The change in the absorption of deep-frying oil and substitution of the lipid between a food material and frying oil were investigated to standardize the absorption rate of frying oil for use in a dietary survey. Pork loin, pork fillet, salmon, horse mackerel and shrimp were used as the food samples. The absorbed amount of frying oil was calculated by the change in fatty acid composition (18:2) of both the food and frying oil before and after deep-frying. The variation in the absorption between each deep-fried food was small in comparison with the change in lipid amount before and after deep frying, i.e. the apparent absorption of frying oil. In contrast, there was wide variation in the substitution of the lipid among the food samples. In particular, the absorption of frying oil by the pork loin, whose lipid content was high, was twice the apparent absorption of frying oil. It is concluded that the difference in apparent absorption of frying oil by each deep-fried food sample depended on the difference in amount of the lipid substitution by deep-frying.
