鲤鱼鱼皮和鱼骨酶溶性胶原蛋白的性质比较

以鲤鱼鱼皮和鱼骨为原料提取得到酶溶性胶原蛋白(PSC),对鱼皮PSC和鱼骨PSC的性质进行比较。电泳结果表明,鱼皮PSC和鱼骨PSC都属于Ⅰ型胶原;2种胶原蛋白中,脯氨酸和羟脯氨酸含量均低于牛皮酸溶性胶原蛋白;粘度测定的结果显示,鱼皮PSC的变性温度为28.1℃,鱼骨PSC的变性温度为30.0℃;差热分析的结果说明,鱼骨PSC的热稳定性高于鱼皮PSC,这与氨基酸分析和粘度分析的结果相一致;傅立叶红外光谱分析结果显示,鱼皮PSC和鱼骨PSC结构具有很大的相似性。     

鲢鱼鱼皮和鱼骨胶原蛋白的提取及理化性质分析

以鲢鱼鱼皮和鱼骨为原料,分别采用酸法和酶法从中提取酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC),探讨其在氨基酸组成、等电点、热变性温度及黏度等方面的差异。结果表明:4种不同类型的胶原蛋白的紫外光谱扫描结果较为类似,在230 nm波长处均出现最大吸收峰,在280 nm波长处吸收峰不明显,氨基酸组成和比例大体类似,均符合Ⅰ型胶原蛋白的特征。鱼皮ASC、鱼皮PSC、鱼骨ASC、鱼骨PSC的热变性温度分别为30.5,31.7,31.2,32.1℃,等电点均在6.7左右。胶原蛋白的黏度随蛋白质量浓度的增加而增加;随Na Cl含量的增加而降低;p H值对胶原蛋白的黏度影响较大,在等电点附近时黏度最低,p H 3时黏度最大。     

冬夏鲤鱼鱼皮和鱼骨胶原蛋白稳定性比较

从冬季(2008 年2 月)和夏季(2008 年7 月)的鲤鱼鱼皮和鱼骨中分别提取酸溶性胶原蛋白,在一定温度下加热,通过蛋白酶的酶解和圆二色谱(CD)法研究其热稳定性。结果显示：冬季鱼皮和鱼骨酸溶性胶原蛋白的变性温度分别为31.0℃和 32.8℃,比夏季鱼皮和鱼骨酸溶性胶原蛋白的变性温度分别低1.0℃和0.6℃。通过圆二色谱(CD)法得到了与此一致的结果。测定结果显示,来源于夏季鱼皮和鱼骨胶原蛋白的热稳定性要优于冬季鱼皮和鱼骨胶原蛋白。     

斑点叉尾鮰鱼皮胶原蛋白的理化特征研究

选用斑点叉尾鮰(Ictalurus punctatus)鱼皮为材料,用乙酸和乙酸-胃蛋白酶,分别提取鱼皮中的酸溶性胶原蛋白(acid-solubilise collagen,ASC)和酶溶性胶原蛋白(pepsin-solubilise collagen,PSC),并对其理化性质特征进行研究研究发现,提取得到的ASC纯度高达93.11％,PSC纯度高达93.46％;紫外吸收分析表明,ASC和PSC的吸收峰值均在233nm处;蛋白图谱中两种胶原蛋白均由两种不同的α链(α1) 2α2组成,具备Ⅰ型胶原蛋白的特征;ASC和PSC的傅里叶红外图谱相似,具有完整的三螺旋结构;ASC的变性温度为34.2℃,PSC的变性温度为33.9℃.     

草鱼皮酸溶性和酶溶性胶原蛋白的提取及性质

本文研究了从草鱼皮中提取酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC)及其部分性质。草鱼皮中ASC和PSC的提取得率以干基计分别为8.0%和18.6%;对草鱼皮ASC和PSC的紫外光谱分析,最大吸收峰都接近223nm;SDS-PAGE电泳图谱显示草鱼皮胶原蛋白是由两条不同的α链组成,分子量都在100kDa以上,与猪皮I型胶原蛋白相似;草鱼皮ASC和PSC热变性温度分别为33.8、34.5℃,只比猪皮的热变性温度(37℃)低3℃左右。结果表明草鱼皮胶原蛋白在功能食品、医药、化妆品、制药等方面有潜在的应用。     

鲢鱼鱼皮中酸溶性胶原蛋白提取工艺研究

以鲢鱼鱼皮为原料,通过单因素试验和正交试验对鲢鱼鱼皮中酸溶性胶原蛋白的提取工艺参数进行分析,并用AR-500动态流变仪对鲢鱼鱼皮中酸溶性胶原蛋白的热变性温度进行分析。结果表明:鲢鱼鱼皮原料中酸溶性胶原蛋白提取的最佳工艺条件为:以乙酸作为提取剂,乙酸浓度0.3 mol/L,料液比1∶60(g/m L),提取时间96 h;此胶原蛋白的热变性起始温度为32.31℃,峰值温度为34.82℃。     

草鱼鱼鳞、鱼皮和鱼骨酸溶性胶原蛋白特性对比研究

从草鱼鱼鳞、鱼皮和鱼骨中提取酸溶性胶原蛋白(ASC),对其特性进行对比分析。紫外光谱和电泳图谱结果显示,3种ASC紫外特征吸收峰出现位置与I型胶原蛋白紫外特征吸收峰出现的位置基本一致,分子结构都至少含有两条α链;傅里叶红外光谱显示,草鱼鱼鳞、鱼皮和鱼骨ASC在酰胺A带的N-H伸缩均以氢键形成缔合体,酰胺Ⅰ带和酰胺Ⅲ带的特征吸收峰表明鱼鳞和鱼骨ASC的α-螺旋结构保存较完整,鱼皮ASC的α-螺旋结构已经被破坏;3种ASC在热稳定性方面存在一定差异,热变性温度鱼骨ASC(34.5℃)鱼皮ASC(32℃)鱼鳞ASC(31℃),可能与胶原存在的组织和所处的环境有关。     

马面鱼皮胶原蛋白的提取及其特性研究

目的:从马面鱼皮中提取酸溶性胶原蛋白,并对其理化性质进行研究,为马面鱼皮的开发利用提供一定理论依据。方法:通过氨基酸分析、UV、FTIR及SDS-PAGE凝胶电泳初步探讨了酸溶性胶原蛋白的结构特征;同时对酸溶性胶原蛋白的等电点、热变性温度、热收缩温度及溶解性进行了研究。结果:氨基酸分析发现,马面鱼皮酸溶性胶原蛋白中甘氨酸含量为24.12%,羟脯氨酸含量为9.31%;每1 000个总氨基酸残基中,甘氨酸为349个,羟脯氨酸70个,未检测到色氨酸、半胱氨酸。UV光谱显示酸溶性胶原蛋白在210 nm波长处有最大吸收。FTIR光谱表明酸溶性胶原蛋白有特殊的三螺旋结构。SDS-PAGE显示酸溶性胶原蛋白有2条α链,1条β链和1条γ链;酸溶性胶原蛋白的等电点为5.70,热变性温度和热收缩温度分别为34.99℃和84.59℃。溶解性结果表明酸溶性胶原蛋白易溶于0.5 mol/L乙酸溶液,Na Cl含量1%~3%时溶解性稳定,之后随Na Cl含量增加,溶解性迅速下降。结论:马面鱼皮酸溶性胶原蛋白具有典型的Ⅰ型胶原蛋白特征,热稳定性较好,不同介质和盐含量对酸溶性胶原蛋白溶解度有很大影响。     

草鱼鱼鳞胶原蛋白的提取及其理化性质研究

以草鱼鱼鳞为原料,在低于蛋白变性温度的条件下提取酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC),并对其理化性质进行系统测定。实验结果表明,ASC 和PSC 的热变性温度分别为30～35℃和28～35℃; PSC 在溶解性能、乳化性能和乳化稳定性方面优于ASC,而在溶液黏度、吸水性能、吸油性能、起泡性以及泡沫稳定性方面,ASC 明显好于PSC。     

金鲳鱼鱼皮酶溶性胶原蛋白的提取工艺优化及基本特性

为提高金鲳鱼加工副产物——鱼皮的利用率,本研究在前期单因素实验的基础上,以加酶量、液料比和提取时间三个单因素建立模型,采用响应面法Box-Behnken设计实验,优化了胃蛋白酶法提取金鲳鱼鱼皮酶溶性胶原蛋白(PSC)的提取工艺,并与酸溶性胶原蛋白(ASC)进行聚丙烯酰胺凝胶电泳、傅里叶变换红外光谱和差示扫描量热仪等基本理化特性的对比研究。结果表明,金鲳鱼鱼皮胶原蛋白的最佳提取工艺为:加酶量1.5%、液料比23∶1 m L/g、酶解时间27.5 h。此条件下通过实验验证得出,金鲳鱼鱼皮胶原蛋白实际提取率为64.68%,与响应面模型理论预测值65.17%基本一致;此外,本实验提取的PSC有较高热变性温度(30.44℃),与金鲳鱼皮ASC有相似的电泳性质和红外峰型,初步鉴定为I型胶原蛋白。该实验为金鲳鱼鱼皮酶溶性胶原的提取提供了理论参考。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.