COMPETITIVE ADSORPTION OF MONOGLYCERIDES AND LECITHIN AT THE VEGETABLE OIL-WATER INTERFACE

Understanding the competitive adsorption behavior of monoglycerides and lecithins is critical, especially in the development and processing of low-fat spreads. In the present study two commercial oil blends, containing different levels of native surface-active impurities, were used. Our data show that lecithin has higher surface activity than the impurities in the oil blends, which in turn are more surface active than the monoglyceride. Hence, in the presence of lecithin the surface-active impurities are excluded from the interface. At high levels of the monoglyceride, lecithin gets incorporated in the reverse micelles and is also removed from the interface. Experiments at different temperatures with soybean oil containing native surface-active impurities also support this hypothesis.