Interfacial Tensions of Commercial Vegetable Oils with Water

The pendant drop method, the current method of choice for interfacial tension measurement, was used to obtain the interfacial tensions of a number of vegetable oils with water. Contrary to the reports of earlier workers, all triglycerides examined had similar interfacial tensions with water, all values being in the range 23-26 mNm−1. Long chain fatty acids, principal contaminants of commercial oils, had little effect on the interfacial tension. When the oils were exposed to alkaline conditions, the mono- and diglycerides formed by hydrolysis caused the interfacial tension to drop rapidly, in agreement with previously reported results for the effect of mono- and diglycerides on interfacial tensions.