几种淡水养殖鱼鲜度变化的特点

本文对常见几种淡水养殖鱼鲜度变化的特点作了研究。结果表明鲢、鳙、草鱼等几种淡水鱼在０℃贮藏下的ＴＶＢ－Ｎ变化，呈现的趋势大体相同。在０℃及－３℃低温下ＴＢＶ－Ｎ变化缓慢，且数量水平较低，在２０℃下则变化迅速，呈直线上升之势。实验结果也表明这几种淡水鱼在０℃下的Ｋ值变化速率随鱼种而异，其大小依次为链、镛＞草鱼＞团头鲂＞鲫。文中根据对草鱼、团头鲂等淡水鱼在不同温度下Ｋ值变化的测定结果作了阿列纽斯图，并     

防腐冰对鱼类保鲜效果研究↑（*）

防腐冰是水中添加防腐剂制成的，它能够增强对鱼在冰鲜期间的保藏效果。本文采用感官检定和ＴＶＢ－Ｎ等鲜度指标，研究了几种Ｎａ＿２－ＥＤＴＡ冰和苯甲酸钠冰对鲅鱼和带鱼的保鲜效果。结果表明：（１）１‰Ｎａ＿２－ＥＤＴＡ冰具有较稳定、持久的抑菌效果，能有效地延缓鱼品感官质量下降和ＴＶＢ－Ｎ上升，冰藏８天的带鱼细菌数，普通冰组为３．７×１０￣５个／ｇ，而１‰。Ｎａ＿２－ＥＤＴＡ，冰组仅为２．１×１０￣４个／ｇ。（２）以感官检定８０分为基准，与使用普通冰相比，使用１‰Ｎａ＿２－ＥＤＴＡ冰保鲜鲅鱼，保藏期由１１６ｈｒ提高到１４０ｈｒ，保鲜带鱼，保藏期由１０４ｈｒ提高到１６４ｈｒ。     

远东拟沙丁鱼保鲜方法的研究

本文研究了远东拟沙丁鱼（Ｓａｒｄｉｎｏｐｓｍｅｌａｎｏｓｔｉｃｔｓ）海上冰鲜、冰盐微冻、冷海水和冷海水微冻保鲜的效果。结果表明，ＴＶＢ－Ｎ和ＦＦＡ值的变化与鱼货质量的感官检验结果有密切关系，ＴＶＢ－Ｎ值为２４ｍｇ％和ＦＦＡ为１１ｕｍｏｌｅ／ｇ，是冰鲜和冰盐微冻保鲜的拟沙丁鱼质量新鲜与否的临界值，而冷海水和冷海水微冻保鲜的临界值为：ＴＶＢ－Ｎ１４ｍｇ％，ＦＦＡ１１ｕｍｏｌｅ／ｇ。８９种保鲜方法的有效保鲜期分别为：冰鲜７天、冷海水６天、冰盐微冻１７－１８天、冷海水微冻１１－１２天。有效保鲜期内微生物的数量在１０３－１０５／ｇ之间变化。冰盐微冻会使鱼体产生脱水作用，冷海水保鲜会使鱼体产生吸水作用，而微冻保鲜和冷海水保鲜会使合体渗入部份食盐。     

蓝圆Shen冷冻鱼糜制作关键技术

本文叙述了蓝圆Ｓｈｅｎ冷冻鱼糜制作的关键技术，以蓝圆Ｓｈｅｎ制作 冷冻鱼糜 ，其ＴＶＢ－Ｎ应控制在２３．６ｍｇ％以下。     

水质,底质改良剂在虾池的应用研究

本文主要研究了水质，底质改良剂对泉州东海村和厦门东屿村虾池水质，底质的改良效果。两处虾池经投放改良剂后，海水中的ＣＯＤ降低７．２～１４．６％，ＮＨ４－Ｎ降低９０％以上，底泥的Ｅｈ值升高１３０ｍｖ，硫化物降低３２．８～７３．４％，底泥间隙水的ＮＨ４－Ｎ降低４１．０～７４．７％，ＣＯＤ降低１５．５～４０．０％。     

养殖鱼类细菌性败血症的菌苗制备技术

选择对养殖鱼类致病的嗜水气单胞菌强毒株，用福尔马林以０．０５％－１．０％的６个浓度及４、２５和６３℃等３种温度灭活制成菌苗，进行安全性和免疫保护试验。结果表明：福尔马林的最佳灭活浓度为０．０５％－０．２％，浓度过高会影响菌苗的抗原性和对鲫的安全性；灭活温度以４℃明显优于６３℃。     

温流水养鱼系统对电厂冷却水影响的研究

对具有水处理设施的温流水养鱼系统的供水、养鱼水及回水进行了水质分析，结果：ＰＨ值、ＤＯ、ＡＬＫ、Ｃａ＾２＋和水温依次下降，经过集中水处理后的回水ＣＯＤ、ＢＯＤ５、ＴＨ、ＳＳ和Ｍｇ＾２＋的值有所下降，ＢＯＤ５去除率为５４．３８％，悬浮物去除率为６７．５４％；ＮＨ４＾＋－Ｎ和ＮＯ２＾－－Ｎ依次升高；电导率无明显变化；而ＮＯ３＾－－Ｎ供水略高于养鱼水，在此基础上讨论了温流水养鱼系统对电厂冷却水的正面影响     

暴发性鱼病菌苗的灭活条件及免疫效果的研究

０．０５％－１．０％的福尔马林、０．０１％－０．１％的新洁尔灭、３．０％－４．０％的氯仿以及６３℃高温均对嗜水气单胞菌灭活作用。温度对嗜水气单胞菌的灭活无明显影响，但低温灭活有利于菌苗抗原性的保持，受试鱼产生的保护作用更强，故以低温４℃时用３．０％－４．０％的氯仿、０．１％－０．２％的福尔马林，０．０３％－０．０５％的新洁尔灭制备的菌苗免疫效果最好。     

二氧化氯改善养殖水环境效果的研究

使用二氧化氯化处理水养殖用水（实验室规模）测定水化学指标及水中细菌数量的变动,结果表明：（１）二氧化氯能够明显中水环境的溶氧（增氧量为５．８－２２．７％）减低水中ＣＯＤ和ＮＨ３－Ｎ值（ＣＯＤ降低幅度为２６．０－５８．８％,ＮＨ３－Ｎ清除率为１９．４－３８．５％）（２）二氧化氯浓度为０．２×１０＾－３ｍｏｌ／ｍ＾３及１．２×１０＾－３ｍｏｌ／ｍ＾３可有显降低海水中弧菌数及细菌总数,随着药物浓度增大,     

氨氮对罗氏沼虾幼体的影响

非离子态氨氮对罗氏沼虾幼体毒性试验结果表明，罗氏沼虾幼体２４小时半致死的ＮＨ３－Ｎ浓度值为４．１０９毫克／升左右，１００％死亡的ＮＨ３－Ｎ值为５．０６１毫克／升；４８小时ＮＨ３－Ｎ的ＬＣ５０值范围为１．０１５－２．１１２毫克／升，ＬＣ值为３．１２７毫克／升；生产池中的ＮＨ３－Ｎ值较低，对罗氏沼虾幼体的生长蜕壳没有什么明显的不利影响。     

养殖大黄鱼冰藏流通的货架期试验

本文于2004年7月对养殖大黄鱼进行了冰藏流通货架期的试验研究，监测了实际流通全过程的鱼体温度和鲜度质量的变化。结果表明，大黄鱼冰藏流通过程的总体设计是合理的，但在夏季，鱼在捕获后的处理加工中没有得到及时的有效冷却，运输和流通中不使用冷藏车、冷藏库，不仅增加了用冰量，而且冰融化较快，大大缩短了冰藏大黄鱼的货架期，冰藏3d后再次在上层加覆盖细碎冰．鱼可保持高品质期4d，货架期5.75d。     

Postmortem Biochemical and Microbiological Changes in Loricariid Catfish (Pterygoplichthys disjunctivus) Muscle During Ice Storage

ABSTRACT

Postmortem biochemical and microbiological changes in loricariid catfish (Pterygoplichthys disjunctivus) muscle were evaluated during ice storage for 20 days. Values of pH remained stable for 15 days (7.4 ± 0.2), and total volatile base-nitrogen (TVB-N) remained under acceptable limits throughout storage, with a final value of 25.2 ± 3.3 mg N/100 g muscle at Day 20. Adenosine-5´-triphosphate (ATP) and derivatives followed a postmortem degradation pattern similar to other species, with the K-value being the best freshness loss indicator. Biochemical and microbiological changes indicated that the shelf life of iced loricariid catfish muscle was 15 days under optimal (0°C) storage conditions.     

鲤鱼冷藏中的鲜度变化与货架期

以感官、化学和微生物为指标,研究了养殖鲤鱼在0℃(冰藏)、5℃、10℃和15℃贮藏过程中的鲜度变化和货架期,并对菌落总数、嗜冷菌、假单胞菌、挥发性盐基氮与感官评价的一致性程度进行了探讨。结果表明,在0℃、5℃、10℃、15℃的贮藏过程中,鲤鱼的高品质期分别为426 h、189 h、95 h和58 h,货架期分别为713 h、382 h、146 h和87 h。各温度高品质期终点和货架期终点时菌落总数分别为6.63±0.45 lg cfu/g、7.18±0.29 lg cfu/g,假单胞菌数分别为5.69±0.75 lg cfu/g、6.50±0.33 lg cfu/g,挥发性盐基氮均值分别为9.90±0.52 mg/100 g、20.52±0.34 mg/100 g。各温度下高品质期终点和货架期终点时各指标均值均无显著差异(P0.05),表明菌落总数、假单胞菌和挥发性盐基氮作为鲤鱼低温贮藏的鲜度指标与感官鲜度评价有较好的一致性。     

去除内脏对冰藏鲤感官、化学和微生物变化的影响

以感官、TVBN、菌落总数、假单胞菌为指标,探讨去除内脏对冰藏鲤(Cyprinus carpio)品质变化及货架期的影响。结果表明,去除内脏和未去除内脏冰藏鲤的高品质期分别为333h和330h,货架期分别为575h和654h;去除内脏鲤冰藏的货架期略短,但无显著性差异(P0.05)。在冰藏过程中二者假单胞菌数量占优势,高品质期终点,去除内脏和未去除内脏鲤的菌落总数(CFU/g)的对数值分别为6.33±0.02和6.07±0.03;假单胞菌数(CFU/g)的对数值分别为6.15±0.19和6.04±0.01;挥发性盐基氮值分别为(10.86±0.50)mg/(100g)和(10.15±0.01)mg/(100g)。货架期终点,二者细菌总数(CFU/g)的对数值分别为7.06±0.18和6.90±0.14;假单胞菌数(CFU/g)分别为6.89±0.13和6.31±0.05;挥发性盐基氮值分别为(19.03±0.90)mg/(100g)、(21.15±0.80)mg/(100g)。二者在高品质期终点和货架期终点的各指标均无显著性差异(P0.05)。与未去除内脏鲤相比,冰藏初期去除内脏鲤的挥发性盐基氮值略低,而其细菌增殖较快且直接进入对数增长期,这可能是由于去除内脏过程对鱼体造成破坏所致,而过了高品质期后,无论是挥发性盐基氮值还是感官评分都比未去除内脏的高,因此去除内脏鲤的货架期略短。     

大菱鲆0、25℃贮藏的鲜度变化和货架期

以感官、化学和微生物为指标,对大菱鲆在冰藏(0℃)、室温(25℃)贮藏过程中的鲜度变化和货架期进行了研究,并探讨了菌落总数(TVC)、挥发性盐基氮(TVBN)、三甲胺氮(TMA)与感官评价的一致性程度。结果表明,0℃和25℃贮藏大菱鲆,高品质期分别为526 h和26 h,货架期分别为763 h和49 h;TVC在高品质期终点分别为6.88、6.38 lg(cfu/g),在货架期终点分别为7.67、7.90 lg(cfu/g);TVBN在高品质期终点分别为15.97、16.46 mg/100g,在货架期终点分别为33.1、28.58 mg/100 g;TMA在高品质期终点分别为1.29、0.74 mg/100 g,在货架期终点分别为12.89、11.37 mg/100g。各指标间均无显著性差异(P>0.05),表明TVC、TVBN值、TMA值作为大菱鲆贮藏中的品质指标保持较好的一致性。大菱鲆0℃和25℃贮藏的主要腐败菌均为假单胞菌属(Pseudomonas spp.),其次为腐败希瓦氏菌(Shewanella putrefaciens)。     

Appraising the Shelf Life of Farmed Cobia,Rachycentron canadum,by Application of a Quality Index Method

Freshness is the main concern of seafood quality, and the principal method to evaluate seafood freshness is sensory evaluation. The aim of this work was to study the quality changes of cobia, Rachycentron canadum, under ice storage through sensory and physical analysis as well as bacterial counting of specific spoilage organisms (SSOs). In particular, the utilization of a quality index method (QIM) scheme was proposed. Samples stored for 0–30 d were analyzed with the QIM. Ten panelists observed and registered the changes occurring in the fish starting on day zero and ending when the fish were spoiled. After developing the scheme, 11 sensory attributes were described in 23 points, which detailed the appearance of skin, eyes, abdomen, gills, and flesh deterioration. The volatile nitrogen compound measurements and microbiological data of the SSOs determined a shelf‐life of 19 d for the samples. Sensory analysis showed a rejection point at 15.67 d of ice storage. The natural degradation of myofibrillar proteins and collagen was observed during ice storage. In conclusion, a shelf‐life of 15 d was defined for raw cobia stored on ice.     

Influence of Monascus Fermentation on Storage Characteristics of Semidry Salted Tilapia

Semidried salted tilapia was fermented and prepared by Monascus (Monascus anka and Monascus purpureus). The sample was restored at 25°C to undergo the preservation test. The color value, total volatile base nitrogen (TVB-N) value, ammoniacal nitrogen content, acid value, and peroxide value were measured on a daily basis for 24 days. Results showed that Monascus contributed to inhibiting the growth of microorganisms and delayed the advent of decomposition. Meanwhile, they could keep the lipids from oxidation and rancidity, which helped the semidried tilapia achieve a satisfying color. The preservation test and the bacterial colony culture test on physicochemical and microbiological indexes under 25°C showed that Monascus fermentation could inhibit the growth of other microorganisms, improved the quality of semidried tilapia, and extended shelf life.     

在不同贮藏温度下鲢肌肉鲜度的变化

以总挥发性盐基氮(TVB-N)和硫代巴比妥酸值(TBA)作为肌肉鲜度的评定指标,研究在冷藏(4℃)和冷冻(-18℃)条件下鲢(Hypophthalmichthys molitrix)背部和腹部肌肉鲜度的变化情况。结果表明,在贮存过程中,鲢背部和腹部肌肉的TVB-N和TBA均符合一级反应动力学模型;随着温度的升高,反应速率加快;在4℃条件下,鲢肌肉一级鲜度的保质期为27～38 h,二级鲜度为51～65 h,到81～88 h腐败变质;在-18℃条件下,鲢肌肉一级鲜度的保质期为11～18 d,二级鲜度为36～43 d,到73～77 d腐败变质;在同一贮存时间,腹部肌肉的TVB-N和TBA均高于背部;并且,鲢肌肉的TVB-N与TBA呈极显著(P<0.01)的正相关关系。     

Quality Index Method (QIM) Scheme Developed for Whole Nile Tilapias (Oreochromis niloticus) Ice Stored under Refrigeration and Correlation with Physicochemical and Microbiological Quality Parameters

ABSTRACT

A quality index method (QIM) scheme was optimized to evaluate the freshness of whole tilapias (Oreochromis niloticus) ice stored under refrigerated conditions, which is the most common format of commercialization between primary producers and retailers. QI showed a high prediction accuracy, estimating a rejection point of 10.8 days. Principal component analysis showed the influence of the storage time on sensory, physicochemical (instrumental color and texture profile, total volatile base nitrogen, thiobarbituric acid-reactive substances, pH), and microbiological (total aerobic mesophilic count and total aerobic psychrotrophic count) quality parameters and the correlations between them. The suitability of the QIM scheme for assessing the freshness of whole tilapia was demonstrated to be a fast and accurate tool to maintain proper quality control along the production chain.