Establishment of a model substrate oil for antioxidant activity assessmentby Oil Stability Index method

A model substrate oil using methyl linoleate was established for the determ ination of the antioxidant activity by Oil Stability Index (OSI) method. OS I values for methyl linoleate with different concentrations (5-100%) in sil icone oil were measured at different temperatures (70-120 degreesC), As the temperature increased, the OSI value decreased in each concentration of me thyl linoleate. Optimal temperature and concentration of methyl linoleate w ere established. The effect Of concentration of antioxidants, alpha -tocoph erol, and butylated hydroxytoluene on OSI values for 10% methyl linoleate m odel oil was measured at 90, 100, 110, and 120 degreesC, The logarithmic re iationship between temperature and OSI using model substrate oil was simila r to that of soybean oil. Furthermore, application of some spice extracts t o this model oil system was carried out to give results that compared well with those available in the literature. Thus, the procedure using methyl li noleate-silicone oil as a model substrate oil is available for evaluating t he antioxidant activity by the OSI method.