MALDI-TOF/TOF Mass Spectrometric Determination and Antioxidative Activity of Purified Phosphatidylcholine Fractions from Shrimp Species.

Purification, characterization, and antioxidative activity in vitro of shrimp phosphatidylcholines (PCs) were investigated. The molecular structures of shrimp PCs were determined by MALDI-TOF/TOF MS. The MS2 fragments produced from protonated PC precursors and sodiated PC precursors were identified. The specific fragments including [M + Na - trimethylamine]+, [M + Na - 205]+, [M + Na - RCOOH - trimethylamine]+, and [M + H - RCOOH - trimethylamine]+ could distinguish the precursor type to confirm PC molecular structures. The antioxidative activities of purified shrimp PC fractions were evaluated by assay of DPPH free radical scavenging activity, and their effects on the oxidative stability of camellia oil were measured by monitoring changes in the peroxide value assay during oxidation. The PC fractions from Penaeus chinesis and Macrobranchium nipponense showed stronger antioxidative activities than those of other species. All of the shrimp PCs at 0.2% (w/w) improved the oxidative stability of camellia oil significantly (P < 0.05) compared to controls. The experimental findings suggest that shrimp PCs might be a valuable source of natural antioxidants for edible oils or other food dispersions.