Exploring the microwave non‐thermal effects on the fatty acid composition of Atlantic salmon ( Salmo salar ) during pasteurization using the same time–temperature profiles method

Abstract

The non-thermal effects of microwave fields on the fatty acid composition of pasteurized Atlantic salmon were investigated using the same time–temperature profiles method. Two pasteurization processes with same time–temperature profiles were designed using a microwave processing system and a water bath. Then, the fatty acid composition of the processed salmon fillets was analyzed using the gas chromatography/mass spectrometry (GC/MS) method. Results showed that the time–temperature profiles during microwave and water bath processing were well suited. With same time–temperature profiles, the fatty acid compositions of salmon fillets processed by microwave and water bath were obviously different. Furthermore, microwave process brought better fatty acid quality in terms of higher values of n-3 PUFA proportion, PUFA:SFA ratio, and lower n-6 PUFA proportion. This demonstrated that microwave fields did have non-thermal effects on the fatty acid composition of salmon with 3.5 min 8 kW microwave radiation and a final temperature of 90℃. Practical applications Microwave processing could provide volumetric heating for solid foods to improve product quality by achieving high-temperature short time process. The microbial safety of microwave thermal processing has been approved by the Food and Drug Administration of United States. Its industrial application is being accelerated. However, besides thermal effects, there also exists non-thermal effects during microwave processing due to the interaction between alternating electromagnetic waves and food molecules. Thus, the influence of microwave non-thermal effects on nutritional quality and chemical safety of foods are attracting great concerns both for consumers and researchers. It is essential to provide theoretical data concerning microwave non-thermal effects to sustain its industrial application. This study investigated the influence of microwave non-thermal effects on fatty acids composition of salmon fillets using same time–temperature profiles method. The results provide important information for quality evaluation of microwave processed foods, which promotes the application of microwave processing in food industry.