Effects of Far-infrared Assisted Hot Air Drying on the Drying Characteristics and Quality of Saury Fillets

In order to investigate the influence of far-infrared assisted hot air drying on the drying characteristics and quality of saury fillets,the far-infrared assisted hot air drying and hot air drying processes were used to dehydrate saury fillets at 50,60,70,80 and 90 ℃,and the quality changes were observed. The results showed that in order to reduce the dry base moisture content of saury fillets to below 43%,the drying time required for hot air drying at 50 to 90 ℃ was 570,435,282,225 and 208 min,respectively,and the time required for far-infrared assisted hot air drying was 510,395,258,204 and 186 min. Increasing the drying temperature was beneficial to shorten the drying time and increase the drying rate,and the far-infrared assisted hot air drying had obvious drying advantages. Low-field nuclear magnetic resonance test results showed that the hard-to-flow water in the saury fillets was converted into free water and diffused outwards to achieve the purpose of drying. In terms of drying quality,the a^* values and b^* values of saury fillets increased to 4.85~8.98 and 12.08~16.01 respectively after drying. With the increase of drying temperature,texture indexes such as hardness,chewability and recovery,and the sensory score of umami,odor and chewability showed an upward trend,the L^* value,TBA value and sensory score of tissue morphology showed a downward trend,while the color scores showed an upward trend and then a downward trend. Compared with hot air drying,far-infrared assisted hot air drying saury fillets had better quality in color and texture characteristics,and higher sensory scores in tissue morphology and odor,but there was no significance difference between two drying methods in TBA value(P>0.05).