Double (W₁/O/W₂) and Simple (O/W₂) Emulsions Prepared with Soybean Flour Dispersion and Vegetable Fat: Partial Coalescence Promotion by Polyglycerol Polyricinoleate and Calcium

Abstract

The objective is to study the partial coalescence process in calcium‐fortified double (W1/O/W2) and simple (O/W2) emulsions prepared with soybean flour dispersion as continuous aqueous (W2) phase and vegetable fat plus polyglycerol polyricinoleate (PGPR) as lipophilic emulsifier (at varied concentration) in lipid phase. Calcium chloride is included in the dispersed aqueous (W1) phase and the W2 phase of W1/O/W2 and O/W2 emulsions, respectively. No partial coalescence is observed in the O/W2 emulsion without PGPR and calcium, while the inclusion of the emulsifier and/or divalent cation promotes the phenomenon. The presence of PGPR in lipid phase or calcium in W2 phase can enhance capture efficiency because of the decrease of electrostatic and steric repulsions between fat globules, the modification of fat crystals, and/or the increased size of individual globules. W1/O/W2 emulsions show a lower partial coalescence degree in comparison to O/W2 emulsions prepared with the same components, attributed to the isolation of a fraction of added calcium in the W1 phase of the former systems. PGPR produces microstructural and rheological changes over time in emulsions subjected to prolonged cold storage; but its effect is reduced in the presence of calcium, probably because of the formation of stronger globule aggregates. Practical applications: This article deals with two parallel phenomena occurring in W1/O/W2 and O/W2 emulsions prepared with soybean flour dispersion as W2 phase and vegetable fat in lipid phase: the promotion of partial coalescence by the lipophilic emulsifier, PGPR; and the aggregation of proteins and fat globules due to the presence of calcium in W2 phase. In this way, the effects of PGPR and/or calcium on partial coalescence are studied in these systems, analyzing their microstructure and rheology. The encapsulation of calcium within the W1 phase of W1/O/W2 emulsions and its impact on partial coalescence is also analyzed. The results obtained in this work can be relevant for the formulation of calcium‐fortified, vegetable food emulsions, showing a texture similar to whipped dairy cream, where PGPR concentration or calcium release can be controlled to adjust the rheological characteristics of the system.

Analytics and applications of polyglycerol polyricinoleate (PGPR)—Current research progress

“…Thus, PGPR was used to stabilize ethanol-in-oil emulsions to deliver an ethanolic extract (Duangkaew et al, 2018), to form stable micelles in glycerol to encapsulate vitamin E (Matsuoka et al, 2017), to substitute glyceryl monostearate to prepare solid lipid nanoparticles and to improve the stability and encapsulation efficiency of nanostructured lipid carrier vitamin D 3 emulsions (Seo et al, 2019), to modulate the crystallization process of mango butter (Qureshi et al, 2020), and to improve the softness and lubrication properties of fresh butter (Panchal et al, 2021), as well as to enhance the antioxidant activity of curcumin and sesamol during oil oxidation (Jokar et al, 2022;Keramat et al, 2022). Moreover, the addition of PGPR increased the partial coalescence degree in vegetable fat cream-like emulsions by enhancing the capture efficiency due to the decreased steric repulsion between fat globules, thereby improving the creaming stability (Gutiérrez Hernández et al, 2023;Rando et al, 2022). As the use of PGPR is strictly regulated, and as PGPR can cause off-tastes when used in a high concentration, it is important to minimize the concentration of PGPR in food applications (Hong et al, 2021).…”