浅谈我国浓海水化学资源的综合利用

海水淡化是解决淡水紧缺的有效途径之一,但海水淡化在获得淡水的同时,需要排出大量的浓海水,浓海水大量直接排放,不可避免地会带来海洋生态环境问题.本文结合我国(尤其是渤海湾)发展海水淡化的实际情况,探讨了几种浓海水化学资源综合利用方案;提出了适合海水淡化事业发展和经济环保的浓海水综合利用工艺.并强调了在进行浓海水综合利用、实现零排放的同时,要改变海洋化工企业的生产结构,提高产品的精细化程度和附加值,只有做到社会效益和经济效益双丰收,才能真正实现海水淡化事业的大发展.     

海水循环冷却系统排放水浓缩规律及制盐研究

文章研究了海水循环冷却系统排放浓海水在室内自然蒸发过程中,CaSO4、NaCl的析出规律、主要离子的浓度变化规律以及日晒盐的化学组成和毒性.试验结果表明:海水循环冷却系统排放浓海水的CaSO4析出点为13.89°Be′,NaCl析出点为25.76°Be′,此时CaSO4的析出率为90.32％;实验制得的日晒盐化学组成符合制盐业一级品标准,并属实际无毒.因此,利用海水循环冷却系统排放浓海水制盐切实可行.     

天津在建海水淡化项目进展顺利

为了有效解决水资源短缺问题,天津正在建设一批海水淡化与综合利用项目,目前各项目建设进展顺利。 这批项目包括天津北疆电厂项目、大港海水淡化项目、天津临港海水综合利用一体化项目和宝成集团海水淡化装备产业项目。     

海水淡化副产浓海水综合利用方案的探讨

我国是水资源严重短缺的国家,海水淡化是解决我国水资源危机的重要措施之一.淡化过程产生的浓海水直接排放将对生态环境造成影响,而其较高的浓度和稳定的性质为海水化学资源的综合利用提供了方便.文章介绍了包括基于盐田法的传统综合利用方案、基于电渗析浓缩制盐方案、基于浓海水化学资源综合提取的方案和反渗透-电渗析集成的方案等浓海水综合利用的方案及其优缺点,探讨了这些技术的应用可行性,提出了发展浓海水综合利用技术的建议.     

淡化副产浓海水对滩晒制盐影响研究

将淡化后副产的浓海水与传统的制盐工艺相结合,一方面可以有效解决大规模浓海水排放所造成的环境问题,另一方面还可以节约盐田土地面积,提高原盐产量,为沿海地区的经济发展提供更大空间。文章分析比较了淡化副产浓海水的理化性质,探讨了副产浓海水对滩晒制盐的影响,提出了消除潜在影响的主要措施和方法。     

海水淡化高盐度尾液排放对海洋生态系统的影响

近年来由于淡水资源短缺和海水淡化处理成本的下降,海水淡化产业在全球范围内蓬勃发展,但高盐度尾液的排放会导致海水盐度升高,进而对海洋生态系统造成一定的影响.本文主要讨论海水盐度升高对海洋营养盐循环、浮游生物、鱼类、海洋微生物及水产养殖业所造成的影响,并对高盐度尾液的排放及存在的问题提出了一些建议.     

海水淡化后浓海水工厂化制盐浅析

文章介绍了海水淡化和海盐生产的基本工艺,分析了海水淡化后浓海水制盐的几种方法,指出浓海水滩晒制盐是现阶段解决浓海水排放难题的一条有效途径.利用浓海水为原料进行滩晒制盐,尤其是利用二次反渗透法排出的高浓度海水,对制盐企业的技术进步具有一定的积极作用,同时也具有较好的经济和社会效益.     

海水体系纳滤膜分离性能研究

利用纳滤膜进行海水体系分离实验,考察了纳滤膜(NF-A)在不同条件下对海水中一价与二价以上离子的截留性能.研究了进料操作压力、操作温度和操作时间对纳滤膜分离性能的影响,并做出解释说明.通过实验确定最佳工艺条件,NF-A型纳滤膜对海水中一价离子(Na ,Cl-,K )截留率＜20%,二价离子(Ca2 ,Mg2 ,SO2-4)截留率＞70%,其中SO2-4的截留率可达99%,从而使一价与二价以上离子充分分离,为进一步海水淡化、提取镁、钾、溴等元素以及制取精制盐提供优质原料.     

海水淡化浓海水综合利用过程对盐藻生长的影响

研究了海水淡化浓海水综合利用过程对盐藻生长及活性物质积累的影响.文章测定了海水淡化浓海水综合利用过程中水样的pH值、盐度、含氮量、Ca、Mg、Fe和P含量.比较不同综合利用过程中盐藻生长状况,测定盐藻的叶绿素a、叶绿素b、β-胡萝卜素.结果表明,与天然海水相比,海水淡化浓海水综合利用过程对盐藻生长具有一定的促进作用,而...     

海水和淡水养殖锯缘青蟹的营养成分分析

利用常规的营养测试方法对海水与淡水养殖锯缘青蟹的肌肉营养成分进行初步研究。结果显示：海水养殖锯缘青蟹水分、粗灰分、粗蛋白和粗脂肪含量分别为70.26%、4.59%、15.57% 和1.09%;淡水养殖锯缘青蟹则分别为78.36%、4.35%、17.42% 和0.75%,表明不同养殖环境中的锯缘青蟹的肌肉水分含量差异较大。共检测出17 种氨基酸,海水与淡水养殖锯缘青蟹肌肉中的必需氨基酸占总氨基酸的比例分别为34.39% 和31.20%,构成比例均符合联合国粮农组织/ 世界卫生组织的评价标准。海水养殖锯缘青蟹肌肉必需氨基酸指数(EAAI)为85.20,而淡水养殖锯缘青蟹则为68.35。海水与淡水养殖锯缘青蟹肌肉的第一限制性氨基酸均为缬氨酸。海水和淡水养殖锯缘青蟹肌肉脂肪酸中,前者的饱和脂肪酸含量要显著高于后者(P ＜ 0.05),EPA+DHA 含量分别为11.18%和9.27%,差异不显著(P ＞ 0.05)。综合数据表明,海水养殖锯缘青蟹肌肉的营养价值稍优于淡水养殖锯缘青蟹,而风味稍差于淡水养殖锯缘青蟹。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

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.     

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

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

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.     

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.