Senior Resercher Shizuoka Prefectural Research Institute of Fishery Yaizu, Shizuoka, Japan
A new method analyzing FA distribution in TAG (Joint JOCS/AOCS Official Method Ch 3a-2019) is advantageous to be applicable to fish oil and milk fat with PUFAs and short-chain FAs. These oils are out of scope in the conventional method (ISO 6800-1997) using pancreas lipase. The official method Ch 3a consists mainly of 3 steps; 1) Regioselective degradation of target TAG to 2-MAG using immobilized Candida antarctica lipase (CALB); 2) SPE fractionation of 2-MAG; 3) FA composition analysis by GC. To the procedure, a novel and quick lipid extraction method was combined for the first time, using trout salmon meat as a starting material in this study. Prior to step 1 of Ch 3a, lipids in fish meat were extracted by one-step FA extraction method (doi:10.1111/1750-3841.13850) using extraction columns. The time for the extraction was reduced to 5 min/sample by the method from 30 min/sample by the conventional, Folch method. Sufficient amounts of lipids for Official Method Ch 3a were obtained by increasing the column load 6 times to the original instruction. The two extraction methods gave similar FA composition and accuracy. Furthermore, newly developed CALB, Lipase CL”Amano”IM (Amano Enzyme) was used as an alternate for Novozym 435 in step 1. In step 2, SPE column Sep-Pak silica (Waters) was replaced by Inert-Sep SI (GL Science). The substitutions gave similar results in FA distribution in lipids extracted from trout salmon meat analyzed by Official Method Ch 3a.