Contribution of phospholipids to the formation of fishy off-odor and oxidative stability of soybean oil

The present study identified that trimethylamine (TMA) was the major source of fishy off-odor in soybean oil, and the component of phosphatidylcholine (PC) was responsible for its formation. The existence of phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidic acid (PA) in soybean oil could retard the deterioration of PC under heat treatment. Soybean phospholipids (SP) produced better results than soybean phosphatidylcholine (NPC) in inhibiting soybean oil oxidation. And soybean phospholipids stripped off phosphatidylcholine (SPSPC) turned out to be the least effective. The synergistic effect of PC and other phospholipids components in soybean oil could enhance the antioxidant ability of individual phospholipids components. The addition of SP and SPSPC could significantly deepen the color of soybean oils under heat treatment, while NPC would not result in color deepening. We come to a conclusion that PC could be an antioxidant in oil system, but more attention should be paid to the formation of TMA in its further application. Practical applications: Knowledge of the effect of phospholipids on the formation of fishy off-odor and oxidative stability in soybean oil is important, because it has been reported by many investigators that phospholipids can be used as a kind of natural antioxidants in oil system. The information of this work can help others to apply the phospholipids in oil industry more appropriately.