ABSTRACT
The protein film adsorbed at the oil-water or air-water interface is the source of many of the unique properties of food emulsions and foams, particularly their stability and interactions, which translate into the shelf-life and textural properties so desired by manufacturers and appreciated by consumers. This is the intuitively attractive picture that the reviews and textbooks would have us believe but the reality is that, despite all the research effort put into studying those interactions, we still do not have a reliable predictor of shelf-life in emulsion products. As for texture, we still have no quantitative instrumental measures of creaminess, mouth-feel, or even perceived thickness. Partly this arises because the interfacial layer in food emulsions is compositionally and structurally complex, but this facile explanation conceals an underlying lack of ability to formulate a realistic interaction potential between emulsion droplets or foam bubbles. That notwithstanding, considerable progress has been made in the last 10 to 15 years in extending our knowledge of the interactions between and within adsorbed protein films, much of it on proteins of interest to the food manufacturer, and much of it reviewed in extenso by Dickinson [1-6].
