EFFECT OF GELLED INNER AQUEOUS PHASE RHEOLOGY ON THE COLOUR DEGRADATION OF MUITLE AQUEOUS EXTRACTS INCORPORATED INTO WATER-IN-OIL-IN-WATER DOUBLE EMULSIONS

The aim of this work was to study different W-1/O/W-2 double emulsions in preserving color muitle aqueous extract (MAE), for which the work was divided into two fold, formulation and analysis of primary emulsion W-1/O and W-1/O/W-2 double emulsions. Sodium alginate (SA), xanthan gum, guar gum, locust bean gum were used as gelling agents of MAE, and it was found that SA produced inner aqueous phase with enhanced viscoelastic properties, resulting in a W-1/O primary emulsion with more uniform mean droplet size and distribution than when using the other gelling agents or ungelled MAE. Subsequently W-1/O/W-2 double emulsions were produced containing MAE gelled with SA or ungelled in the inner aqueous phase stabilized using pure gum Arabic (GA) or a blend of GA-mesquite gum (MG) in a 70:30 ratio in the outer aqueous phase. The double emulsion formulated with gelled MAE and 70:30 GA-MG blend exhibited more uniform mean inner water and outer oil droplet sizes, and protected best the anthocyanins contained in MAE to preserve its color when exposed to 8 h sunlight, providing a half-time life (t(1/2)) of 55.23 h. The double emulsion formulated with ungelled MAE and stabilized with pure GA displayed a t(1/2) of 7.40 h.