养殖场采样及市售草鱼肉气味成分的比较

以市售及养殖场采样的草鱼为原料,并与市售草鱼作对照,探究了池塘养殖饲料和生活环境对草鱼肉气味成分的影响。用电子鼻对两种草鱼背肉、腹肉的气味进行检测,并采用聚二甲基硅氧烷-二乙烯苯(PDMS/DVB)涂层的固相微萃取头萃取草鱼的挥发性成分,结合气相色谱-质谱联用仪(GC-MS)进行分离鉴定。结果表明,电子鼻能判别出养殖场采样草鱼与市售草鱼肉气味之间的差异。养殖场采样草鱼以及市售草鱼背肉、腹肉分别鉴定出27种、22种、44种及42种挥发性成分,均以挥发性羰基化合物和醇类为主,两者的相对百分含量分别为91.60%、98.35%及88.38%、74.88%。但养殖场采样草鱼的己醛、(E)-2-辛烯-1-醇含量高于市售草鱼,这两种成分一般分别表现为青草味和泥土味。因此可以认定,这种气味差异与草鱼在养殖中的生活环境及饲养条件有关。     

Ecology of Listeria spp. in a fish farm and molecular typing of Listeria monocytogenes from fish farming and processing companies

This study focused on the ecology of Listeria monocytogenes in a fish farm by following the changes in its occurrence in different types of samples for a three year period. In addition, L. monocytogenes isolates from different seafood industry areas were compared with pulsed field gel electrophoresis (PFGE) typing to discover possible associations between primary production, further processing and final products. Weather conditions were found to have a strong influence on the probability of finding Listeria spp. in a fish farm environment. The number of samples contaminated with Listeria spp. was typically bigger after rainy periods. Brook and river waters as well as other runoff waters seemed to be the main contamination source at the farm studied. The farmed fish originally found to carry L. monocytogenes become gradually Listeria free. The time needed for the purification of the fish was several months. The sea bottom soil samples were the ones that preserved the L. monocytogenes contamination the longest time. It can be stated that the fish and fish farm equipment studied did not spread listeria contamination. On the contrary, they were found to suffer from listeria contamination coming from outside sources like the brook water. There was a wide range of different L. monocytogenes PFGE-pulsotypes (30) found at 15 Finnish fish farms and fish processing factories. L. monocytogenes isolates from the final products often belonged to the same pulsotypes as did the isolates from the processing environment as well as from the raw fish. This suggests that, in addition to the fish processing factory environment, the fish raw materials are important sources of L. monocytogenes contamination in final products.     

Seasonal dynamics of fatty acid content of a common food fish from the Yenisei river,Siberian grayling, Thymallus arcticus

Seasonal variations of fatty acid contents in muscle tissue of one of the main food fish species in Siberian rivers, grayling, Thymallus arcticus, were studied over 3 years. Under a comparatively low range of water temperature variations, spawning appeared to be the main cause of seasonal changes in contents of quantitatively prominent and essential fatty acids in fish filets. In general, fish accumulated essential polyunsaturated fatty acids (PUFA), such as eicosapentaenoic (EPA) and docosahexaenoic (DHA), in their muscle tissue before reproductive seasons and then the PUFA seemed to be transferred into gonads during their formation. Hard roe of Siberian grayling had 3–4 times higher PUFA contents, than had that of the muscle tissue. The fish species, T. arcticus, was found to be a valuable source of the essential PUFA, including EPA and DHA, for human diet.     

我国大宗淡水鱼产业发展现状与体系研究进展

功能性质是衡量鱼明胶品质的重要因素,直接关系着鱼明胶的实际应用范围和价值。为探究提取温度对乌鱼鱼鳞明胶功能性质的影响,本研究以乌鱼鱼鳞为原料,采用热水法提取明胶,考察了不同温度（60、70、80、90、100 ℃）提取对鱼鳞表面形态、鱼鳞明胶得率、功能性质（起泡性、乳化性、凝胶强度、凝胶温度、胶融温度）的影响,并进一步通过SDS-PAGE、傅里叶变换红外光谱、扫描电镜探究鱼鳞明胶的结构特性。结果表明：当提取温度从60 ℃逐步升高到100 ℃,乌鱼鱼鳞表面的破损越来越严重,鱼鳞明胶得率从31.72%增加到50.97%,起泡能力从23.33%提升至73.33%,乳化活性从15.13 m²/g增长到17.27 m²/g,而凝胶强度、凝胶温度、胶融温度则从677.82 g、20.80 ℃、28.70 ℃分别降低至372.91 g、15.80 ℃、23.90 ℃。此外,随着提取温度的提升,电泳图中乌鱼鱼鳞明胶α₁、α₂、β链三条特征带逐渐模糊,红外光谱结果表明鱼鳞明胶都具有特征吸收峰（酰胺A、酰胺Ⅰ、酰胺Ⅱ、酰胺Ⅲ）且酰胺A带波数先升高后降低,扫描电镜结果显示鱼鳞明胶多孔网格结构的紧密程度降低。上述研究结果可为乌鱼鱼鳞明胶产业化提供理论依据。

     

淡水鱼加工副产品中蛋白质提取及鱼冻的配方研究

以淡水鱼加工中产生的鱼头、鱼皮、鱼骨和鱼鳞等副产物进行胶原蛋白的提取．以提取液制备鱼冻：经单因子试验和正交试验获得蛋白质提取的最佳工艺条件为：在原料中加入浓度为2倍体积的2％的食盐溶液（V：V）在90℃,pH值为4．2条件下恒温提取2h;鱼冻的最佳配方为：提取液100g、卡拉胶1．0g、KCl 1．0g、白砂糖6g、柠檬酸0．10g;香辛料的加入量为：1％姜、1％蒜和1％葱。最终制得的鱼冻中含有丰富的胶原蛋白,并具有一种特殊风味。     

3种养殖淡水鱼重金属含量测定及健康风险评价

目的 了解福建省主要养殖淡水鱼中重金属含量水平及进行鱼类食用安全性评价,为福建省淡水鱼健康养殖和食用安全性提供参考依据。方法 选择草鱼、罗非鱼和鳗鱼为研究对象,测定和分析其重金属含量,运用单因子污染指数法、综合污染指数法和目标危险系数法进行污染评价。结果 3种养殖淡水鱼肌肉中重金属含量最高的是Cr。Cd与Pb和Hg呈极显著相关,与As呈极显著负相关;Cr与Hg呈显著负相关;Hg与As呈极显著负相关。5种重金属均未出现超标现象,草鱼受到As轻度污染、罗非鱼受到Pb和As轻度污染、鳗鱼受到Cd和Pb轻度污染,但3种淡水鱼未受到综合污染。结论 食用该批次生产的草鱼、罗非鱼和鳗鱼不存在潜在健康风险,今后应继续保持高压监管,并对出现的个别重金属的污染风险进行更精准的管控。     

膜技术分离纯化淡水鱼内脏中复合酶的工艺研究

主要探讨了小型工业化水平的膜技术分离纯化复合酶的工艺,通过比较选取超滤膜I除杂及纳滤膜II浓缩,其酶比活力分别为6901.1U/mL和58659.4U/mL,表明复合酶产品具有较高的生物催化活性,纯化倍数分别达到了150.7倍和1280.8倍,通过SDS-PAGE测得其相对分子量为22.6~36.0ku。证明选用膜技术分离纯化复合酶是完全可行的。     

Mercury content in some marine fish from the Alexandria coast

The total Hg of 6 marine fish species, caught from the 3 main fishing grounds along the coast of Alexandria, was determined and the distribution among the different organs was studied. It was found that the total Hg levels in fish differed according to species, size, and organs of fish as well as fishing ground. The highest value was found in large size especially in the viscera of Mullus barbatus obtained from El-Mex fishing ground.     

EPA and DHA quantification in two species of freshwater fish from Central Amazonia

The levels of the fatty acids EPA and DHA were determined for two species of fish (Hypophthalmus sp. and Cichla sp.), in the muscular tissue and in the orbital cavity, in two different seasonal periods in the Brazilian Amazonian area. Relatively high amounts (oil mg/g) for freshwater fish were found for DHA in the two species. Hypophthalmus sp. presented a higher concentration of EPA (20 ± 3 mg/g) and DHA (18 ± 3 mg/g) in the wet seasonal period in the muscular tissue, without a significant difference between the two acids. Higher concentrations of DHA were detected in the flood period in the muscular tissue (55 ± 9 mg/g) of Cichla sp. but with reduced concentrations of EPA (5 ± 1 mg/g).     

转谷氨酰胺酶在淡水鱼制品中的应用

试验研究了添加转谷氨酰胺酶对鱼肉蛋白凝胶强度以及色差的影响,试验先采用单因素分析了转谷氨酰胺酶不同的添加量、不同的作用温度以及不同的作用时间对淡水鱼制品的凝胶强度、色差的影响,然后又经3因素3水平正交设计确定了转谷氨酰胺酶的最适添加量、最适作用温度及最最佳作用时间。经试验证明,转谷氨酰胺酶的最适的添加量为6%,最适的作用温度和作用时间分别为40℃和1.5h。     

Total mercury and methylmercury content in edible fish from the Mediterranean Sea

The objective of this study was to determine the current levels of total mercury and methylmercury in the muscle tissues of different fish species caught in the Mediterranean Sea to ascertain whether these concentrations exceed the maximum level stipulated by the European Commission Decision. Total mercury concentrations in the muscles of skates ranged from 0.18 to 1.85 mg/kg (wet weight) (average, 1.00 mg/kg) while levels of 0.11 to 1.92 mg/kg (wet weight) (average, 0.70 mg/kg) and 0.21 to 1.74 mg/kg (wet weight) (average, 0.70 mg/kg) were recorded for blue whiting and red mullet, respectively. For 66.7% of long nose skate samples, 61.4% of thornback ray samples, 42.8% of winter skate samples, and 38% of starry ray samples, the total mercury concentrations exceeded the prescribed legal limit (1.0 mg/kg [wet weight]). Concentrations exceeding the maximum total mercury level stipulated by the European Commission Decision (0.5 mg/kg [wet weight]) were observed in 63.6 and 40% of blue whiting and striped mullet samples, respectively. Mercury was present in the different species almost completely in the methylated form at 55 to 100%. Weekly intakes were estimated and compared with the provisional tolerable weekly intake recommended by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives.     

Metal content determination in four fish species from the Adriatic Sea

Concentrations of As, Cd, Cu, Hg and Pb were measured by atomic absorption spectrometry (AAS) in muscle tissues of four fish species: anchovy (Engraulis encrasicholus), mackerel (Scomber japonicus), red mullet (Mullus surmuletus) and picarel (Spicara smaris) from the Croatian waters of the Adriatic Sea during 2008 and 2009. Metal levels measured in anchovy were in the following ranges (mg kg⁻¹): As 0.01–54.8, Cd 0.001–0.02, Cu 0.001–6.29, Hg 0.001–0.52 and Pb 0.001–0.34 mg kg⁻¹. Metal ranges in red mullet were (mg kg⁻¹): As 0.01–70.9, Cd 0.002–0.85, Cu 0.001–57.3, Hg 0.001–2.07 and Pb 0.001–0.27 mg kg⁻¹. Metal level ranges measured in mackerel were (mg kg⁻¹): As 0.01–36.4, Cd 0.001–0.1, Cu 0.001–15.9, Hg 0.001–0.78 and Pb 0.002–0.24 mg kg⁻¹. In picarel, metal level ranges were (mg kg⁻¹): As 0.01–54.6, Cd 0.001–0.1, Cu 0.08–32.9, Hg 0.001–0.207 and Pb 0.001–0.46 mg kg⁻¹. Significant differences in metal concentrations were found among fish species. The results presented on metal contents in the examined species give an indication of the environmental conditions. Concentrations of Cd, Cu, Hg and Pb obtained were far below the established values by the European Community regulations. However, arsenic levels found in red mullet were higher than the recommended legal limits for human consumption and as such may present a human health issue.     

云南省淡水湖泊鱼虾中多氯联苯食用安全性评估

目的对云南省5个淡水湖泊中鱼虾体内的多氯联苯(polychorinated biphenyl,PCBs)污染水平进行调查研究。方法采用气相色谱-质谱联用仪进行检测分析,根据检测结果对云南省淡水湖泊中的鱼虾体内多氯联苯的含量进行食用安全性评估。结果云南省淡水湖泊中鱼虾体内的多氯联苯检出率为90%,多氯联苯的含量范围为ND～1.16μg/kg,平均含量为0.27μg/kg,低于国家标准限量。云南省淡水湖泊中鱼虾体内的多氯联苯按照世界卫生组织(World Health Organization,WHO)规定的多氯联苯毒性当量(toxic equivalent quantity,TEQ)分布于ND～6.51×10~(-5)μg/kg,平均值为1.21×10~(-5)μg/kg,低于欧盟的行动标准限量。结论云南省居民从云南省淡水湖泊鱼虾体内摄入持久性有机污染物多氯联苯的剂量较低,引起的健康风险较低。     

Mercury levels in hair from people eating large quantities of Swedish freshwater fish

Mercury concentrations in hair were related to fish-eating habits in a group of 50 people reported to have a high consumption of freshwater fish. Mercury levels in hair ranged from 0.3 to 10.8 mg/kg with a mean +/- SD of 3.2 +/- 2.3 mg/kg. The average mercury level in hair from men was significantly higher than that in hair from women (3.8 +/- 2.6 mg/kg versus 2.4 +/- 1.8 mg/kg. Seven individuals (14%) had levels above 6 mg/kg. In people with equal fish consumption, significantly higher mercury levels were found in the hair of those eating fish from lakes M?laren and V?ttern than in those eating fish from Lake Hj?lmaren. It has been reported that fish from the latter lake contains approximately 0.2 mg/kg mercury, whereas fish from the other two lakes contains approximately 0.4 mg/kg. The mean mercury level in hair was higher in the group eating freshwater fish more than three times a week (greater than or equal to 500 g fish flesh/week) than in the group eating less, although the difference was of borderline significance. Within couples (n = 16) eating equal numbers of fish meals per week, the men had significantly higher levels (mean 3.7 mg/kg) than the women (mean 2.5 mg/kg). The results from the present study show that people with a high consumption of Swedish freshwater fish have elevated levels of mercury in their hair, when compared with previously reported levels in the hair of Swedish pregnant women.     

淡水鱼加工副产物功能成分的提取与应用研究进展

淡水鱼由于其营养价值丰富,在世界范围内的需求量持续增加。然而,在其加工过程中产生大量副产物,这些副产物并没有得到充分的利用,造成资源的浪费并给生态环境带来了巨大的压力,不利于淡水渔业的持续健康发展。鉴于此,淡水鱼加工副产物依据其特性逐步被开发应用。本文对近年来淡水鱼副产物的加工利用及其各类活性研究进行综述。首先介绍加工副产物中常见功能性成分的提取技术与开发,其次分别阐述淡水鱼加工副产物的应用研究,如抗氧化、抗炎、延缓衰老以及在食品加工和储存中的应用,最后对淡水鱼加工副产物未来的发展趋势进行展望,旨在为淡水鱼加工副产物有效成分提取及应用提供参考,进一步提升资源的综合利用潜力,促进我国淡水鱼产业的高质量发展。     

淡水鱼肠道中抗芽孢杆菌性乳酸菌的筛选与鉴定

从淡水鱼肠道中筛选对芽孢杆菌具有较强拮抗活性的乳酸菌,结果表明:从鲤鱼肠道分离的菌株LY-19对蜡样芽孢杆菌和地衣芽孢杆菌的抑菌直径分别为16.89 mm和17.43 mm,活性主要来自无细胞上清液,在p H3.0⁴.5范围内保持抗菌活性,经中性蛋白酶、胃蛋白酶、木瓜蛋白酶处理后丧失部分抑菌活性,对α-淀粉酶不敏感,在40¹21℃范围内处理30 min后其拮抗活性基本不变,初步判定乳酸菌产生的抑菌物质为II型非糖基化类细菌素。根据生理生化特性和16S r DNA鉴定为清酒乳杆菌（Lactobacillus sakei）。      

Studies of the iced storage characteristics and composition of a variety of Bolivian freshwater fish. 1. Altiplano fish

The iced storage characteristics of three Bolivian freshwater fish species from the Altiplano region were monitored using chemical, microbiological and sensorial methods. Fish studied were: pejerrey (Busilichthys bonariensis) captured in two locations, Lake Poopo and Lake Angostura; trout (Sulmo gairdneri) from Lake Titi-caca and carp (Cyprinus carpio) from Lake Angostura. The proximate composition and physical nature of these fish are presented. The shelf lives of these species, as deter-mined by both sensory and microbiological evaluations, were found to be: pejerrey from Lake Poopo: 20–21 days, pejerrey from Lake Angostura: 15-19 days, carp from Lake Angostura 17–20 days and trout from Lake Titicaca: 15–18 days. The value of the various methods used to monitor quality changes are discussed.     

Influence of the addition of Helianthus tuberosus L. fermented with different lactobacilli on acrylamide content in biscuits

The aim of the study was to investigate the effect of the addition of Helianthus tuberosus L. fermented with different lactobacilli (Lactobacillus sakei KTU05‐6, Pediococcus acidilactici KTU05‐7 and Pediococcus pentosaceus KTU05‐9) on acrylamide content in biscuits. Results of study indicated that submerged fermented Helianthus tuberosus L. tubers had the significantly (P ≤ 0.05) lower pH, higher total titratable acidity and from 1.2 to 1.3 times higher protease and from 1.2 to 2.0 higher alpha‐amylase activities compared with treated by solid‐state fermentation. The acrylamide content in all biscuit samples enriched with submerged fermented Helianthus tuberosus L. was measured lower than 10 μg kg^?1. Submerged fermentation with selected lactobacilli provided specific characteristics of fermented Helianthus tuberosus products which had effect on the asparagine reduction in plant additives, thus reducing acrylamide content in biscuits enriched with Helianthus tuberosus L.