Sex-Specific Differences in Quality and Flavor Traits of Gonads from the Sea Urchin (Heliocidaris crassispina): An Integrated Sensory and Metabolomic Analysis

To investigate sex-specific differences in gonad quality and flavor characteristics of the sea urchin Heliocidaris crassispina, female and male gonads were compared using proximate composition, colorimetry, E-tongue, E-nose, LC-MS, and HS-SPME-GC-MS. No significant sex differences were observed in wet weight, test diameter, gonadosomatic index, moisture, or crude fat, whereas female gonads showed higher crude protein content, lightness, and yellowness. E-tongue and E-nose analyses revealed distinct sex-dependent taste and odor fingerprints. Metabolomics identified 366 differential non-volatile metabolites and 53 differential volatile metabolites, mainly involving lipids, organic acids and derivatives, dipeptides, nucleotide-related compounds, hydrocarbons, terpenoids, aldehydes, ketones, and esters. Female gonads were enriched in phospholipids, lysophospholipids, dipeptides, and nucleotide precursors, whereas male gonads contained higher levels of acylcarnitines, hydroxy fatty acids, 3-carene, and hydrocarbons. These findings provide metabolomic evidence for sex-dependent flavor differences and support quality evaluation of sea urchin products.