Oxidation kinetics of polyunsaturated fatty acids being esterified into glycerophosphocholine and glycerophosphoethanolamine in dried scallop during storage

Hongkai Xie, Ting Lu, Yan Shen, Min Zhang, Beiwei Zhu

National Engineering Research Center of Seafood, China; National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, China; National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, China; National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, China

Objective: The difference in oxidative susceptibility of glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE) and the effects of the same polyphenolic antioxidant on such susceptibility in dried scallop during storage were investigated.
Methods Used: Phospholipid (PL) fractions containing GPC and GPE were extracted from dried scallops at selected storage times and their fatty acids were determined. The changes in contents of four representative PUFAs including α-linolenic acid (ALA), arachidonic acid (AA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) being esterified into GPC or GPE were used to fit kinetic models, which were employed to obtain the reaction rate constant (k) to reflect the oxidation rates of different PL classes.

Results: The results indicated that the oxidation of PUFAs (ALA, AA, EPA, and DHA) being esterified into GPC and GPE under two storage temperatures (15 °C and 25 °C) all followed the first-order kinetic model, and GPE had a greater oxidation rate than GPC under the experimental conditions. The natural phenolics effectively inhibited the oxidation of PUFAs being esterified into GPE as well as GPC, and retained the nutritional value of dried scallop after long term storage. By contrast, GPC could more effectively be protected by the polar polyphenolic antioxidant compared with GPE.

Conclusions: This finding demonstrates that monitoring of substrate loss and using of kinetic models of PUFAs being esterified into different PL classes may offer insights into further chemical and nutritional studies on food systems that contain complex PL class compositions.