Effect of formulation and pH on rheological properties, particle size distribution, and stability of oil-in-water beverage emulsions

Beverage emulsions are oil-in-water (o/w) emulsions prepared by dispensing vegetable oils in an aqueous base containing hydrocolloids, preservatives, acid and colors. Stability of such emulsions, in both concentrated forms and diluted final preparations, is a requirement and physical separation (creaming) is a critical problem in the beverage industry. The main objective of this research was to investigate the concentration effects of different hydrocolloids, both individually and in combinations, at two pH levels (neutral and 3.4) on the associated rheological properties, particle size distribution, and stability of prepared o/w emulsions and determine optimal conditions for their stability in both concentrated (2 weeks) and diluted forms (2 months).;Viscous and elastic properties of the concentrated emulsions as well as their opacity increased with an increase in hydrocolloid concentration. Gelatin type 'A' at neutral pH and type 'B' at pH 3.4 was less stable possibly due to protein aggregation close to their iso-electric points and loss of repulsive force. Modified starch had a smaller average particle size and possessed suitable stability at both pH levels. Modified gum Arabic was more stable at neutral pH. In simulated beverages, those containing modified starch, modified gum Arabic, type 'A' gelatin-modified starch conjugates exhibited stability with no signs of creaming with thermal and high pressure pasteurization. Obtained results provide useful information for the preparation of novel stable juice and milk beverages, without the historically employed weighting agents (brominated vegetable oil, ester gum, sucrose acetate isobutyrate) for stabilizing beverages.;Oil-in-water emulsions were made using gelatins (Types "A" and "B"), modified starch and modified Arabic gum alone and with selected viscosity builders (Xanthan gum and propylene glycol alginate), and their rheological properties, and their physico-chemical properties were evaluated. Emulsions demonstrating reasonable stability were selected and incorporated into a simulated juice base and a mimicked dairy beverage. Creaming behavior and stability of simulated beverages, containing 2% emulsion, were evaluated over a storage period of 2 months.