暂养环境因子对斑点叉尾鮰肌肉理化性质与质构特性的影响

以斑点叉尾鮰（Ictalurus punctatus）为研究对象，通过控制暂养温度（12、16、20、24 ℃）、氨氮质量浓度（0、5、10、20 mg/L）和暂养密度（1∶2、1∶3、1∶4、1∶5，m/V），考察不同环境因子对斑点叉尾鮰肌肉理化特性（水分含量、pH值和持水力）与质构特性的影响。结果表明：暂养温度24 ℃组鱼肉的水分含量与持水力显著低于其他温度组（P＜0.05）；12 ℃组鱼肉的水分含量、pH值和持水力较稳定，且肌肉弹性和咀嚼性显著高于其他温度组（P＜0.05）；水体氨氮质量浓度为0 mg/L时，鱼肉pH值稳定在7.12～7.15，持水力稳定在65%左右，随着暂养时间的延长，该组鱼肉硬度显著下降（P＜0.05），弹性和咀嚼性有所上升，回复性与凝聚性维持在稳定水平；暂养密度不低于1∶4（m/V）时，鮰鱼肌肉水分含量和持水力均随暂养密度的下降而显著上升（P＜0.05）；在整个暂养期间，1∶4（m/V）组鱼肉弹性大部分显著高于其他密度组（P＜0.05），且其鱼肉弹性和咀嚼性随着暂养时间的延长呈上升趋势，回复性和凝聚性随着暂养时间的延长呈下降趋势，而肌肉硬度与黏性无显著变化。综上，温度12 ℃、氨氮质量浓度0 mg/L、暂养密度1∶4（m/V）的暂养环境较有利于维持和提高斑点叉尾鮰肌肉品质。

Effects of Environmental Factors during Temporary Rearing on Physicochemical Properties and Texture Characteristics of Ictalurus punctatus Muscles

In this work, the effects of different environmental factors during temporary rearing on the physicochemical properties such as moisture content, pH and water-holding capacity and texture properties of Ictalurus punctatus muscle were investigated by controlling temperature at 12, 16, 20 or 24 ℃, ammonia nitrogen concentration at 0, 5, 10 or 20 mg/L and density at 1:2, 1:3, 1:4 or 1:5 (m/V). Our results demonstrated that in the 24 ℃ group, the water content and waterholding capacity of fish muscle were significantly (P < 0.05) lower than those in the other temperature groups. In the 12 ℃ group, the physicochemical properties were more stable, and the springiness and chewiness were significantly (P < 0.05) higher than those in the other temperature groups. When the concentration of ammonia nitrogen in the water was 0 mg/L, the pH of fish muscle was stable in the range of 7.12–7.15, and the water-holding capacity was maintained about 65%; the hardness decreased significantly with increasing rearing time (P < 0.05), and the springiness and chewiness increased, whereas the resilience and cohesiveness remained at a stable level. Moreover, the water content and water-holding capacity increased significantly (P < 0.05) with decreasing temporary rearing density up to 1:4 (m/V). At most temporary rearing times, the springiness of fish flesh in the 1:4 density group was significantly (P < 0.05) higher than that in the other density groups. With the extension of rearing time, the springiness and chewiness increased, and the resilience and cohesiveness decreased, while there was no significant change in the hardness or adhesiveness. In conclusion, the muscle quality of Ictalurus punctatus could be maintained or even improved in a temporary rearing environment with a temperature of 12 ℃, an ammonia nitrogen concentration of 0 mg/L and a density of 1:4 (m/V).