Novel Water-in-Water Emulsions: Formation, Stabilization and Possible Applications as Drug Delivery Systems

Water-in-water (W/W) emulsions are colloidal dispersions formed in aqueous two-phase systems, because of thermodynamic incompatibility between two hydrophilic macromolecules in aqueous solution, in absence of surfactant and without oil [1]. W/W emulsions can be can be prepared in mixtures of edible macromolecules, such as proteins and polysaccharides (Fig. 1). These fat-free emulsions can be highly interesting for formulation of functional food products and oral delivery of active components.

We have obtained W/W emulsions in aqueous mixtures of gelatin and carboxymethyl cellulose and these emulsions could entrap probiotic bacteria [2]. In another work, we used gelatin-in-maltodextrin W/W emulsions for the encapsulation of lactase inside gelatin microgels cross-linked with genipin. The enzyme showed a high degree of activity and gelatin microgels provided protection in a simulated gastric fluid [3]. More recently, we obtained multiple water-in-water-in-water emulsions by a simple method that consisted in cooling down gelatin-in-maltodextrin (G/M) emulsions, leading to the spontaneous formation of inner maltodextrin droplets and producing M/G/M multiple droplets [4]. The colloidal stability of M/G/M emulsions was much increased by the adsorption of mucin particles at the G/M interface.

Fig. 1. Fluorescence optical microscopy images of W/W emulsions. (a) Dextran-in-in gelatin emulsions; (b) Gelatin-in-maltodextrin emulsions, with mucin particles at the interface.


[1] J. Esquena, Current Opinion in Colloid and Interface Science, 25 (2016) 109

[2] Singh P., Medronho B., Miguel M.G., Esquena J., On the encapsulation and viability of probiotic bacteria in edible carboxymethyl cellulose-gelatin water-in-water emulsions, (2018) Food Hydrocolloids, 75, pp. 41 – 50

[3] Beldengrün Y., Aragon J., Prazeres S.F., Montalvo G., Miras J., Esquena J., Gelatin/Maltodextrin Water-in-Water (W/W) Emulsions for the Preparation of Cross-Linked Enzyme-Loaded Microgels, (2018) Langmuir, 34 (33), pp. 9731 – 9743.

[4] Beldengrün Y., Dallaris V., Jaén C., Protat R., Miras J., Calvo M., García-Celma M.J., Esquena J., Formation and stabilization of multiple water-in-water-in-water (W/W/W) emulsions, (2020) Food Hydrocolloids, 102, art. no. 105588.


nov. 10 2023


12:00 - 13:00


Aula 102, ETSEQ


  • Jordi Esquena Moret
    Jordi Esquena Moret
    Institute of Advanced Chemistry of Catalonia (IQAC), Barcelona

    Dr. Jordi Esquena finished his Ph.D Thesis in 1996, in the Chemical and Environmental Research Institute of Barcelona (IIQAB-CSIC). After a post-doctoral period of 3 years at the University of Hull, UK, he joined the Institute of Advanced Chemistry of Catalonia (IQAC-CSIC) in 2000, where he is a member of research staff since 2006.

    His scientific production can be summarized in ≈116 Publications in indexed journals; 8 Book chapters; 3 Patents; 8 publications in technical journals and ≈40 publications in conference proceedings. These publications have resulted in >5000 citations in indexed journals, with H-index = 30.