Comparison of Drying Characteristics of Sardines under Different Drying Methods

In order to study the effects of different drying methods on the drying characteristics of sardine meat, the sardines were treated by five drying methods:Cold air, hot air, microwave vacuum, cold air microwave vacuum and hot air microwave vacuum. The effects of different drying methods were studied on the color, texture, moisture content, microstructure and protein secondary structure of sardines.The results showed that the effect of different drying methods on color of dried fish was significantly different (p<0.05).Microwave vacuum drying helped to increase the brightness of fish and was closest to fresh meat. And cold wind microwave vacuum showed good chromaticity. The effect of different drying methods on texture was significant (p<0.05). In drying modes, microwave vacuum drying had the effect of reducing hardness, chewing degree and enhancing elasticity.The muscle fibers treated by hot air and cold air were close in microstructure. The muscle of cold air treated by microwave vacuum showed loose and dense reticular shape. Drying made a large amount of non-flowable water loss, moisture migration, microwave vacuum and hot air-microwave vacuum, cold air-microwave vacuum drying to loosen muscle fibers. At the same time, drying destroyed the protein secondary structure, making α-helix converted to β-sheet and random coil, and the effect of cold air drying on its secondary structure was minimal. The results would provide theoretical basis for the production and processing of sardines.