Peculiarities of walnut oil state in some food emulsions

Abstract

The replacing of traditional lipids with more health-promoting oils containing polyunsaturated fatty acids (PUFA) is a modern trend in food industry. The principles of emulsions formation containing walnut oil (up to 90% PUFA) were studied in order to accumulate information that would help to design new functional products. The phase diagrams of the state of three-component systems – Walnut oil / Water / Ethanol and Walnut oil / Polyphenol extract / Water were investigated. It was shown that walnut oil was more prone to form W/O emulsions than O/W ones, that can possibly be explained by the presence of natural surfactants in it. This property of walnut oil was used within the functional spread obtaining. It has been established that the elaborated product represents an emulsion, in which water micelles and air inclusions are dispersed in continuous lipid phase, consisting of solid lipids. Withal, the structure stability of spread rich in PUFA from walnut oil was ascertained being almost analogous to milk-based butter, retaining its functionality and high biological value within a month at the temperature regime up to 5ºC.