Based on the competition between the electron transfer effect of nitrogen-doped carbon dots (N–CDs)/Fe ³⁺ and the complexation reaction of As(v)/Fe ³⁺ , an “off–on” fluorescence assay was developed to detect As(v) in complex food substrates.

The flavor characteristics of three commercially important, cultivated mussel species (Mytilus coruscus, Mytilus galloprovincialis, and Perna viridis) were investigated through analyses of free amino acids, organic acids, 5′-nucleotides, fatty acids, and volatile organic compounds (VOCs). Distinct differences among species–sex groups were observed in both volatile and non-volatile flavor compounds. M. coruscus and M. galloprovincialis showed greater umami potential than P. viridis. Female M. galloprovincialis exhibited the highest equivalent umami concentration (EUC) (2.56 ± 0.21 g MSG/100 g), whereas male M. galloprovincialis and male M. coruscus contained the highest levels of sweet-tasting amino acids (605.42 ± 28.72 mg/100 g) and umami-tasting amino acids (209.29 ± 13.31 mg/100 g), respectively. Gas chromatography–ion mobility spectrometry (GC-IMS) analysis identified 67 volatile compounds, and 12 key discriminative volatiles were selected, including three aldehydes, four ketones, three alcohols, 2-ethylfuran, and acetic acid. Males generally showed higher omega-3 polyunsaturated fatty acids (ω-3 PUFAs)and omega-6 polyunsaturated fatty acids (ω-6 PUFAs) proportions than females, with the highest ω-3 PUFAs proportion in male M. coruscus (45.12 ± 0.22%) and the highest ω-6 PUFAs proportion in male P. viridis (8.13 ± 0.30%). Correlation analysis suggested that ω-6 PUFAs were more closely associated with aldehydes, whereas ω-3 PUFAs were more closely associated with alcohols and ketones. These associations provide preliminary evidence for understanding flavor differences among cultivated mussel groups.

The effects of frozen storage on the quality and flavor of female and male Mytilus coruscus were investigated at −18 °C for 0, 90, and 150 days through analyses of physicochemical properties, free amino acids, 5′-nucleotides, fatty acids, and volatile organic compounds. Distinct sex-dependent changes were observed in the quality and flavor profiles. After 150 days, the centrifugal loss reached 1.2 and 1.5 times the fresh levels in females and males, respectively, whereas total volatile basic nitrogen reached 2.7 and 2.4 times the corresponding fresh levels. Malondialdehyde increased to approximately 3.3 times the fresh level in both sexes and was 1.7 times as high in females as in males. Males generally showed higher free amino acid levels, whereas females showed higher equivalent umami concentrations at selected stages. Gas chromatography-ion mobility spectrometry revealed sex-dependent volatile organic compound (VOC) profiles. Aldehydes were enriched in females after 90 days, whereas males retained more pronounced ketone- and ester-related characteristics. Fourteen key discriminative VOCs were selected. Correlation analysis linked changes in VOC profiles with nucleotide degradation, amino acid changes, fatty acid composition, and lipid oxidation; notably, 1-penten-3-one was positively correlated with malondialdehyde and negatively correlated with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (ARA). These associations provide new insights into sex-specific changes in flavor-related chemical profiles during frozen storage and provide a scientific basis for improving quality evaluation and frozen-storage strategies for mussels in the seafood industry.