervates. ACS applied materials & interfaces, 12(13), 15802-15809.

In this paper, the authors revisit the well-known simple coacervates of prolamins such as zein in mixed solvents to explore whether they can be used for plant-based encapsulation systems. The authors show that, for zein in mixed water/ propylene glycol (PG) solvents, limonene droplets encapsulation is possible but only under specific conditions. This limitation is attributed to the very different physical properties of the simple zein coacervates as compared to those of the more extensively studied complex coacervates. In particular, interfacial tension measurements  using an automatic drop tensiometer (TRACKER™  by TECLIS) showed that the spreading of zein coacervates at the interface of the droplets is thermodynamically favorable due to their extremely low interfacial tensions in both the dispersed (∼0.24 mN/m) and oil phases (∼0.68 mN/m). However, the kinetics of coacervate droplet deposition and the interactions among coacervate droplets that oppose coacervate droplet coalescence are highly pH-dependent, leading to a sharp pH optimum (around pH 8) for capsule formation.

TECLIS product: TRACKER™  automatic drop tensiometer

Key words: plant protein, simple coacervation, encapsulation, interfacial tension, wetting

Can pea proteins be used for

micro-encapsulation applications?

Reference: Francisco, C. R. L., de Oliveira Júnior, F. D., Marin, G., Alvim, I. D., & Hubinger, M. D. (2020). Plant proteins at low concentrations as natural emulsifiers for an effective orange essential oil microencapsulation by spray drying. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 607, 125470.

In this work, pea and soy proteins (PPC and SPI respectively) were used as emulsifiers for the encapsulation of orange essential oil (OEO, rich in d-limonene) by emulsification followed by spray drying. PPC is moderately soluble in water which resulted in a lower adsorption at the oil-water interface compared to SPI as shown by surface tension measurements with an automatic drop tensiometer (TRACKER™  by TECLIS). This solubility difference resulted in oil-in-water emulsions stabilized with PPC or SPI with different physicochemical properties and stability. Despite this, the spray-dried microparticles produced using PPC or SPI present similar physical properties overall which promotes the protection of the encapsulated OEO.

TECLIS product: TRACKER™  automatic drop tensiometer

Key words: plant protein, essential oil, emulsion stability, spray-drying, micro-encapsulation