船冻和岸冻对鲐鱼贮藏鲜度的影响

以鲐鱼的感官评定、持水力、肌动球蛋白的盐溶性、Ca2+-ATPase活性、巯基含量、挥发性盐基氮值(TVB-N)、组胺含量和硫代巴比妥酸值(TBA)为指标,研究船冻和岸冻鲐鱼在-18℃贮藏过程中鲜度的变化情况。结果表明,随着贮藏时间的延长,船冻鲐鱼的TVB-N值、组胺含量和TBA值均低于岸冻鲐鱼,而船冻鲐鱼的感官评分、持水力、肌动球蛋白的盐溶性、Ca2+-ATPase活性和巯基含量都高于岸冻鲐鱼,下降速度也较岸冻鲐鱼缓慢。船冻技术不但有利于延长鲐鱼的贮藏时间,而且确保其在贮藏期间的肉质鲜度。

不同解冻方式对鲐鱼鲜度及品质的影响

采用4种解冻方式(空气解冻、静水解冻、微波解冻、鼓气流水解冻)对-18℃贮藏的船冻鲐鱼进行解冻,分析其持水力、挥发性盐基氮(total volatile basic nitrogen,TVB-N)值、组胺含量、盐溶性蛋白含量、质构值的变化,并进行电子鼻分析和微观结构的观察。结果表明:解冻时间、TVB-N值和组胺之间、持水力与解冻损失率和盐溶性蛋白含量之间分别有极显著的相关性(P<0.01)。电子鼻的Fisher判别分析能明显区分各种解冻方式,其检测结果与TVB-N值和组胺含量的测定结果一致。4种解冻方式中,鼓气流水解冻后鲐鱼的持水力、盐溶性蛋白含量最高,质构特性最好,肌束排列紧密,肌内膜较完整,鲜度比微波解冻稍差,与静水和空气解冻相比缩短了解冻时间,与微波解冻相比大大节约了成本。因此,鼓气流水解冻是一种理想的鲐鱼解冻方式。

The Investigation of the Effect of Heaving and Pitching on Wave-Induced Vertical Hull Vibration of a Container Ship in Regular Waves

The aim of this paper is to investigate the effect of heaving and pitching of ship motion due to springing bending moment. The investigation was conducted both experimentally and validated theoretically. Series of experiment were carried out using a container model-ship of which length was 3 meter, and the possibility of the so-called nth resonant springing vibration is tested by taking n from n = 2 to n = 4. The bending moment due- to vibration is also measured. The following conclusions were obtained： （l） Occurance of the higher order resonant vibration between 2nd-4th is recognized experimentally; （2） The results indicated that heaving and pitching of ship motion influenced the springing bending moment accurately.