Seasonal Variation of Lipid Profile of Oyster Crassostrea talienwhanensis from the Yellow Sea Area

Investigation of oyster Crassostrea gigas lipid profile from three sea areas of China based on non-targeted lipidomics for their geographic region traceability

The present study sought to analyze the lipid profiles of oyster Crassostrea gigas from Yellow Sea (YS), East China Sea, and South China Sea (SCS) through the untargeted lipidomics strategy based on UPLC-Q-Exactive Orbitrap mass spectrometry and multivariate statistics. The results elucidated that geographical differences had profound effects on the lipid content, composition, and lipid molecular profiles. Notably, oysters from the YS group contained the highest lipid content, including triacylglycerol, diacylglycerols, and the majority of phospholipid molecule species, while oysters from the ECS group contained most of the phosphatidylcholine species and the SCS group contained most of the sphingolipid species. Totally, 1155 lipid molecular species belonging to 21 subclasses were identified; of them, 45 lipid molecular species could serve as differential marker for lipid of oysters from different sea areas. Overall, lipidomics could be a potential approach for discrimination of lipid characters between marine shellfishes for geographical origin traceability.

Current Progress in Lipidomics of Marine Invertebrates

Marine invertebrates are a paraphyletic group that comprises more than 90% of all marine animal species. Lipids form the structural basis of cell membranes, are utilized as an energy reserve by all marine invertebrates, and are, therefore, considered important indicators of their ecology and biochemistry. The nutritional value of commercial invertebrates directly depends on their lipid composition. The lipid classes and fatty acids of marine invertebrates have been studied in detail, but data on their lipidomes (the profiles of all lipid molecules) remain very limited. To date, lipidomes or their parts are known only for a few species of mollusks, coral polyps, ascidians, jellyfish, sea anemones, sponges, sea stars, sea urchins, sea cucumbers, crabs, copepods, shrimp, and squid. This paper reviews various features of the lipid molecular species of these animals. The results of the application of the lipidomic approach in ecology, embryology, physiology, lipid biosynthesis, and in studies on the nutritional value of marine invertebrates are also discussed. The possible applications of lipidomics in the study of marine invertebrates are considered.

Simultaneous quantification of 24 aldehydes and ketones in oysters (Crassostrea gigas) with different thermal processing procedures by HPLC-electrospray tandem mass spectrometry

Aldehydes and ketones are secondary oxidation products resulting from lipid oxidation that occurs during food processing. These small molecule compounds not only have an impact on the quality, odor and flavor of food, but also play a role in the pathogenesis of many human diseases. In this study, a HPLC-MS/MS analytical method was developed and validated for the simultaneous determination of 24 aldehydes and ketones. The coefficients of determination (R²) for all aldehydes and ketones were higher than 0.9975 at the range of 0.2-2000 ng/mL. The recoveries were in the range 71.20-108.13% with RSD < 10%. The method was tested by analyzing lipids from oysters with different thermal processing (boiling, frying, roasting and air frying) procedures; the highest concentration for saturated aldehydes and ketones while the highest content of unsaturated aldehydes in boiling treatment. Meanwhile, fatty acid oxidative decomposition was in agreement with aldehydes and ketones formation. Moreover, principal component analysis, orthogonal partial least-squares discriminant analysis and variable importance in projection value showed that lipid oxidation is positively related to the formation of a variety of aldehydes and ketones.