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

In this study, the effect of sol-gel transition of oil phase (O) and inner aqueous phase (W-1) on the physical and chemical stability of a model PUFA rich-W-1/O/W-2 double emulsion (DE) was investigated. Thermal-driven gelation of O and W-1 was performed using monoglyceride and kappa-carrageenan, respectively. To accelerate lipid oxidation, ferrous sulfate was encapsulated in W-1. Using this approach, O gelation reduced the volume-weighted size (d(4,3)) of DEs droplets and provided good physical stability. However, non-gelled DEs and those containing gelled W-1 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 W-1 gelation; however, the O gelation led to a higher oxidation rate. Oxidation kinetic parameters induced by a hydrophilic (gallic acid) and a lipophilic (alpha-tocopherol) antioxidant showed that DEs containing gelled O droplets presented high physical and oxidative stability when alpha-tocopherol was present.