A 13C-NMR study of lipid alterations during fish canning: effect of filling medium

Abstract

Carbon-13 nuclear magnetic resonance spectroscopy was applied to study the effect of the filling medium on lipid modifications occurring during the industrial canning of tuna (Thunnus alalunga). In the two media studied—brine and soybean oil—increases in the free fatty acid level were observed with preferential hydrolysis of polyunsaturated fatty acids esterified in the sn-2 position of the glycerol moiety. The extent and mechanism of lipolysis seem to be independent of the filling medium used. Quantitative results obtained for the main lipid classes showed dilution of the natural lipids of muscle by triacylglycerols from the filling medium in oil-filled cans.