Monitoring the effects of storage in caviar from farmed Acipenser transmontanus using chemical, SEM, and NMR methods

The effects of storage at 4 DegC on the quantity and quality of chem. components in the caviar from farmed Acipenser transmontanus were analyzed by SEM, chem. methods, and NMR and MRI techniques. Particular attention was focused on the lipid components, the distribution and mobility of which were strongly affected by the storage time. MRI and relaxation data indicated that lipids are endowed with 2 different mobility regimes, one slow (short T1) and one fast (long T1), both lengthening with the storage time. Chem. anal. assessed a total fat content that remained practically unchanged and a const. fatty acid compn. during the total storage time. The combination of the 2 methods allowed one (a) to suppose that a mechanism of lipid hydrolysis (faster in unsalted than in salted eggs) is still occurring during storage of caviar at 4 DegC for up to ~4 mo and (b) to exclude that an intensive oxidative process is active in the same storage period.