一种以鱼鳞为原料的多产物联产工艺的建立与优化

鱼鳞中含有丰富的胶原和钙,可以作为生产胶原类产品和补钙产品的原料。为了提高鱼鳞的综合利用效果,解决鱼类加工过程中因副产物污染产生的环境问题,本研究以鱼鳞为原料,研究联合生产有机酸钙、胶原和胶原蛋白肽的工艺。具体地,鱼鳞先经过超声波辅助柠檬酸脱灰制备柠檬酸钙,再采用超声波辅助胃蛋白酶提取胶原,最后将提取胶原后的鱼鳞残渣用于制备胶原蛋白肽,并对所建立的联产工艺进行验证。结果表明,鱼鳞脱灰制备柠檬酸钙的条件为:超声波功率120 W,料液比1∶20 g/m L,柠檬酸浓度6%,处理时间180 min,草鱼鳞、鲢鱼鳞、沙丁鱼鳞的脱灰率分别为97.8%、97.6%、98.1%;胶原提取条件为:超声波功率180 W,料液比1∶20 g/m L,胃蛋白酶用量2000 U/g,处理时间8 h,草鱼鳞、鲢鱼鳞、沙丁鱼鳞胶原溶出率分别为40.1%、42.2%、56.2%;胶原制备条件为:底物浓度5%,胃蛋白酶用量280 U/g,初始p H2,处理温度65℃,草鱼鳞、鲢鱼鳞、沙丁鱼鳞胶原蛋白肽溶出率分别为91.7%、89.3%、88.9%。从鱼鳞中连续提取制备有机酸钙、胶原和胶原蛋白肽的工艺具有较好的可靠性和稳定性,有望在工业化生产中得到应用。     

可降解可食性鱼鳞胶薄膜的研制

以罗非鱼鱼鳞为原料,对热水法提取罗非鱼鱼鳞胶工艺进行研究。实验将粉碎后的干鱼鳞直接采用热水提取,对提取条件(温度、料液比、时间)进行优化。确定热水提取法最佳条件:料液比为1∶30(g/mL)、提取温度为85℃、提取时间为6 h,此时可得到较大提取率38.29%。同时,以罗非鱼鱼鳞胶原蛋白和壳聚糖为原料制备复合膜,测定了共混膜的力学性能,结果表明:复合膜的最佳组成是2%壳聚糖溶液与6%胶原蛋白溶液的体积比为1∶1,甘油浓度为25%。复合膜拉伸强度厚度约为35μm~50μm,拉伸强度达到14.45 MPa,断裂伸长率为39.82%。可替代塑料膜或塑料袋用作可食用、可降解的食品内包装膜,也用于豆奶粉、茶叶、方便面调味料的包装。     

尖吻鲈鱼鳞和鱼皮胶原蛋白的提取及其理化特性分析

以尖吻鲈鱼鳞和鱼皮为原料,提取并分离纯化酶溶性胶原蛋白,通过十二烷基硫酸钠-聚丙烯酰胺凝胶 电泳（sodium dodecyl sulfate-polyacrylamide gel electropheresis,SDS-PAGE）、氨基酸组成分析、差示扫描量热 （differential scanning calorimetry,DSC）、傅里叶变换红外光谱、X射线衍射和Zeta电位以及溶解度研究,分析 和比较了其主要理化性质。冷冻干燥后鱼鳞和鱼皮胶原蛋白得率（干质量）分别为2.3 g/100 g和47.3 g/100 g; SDS-PAGE结果显示两种胶原蛋白构型均为[α1(Ⅰ)]2α2(Ⅰ),初步判断属于Ⅰ型胶原蛋白;DSC结果显示鱼鳞和鱼 皮胶原蛋白热变性温度（Td）分别为37.54 ℃和36.74 ℃;傅里叶变换红外光谱和X射线衍射结果显示胶原蛋白经 胃蛋白酶处理后仍能保持其完整的三股螺旋结构;Zeta电位结果显示鱼鳞和鱼皮胶原蛋白等电点分别为pH 6.40和 pH 6.64;溶解度研究结果显示两种胶原蛋白在酸性条件和低NaCl质量浓度下均表现出良好的溶解性。     

鱼鳞胶原蛋白的酶法提取工艺研究

以草鱼鱼鳞为原料,采用酶解法提取鱼鳞中的胶原蛋白,用正交实验优化提取工艺,并测定了鱼鳞的基本组成成分和鱼鳞胶原蛋白的氨基酸组成。     

淡水鱼鳞水解胶原蛋白的酶法制备

对几种常见淡水鱼鳞的基本成分和氨基酸组成进行测定,研究酶解鱼鳞制备水解胶原蛋白的工艺,并采取正交试验时水解条件进行优化.结果表明:淡水鱼鳞主要由蛋白质和灰分组成,粗蛋白含量高达55%以上;氨基酸组成显示淡水鱼鳞羟脯氨酸含量丰富,是制备水解胶原蛋白的良好原料.正交实验结果表明:55℃、E/S为3%、酶解2 h、底物浓度100 g/L时水解效果最好,此时,水解产物分子量较小,且分布集中.     

罗非鱼皮硫酸皮肤素与胶原蛋白同时提取工艺优化及初步鉴定

针对鱼皮单独提取硫酸皮肤素造成资源利用率不高的问题,该研究以罗非鱼皮为原料,采用低温酶提酸促溶法同时提取硫酸皮肤素与胶原蛋白,通过单因素试验及响应面优化提取工艺,并利用醋酸纤维素薄膜电泳、聚丙烯酰胺凝胶电泳、傅里叶变换红外光谱等对罗非鱼皮硫酸皮肤素与胶原蛋白进行初步鉴定。结果表明,最佳提取工艺为中性蛋白酶加酶量5 930 U/g,提取时间25.8 h,提取温度28.5℃,料液比1∶40(g∶mL),在此条件下罗非鱼皮硫酸皮肤素得率为132.12 mg/100 g,胶原蛋白提取率为53.14%,二者分别具有典型的硫酸皮肤素及胶原蛋白特征。该研究为同时提取罗非鱼皮硫酸皮肤素与胶原蛋白提供了理论依据,为罗非鱼皮下脚料的高效利用提供了一种新途径。     

金鲳鱼内脏酸性蛋白酶的提取及应用研究

以金鲳鱼为原料,依次通过p H7.0的磷酸钠缓冲液浸提法和0%~55%硫酸铵分级沉淀法,从内脏中初步纯化出蛋白酶。探讨了温度和p H对酶活力的影响。蛋白粗酶分别应用于罗非鱼鱼皮明胶水解产物的制备、罗非鱼鱼鳞中提取胶原蛋白和虾壳中提取虾青素,同时与猪胃蛋白酶进行了比较。结果表明,金鲳鱼内脏蛋白酶的最适温度为25℃,最适p H为4.0。该酶应用于制备罗非鱼鱼皮明胶水解产物,其酶解能力强于猪胃蛋白酶;应用于提取罗非鱼鱼鳞胶原,胶原的得率为0.65%,不及猪胃蛋白酶;应用于提取虾壳中的虾青素,得到虾青素含量为(65.41±2.51)μg/g,其DPPH自由基清除率为(84.97±2.62)%,活性强于猪胃蛋白酶提取组。因此,研究结果为金鲳鱼内脏蛋白酶进一步利用提供了理论基础。     

白鲢鱼鳞胶原蛋白提取工艺条件优化研究

利用白鲢鱼鳞为原料,采用酶法提取胶原蛋白,并利用响应面分析法对影响鱼鳞胶原蛋白提取率的关键因素的分析,得到酶法提取白鲢鱼鳞胶原蛋白的最佳工艺条件为底物浓度2.89％、加酶量0.26％、酶解温度58℃、酶解时间54min,在此条件下提取,提取液中胶原蛋白提取率可达57.84％以上.     

草鱼鱼鳞胶原蛋白酸酶分步提取工艺研究

为实现鱼鳞胶原蛋白的高效提取,在优化脱钙、混酸法和酶法提取工艺基础上,对鱼鳞胶原蛋白的酸酶进行分步提取。研究发现,鱼鳞最佳脱钙工艺为料液比8:100(g/mL),盐酸浓度1.0 mol/L,反应时间1.0 h,反应温度20℃;混合酸法提取鱼鳞胶原蛋白的最佳条件为醋酸料液比1:12(g/mL),柠檬酸料液比1:10(g/mL),乳酸料液比1:12(g/mL),即混合酸料液比为1:34(g/mL),其中,0.8 mol/L柠檬酸、1 mol/L乳酸、0.8 mol/L醋酸的体积比为6:5:6,提取时间2 d,胶原蛋白的提取率为48.14%;最佳酶法提取条件为胃蛋白酶用量450 U/g,提取温度30℃,提取时间72 h,该条件下提取率为45.26%。酸酶耦合法优于单一方法或同种方法两次提取的效果,可实现酸溶性和酶溶性胶原蛋白的连续提取,先酸后酶法胶原蛋白的提取率达84.61%,SDS-PAGE凝胶电泳发现其为Ⅰ型胶原蛋。     

草鱼鱼鳞中活性胶原蛋白提取工艺及参数优化

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),并对鱼鳞原料的前处理方法、胶原蛋白提取工艺进行优化。结果表明,在鱼鳞原料的前处理工艺中,以0.1mol/L 的Na2CO3 溶液为试剂脱除原料中杂蛋白的最佳工艺条件为室温、料液比1:40(g/mL),300r/min 搅拌处理3 次,每次6h;以0.3mol/L 的EDTA 为试剂脱除原料中矿物质杂质的最佳工艺条件为室温、料液比1:60,搅拌处理3 次,每次12h;ASC 的最佳提取工艺条件为：提取温度不高于25℃,料液比1:60,醋酸浓度0.8mol/L,提取3 次,每次24h;PSC 的最佳提取工艺条件为：胃蛋白酶用量为鱼鳞原料质量的3.0%、醋酸浓度0.8mol/L、料液比1:30、提取温度4 ℃、提取2 次,每次24h。     

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.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status