Effect of sol-gel transition of oil phase (O) and inner aqueous phase (W1) on the physical and chemical stability of a model PUFA rich-W1/O/W2 double emulsion

Abstract

In this study, the effect of sol–gel transition of oil phase (O) and inner aqueous phase (W1) on the physical and chemical stability of a model PUFA rich-W1/O/W2 double emulsion (DE) was investigated. Thermal-driven gelation of O and W1 was performed using monoglyceride and κ-carrageenan, respectively. To accelerate lipid oxidation, ferrous sulfate was encapsulated in W1. Using this approach, O gelation reduced the volume-weighted size (d4,3) of DEs droplets and provided good physical stability. However, non-gelled DEs and those containing gelled W1 exhibited extensive flocculation and coalescence. Moreover, oleogelation resulted in a predominant elastic behavior with weak frequency dependence of viscoelastic properties. Oxidation was significantly reduced by W1 gelation; however, the O gelation led to a higheroxidation rate. Oxidation kinetic parameters induced by a hydrophilic (gallic acid) and a lipophilic (α-tocopherol) antioxidant showed that DEs containing gelled O droplets presented high physical and oxidative stability when α-tocopherol was present.