Analysis of Seafood Flavor by SPME-GC/MS

Shellfish are appreciated for the sensory properties (odour, texture, taste and appearance) and are consumed as raw, cooked or processed. Free amino-acid profile, fatty acid composition, and volatile fraction are important parameters with a strong influence on the aroma and flavour of shellfish as well as on their evolution during the refrigeration storage. Objective of this work was to select an idoneous procedure for the determination of volatile compounds that characterizes fresh bivalve molluscs (Mytilus galloprovincialis, Ostrea edulis, Cerastoderma edule, Venerupis pullastra, Ensis ensis) and a crustacean (Pollicipes polymerus), all from Ria De Vigo (Galicia, Spain). Analytes were concentrated on a fused silica fibre with carboxen-polydimethylsiloxane coating employed in headspace mode (HS-SPME) and selectively determined using gas chromatography in combination with mass spectrometry (GC–MS). After testing different incubation temperature (60-80-100 °C), incubation time (5’-15’-30’) and in vial extract volume (1-3-6 mL), the best combination selected for the analysis execution was 80°C, 30’, 6 mL. A saline extraction of the raw edible part of the animals was incubated to concentrate analytes. Quantification and identification of volatile compounds was performed by MS in selected ion monitoring mode (SIM) using the internal standard method. This study demonstrated that a major composition of alcohols and aldehydes characterizes the volatile profile of the analyzed samples. In particular, 2,4-octadien-1-ol and 1-penten-3-ol characterize M. galloprovincialis; 1,5-octadien-3-ol and 1-octen-3-one characterize O. edulis; 1,5-octadien-1-ol and 2,6-nonadienal characterize C. edule; 1,5-octadien-3-ol and 2,4- heptadienal characterize V. pullastra; benzaldehyde and 1-octen-3- ol characterize E. ensis; 9,12,15-octadecatrienal and indole characterize P. cornucopia.