Rheological, Structural, and Microstructural Properties of Ethanol Induced Cold-set Whey Protein Emulsion Gels: Effect of Oil Content

The aim of this research was to prepare ethanol-induced cold-set emulsion gels contain different content of oil and to investigate the effect on the rheological, textural, and microstructural properties. The results showed that the gelation rate, gel strength, water-holding capacity (WHC), and hardness of the ethanol-set emulsion gels improved as the content of oil increased. Rheological analysis showed that the emulsion gels changed from combined polymer/particle gel behavior at low oil contents to particle gel behavior at high oil contents. The emulsion gels contained a three-dimensional network of aggregated oil droplets at high oil contents, while they contained an even distribution of isolated droplets at lower oil contents. The results showed that the properties of the ethanol-set emulsion gels could be modulated by altering the oil content because the oil droplets acted as active fillers. Ethanol-induced gelation presents an intriguing possibility for encapsulation of alcohol-soluble, lipid-soluble and heat-labile bioactive compounds.