Multi-omics techniques were combined with microstructure, molecular sensory science and non-volatile matrices for the first time to investigate variations in organic macromolecules and flavor in caviar during preservation. After 4–6 weeks of storage, the peroxide value was 35.38 mg/g and the accumulation of thiobarbiturates was significant with caviar membranes exhibiting a decrease in elasticity and an increase in viscosity. Sixteen key volatile compounds were detected by GC–MS, while the volatile compounds that contributed to the differences in caviar flavor at different storage times were mainly tetradecane, ( E )-2-hexenal, and heptanal. The pathways associated with flavor release during storage were mainly abundant in the linolenic acid metabolism, alanine metabolism, and glycerophospholipid metabolism pathways. The correlation of 11 differential proteins and 24 differential lipids with odorants was further explored, such as arginine, proline, alanine, PE (20:4/22:6), PE (16:1/18:2), and PE (20:5/18:2). Overall, Aspartate, glutamate, oleic acid, linoleic acid, and phospholipids enriched in C22:6 and C18:2 chains are potential metabolic markers. This study provides a basis from a multi-omics perspective for the investigation of the relationship between quality deterioration and precursor metabolism in caviar storage process.
The effect of different cooking methods on protein and lipid oxidation of farmed sturgeon (Acipenser gueldenstaedtii) was investigated. In this study, the fish fillets were cooked using five different methods (boiling, steaming, microwaving, roasting and deep-frying), to an internal temperature of approximately 85 °C. General indexes for protein oxidation (carbonyls, free thiols and Schiff bases) and lipid oxidation were evaluated by spectrophotometric and fluorimetric methods. Side-chain modifications of amino acid residues were pinpointed by gel- and MS-based proteomic technology. The results are as follows: (1) cooking, especially roasting and frying, significantly increased the levels of carbonyls and Schiff bases and decreased the amounts of free thiols. (2) Oxidation of aromatic amino acids and extensive oxidation of lysine to carbonyl-containing compounds were characterized in all the cooked samples. (3) Indirect protein oxidation caused by interacting with lipid-derived aldehydes like malondialdehyde (MDA) and 4-hydroxynonenal (HNE) was also observed and much more pronounced in roasted and fried samples, giving a footprint of lipid–protein interaction during cooking. In summary, cooking treatment can induce protein oxidation in sturgeon fillets with a variety of modifications occurring at the protein primary structure. Molecular mapping of protein oxidation is conducive to understand the mechanism of cooking-induced protein oxidation and allows better control of the nutritional properties of protein-based products.
危险品化学品经营许可证（带存储）