Production and quality of fish fingers from different fish species

Abstract Production of fish fingers was achieved by using fish species such as sardine (Sardina pilchardus, Walbaum, 1792), whiting (Merlangius merlangus, Linnaeus, 1758) and pike perch (Sander lucioperca, Linnaeus, 1758). Quality changes of battered fish patties during a period of 8 months at –18 °C were investigated. According to the results of microbiological and chemical analysis, fish fingers were found to be within acceptable limits during frozen storage for 8 months. However, sensory analysis showed that, at the end of the frozen storage, fish fingers made from sardine could not be consumed because of rancidity.     

DNA-based identification of fish species implicated in Puffer fish poisoning

A method for identification of fish species using three different mitochondrial DNA regions, 16S rRNA, cytochrome b and cytochrome c gene fragments, was investigated. The combined use of all three regions enabled reliable species identification in not only raw fish, but also dried, seasoned and boiled fish, products. Furthermore, the method was applicable even to vomitus from a patient involved in a puffer fish poisoning incident. However, further improvement is necessary to discriminate between closely related species such as Takifugu rubripes and T. chinensis, because they showed close similarity in the nucleotide sequences in the three gene fragments analyzed in this study.     

铁质强化型鱼蛋白的研制

研究了以低值鱼为原料的鱼蛋白酶解条件及脱苦、脱腥等工艺技术,选择焦磷酸铁作为铁质营养添加剂,并确定最佳添加量,以制得具有铁质强化功能的酶解鱼蛋白质。     

Iron content in common Cambodian fish species: Perspectives for dietary iron intake in poor,rural households

Iron deficiency is the most widespread nutritional disorder in Cambodia. Sixteen Cambodian fish species were screened for iron, zinc and calcium contents. Esomus longimanus has a higher iron content (451 mg Fe/kg dry matter, SD = 155, n = 4) than other species. Iron pools were measured as inorganic iron (I-Fe) by the ferrozine method, haem-bound iron (H-Fe) by the acetone method and total iron (T-Fe) by atomic absorption spectrometry. I-Fe + H-Fe accounted for <50% of T-Fe in E. longimanus, indicating a pool of complex bound, probably high-molecular weight non-haem iron (Hm-Fe). In a field study, thirty rural women were interviewed about traditional use of E. longimanus; their cleaning and cooking practices were observed and the amounts of fish consumed were recorded and meal samples were collected for iron analysis. Calculations based on the iron content and a high bioavailability of Hm-Fe showed that a traditional fish meal, sour soup, covered 45% of the daily iron requirement for women.     

Identification of fish species in smoked fish products by electrophoresis and isoelectric focusing

Summary Different species of fresh fish and smoked fish products were analysed by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis and isoelectric focusing. It was possible to differentiate and identify species of fish in smoked samples and draw some conclusions about the type of smoking process employed.

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Artbestimmung in geräucherten Fischprodukten durch Elektrophorese und isoelektrischer Focussierung

Zusammenfassung Proben von verschiedenen Arten von Frischfisch und von geräucherten Fischprodukten wurden mit Hilfe von SDS-Polyacrylamid-Gelektrophorese und isoelektrischer Focussierung analysiert. Es war möglich in den geräucherten Proben zwischen verschiedenen Fischarten zu unterscheiden und die Fischart zu bestimmen. Ebenso waren Rückschlüsse auf den angewendeten Räucherungsprozeß möglich.

     

雨生红球藻转化条件及虾青素积累的研究

在单因素试验基础上,选择转化光照强度、转化温度和转化时间为自变量,虾青素含量为响应值,利用Box-Behnken实验和响应面分析法,对转化条件进行优化。结果表明,在温度29.92℃,pH值10,光照7203.95lx的条件下转化10.6d,虾青素含量可达（33.796±1.556）mg/L,与未优化转化条件时相比,提高了0.99倍。     

应用DNA条形码技术鉴定烤鱼片、鱼干中河鲀鱼鱼种

应用DNA条形码技术对北京和厦门市市售烤鱼片、鱼干中河鲀鱼成分进行鉴定。方法 以烤鱼片、鱼干中提取基因组DNA为模板,利用针对河鲀鱼细胞色素氧化酶亚基Ⅰ(COⅠ)基因的特异性引物进行PCR扩增,将扩增产物克隆并测定线粒体COⅠ基因序列。将测序结果与GenBank中已有河鲀鱼的DNA序列进行BLAST比对,并且构建分子进化树。结果 本研究27份样品中有15份能扩增出特异性条带。通过BLAST比对和进化树分析,将15份样品归属到不同的河鲀鱼鱼种中。结论 北京和厦门市市售烤鱼片和鱼干中存在混入河鲀鱼的现象,应加强监管和规范产品的加工程序以避免中毒事件发生。     

Deposition and cycling of sulfur controls mercury accumulation in Isle Royale fish

Mercury contamination of fish is a global problem. Consumption of contaminated fish is the primary route of methylmercury exposure in humans and is detrimental to health. Newly mandated reductions in anthropogenic mercury emissions aim to reduce atmospheric mercury deposition and thus mercury concentrations in fish. However, factors other than mercury deposition are important for mercury bioaccumulation in fish. In the lakes of Isle Royale, U.S.A., reduced rates of sulfate deposition since the Clean Air Act of 1970 have caused mercury concentrations in fish to decline to levels that are safe for human consumption, even without a discernible decrease in mercury deposition. Therefore, reductions in anthropogenic sulfur emissions may provide a synergistic solution to the mercury problem in sulfate-limited freshwaters.     

Identification of tetrodotoxin and fish species in a dried dressed fish fillet implicated in food poisoning

There were five victims of neurotoxic food poisoning from a dried dressed fish fillet in Changhua County, Taiwan, in February 2000. The toxicity of the dried dressed fish fillets was 243 mouse units per g according to a tetrodotoxin bioassay. The partially purified toxin was identified as tetrodotoxin and anhydrotetrodotoxin. The sequence of the 376-nucleotide region in the cytochrome b gene of the mitochondrial DNA exhibited the same genotype as that of the toxic puffer fish Lagocephalus lunaris. The same single restriction site for Hinfl was found in the polymerase chain reaction (PCR) products from the dried dressed fish fillet and the muscle of L. lunaris, yielding two DNA fragments of 170 and 206 bp. However, no restriction site for Hinfl was found in the PCR products from other toxic puffer fishes, including Takifugu niphobles, Takifugu oblongus, and Takifugu rubripes. Therefore, the species of the dried dressed fish fillet was identified as L. lunaris and its causative agent was identified as tetrodotoxin.     

Challenges in the identification of species of canned fish

The identification of fish species becomes a problem when the usual identifying characteristics are removed on processing and only a portion of flesh is available. When the flesh is raw or cooked under normal conditions, the species is readily established by electrophoresis of the muscle proteins. The procedure cannot be used for heat-sterilised canned fish as the proteins are severely denatured. DNA is also degraded but techniques are now available for targeting and amplifying species-specific fragments. The amplified products can then be analysed by a range of techniques some of which are suitable for food control laboratories.     

Effect of elevated accumulation of iron in ferritin on the antioxidants content in soybean sprouts

Cultivation of soybean sprouts in abiotic stress conditions, resulted from the presence of 5–25?mM FeSO₄ in the culture media, causes a strong overexpression of ferritin. Accumulation of ferritin iron in sprouted seeds germinated in the 20?mM solution of FeSO₄ was 67 times higher than in sprouts germinated in distilled water. The cultivation conditions also influence on another antioxidant content—mainly β-carotene content, which increased 28 times (in sprouts cultured in 10?mM FeSO₄ solution) in comparison to the content in dry seeds. Obtained in stress conditions sprouted seeds contain less tocochromanoles than raw seeds. However, their total tocochromanol content was higher than in sprouted seeds cultured in distilled water in every examined concentration of Fe²⁺. A total antioxidant activity is increased only during culturing in 0–10?mM media, and it is positively correlated to the total phenolic compounds content (r?=?0.8498). We concluded that germination in high abiotic stress also causes the increase in different antioxidants content, not only in ferritin, which is directly involved in the process of iron detoxification.     

Determination of metals in fish species from Aegean and Mediterranean seas

Determination of metal levels in muscles and livers of twelve fish species from Aegean Sea and Mediterranean Sea by ICP-AES was made. The levels of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in muscles of fish were <0.01–0.39, <0.01–0.45, 0.07–1.48, 0.51–7.05, 9.18–136, 0.18–2.78, 0.03–1.72, 0.21–1.28 and 3.51–53.5 mg kg⁻¹, respectively. Metal levels in muscles were generally lower than those in livers. Metal concentrations in the edible parts of fish were assessed for human uses according to provisional tolerable weekly intake (PTWI) and provisional tolerable daily intake (PTDI). The estimated values of all metals in muscles of fish in this study were below the established values. Therefore, it can be concluded that these metals in edible parts of the examined species should pose no health problems for consumers.     

Chemical characterization and properties of five deep-sea fish species

Some important flesh properties were determined for the deep-sea species Portuguese dogfish (Centroscymnus coelolepis), leafscale gulper shark (Centrophorus squamosus), black dogfish (Centroscyllium fabricii), roughhead grenadier (Macrourus berglax), and mora/deepsea cod (Mora moro).Chemical composition, water holding capacity, cook loss and shelf-life, as indicated by bacterial counts, were determined. For some of the species investigated, variations could be observed between fish caught in spring and fish caught in summer. The fish used in this study were caught at Hatton Bank in the North Atlantic, where fishing takes place mainly from April to September.     

Use of pretreatment zones and zero-valent iron for the remediation of chloroalkenes in an oxic aquifer

Pretreatment zones (PTZs) composed of sand, 10% zero-valent iron [Fe(0)]/sand, and 10% pyrite (FeS2)/sand were examined for their ability to prolong Fe(0) reactivity in above ground column reactors and a subsurface permeable reactive barrier (PRB). The test site had an acidic, oxic aquifer contaminated with tetrachloroethylene (PCE) and trichloroethylene (TCE). The 10% FeS2 and 10% Fe(0) PTZs removed dissolved oxygen and affected the pH and E(h) in the PTZ. None of the PTZs had any effect on pH or E(h) in the 100% Fe(0) zone. Nitrate and sulfate were removed more quickly in the Fe(0) zones preceded by either the 10% Fe(0) PTZ or 10% FeS2. PCE first-order degradation rate constants (k(obs)) decreased significantly (> 80%) with increasing column pore volumes regardless of the PTZ material used. k(obs) finally leveled off after approximately 1 yr of operation. The column results predict that the PRB will experience a breakthrough of PCE in 3-5 yr and illustrate the importance of incorporating temporal variations in degradation rate constants when designing PRBs.     

Methylmercury levels in predatory fish species marketed in Canada

Mercury was detected in all analysed samples of swordfish, marlin, shark and tuna purchased from major supermarket outlets and fish retailers in three cities across Canada. Total mercury and methylmercury levels ranged up to 3845 and 2346 ng g^-1, respectively. Swordfish contained the highest levels, followed by shark, fresh/frozen tuna and marlin. Levels in canned tuna were considerably less than the other examined samples. Methylmercury was extracted with toluene from enzymatically hydrolysed samples after the addition of sulphuric acid and potassium bromide. An L-cysteine back-extraction was used to separate the methylmercury from most organic co-extractives. Analysis of methylmercury (as methylmercury bromide) was by gas chromatography with pulsed discharge detection.     

鱼种和亲水胶体对鱼糜制品凝胶性质的影响

考察了添加复合亲水胶体对鲢鱼、带鱼、金线鱼等鱼糜制品凝胶特性的影响。结果发现,添加亲水胶体后,带鱼鱼糜制品凝胶强度从58.38 g·cm提高至107.27 g·cm,金线鱼鱼糜制品从328.68 g·cm下降至137.55 g·cm,但鲢鱼鱼糜制品没有明显变化。另一方面,添加亲水胶体后鱼糜制品的硬度、粘结性、咀嚼性等发生下降,但水分含量、持水性、蒸煮吸水率均有显著提高。而且,添加亲水胶体后带鱼鱼糜制品中肌球蛋白重链的降解受到一定的抑制。SEM结果发现亲水胶体可以填充到带鱼和鲢鱼鱼糜制品中,但在金线鱼鱼糜凝胶结构中容易形成胶体块状,导致凝胶强度下降。      

鱼种和亲水胶体对鱼糜制品凝胶性质的影响

考察了添加复合亲水胶体对鲢鱼、带鱼、金线鱼等鱼糜制品凝胶特性的影响。结果发现,添加亲水胶体后,带鱼鱼糜制品凝胶强度从58.38 g·cm提高至107.27 g·cm,金线鱼鱼糜制品从328.68 g·cm下降至137.55 g·cm,但鲢鱼鱼糜制品没有明显变化。另一方面,添加亲水胶体后鱼糜制品的硬度、粘结性、咀嚼性等发生下降,但水分含量、持水性、蒸煮吸水率均有显著提高。而且,添加亲水胶体后带鱼鱼糜制品中肌球蛋白重链的降解受到一定的抑制。SEM结果发现亲水胶体可以填充到带鱼和鲢鱼鱼糜制品中,但在金线鱼鱼糜凝胶结构中容易形成胶体块状,导致凝胶强度下降。