超声波辅助盐渍对鲩鱼干品质和微观结构的影响

为加快鲩鱼干盐渍和干制工序的进程，本研究将超声波作为辅助鲩鱼盐渍的一种处理方式。将鲩鱼块置于相同频率（40 kHz）、不同功率（0 W、120 W、240 W、360 W和480 W）的超声波下进行辅助盐渍，然后利用低温热泵干燥方式进行干燥（湿度为50%，温度为20 ℃），研究超声波对盐渍液的温度效应和超声波对鲩鱼干的水分含量、含盐量、质构、感官评价以及微观结构的影响。结果表明超声波具有明显的热效应，在开放式的盐渍容器中，超声波辅助盐渍180 min可以使盐渍液温度较环境温度增加4~16 ℃。鲩鱼经过超声波辅助盐渍120 min后进行50 h的干制，鲩鱼干的含盐量、弹性和感官评价的评分别由3.58%、0.70 g、29.00增加到5.21%、0.84 g、43.00，水分含量和硬度分别由27.04%、2355 N减少到24.88%、1582 N；石蜡切片和电镜扫描结果表明超声波辅助盐渍可以彻底破坏了肌肉纤维之间的结缔组织，食盐可以快速进入肌肉纤维细胞内部，使鲩鱼肌肉组织更加饱满。综合而言，超声波辅助盐渍可以明显加快鲩鱼的盐渍和干制速率，提高产品鲩鱼干的品质。
The grass carp salting was treated with ultrasound to reduce the salting and drying time. The effects of ultrasound treatment on the saline temperature , moisture content, salinity, texture, microstructure and sensory evaluation of dried grass crap were investigated after salting treatment assisted with different ultrasound power (0 W, 120 W, 240 W, 360 W and 480 W) at 40 kHz and then dried with low temperature heat pump operated at 20 ℃ with 50% humidity. Results showed that the ultrasound had an obvious heat effect. Compared to the ambient temperature, the temperature of saline could be increased by 4~16 ℃with ultrasound treatment (180 min) in an open salted container. The salinity, elasticity and sensory scores increased from 3.58%, 0.70 g, 29.00 to 5.21%, 0.84 g and 43.00, respectively, after treated with ultrasound-assisted salting 120 min and then dried with heat pump for 50 h, and the moisture content and hardness decreased from 27.04% and 2355 N to 24.88% and 1582 N, respectively. Results of paraffin sections and scanning electron microscopy showed that the ultrasound-assisted salting treatment completely destroyed the connective tissues among the muscle fibers, and a quick salt could enter into the muscle fiber cells, which made muscle tissues more full. Consequently, ultrasound-assisted salting could accelerate the rates of salting and drying of grass crap, which improved the quality of dried grass crap product.