Stability of alcoholic emulsions containing different caseinates as a function of temperature and storage time

Abstract

Alcoholic emulsions were prepared with three different caseinate batches at 3 and 4% (w/v) protein content and 16.9% (v/v) ethanol content. Two storage temperatures (25 and 40 °C) and three storage times (0, 25 and 45 days) were used. The rheological behaviour and particle size distribution of samples were obtained. The caseinate batches #106 and #102 stabilized the emulsion up to 45 days storage time. While emulsions prepared with caseinate batch #103 never achieve stabilization. Stability of the emulsion was also proven by adding ethanol and visually detecting coalescence, the protein content showed to be crucial to reduce coalescence, for all emulsions with 4% protein content, coalescence visually appeared at higher alcohol content than for emulsion with 3% protein content. For the emulsion prepared with caseinate batch #103, coalesce was detected at the lowest alcohol concentrations (<30%), while for emulsion prepared with caseinate batch #102 coalescence was detected at the highest alcohol concentrations (>40%) this effect was consistent with the inverse of ions content. Viscosity was found to increase with storage time in all the blends. The volumetric diameter (4,3) was a function of storage time and in all cases the coalescence increases.