Measurement of Lipid Contents Using Different Solvents and Methods

Lipid contents of fish meal, soybean cake, fish oil and soy oil were measured by using Soxtec extraction at high temperatures and ether, petroleum ether and chloroform-methanol (2∶1) as solvents, and using Folch et al(1957)′s extraction with chloroform-methanol (2∶1) at room temperature. Samples sizes were aroud 1 g for the Soxtec extraction, and 50-90 mg for Folch et al′s extraction. Significant differences were found in values measured with different methods. Most marked differences were found for the fish meal and soybean cake between chloroform-methanol extraction and other methods, as chloroform-methanol extraction resulted in much higher values. For fish oil and soy oil, the chloroform-methanol extraction at room temperature showed higher values.