Enzymatic Hydrolysis of Phospholipids in Cod Flesh during Storage in Ice

Abstract

Enzymatic hydrolysis of phospholipids in cod flesh during storage in ice for 30 days were studied. The contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in the flesh dcereased slowly during first 4 days of storage and then rapidly to 20 days. Thereafter, the decrease of the contents almost ceased. During storage for 30 days, 72.2% of PC and 71.8% of PE were hydrolyzed. Contrary to this, the content of free fatty acid (FFA) increased slowly during the first 4 days of storage and then rapidly up to 20 days.
Major PC in the cod flesh were those having fatty acid combinations of (C₁₆, C₂₂), (C₁₆, C₂₀), (C₁₈, C₂₂), and (C₁₈, C₂₀). Percentages of PC having the combinations of (C₁₆, C₁₆) and (C₁₆, C₁₈) increased rapidly during storage in ice, while those of (C₁₆, C₂₀), (C₁₆, C₂₂) and (C₁₈, C₂₂) decreased. In the case of PE, prominent fatty acid combinations were those of (C₁₈, C₂₂), (C₁₆, C₂₂), (C₂₀, C₂₂), (C₂₂, C₂₂), and (C₂₀, C₂₀). During storage, percentages of PE having the combinations of (C₁₆, C₁₈) and (C₁₆, C₂₀) increased, while those of (C₂₀, C₂₂) and (C₂₂, C₂₂) decreased.
From these reults, it was suggested that the PC having fatty acid combinations (C₁₆, C₁₆) and (C₁₆, C₁₈) and the PE having those of (C₁₆, C₁₈) and (C₁₆, C₂₀) were synthesized in the flesh during storage in ice from glycerylphosphorylcholine, glycerylphosphorylethanolamine and FFA which had been produced from PC and PE with enzymatic hydrolysis.