Determination of Formulation Conditions Allowing Double Emulsions Stabilized by PGPR and Sodium Caseinate to Be Used as Capsules

Abstract

Water-in-oil-in-water (W/O/W) double emulsions stabilized by polyglycerol polyricinoleate (PGPR), a lipophilic food grade small polymer, and sodium caseinate, a hydrophilic milk protein, were developed to encapsulate vitamin B12, a model hydrophilic substance easy to titrate. Using rheology, sensitive to drop size evolution and water fluxes, static light scattering, and microscopy both giving the evolution of drops' size and vitamin B12 titration assessing the encapsulation, we were able to detect independently the double emulsion drop size, the encapsulation loss, and the flux of water as a function of time. By differentiating the PGPR required to cover the W-droplets' surface from PGPR in excess in the oil phase, we built a PGPR-inner droplet volume fraction diagram highlighting the domains where the double emulsion is stable toward encapsulation and/or water fluxes. We demonstrated the key role played by nonadsorbed PGPR concentration in the intermediate sunflower oil phase on the emulsion stability while, surprisingly, the inner droplet volume fraction had no effect on the emulsion stability. At low PGPR concentration, a release of vitamin B12 was observed and the leakage mechanism of coalescence between droplets and oil-water interface of the oily drops (also called globules hereafter), was identified using confocal microscopy. For high enough PGPR content, the emulsions were stable and may therefore serve as efficient capsules without need of an additional gelling, thickening, complexion or interface rigidifying agent. We generalized these results with the encapsulation of an insecticide: Cydia pomonella granulovirus used in organic arboriculture.

Cross-linking of double oil-in-water-in-oil emulsions: A new way for fragrance encapsulation with tunable sustained release

“…In agriculture, pesticides are encapsulated to be released with time [2][3][4] allowing them to be more effective and safer to both operators and environment [5,6]. In food, flavors are encapsulated for taste masking, for protecting ingredients from the external environment or oxidation [7][8][9] or as additional vitamin provider [10,11]. In stickers, cardboard, books and magazines, scratch and sniff technology is used to provide a sensory experience to the reader.…”

Production of reduced‐fat whipped toppings by solid fat‐based W/O/W double emulsions: proof of concept

“…The O/W emulsion containing 5.0 wt% of PGPR had more PGPR at the outer O/W interface compared to the W/O/W double emulsion: as a large amount of the PGPR will be situated at the internal W/O interface in the double emulsion, less PGPR remains available for adsorption at the external interface. If the surface area of a PGPR molecule polar head is 100 Å 2 (Nollet et al , ), a double emulsion yield of 60% is assumed and the size of the internal water droplets was at most 1 µm (according to the largest internal droplets seen on microscopic images), it can be calculated that at least 54% of the PGPR of the oil phase is present at the internal interface of our double emulsions. This phenomenon may explain the earlier rise in viscosity in the O/W emulsion containing 5.0 wt% PGPR compared to the W/O/W reference emulsions (Fig.…”

Double emulsions for iron encapsulation: is a high concentration of lipophilic emulsifier ideal for physical and chemical stability?

“…4,32 We calculated that PGPR was most likely present in large excess (83.7% to 93.7%) for all tested concentrations (Table 1). Nollet et al 33 determined the critical micellar concentration of PGPR in sunflower oil, which they found to be 10 g kg −1 . This would imply that in our case, emulsions made with PGPR concentration equal to or above 25 g kg −1 would contain excess PGPR as reverse micelles in the oil phase.…”