Antioxidant Systems in Squid Eyes

Lipid Profiles and the Presence of Water Soluble Antioxidants

Abstract

Squid eye lipids were characterized. The main lipid were found to be free cholesterol (27.3%), phosphatidylcholine (PC; 30.7%) and phosphatidylethanolamine (32.8%). Major fatty acids in squid eye lipids were 22 : 6n-3 (DHA; 33.3%), 20 : 5n-3 (EPA; 15.6%), and 16 : 0 (28.4%) and main molecular species of squid eye PC was 1-16 : 0-2-DHA-PC. Comparative study of oxidative stability indicated squid eye PC to be more stable toward oxidation than soybean PC in liposomes. 1124μg/g lipid of α-tocopherol were found in squid eye lipids, and water soluble extracts showed strong antioxidant activity in liposome and emulsion systems. The high level of tocopherol and the presence of water soluble antioxidants may be essential for protecting squid eye lipids from oxidation.