Effect of linalool on lamellar-structured emulsions: From molecular organization to organoleptic properties

An original approach has been developed to investigate the behaviour of linalool, a volatile compound widely used in the flavour and fragrance industry, incorporated in a model lamellar emulsion stabilized by an alkyl polyglucoside (APG). The surface activity of amphiphilic linalool was first studied in aqueous solutions, to predict its partition in multiphase colloidal systems. Results showed the high interfacial activity of linalool and its ability to act as a co-surfactant. The air/matrix partition coefficient was determined using headspace gas chromatography (HS-GC) and highlighted the different interactions between linalool and the emulsion phases. The molecular organization of lamellar emulsions was affected by the addition of linalool, as evidenced by combined microscopic observations, static light scattering (SLS) and X-ray diffraction measurements. As microstructure and rheological properties are closely linked, the viscoelastic properties of the samples were also investigated. The particle diameter, viscoelastic parameters and consistency of the emulsions were found to decrease with the addition of linalool. Finally, some textural and sensory properties of emulsions were evaluated and showed that the effect of linalool on the microstructure of the samples could also be perceived at the macroscopic scale, on their organoleptic properties. Our original approach could be used as a powerful tool for the future development of flavoured or fragranced emulsions.