Enzymatic Hydrolysis of Phospholipids in Cod Flesh during Cold Storage

Abstract

Enzymatic hydrolysis of phospholipids in cod flesh during storage at -16°C for 24 weeks were studied. The contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) decreased rapidly during storage for up to 11 weeks and then slowly. During storage for 24 weeks, 72.5% of PC and 52.2% of PE were hydrolyzed: pc was hydrolyzed faster than PE. Contrary to this, the content of free fatty acid increased rapidly during storage for up to 11 weeks and then slowly.
Major PC in the cod flesh were those having fatty acid combinations of (C₁₆, C₂₂), (C₁₆, C₂₀), (C₁₈, C₂₂), (C₁₈, C₂₀), (C₂₀, C₂₂), and (C₁₆, C₁₈). Percentages of PC having the combinations of (C₁₆, C₂₂), (C₂₀, C₂₂), (C₁₆, C₁₈), and (C₂₂, C₂₂) increased slightly during storage, while those of (C₁₆, C₂₀) and (C₁₈, C₂₀) decreased. In the case of PE, major fatty acid combinations were those of (C₁₈, C₂₂), (C₁₆, C₂₂), (C₂₀, C₂₂), (C₂₂, C₂₂), (C₂₀, C₂₀), (C₁₈, C₂₀), and (C₂₂, C₂₂) During storage, percentages of PE having the combinations of (C₁₈, C₁₈) and (C₂₂, C₂₂) increased slightly, while toshe of (C₁₈, C₂₂), and (C₂₀, C₂₂) decreased.
From these results, it was presumed that the PC and Pe having certain fatty acid combinations in cod flesh are hydrolyzed preferentially by lipolytic enzymes during cold storage.