Metabolomic approaches to analyze the seasonal variations of amino acid, 5′-Nucleotide, and lipid profile of clam (Ruditapes philippinarum)

This study investigated the changes in free amino acids (FAAs), 5′-nucleotides, and lipid compositions of Manila clams ( Ruditapes philippinarum ) collected from December 2017 to November 2018. High-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry was used to quantify twenty-one FAAs and six 5ʹ-nucleotides. Lipid profiles were explored by ultra-performance liquid chromatography coupled with a Q-Exactive Orbitrap mass spectrometer with an untargeted lipidomic approach. Results showed significant monthly changes of FAAs, 5′-nucleotides, and lipids profiles. Alanine , glutamic acid , glycine, and aspartic acid , which contributed to the sweet and umami flavor, were the most abundant FAAs in Manila clams. Totally 90 glycerides, 76 glycerophospholipids , 21 lyso-glycerophospholipids, and 52 fatty acids were identified in Manila clams. Among these lipids, most of them possessed a high-level of unsaturation degree. The unsaturation degree of lipids in February, March, and April was the highest, showing the best nutritional value of Manila clams.