In order to find a suitable method for the measurment of solid fat index (S.F.I.) by a differential scanning calorimeter (DSC) and analysis of its result, dilatometry and high-resolution nuclear magnetic resonance (NMR) method were compared with this method. Difference in the measured values according to different commercial apparatus and between laboratories was also examined.
1) S.F.I. was measured with samples prepared by mixing liquid soybean oil and hardened beef tallow in various proportions. Melting heat from 0°C to the end of melting is proportional to the amount of hardened beef tallow, therefore, the heat of melting of 100% hardened beef tallow, 37cal/g, was used to calculated the S.F.I. The S.F.I. of all the samples at 30°C was slightly different from the values obtained by dilatometry but agreed with that from high-resolution NMR method.
2) Measurement of stepwise hydrogenated hardened beef tallow showed that the S.F.I. below 40 agreed well with the results from NMR and dilatometry.
3) As compared with other methods, temperature dependence of the S.F.I. measured by the DSC tends to the higher temperature side by about 3°C. This difference is considered to be due to the dynamic nature of measurement conditions in DSC whereas those in other methods are static.
4) There was no measurement error according to the kind of commercial apparatus used or between laboratories by this DSC, and reproducibility by the use of the same apparatus was relatively good.
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