壳聚糖对无水保活单环刺螠品质的影响

目的:降低单环刺螠运输成本,减少单环刺螠营养损失。方法:采用壳聚糖对单环刺螠进行前处理,测定无水保活前、后及复水后3种状态下单环刺螠的主要营养及生理指标变化。结果:壳聚糖保活单环刺螠的较适质量浓度为3 g/L,经壳聚糖前处理后,无水保活64 h后存活率为67%,壳聚糖处理后的试验组其存活率、肌糖原、持水力、水分、乳酸含量均显著性高于对照组(P＜0.05);与未复水相比,复水后,试验组和对照组蛋白质、乳酸、脂肪、水分含量均极显著下降(P＜0.01)。结论:壳聚糖处理提高了无水保活单环刺螠的存活率及品质。     

单环刺螠废弃内脏中粗多糖的提取工艺优化

利用热水浸提的方法进行单环刺螠（海肠）废弃内脏中多糖的提取。采用单因素试验和L₉（3⁴）正交试验设计,研究不同pH值、料液比、提取时间和提取温度对单环刺螠内脏多糖提取率的影响。并采用Fenton体系测定单环刺螠内脏多糖对羟自由基（·OH）的清除作用。单环刺螠内脏多糖提取的最佳工艺条件为pH10、料液比1:40（g/mL）、时间3h、温度60℃。单环刺螠内脏多糖在质量浓度为50μg/mL时,对羟自由基清除能力可达60%,且具有剂量效应。     

养殖水产品中四环素类抗生素残留的高效液相色谱测定法

建立了HPLC检测养殖水产品中四环素类抗生素残留的方法,采用乙酸乙酯(Imol/L) 乙酸镁(0.05mol/L) EDTA(0.001mol/L)的混合液提取样品中的四环素、土霉素、全霉素.以上述混合液-甲醇(72:28,v/v)为流动相,流速1mL/min,检测波长370hm.在0.05～1.0mg/L范围内峰面积与抗生素浓度呈良好的线性关系(r＞0.99).检出限分别为0.013mg/g(土霉素)、0.016mg/g(四环素)、0.014mg/g(金霉素),平均加标回收率分别91.2%(土霉素)、88.5%(四环素)、95.6%(金霉素),精密度(RSD)小于5%.     

单环刺螠糖胺聚糖抗凝血机制初步研究

采用人乏AT-Ⅲ血浆、乏HCII血浆及两种肝素辅因子均缺乏的血浆,探讨单环刺螠糖胺聚糖的抗凝血途径;通过纠正乏因子血浆所致的凝固时间延长的能力测定人血浆凝血因子Ⅱ、Ⅴ、Ⅶ、Ⅷ、Ⅸ、Ⅹ、Ⅺ、Ⅻ的活性,凝固法测定纤维蛋白原浓度;体外复钙凝血实验,研究糖胺聚糖对复钙凝血时间的影响;甲基百里酚蓝比色法测定大鼠和小鼠血清中钙离子浓度。结果表明:单环刺螠糖胺聚糖的抗凝血酶作用主要呈AT-Ⅲ依赖性,并能够钝化肝素辅因子Ⅱ抑制凝血酶的活性;单环刺螠糖胺聚糖显著降低血浆凝血因子Ⅴ、Ⅶ、Ⅹ、Ⅷ、Ⅸ、Ⅺ、Ⅻ的活性(p0.05);糖胺聚糖可通过屏蔽血液中Ca2+,延长大鼠血复钙凝血时间,极显著降低大鼠和小鼠血液中的钙离子浓度(p0.01),且其降低血液钙离子浓度的作用极显著优于肝素钠(p0.01)。     

红外光谱法测定水产品中石油烃残留

目的 建立微波消解前处理结合红外光谱法测定水产品中石油烃残留量的分析方法。方法 试样经微波消解后,用四氯乙烯液-液萃取,萃取液经活化硅酸镁和无水硫酸钠去除干扰后,氮气吹至近干,四氯乙烯定容,经红外光谱检测,记录2930 cm-1、2960 cm-1、3030 cm-1处的吸光度值,计算出石油烃在生物体内的含量。结果 石油烃质量浓度在0.4~100 mg/L范围内呈良好的线性关系（R2＞0.998）,当使用含水率6%活化度的硅酸镁,填充高度为60 mm时为最佳吸附条件,在此条件下测试的方法检出限（limit of detection,LOD）为0.18 mg/kg,定量限（limit of quantitation,LOQ）为0.57 mg/kg,精密度（relative standard deviations, RSDs）在1.99%～6.36%之间,加标回收率在91.5%～110.5%之间（n=5）。结论 该方法具有检测范围宽、稳定性好、准确度高的优点,能满足水产品中石油烃残留量检测需要。     

高效液相色谱和离子色谱测定水中短链脂肪酸的方法比较

从分离谱图、分析时间、线性范围、检出限、精密度和加标回收率角度,对离子色谱和高效液相色谱(HPLC)测定水中的短链脂肪酸的方法进行比较。HPLC使用SunFire~(TM)C18色谱柱,流动相为磷酸二氢钾溶液和甲醇,梯度洗脱,流速1.0 m L/min。离子色谱法使用Dionex~(TM)ATC-3色谱柱,流动相为不同浓度氢氧化钠溶液梯度洗脱,流速1.5 m L/min。结果表明:HPLC的分析时间、线性范围、检出限、保留时间精密度、峰面积精密度和加标回收率分别为14.5 min、0~1 200 mg/L、15.57~23.23 mg/L、0.079%~0.597%、1.12%~3.50%和96.1%~112.0%,离子色谱法的相应指标分别为13.0 min、0~20 mg/L、0.03~0.10 mg/L、0.000%~0.053%、1.18%~2.69%和98.2%~122.0%。HPLC线性检测范围宽,但检出限相对高。离子色谱法检出限低,但线性检测范围窄,过高的进样质量浓度使得分离效果不佳。应根据样品实际质量浓度,选择合适检测方法。     

高效液相色谱法测定食用油中塑化剂的含量

建立了高效液相色谱(HPLC)对食用油中两种邻苯二甲酸酯污染物(邻苯二甲酸二乙酯(DEP)和邻苯二甲酸二丁酯(DBP))进行定性和定量分析的方法。样品用甲醇离心萃取,经弗罗里硅土固相萃取柱净化后,用HPLC进行定性和定量分析。结果表明:邻苯二甲酸二乙酯和邻苯二甲酸二丁酯在5.0⁴0mg/L浓度范围内具有良好的线性关系,线性相关系数(R2)均大于0.998,三个水平的样品添加回收率在82.2%40mg/L浓度范围内具有良好的线性关系,线性相关系数(R2)均大于0.998,三个水平的样品添加回收率在82.2%⁹0.4%,精密度在0.14%90.4%,精密度在0.14%².52%之间,两种目标化合物的检出限为0.1mg/L和0.05mg/L。本方法具有操作简单、精密度高、重现性好等优点,适用于食用油中邻苯二甲酸酯类物质的检测。     

塑料食品包装材料中双酚A的迁移量检测

目的检测液体食品模拟物中源于塑料包装材料的双酚A(bisphenol A,BPA)的迁移量。方法建立高效液相色谱检测双酚A的方法学,通过液体食品模拟物探讨了时间、温度、酸度、乙醇浓度、微波加热时间、油脂6种因素对BPA迁移率的影响。结果 BPA在0.0464~1.044μg/m L内线性关系良好(r2=0.9993),精密度、稳定性、重复性的RSD分别为0.81%、1.42%、2.59%,加样回收率范围为95.0%~96.9%,RSD为0.80%。通过对液体食品模拟物中BPA含量的检测,发现随着储存时间延长、温度升高、酸度和乙醇浓度增加、微波加热时间延长、油脂增加,BPA从塑料食品包装材料转移到饮用品中的迁移率增加。结论正确使用塑料食品包装,对于减少BPA在体内蓄积至关重要。     

HPLC标准曲线法测定酵母中谷胱甘肽

通过HPLC标准曲线法进行酵母中还原型和氧化型谷胱甘肽含量测定的研究,利用Intersil ODS-3 C_(18)柱,以庚烷磺酸钠-磷酸盐缓冲溶液(pH3.0)和甲醇(v∶v=90∶10)为流动相,流速为1.0 mL/min,检测波长为210 nm,得到氧化型和还原型谷胱甘肽的相关系数均为0.9999,检测限分别为2.40 mg/L、2.27 mg/L,定量限分别为9.0 mg/L、8.5 mg/L,精密度分别为2.00%、0.94%,回收率分别为100.12%~103.43%和95.23%~96.44%之间。     

红薯源性成分微滴式数字PCR的检测与定量分析

本文根据红薯单拷贝物种基因β-淀粉酶基因(Ipomoea batatas beta-amylase gene,β-AMY)特异性片段设计引物组和探针,建立了红薯成分特异性定量检测的微滴数字PCR检测方法及β-AMY基因拷贝数浓度(copy number/μL)与红薯质量(mg)的线性关系,并对方法的特异性、灵敏度和适应性均进行了测试。结果显示建立的红薯成分数字PCR检测方法特异于红薯成分检测,在20μL反应体系中定量下限(limit of quantitation,LOQ)和检测下限(limit of detection,LOD)分别为2.53 copies/μL和0.67 copies/μL。根据建立的拷贝数浓度(copy number/μL)与红薯质量(mg)的线性关系,对红薯质量百分比为5%和25%的样本进行定量检测,检测结果经换算得到的红薯含量分别为4.15%和21.33%,回收率分别为83.06%和85.31%,RSD值在6.33%～6.95%之间,表明本方法可对质量百分比为5%及以上的红薯成分进行准确定量,在定量检测方面具有较大应用潜力,可为市场监管提供了技术支持。     

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