金枪鱼的冻结保鲜法

金枪鱼以体大肉鲜而著称,是日本人生吃鱼片的主要原料,属高档鱼类。因其体重几十公斤至几百公斤,冻结至中心温度-15℃需要几天,这样慢冻质量就差了,而冻速太快又会引起肚皮冻裂,导致商品外观质量降低。下面介绍几种冻结法。一、日本CaCl_2盐水冻结法日本80年代开始研究用CaCl_2盐水冻结金枪鱼的保鲜法,CaCl_2盐水比NaCl盐水水温低,冻结速度     

关于鱼类精液的保存

鱼类精液的保存法，有以冻结形式作长期保存的冻结保存法和不冻结仍按液态状作较短期保存的液态保存法两种。其中，液态低温保存的研究，早在十九世纪就开始了。近年来，在液态低温保存时，增加了适当的稀释液，精子保存的时间延长了。不过作为长期、稳定的精液保存法，仍然是冻结保存有效。     

船舶制冷系统运行管理中的节能措施

近几年来，随着燃油价格的上涨和渔业资源的衰减，节能增效已成为提高船舶作业经济性的重要手段。作为占船舶耗能总量很大比例的制冷压缩机的耗电量，已引起人们的重视。如何降低制冷压缩机的耗电量，提高制冷效率已成为人们比较关心的问题。本文主要论述、分析了船舶制冷系统在运行管理中的几种节能措施，以供参考。 一、采用能量调节，使制冷量与负荷匹配，降低耗电量 船舶制冷压缩机的选用是根据船舶冷藏的最大负荷来确定压缩机的容量及型号。实际作业中，冷藏负荷随着渔获量、冻结量、冻结时间，作业海区环境以及其它随机因素的变化而变…     

圣保罗平板冻结机的使用与维修

圣保罗(SABROE)平板冻结机是一种先进的制冷设备，具有结构紧凑、性能可靠、操作方便等特点，目前被广泛应用于水产品的急冻加工。PFP145圣保罗平板冻结机为丹麦设计制造，该型机系采用双级压缩制冷方式，平板蒸发温度可达-50℃以下，这与其它型号的单级冻结机有很大不同。机体由上下两部分组成。上部分是冻结平台，     

鱼类游泳速度分类方法的探讨

游泳速度是评价鱼类游泳能力的重要指标。本文对常用的几种鱼类游泳速度概念和分类方法进行了总结。目前,以时间长度作为分类标准可将游泳速度分为巡航游泳速度(Cruising swimming speed,T200min)、长时游泳速度(Prolonged swimming speed,200minT20s)、冲刺游泳速度(Burst swimming speed,T20s)3类。但由于时间长度的选择缺乏令人信服的依据,很多学者并未遵循这一时间界定标准进行各类试验,致使游泳速度的界定出现混乱,从而使以时间长度作为分类依据的方法失去意义。作者综合多数学者的研究方法,以鱼类的游泳状态作为依据,重新对鱼类游泳速度进行分类,并在这一分类基础上拓展引申出最大探顶游泳速度这一新概念,并对其推求方法和实际意义进行了探讨。根据新的分类方法,鱼类游泳速度主要分为5大类:最优巡航速度(Optimum swimming speed)、最大续航速度(Maximum sustained swimming speed)、临界游泳速度(Critical swimming speed)、最大探顶游泳速度(Maximum domed swimming speed)、冲刺游泳速度(Burst swimming speed)。其他游泳速度概念基本可以按照上述分类进行归并。借助最大探顶游泳速度这一概念,作者进一步探讨了其与最大续航速度、临界游泳速度3者之间的联系,认为在某种程度上这3种游泳速度作为评价鱼类游泳能力的指标具有一致性。     

因地制宜变“害”为益：—丹江口水库凶猛鱼类控制利用刍议

大型水库的凶猛鱼类既是渔产量的主要组成部分,又是影响渔产量的因素之一。如何解决凶猛鱼类与放养鱼类之间的矛盾,使两者都能得到合理的利用,已成为水利渔业研究的重要内容之一。本文分析了凶猛鱼类在水体生态系统中的作用与地位,根据凶猛鱼类生长和食性特点,以及丹江口水库渔具、渔法特点,提出了在大型水库对凶猛鱼类应采取“分而治之,控制利用”的策略,并依据丹江口水库不同水域的特点,具体阐述了控制利用方法与措施。     

从冷库利用现状浅谈水产冷库发展

冷库技术经济指标是企业经营管理情况的综合反映。搞好各项技术经济指标的核算工作,是冷库进行科学经营管理的基础,是制定某些计划、规划的依据。冷库的冻结、冷藏、制冷利用率是其中的三项主要指标,也是衡量冷库利用状况的主要依据。现就几年来我省水产冷库冻结、     

卧式平板冻结机的操作方法

众所周知、卧式平板冻结机具有冻结速度快（平均冻结速度5～30mn／h）、冻品质量好、节约能量以及钢材消耗量少、结构紧凑、占地面积小、操作方便、劳动条件较好等特点．是一种比较先进的冻结设备。但是．如果不了解其特点与性能、盲目操作。不但不能发挥它的优点、而且有可能损坏设备或造成人身伤亡事故和经济损失。为此，我们针对从日本引进的卧式平板冻结机的特点，制订了一套比较完整的操作方法，要求操作人员遵照执行。由于操作时有章可循。严格要求．所以，该两台卧式平板冻结机从1986年先后投入使用至今，设备仍完好无损，也没有发生…     

我国鼓风冻结技术及连续式鼓风冻结装置的发展现状

送风温度、风速、送风方式、气流组织方式等是影响鼓风冻结性能的主要因素,也是引领鼓风冻结技术发展进步的突破点。文章从以上几个方面对我国鼓风冻结技术的特点和发展现状作了分析与介绍,并综述了我国目前广泛使用的隧道式、传送带式、流态化、气流上下冲击式、空气鼓风与液氮喷淋结合式等多种连续式鼓风单体快速冻结装置的特点及应用情况。     

渔船用多用途制冷系统

丹麦一家公司为中小型渔船设计制造了一种多用途小型制冷系统。该系统具有体积小、噪音低、用海水和淡水都可制冷等特点。 整套制冷系统包括压缩机、海水冷凝器、液体分离器、温度控制器、安全设备、液压设备、启动器和控制板等。该系统以平板式冻结机为主     

Theoretical and practical analysis of waste heat recovery system in off-season rainbow trout production

The supply of heat for fish farms, especially during off-season production, is necessary for the establishment of commercial aquaculture. For this purpose, research was carried out on the supply of heating ener to a rainbow trout farm (cold water fish) using a waste heat recovery system in the city of Meshgin in Ardabil province. The study area has 20 indoor pools and 14 unguarded pools. The 14 pools that are in the indoor area, are used for this study. Seven pools of these 14 pools were at high altitude and other 7 pools were at low altitude. After collection of the temperature data for waste water ponds that had provided optimum temperature conditions in the off-season using geothermal fluid, three modes for waste heat recovery were designed according to the thermal, flow and physicochemical properties of the waste pond. In the first mode, the output of the first seven pools and the second seven pools were combined and the fluid flow rate reached to 24.92 L/sec. In the second mode, the output of the second seven pools (8.15 L/sec) was used to recover heat, and in the third case, the output of the first seven pools (at high-altitude pools and with the flow rate of 16.77 L/sec) was used to recover heat. After obtaining technical approval and determining the economic value of each component of the waste heat recovery circuit from specialized companies in Iran, the proposed systems were analyzed theoretically with COMSOL software. Because there was no equal rate of flow, velocity or geometry for comparison between the optimum state in the theoretical conditions of practice, the temperature differences between the input hot water and output cold water were used for all three modes of heat recovery. Technically, the results indicate that the second mode is best in both the theoretical and practical modes of the waste heat recovery circuit. The first mode recovery system had the smallest temperature difference between the hot water inlet and cold water outlet. Economically, the minimum cost of establishing a heat recovery system was for the second mode, with a decrease of 60.65% and 38.83% compared to the third and first modes, respectively. Considering technical and economic factors, the waste heat recovery system of the second mode was the most appropriate choice for the trout farm, both theoretically and practically. The first and third modes ranked next, respectively.     

Quality of Atlantic Cod Frozen in Cell Alive System,Air-Blast,and Cold Storage Freezers

ABSTRACT

Gutted Atlantic cod, packed in cartons, were frozen immediately after killing in a magnetic field (cell alive system). The results were compared with traditional air-blast freezing or by putting the cartons directly in a cold storage room (without forced convection of air). After frozen storage, external and fillet properties were compared. In spite of differences in freezing rates, only minor differences were found among treatments. The mechanism for the freezing of fish in the magnetic field, under the current conditions, appeared to be similar to that of traditional freezing methods.     

Effect of water temperature on the physiology of fish spermatozoon function: a brief review

Motility is a key factor in function of the spermatozoon and determines semen quality and fertilizing capacity. Effective motility occurs when sperm is diluted in a swimming solution, the adequacy of which is determined by factors varying according to fish species. Spermatozoon motility rate and velocity, as well as duration of the motility period, are influenced by the temperature of the water in which broodfish are held. Increase in temperature of swimming medium beyond the optimal increases cell metabolism, leading to an increase in velocity with rapid depletion of energy resources, promoting early cessation of movement. The aim of this review was to discuss current information on the influence of temperature on quantitative spermatozoon properties, which could affect sperm function. Our findings provide a greater understanding of fish sperm physiology and a biological foundation for the further development of spermatozoon motility investigations as well as reproduction technologies.     

Effects of steam pelleting or extrusion on digestibility and performance of silver perch Bidyanus bidyanus

The effects of different processing techniques on apparent digestibility coefficients (ADCs) and performance of silver perch Bidyanus bidyanus were evaluated. Results of a factorial digestibility trial, in which three diets (SP35, 95LC1 and 95LC2) and three processing methods (cold pelleted, steam pelleted and extruded) were evaluated, indicated that extrusion, but not steam conditioning, significantly improved ADCs of dry matter (DM) and energy. ADCs of DM and energy of cold‐pelleted diets were statistically similar to steam‐pelleted diets, and ADCs of nitrogen were unaffected by processing method. No interaction was found between diet type and processing method for DM, energy or nitrogen ADCs. A performance trial indicated that feed intake, weight gain and specific growth rate of fish fed steam‐pelleted diets was greater than those of fish fed extruded diets. Feed conversion and digestible protein efficiency was better in fish fed extruded diets. The results indicated that extruded diets were better utilized than steam‐pelleted diets; however, voluntary intake of extruded diets may have been limited. Fish fed cold‐pelleted SP35 exhibited inferior performance compared with fish fed steam‐pelleted or extruded SP35. Reduced performance of fish fed this diet may relate to poor utilization of digestible protein or reduced palatability. Diets for silver perch with similar formulations to SP35 and 95LC2 should be steam pelleted.     

A 3D MRI-based Numerical Model Dedicated to Industrial Thawing of Large Tuna Fishes

Industrial thawing of raw tuna fishes for the canning industry is of great importance in the global economy. Due to the heat transfer limitations within large sample pieces, these processes need to be improved to reduce fluid and energy consumption. In this work, the water immersion thawing process of yellowfin tuna was studied from both experimental and numerical approaches. First, the heat transfer model is validated with precooked tuna samples undergoing forced-air convection thawing. Then, the water immersion thawing process of yellowfin was studied with temperature measurements performed under an industrial environment. The numerical model considers the real geometry of the yellowfin using magnetic resonance imaging (MRI) integrated into a 3D finite element model. Overall, good agreement was found between experimental and predicted temperatures by considering a uniform convective heat transfer coefficient. A simplified 2D model can accurately predict the thawing time, but a 3D model is needed to predict the spatiotemporal temperature distribution in the product. The results have also shown the strong influence of the ambient temperature on the thawing time. This original approach considering the real fish geometry could now be used with different sized-tuna and various thawing kinetics to reach optimal processing conditions while improving product quality.     

鱼类精子超低温冷冻保存技术及其应用

鱼类精子的超低温冷冻保存对鱼类种质资源保护、低温生物学、遗传育种和水产养殖业都具有重要的意义。鱼类精子超低温冷冻保存技术主要包括冷冻保存方法、抗冻保护液、降温、解冻速率、冷冻保存温度、抗冻剂去除等过程。本文就鱼类精子超低温冷冻保存技术及其应用进行了综述。     

速冻温度对罗非鱼片品质的影响

通过测定不同冷冻方式冻罗非鱼片的理化指标,试图找到最优处理方式,并为冻罗非鱼片工厂化生产提供参考。通过设置双螺旋冷冻机不同的冷冻温度(-35℃、-38℃、-41℃、)冻结新鲜罗非鱼片,将冻结后的鱼片置于-18℃的冷库贮藏,每隔7 d对鱼片样品的pH、水分活度(Aw)、质构参数、挥发性盐基氮(TVB-N)等物理及化学指标进行检测并分析结果。数据表明,冷冻温度对鱼片色差值、失水率、硬度有较大影响,且冷冻温度越低,鱼片品质越好,对咀嚼性、弹性、TVB-N影响不大,对pH则无明显影响。综上,在现有加工工艺的冷冻温度波动范围内,选择较低冷冻温度,提高冻结速率可延缓冻罗非鱼片品质劣变速度,故建议企业加工时,将冷冻温度控制在-40℃,冷冻时间控制在40 min以尽可能保持鱼片品质。     

水产品蒸煮设备中CO2热泵蒸发器仿真试验

为研究水产品蒸煮装备用CO₂热泵中蒸发器的性能变化,通过建立CO₂热泵Simulink动态仿真模型,并搭建用于水产品蒸煮用CO₂热泵试验台,采用仿真计算与试验验证结合的方法,在此水产品蒸煮装备中,控制蒸发温度-5℃~-15℃,研究不同蒸发温度对结霜性能、制热量、热泵系数、压缩比性能参数的影响。结果显示:蒸发温度从-5℃变化到-15℃,结霜速率逐渐增大,在仿真和试验中,热泵蒸煮装备的制热量分别增加0.73 kW、0.70 kW,热泵系数分别降低0.29、0.32,压缩比分别增大0.52、0.50,其中,仿真与试验结果的最大误差率11.79%,最小误差率7.71%,仿真与试验结果吻合度较高。研究表明:在满足水产品加工需求的前提下,为提高加工系统效率,应降低蒸发温度;建立的CO₂热泵仿真平台可以较好地仿真水产品蒸煮装备的运行状况,可为CO₂热泵在水产品蒸煮的实际应用中提供指导作用。     

Evaluation of Processing Methods on the Nutritional Quality of Sea Cucumber (Apostichopus japonicus Selenka)

The close relationship between the consumption of sea cucumber and health status stems from the nutritional and functional substances found in sea cucumber that play a key role in the prevention of different diseases. The processing methods have a great effect upon the nutritional and functional substances in sea cucumber. A superior product should not only be abundant in nutritional substances, but also require an easy and cost effective processing method. This study compared the influence of processing methods on the stability of macronutrients and micronutrients present in sea cucumber in order to recommend products that could provide high nutritional quality. The five processes investigated were hot air drying (60°C), vacuum freeze-drying (0.5 cm thickness material, 5–10 Pa vacuum degree, ?85 to ?90°C cold trap temperature, ?25°C material temperature), sun drying, double-distilled water cooking followed by sun drying, and 3.5% sodium chloride solution cooking followed by sun drying. A significant decrease of all the chemical compositions determined was shown in all the sea cucumber products treated by the five processing methods (p < 0.05). Among all the processing methods, hot air drying resulted in the highest nutritional quality of the product. Moreover, hot air drying can be operated easily with low cost.     

热应激对鱼类hsp70基因和caspase-3基因影响的研究进展

鱼类对温度的适应因其种类不同而有差异,这是长期进化和演变的结果。本文通过对不同种鱼类的最大临界温度和高起始致死温度这两个热耐受性指标、耐热相关基因的表达等进行了综述,发现影响鱼类耐热能力的重要因素是基础水温和温度升高的速率,以及生物的生理及遗传,进而掌握不同鱼类的耐热能力,并对在高温胁迫下表达差异显著的hsp70基因和caspase-3细胞凋亡相关基因进行了分析讨论;发现热应激使hsp70在鱼类体内的合成速度显著增加,以提高鱼类的抗应激能力,同时也会使caspase-3基因被激活,诱导细胞发生凋亡。