Abstract
Microwave thermal processing is a promising technology to greatly improve product quality by achieving high-temperature short-time (HTST) processing for solid foods. And the non-thermal effect of microwave fields on nutritional quality is a major public concern. To distinguish the non-thermal effect of microwave fields, the thermal effect of HTST processing should be revealed first. The objective of this study was to investigate the effects of different HTST processing on quality of Pacific saury fillets using extracted fatty acids as the indicator. A self-developed thermal processing system was used to conduct the HTST processing with different heating rate (5.48-18.30°C/min), maximum heating temperature (123, 133 °C), and thermal processing level (F 0 = 3.0 min, 6.0 min). Results showed that the extraction coefficient of lipids and fatty acids decreased with increasing heating rates, which implied less thermal damage of fish tissue, while higher thermal processing level increased these extraction coefficients. However, higher maximum processing temperature caused serious thermal damage of fatty acids, especially for PUFAs. Furthermore, changing pattern of each fatty acid during different HTST processing was revealed, which provided fundamental data for designing microwave thermal processing and exploring microwave non-thermal effects.