Interfacial tensions of vegetable oil/water systems: Effect of oil purification

Abstract Methods were developed to determine the interfacial tension (IT) of vegetable oil/water systems as a function of time, and to remove interfacially active contaminants from commercial vegetable oils. Interfacial tensions between commercial vegetable oils and water decreased with time due to the presence of impurities. Interfacial tensions of purified oils against water were substantially higher than those reported in the literature, and remained unchanged with time, thereby indicating the absence of surface chemical impurities in the oil. The lowering of IT in the case of commercial oils was ascribed to the presence of mixtures of monoglycerides.