Effect of Various Hot‐Air Drying Processes on Clam Ruditapes philippinarum Lipids: Composition Changes and Oxidation Development

Clam Ruditapes philippinarum was processed by hot‐air drying and the changes of its lipids were evaluated by analyzing lipid classes, phospholipid classes, fatty acids, as well as oxidation parameters including peroxide value (POV), thiobarbituric acid‐reactive substances (TBARS) value, total oxidation value (TOTOX), and oxidation test (OXITEST). The hot‐air drying process reduced the contents of triacylglycerol, phosphatidylcholine, and phosphatidylethanolamine, indicating the hydrolysis of lipids. Meanwhile, the hot‐air drying process significantly decreased the proportion of n‐6 polyunsaturated fatty acid (PUFA), and consequently increased the PUFA ratio of n‐3/n‐6. Interestingly, the POV, TBARS and TOTOX decreased after the hot‐air drying process. However, significant decline of the induction period for the dried clam tissue at elevated temperatures indicated their higher oxidation level, poor oxidative stability and reduction of shelf‐life. Therefore, OXITEST method turned out to be an effective tool for estimating the level of lipid oxidation for hot‐air dried clam.