Rheology and Stability of Beverage Emulsions in the Presence and Absence of Weighting Agents: A Review

Abstract

Cloudiness or opacity (cloudy appearance) is an important property in citrus beverages, since it enhances their juice-like appearance and gives it a natural fruit juice appeal. This property is achievable through the addition of oil-in-water emulsions known as clouding agents. These emulsions are thermodynamically unstable and tend to break down during storage. Moreover, product and legal constraints put severe limits on materials that can be used to insure emulsion stability, particularly the introduction of weighting agents into the oil phase. Weighing agents (density-adjusting agents) are lipophilic compounds with specific gravity higher than that of water and have a restricted use because of the perceived health risk disadvantage, undesirable taste, and oxidative instability. The stability of beverage emulsions is a problem of serious concern faced by the flavor and beverage industry. This paper provides an overview of research carried out by the authors on basic factors affecting the physical stability of beverage cloud emulsions having a bearing on droplet size/distribution, rheological properties of emulsion and phases components, and the stability of emulsion in concentrated and diluted forms with or without addition of weighting agents.