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

Abstract

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.