国外关于鱼类的几种解冻方法

近几年来，国外对食品的解冻进行了广泛深入的研究。解冻方法或设备有超声波解冻，占0．56％；热幅射解冻，占1．69％；接触炉解冻，占3．37％；蒸汽真空解冻，占28．1％；水解冻，占22．5％；微波解冻，占13．48％：在一些欧洲国家如英国、西德等大量发展蒸汽真空解冻的设备，加拿大·丹麦·荷兰、南非等国得到广泛的应用。     

出口冷冻鳕鱼片的加工方法及加工环境

１ 工艺流程２ 工艺要求２．１ 选 料 选料时应注意以下要点：原料鱼血点越少越好，应无风干；尽可能选无脏原料；去头位置越向后越好；原料鱼切面应为白色，鱼体无创伤；原料鱼应软而不松；检查净重是否符合标志重量。２．２ 解 冻 解冻是手工加工的头道工序，解冻的好坏直接影响到加工工序的流畅和加工产品的质量。解冻要根据季节的变化．一般采用槽式注水式解冻法、实行自然解冻、固定水和流动水３个环节相结合的解冻方法，最终达到出槽时鱼体中心温度为０～４Ｃ。要求解冻工人具备较强的责任心，每２小时测一下解冻水温度。经常翻动鱼块…     

鼓泡流水解冻技术的研究

序言将冻结食品中的冰结晶融化回复到水的状态称为解冻。能回复到冻结前食品质量而没有变化这谓理想解冻。但解冻过程中经常出现滴水、损耗、变色现象、这同解冻使用的介质温度（影响解冻速度、解冻后温度）有关。将冻品放在空气或水中融化称自然解冻法、由于气温、水温变化,解冻时间长短不一、解冻后也不能保证食品的质量。采用机械装置解冻．其作业性优良,并能得到稳定质量的解冻品,但在使用时应根据食品种类、形状、状态及解冻后的用途选择解冻方法和解冻装置。l鼓泡流水解冻目前国内水产品加工企业大多采用自然解冻或喷淋或水池流水…     

流动湿空气解冻装置电气控制系统的研究

流动湿空气解冻装置是对水产品和肉类冻声进行解冻的装置，它用蒸汽对装置内加温，并控制蒸汽的流量，在较低温度下解冻。电气控制系统对温度和风机进行控制。本文对温度控制系统和风机控制系统分别作了介绍，并对上些具体电路进行了分析。     

法国研制成隧道式微波解冻装置

法国研制成一种隧道式微波解冻装置，该装置可以解冻各种形状的整条鱼和冻鱼片。从该微波装置产生的热能渗透到鱼体或鱼片中心，供热时间只需10～15分钟，并不损伤鱼体的外观，鱼皮仍保持完整无损。用微波蒸煮比用水蒸煮的鱼，在体重上只损耗10％左右，蛋白质的损耗值相同。     

冲击式速冻机中送风孔板对鱼体冻结效率的影响

为探明冲击式速冻机中送风孔板对鱼体冻结效率的影响，以小黄鱼为研究对象，通过数值模拟和试验验证，研究了送风孔板的排布方式、送风孔板孔径和鱼体中心距上下送风孔板的距离对鱼体冻结效率的影响，分析了不同送风孔板排布方式、送风孔板孔径及送风距离下鱼体的温度分布及中心温度变化情况。结果显示：上下送风孔板交错排布避免了两侧风的对冲损耗，使得冻结速率最高、冻结时间最短；送风孔板孔径的增加有效减小了第二阶段的鱼体冻结和第三阶段的鱼体降温时间；上下孔板距鱼体中心的距离越短，冻结时间越短。研究表明：筛选出适宜的送风孔板结构和参数，可为水产品冷冻提供新的工艺指导，为冲击式速冻机的优化设计提供技术参考。     

英国艾弗斯公司最近提供的水产品加工机械

座落在英国赫尔的艾弗斯(Afos)股份有限公司向英国希尔瓦特鱼类养殖公司提供了一条完整的鱼类加工生产线。该生产线包括喷水解冻装置、切鱼片流水生产线、自动输送带、自动腌鱼机、烟熏干燥器以及小推车。操作时，先使用不锈钢喷水解冻装置解冻鱼块，然后用水平输送带将鱼送到切鱼片机上进行切片加工。鱼片切成后，再输送到自动腌鱼机上进行浸渍。     

真空水蒸汽解冻装置的方案设计

真空水蒸汽解冻装置的方案设计叶于明，程有凯，赵世明（大连水产学院，１１６０２３）ＹｅＹｕｍｉｎｇＣｈｅｎｇＹｏｕｋａｉＺｈａｏＳｈｍｉｎｇ（ＤａｉａｎＦｉｓｈｅｒｉｅｓＵｎｉｖｅｒｓｉｔｙ，１１６０２３）关键词真空，解冻装置，方案设计ＫＥＹＷＯＲＤＳ...     

冻鱼低频声波解冻与水解冻

目前快速冻结和快速解冻技术均已取得了显著的进展。溯自1842年以来，对鱼类冻结方法已着手进行研究；而对改进解冻速度和方法的研究，直到本世纪五十年代才引起重视。一些水产企业由于发展具有散装冷冻和储藏能力的大型渔船，促使散装鱼货的解冻方法应运而生。为了处理大量的冻鱼，陆上企业必须配套与生产相适应的解冻能力。关于所用的解冻方法，当然首先要考虑质量问题，其次也应顾及设备的规模和运行成本等。     

三种解冻方法比较研究

本文以速冻悲崔贻贝为试验材料，对空气解冻，红外解冻和微波解冻等三种解决方法进行了比较研究。通过测定解冻至５℃所需的时间和解冻后产品的感官评价、ＴＶＢ－Ｎ值及还原糖含量等质量指标来进行分析比较。实验结果表明，从解冻时间和解冻后产品质量的角度来看，选择微波解波法较适宜。符合现代流水线生产的需要，可为水产品解冻生产实际提供指导和参考。     

Effect of Different Thawing Methods and Multiple Freeze-Thaw Cycles on the Quality of Common Carp (Cyprinus carpio)

The effect of different thawing methods—running water, microwave, slack water (25°C), air (25°C), and refrigerator (4°C)—and multiple freeze-thaw cycles (0, 1, 3, and 5) on the quality of common carp were investigated. Microwave thawing showed the lowest score for sensory assessment and the highest cooking loss (p < 0.05), while 4°C refrigerator thawing showed less thawing loss and cooking loss but required the longest thawing time. Ca²⁺-ATPase activity and sulfhydryl content of air thawing were lower (p < 0.05), while no significant differences were observed among other thawing methods. Water loss and the thiobarbituric acid reactive substances (TBARS) value increased (p < 0.05) when freeze-thaw cycles increased. The sensory scores and hardness decreased significantly when the freeze-thaw cycles increased (p < 0.05). A significant decrease (p < 0.05) was observed in salt-extractable protein content after five freeze-thaw cycles. Different thawing methods affected the quality of common carp. Frozen common carp subjected to freeze-thaw cycles resulted in accelerated lipid and protein oxidation and caused mechanical damage to muscle tissues.     

Simple freezing and thawing protocol for long-term storage of harvested fresh Undaria pinnatifida

The development of a simple and effective long-term storage protocol for harvested fresh Undaria pinnatifida is required to increase the market for U. pinnatifida products. We investigated the quality of U. pinnatifida after the application of various freezing and thawing methods to establish an optimum storage protocol. Four freezing temperatures (?40, ?30, ?20, and ?10?°C), four freezing conditions (in air without seawater and with 50, 75, and 100?% seawater), and four thawing times (6, 12, 18, and 24?h) were employed. Changes in color value, tensile strength, total bacterial count, and most probable number of coliforms were measured. The best method for preserving the overall quality of U. pinnatifida is freezing at ?30?°C with 50?% seawater and thawing in running tap water for 6?h. During retail display, changes in color, odor, tensile strength, and bacterial count of U. pinnatifida that had been freeze-thawed under optimum conditions were also measured, and a sensory evaluation was performed. There was no significant difference compared with the control within two?days at 10?°C. In conclusion, we developed a simple and effective long-term storage protocol that led to no significant loss of quality of fresh U. pinnatifida.     

凡纳滨对虾虾仁在冻藏过程中品质变化研究

以凡纳滨对虾（Penaeus vannamei）为研究对象,经过去头和去壳处理后,于-35℃冷冻过夜,然后置于-18℃条件下进行保藏试验。通过测定解冻损失率和肉色变化,明确冻藏期间虾肉的质量变化规律,结合腺苷三磷酸（ATP）及其降解产物、总挥发性盐基氮（TVB-N）和酸碱度（pH）等鲜度指标的测定结果,分析对虾在冻藏条件下鲜度的变化规律,旨在为其生产加工提供理论依据。研究结果表明,冷冻保藏至第18天时解冻损失率达到最大,同时表面色差（L^＊）也达到最大值41.56。而虾肌肉中的ATP质量摩尔浓度冻藏第1天就降低了71.78%,次黄嘌呤（Hx）和次黄嘌呤核苷（HxR）则一直维持在较低水平。第10天鲜度指标（K值）达到最大值7.18%,并能比较稳定地保持这一水平,结合TVB-N测定结果,发现冻藏至第30天时,虾肌肉中的TVB-N仍未超过腐败临界值。因此,冻藏处理可以保持凡纳滨对虾的鲜度,使各项理化指标维持在较低水平,但会加重解冻损失现象。     

泥鳅胚胎玻璃化液超低温冷冻保存研究

泥鳅胚胎（胚孔封闭期）用10＃玻璃化液作为低温保护剂，经低温（－196℃）冷冻保存17h后，38℃水浴解冻，解冻后的胚胎获得了成活。在稀释液B1、B2、B3中分别有26．7％，15．0％，3．0％成活的胚胎。解冻后的胚孔封闭期胚胎经过50h的培养，胚胎从胚孔封闭期发育至尾鳍出现期。     

The Use of Dairy Protocols for Sperm Cryopreservation of Blue Catfish Ictalurus furcatus

The commercial‐scale production of fish by use of artificial (induced) spawning would require reliable, large‐volume sources of sperm. Cryopreservation can be used to preserve and store sperm within commercial and research germplasm repositories, but is limited in its application to aquaculture. Straw volume and cooling chamber size restrict the quantity of sperm that can be frozen, and straws must be filled by hand. In contrast, the dairy industry has refined methods for freezing of bull sperm, including automation of straw filling and the use of large cooling chambers. These methods could be used for commercial‐scale cryopreservation of fish sperm, although application would require testing. To supply sperm in large volumes, bags originally developed for swine semen could be cooled using dairy protocols and used as a container for fish sperm. The current study documented the use of commercial‐scale dairy cryopreservation techniques for the production of hybrids of channel catfish Ictalurus punctatus (female) by blue catfish Ictalurus furcarus. Four cryoprotectants (methanol, dimethyl sulfoxide, dimethyl acetamide, and glycerol) were initially evaluated for use with blue catfish sperm. During May 2000 and March to April 2001, suspensions of blue catfish sperm were cryopreserved with 10% methanol in 0.5‐mL French straws and in commercial swine semen bags (Cochette^* bags, IMV International. Minneapolis, Minnesota, USA). Cryopreservation took place at a dairy breeding cooperative, using technology employed for bull semen. Sperm motility before freezing was 26 ± 18% during Year 1 (2000) and 62 ± 30% during 2001. Sperm were thawed at 40 C and used to fertilize the eggs of channel catfish (yielding hybrids). Motility after thawing for sperm frozen in 0.5‐mL straws was 11 ± 10% during 2000 and 50 ± 24% during 2001. Motility after thawing was 41 ± 17% for sperm frozen in swine semen bags in 5‐mL aliquots and 43 ± 10% for sperm frozen in 10‐mL aliquots. Neurulation of eggs fertilized with thawed sperm from straws was 83 ± 13% during 2000 and 54 ± 27% during 2001. Neurulation was 57 ± 24% using sperm frozen in swine semen bags in 5‐mL aliquots and 55 ± 10% using sperm frozen in 10‐mL aliquots. There was no correlation between sperm motility before freezing (in 0.5‐mL straws) and after thawing during 2000 (r= 0.52) or during 2001 (r= 0.49). In addition, there was no correlation between initial motility and neurulation of channel catfish eggs fertilized using thawed sperm during 2000 (r= 0.14) or during 2001 (r= 0.29). Sperm of blue catfish can thus be cryopreserved at a commercial scale using dairy protocols and can be made available for the production of hybrid catfish when viable eggs are available.     

The Aerobiological Pathway of a Fish Pathogen: Survival and Dissemination of Aeromonas salmonicida in Aerosols and its Implications in Fish Health Management

The aerobiological (aerosol) pathway of Aeromonas salmonicida subspecies salmonicida (ATCC 33658) was investigated. Results indicate that viable A. salmonicida can travel as an aerosol/droplet spray at least 104.1 cm (limits of the test chamber used) when carried by air currents. Additionally, viable A. salmonicida was recovered from water exposed to an experimentally generated aerosol/droplet spray of A. salmonicida downwind from the contaminant source. It is possible that viable bacterial aquatic animal pathogens can be spread via the airborne route. This possible route of pathogen introduction could effect current management or system designs, especially when aquaculture systems consist of tanks in close proximity.     

Effects of developmental stage, seawater concentration and rearing temperature on cryopreservation of Pacific oyster Crassostrea gigas larvae

ABSTRACT: For the development of a stepwise cryopreservation technique for larvae of the Pacific oyster Crassostrea gigas , various conditions were examined. Larvae at 9, 12, 15, 18 and 21 h after insemination were cooled at a rate of −1°C/min (seeding at −8°C for 15 min) and then plunged into liquid nitrogen at −35 or −40°C using 1.5 M dimethyl sulfoxide (DMSO) and 250 mM trehalose as cryoprotectants. Among these larvae, 15 h after insemination (the trochophore stage before formation of the shell gland) showed the highest motility and the best external appearance after thawing. Trochophore larvae were cryopreserved in preservation media containing different dilutions (1/4, 1/6, 1/8, 1/10 and 1/30) of seawater. Larvae preserved in the 1/4 seawater medium showed the highest appearance of shelled larvae 4 days after thawing. Trochophore larvae reared in seawater at 21, 25 or 29°C were cryopreserved for 8 months and then reared at 26°C after thawing. Larvae reared at 25°C showed the highest survival rate and normal larval ratio at day 6 after thawing, although larvae reared at 21°C showed the highest rates until day 4. One larva developed at 25°C succeeded to settle.     

反复冷冻-解冻对鲢品质的影响

研究鲢(Hypophthalmichthys molitrix)在冷冻-解冻过程中的品质变化规律。鲢于–18℃条件下冻藏10 d,流水解冻后再贮藏于–18℃条件下,5 d后解冻,共反复冷冻-解冻5次。在解冻1、3、5次后随机取3条鲢测定其解冻损失、蒸煮损失、硬度、咀嚼性、恢复性、硫代巴比妥酸(TBA)值、L*值、b*值、盐溶性蛋白(SSP)含量、Ca2+-ATP酶活性、总巯基含量、表面疏水性和感官值等指标,评价反复冷冻-解冻对鲢品质的影响。结果表明,在第1次冷冻-解冻时,硬度、咀嚼性、恢复性、盐溶性蛋白(SSP)含量和Ca2+-ATP酶活性与鲢初始值相比显著降低(P<0.05),b*值和表面疏水性显著升高(P<0.05);解冻损失、L*值和TBA值在第3次冷冻-解冻时显著上升(P<0.05);总巯基含量在第5次冷冻-解冻时显著下降(P<0.05);而蒸煮损失在冷冻-解冻过程中没有显著变化(P>0.05);感官值在第5次冷冻-解冻时为47,感官品质已不可接受。各指标变化表明,鲢品质会随着反复冷冻-解冻次数增加而下降,在运输、贮藏和销售过程中要防止温度波动,避免反复冻融对鲢品质造成不利影响。     

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.     

The 70-kDa Heat-shock Protein as a Potential Biomarker of Quality of the Parapenaeus longirostris Shrimp Flesh

The deep-water rose shrimp, Parapenaeus longirostris, is a target species of the Mediterranean fisheries mostly caught by trawlers offshore, processed, and frozen on board. The effects of thawing on shrimp muscle exudate collected at 0, 1, 2, 3 days after thawing were investigated. In total, 70-kDa heat-shock protein (Hsp70), alpha (α)-enolase, and manganese superoxide dismutase (Mn-SOD) were selected as metabolic and stress-related proteins and analyzed by immunoblotting on exudates. Data were compared for the amount of exudates collected and the pH values. Among the investigated proteins, only the Hsp70 levels showed a decrease related to the post-thawing period and correlated with both the significant increase of the exudate amount and the pH values. These data strongly suggest the potential use of Hsp70 as an early predictive biomarker for quality of the P. longirostris shrimp after thawing.