Comparison of the flavor qualities between two varieties of Mercenaria mercenaria

The saltwater hard clam Mercenaria mercenaria (M. mercenaria) as a representative of low-value shellfish, enhancing its flavor quality, is the key to enter the high-end market. Nevertheless, there has not been reported research on the flavor quality of M. mercenaria. This study compared the flavor quality of selective and non-selective saltwater hard clams of M. mercenaria by using various indicators: proximate component, free amino acids, nucleotides, and metabolomic analysis. The results indicated that selective breeding contributed to the significant improvement contents of crude protein, flavor-associated free amino acids (glutamic acid, aspartic acid, proline, etc.), and nucleotides (AMP) (P < 0.05). Then, the metabolome was utilized to assess the metabolite changes in the pre/post-selective breeding of M. mercenaria and further understand the flavor characteristics and metabolic status. In the metabolomics assay, among the 3143 quantified metabolites, a total of 102 peaks were identified as significantly different metabolites (SDMs) between the selective and non-selective varieties of M. mercenaria (VIP > 1 and P < 0.05). These results can provide new insights for future research on improving the quality of saltwater bivalves through selective breeding.