The Effect of Frying Process on Lipids in Small Yellow Croaker (Larimichthys polyactis) and Frying Oil

The effect of frying process on lipid oxidation in small yellow croaker and frying oil was evaluated in this study. Parameters including the proximate composition, the contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), acid value (AV), peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), and fatty acid composition were measured. After frying, lipid content as well as triacylglycerol content in small yellow croaker was increased, and the profile of fatty acid in small yellow croaker was changed due to the exchange of moisture and the absorption of lipid with frying oils. However, the decrease of PC and PE contents during frying process proved the occurrence of lipid hydrolysis, while the increase of POV indicated that lipid oxidation occurred. In addition, the water-rich small yellow croaker also accelerates the exchange of moisture and free fatty acid between small yellow croaker and frying oil and further accelerates the hydrolysis and oxidation of palm oil and soybean oil. In conclusion, the lipid profile of small yellow croaker was significantly changed during frying, and the nutritional value of fried products was time-dependently reduced upon frying.