Assessment of Color and Sensory Evaluation of Frozen Fillets from Pangasius Catfish and Nile Tilapia Imported to European Countries

The current study was designed to assess the color and sensory evaluation of frozen fillets of Pangasius catfish and Nile tilapia imported to Poland, Germany, and Ukraine in order to evaluate the possible impact of negative media image of these fish fillets on the sensory expectations of the consumers. The study used two trials of sensory evaluation: Blind and informed, on a group of untrained respondents and additional color analysis using the Commission Internationale de l’Éclairage (CIE) L*a*b* scale. The lowest grades during sensory evaluation in all measured parameters were given to Pangasius imported to Ukraine and Poland. The grades of Pangasius and tilapia imported to Germany were similar and significantly higher than of other Pangasius groups. Generally tilapia fillets were marked as better than Pangasius fillets. Moreover the present study found that there was considerable percentage of customers which are susceptible to various commercial frauds since they marked Pangasius higher when they thought they are consuming turbot. This study also showed that the negative image of Pangasius presented through various mass-media might have a negative impact on consumer’s perspective of Pangasius consumption.     

苯醚甲环唑和丙环唑对罗非鱼的急性毒性研究

以罗非鱼为供试对象,研究苯醚甲环唑和丙环唑对其的急性毒性,观察96 h内罗非鱼的中毒反应和死亡情况。结果显示,苯醚甲环唑对罗非鱼96 h LC50为4.31 mg/L,丙环唑对罗非鱼96 h LC50为4.85 mg/L,表明这两种药物对罗非鱼为高毒药物。     

我国罗非鱼出口现状及对策

罗非鱼是我国水产品出口的拳头产品,近年来保持快速增长的态势。但随着2014年12月美国多次检出我国出口罗非鱼磺胺类药物残留并对相关企业实施"自动扣检"措施,罗非鱼出口严重受阻,产业遭受致命打击。本文通过分析比较了我国近年来罗非鱼出口贸易情况,并对其出口不合格情况进行系统的整理和分析,发现罗非鱼产业存在产品加工程度较低、产业依赖出口且市场过于集中无定价权、养殖大环境日益恶化违规用药等违法违规行为屡禁不止等问题,通过对这些问题进行分析研究,建议采取加强源头监管、推进产业转型升级、促进行业自治、构建多元化市场格局和推进国际共治等对策措施,以期对提高罗非鱼出口产品质量和完善我国出口水产品质量安全管理体系提供一定参考。     

罗非鱼肉及下脚料在食品工业中应用研究

本文介绍了肉类加工中新型肉制品罗非鱼得加工和保鲜技术。同时还介绍了加工过程中附带的鱼骨、鱼皮等下脚料在食品工业中的应用。     

Effects of mercury accumulation on the electrophoretic patterns of the serum, haemoglobin and eye lens proteins of Tilapia mossambica (Peters)

Two test concentrations of mercury (0.01 and 0.04 ppm) were used for studies on the uptake of mercury by the tissues and alteration in the electrophoretic patterns of blood serum, haemoglobin and eye lens proteins. Haemoglobin showed an increase in protein in the faster moving band. Significant changes were seen in the patterns of serum protein with respect to number, mobility and intensity of the protein fractions in the fish exposed to higher concentration of mercury (0.04 ppm). The patterns of eye lens protein were quite constant throughout the period of exposure.Short-term experiments on the fish serum electrophoresis were carried out using higher concentrations of mercury in the medium (0.4, 0.6 and 0.8 ppm). These were just below the lethal level. Sampling was done at 3, 24, 48 and 72 h intervals. From 24 h onwards there was a significant increase in the intensity of the lower mobility bands and there was a decrease in the higher mobility bands. After 48 and 72 h, a distinct extra band was seen between the first two fast-moving bands at all the three high concentrations of mercury used. These patterns were very similar to the pattern observed with the lower concentration of mercury in the medium (0.04 ppm) after the 11th week exposure period, which was found to affect the survival or growth potential of the fish. This study shows that exposure to a large amount of mercury over a short period has an effect similar to small amounts over a long period. The serum electrophoretic patterns obtained after 48 and 72 h exposures to sublethal concentrations of mercury, and which were similar to the one obtained in 0.04 ppm mercury concentration after the 11th week exposure period, can be regarded as the “stress pattern” of T. mossambica serum. The use of fish blood morphology as a biological index of water quality has been indicated.     

罗非鱼骨骼肌中胶原蛋白分解酶的提取纯化及活性

新鲜罗非鱼肉匀浆离心后经硫酸铵分级沉淀、SephadexG-100凝胶柱层析、DEAESephadexA-50阴离子交换后,得到经SDS-PAGE证实的纯品.650g罗非鱼骨骼肌可制备总活力14835U,比活力526.4U/mg的胶原蛋白分解酶,纯化倍数为111.53倍.     

内源化学反应及细菌活动对冰温贮藏罗非鱼片腐败变质的贡献研究

目的 评估内源化学反应及细菌活动对冰温贮藏罗非鱼片腐败变质的贡献。方法 研究经抑菌处理及未经抑菌处理的罗非鱼片在冰温贮藏期间的菌落总数、挥发性盐基氮(totalvolatilebasicnitrogen,TVB-N)值、pH、硫代巴比妥酸(thiobarbituric acid, TBA)值及感官鲜度的变化,采用电子鼻监测挥发性成分的变化,并对未经抑菌处理罗非鱼片各指标与菌落总数间进行皮尔逊相关性分析。结果 贮藏期间经抑菌处理的样品的菌落总数始终小于5.05 log CFU/g, TVB-N值小于3.00 mg/100 g, pH及电子鼻测定的各种挥发性成分基本未变,未发生感官腐败,虽然TBA值有所增加(P<0.05),但始终低于0.05 mg MDA/100 g。而未经抑菌处理的罗非鱼片,菌落总数在21 d时达到9.19 log CFU/g, TVB-N值增至40.69 mg/100 g, pH由6.65增至7.63,电子鼻测定的氮氧化合物、硫化物及有机硫化物骤增, TBA值增至0.072 mg MDA/100 g,显著高于抑菌处理的样品,感官腐败明显。结论 冰温贮藏条件下内源...     

Changes in textural and rheological properties of gels from tilapia muscle proteins induced by high pressure and setting

Tilapia meat pastes were prepared with a combination of hydrostatic pressure (200 MPa) and setting (50 °C) treatments, to investigate the changes in their rheological properties, gel-forming ability, whiteness and protein solubility of their gels. The control, a cooked gel (90 °C/30 min), was elastic and white, with low gel-forming ability. Gels formed by setting were elastic, rigid and mainly consisted of covalent bonds. Gels formed by pressurisation were soft and consisted of hydrogen bonds and hydrophobic interactions. Pressurisation prior to setting reinforced the gel structures, by formation of both covalent and non-covalent bonds. Setting prior to pressurisation did not alter the characteristics of the gel. Setting under pressurisation constructed a viscous gel with non-covalent bonds. Various fish gel products were formed in this study.     

基于质量安全的我国罗非鱼生产经营模式 调研与述评

罗非鱼是我国水产业中最具国际竞争实力的品种,近年受出口贸易竞争和链球菌病的影响,罗非鱼质量安全容易被忽视,产业可持续发展不容乐观。论文概述了海南省、广东省、广西壮族自治区、福建省和北京市五个地区罗非鱼典型生产经营模式,分析了各模式下养殖产品质量安全现状及产生问题的原因。针对问题,提出了建立优质优价的市场机制、开拓国内市场减少出口依赖、推广生态健康的养殖模式、利用产业技术体系平台推动产业链资源整合、开展一体化的经济模式标准化生产、发挥行业管理协会应有作用等建议,提高产品质量,促进产业健康可持续发展。     

Comparative studies on molecular changes and pro-oxidative activity of haemoglobin from different fish species as influenced by pH

Oxygenation, autoxidation as well as pro-oxidative activity of haemoglobins from tropical fish (Asian seabass, tilapia and grouper) as influenced by different pH (6, 6.5 and 7) were comparatively studied. Relative oxygenation of all haemoglobins decreased in the acidic conditions. Haemoglobin from Asian seabass was more oxygenated and stable against autoxidation at both pH 6 and 7, compared to those from tilapia and grouper. Haemoglobin from tilapia and grouper was fully oxidised at pH 6 after 120 h. Lipid oxidation of washed Asian seabass mince added with haemoglobin from various fish at different pH (6, 6.5 and 7) was monitored during 10 days of iced storage. Haemoglobins accelerated lipid oxidation more effectively at pH 6, compared with pH 6.5 and 7 as indicated by the higher peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS). At the same pH values, haemoglobins from tilapia and grouper were more pro-oxidative than that from Asian seabass as evidenced by the higher PV and TBARS (P < 0.05). Volatile lipid oxidation compounds detected by gas chromatography–mass spectrometry (GC–MS) were also formed at higher rate in the washed mince added with haemoglobin from tilapia or grouper with coincidental stronger fishy odour development, compared to the control and that added with haemoglobin from Asian seabass. Thus, lipid oxidation in fish muscle was more likely governed by haemoglobin, whose pro-oxidative activity varied depending upon the pH as well as molecular properties of haemoglobin.