Effect of lemon balm (Melissa officinalis L.) essential oil on some characteristics of oil/water food emulsions

Abstract

Food emulsions are used on a daily basis by people, therefore it is of great importance to study the factors that can influence their stability. The aim of this work is to track the influence of lemon balm essential oil (Melissa officinalis L.) on the change of some physical and chemical indicators, kinetic (turbidity) and thermodynamic (Gibbs free energy, enthalpy and entropy) parameters, which are related to their stability. 24 food emulsions were developed with oleic type sunflower oil acting as an oil phase in concentrations of 20 and 30%, soybean protein emulsifier in concentrations of 1, 2, and 3% and lemon balm essential oil in concentrations of 0.1, 0.2 and 0.3%. The pH of the emulsions was determined, microscopic photographs were taken to measure the sizes of the colloidal particles, turbidity was observed for 15 days, their absorbance was determined, Gibbs energy, enthalpy and entropy were calculated. The most stable is the emulsion with 30% oil phase, 3% soybean protein emulsifier and 0.3% lemon balm essential oil.