Abstract: Changes in the functional properties of myosin and the tissue microstructure of hooked, trawl-netted, and radar-netted hairtail (Trichiurus haumela) were investigated under different heating temperatures. Hairtails were water bathed at 30, 50, 70 or 90 ℃ and evaluated for cooking loss and water-holding capacity (WHC) as well as myosin turbidity, solubility, emulsifying capacity, foaming capacity and foam stability, and carbonyl content after 10 min. Besides, hematoxylin-eosin (HE) staining was used to analyze the effects of different heating temperatures on the tissue microstructure of hairtails. The results showed that as the heating temperature rose, the cooking loss and water-holding capacity of muscle decreased gradually for the three kinds of hairtail. Myosin turbidity and carbonyl content increased, and solubility, emulsifying activity index (EAI) and emulsion stability index (ESI), foaming capacity and foam stability decreased continuously. The decrease in muscle WHC and myosin solubility and the increase in myosin turbidity were all smaller in radar-netted hairtails than in the two other kinds. In addition, the HE staining results showed that with increasing heating temperature, the space between muscle fiber bundles in muscle tissues increased for all kinds of hairtail, and different degrees of breakage occurred. When the heating temperature was 50 ℃, the structure of collagen and muscle fibers was the most complete in the muscle tissue of radar-netted hairtail. Summarily, the muscle quality of all three kinds of hairtail decreased with the increase in heating temperature, and the muscle quality of radar-netted hairtail was the most stable.

Key words: hairtail; heat processing; myosin; functional properties; microstructure