碱—酶法提取硫酸软骨素的工艺研究

研究以猪软骨组织为原料,采用碱液提取和酶解相结合的方式提取硫酸软骨素。通过对影响碱液提取效率和酶解效果因素的研究,确定了碱液提取的最佳条件为:碱液的体积分数7.5%、提取温度为50℃、提取时间2 h、提取2次。酶解的最佳条件为:采用木瓜蛋白酶和胰蛋白酶的混合酶1∶1(w∶v)、添加质量分数1.0%,pH值8、提取36 h。     

菠萝蛋白酶酶解鱼鳞蛋白的工艺优化研究

鱼鳞中含有丰富的蛋白质资源,对其进行温和、环保的酶法水解受到更多的关注.本文采用菠萝蛋白酶水解鱼鳞蛋白,制备胶原多肽制品.通过考察温度、时间、酶量、料液比等单一因素对酶解的影响,设计了L9(34)正交实验,最终获得了菠萝蛋白酶水解鱼鳞蛋白的优化工艺条件,即温度60℃,时间3h,酶量4％(质量分数),底物浓度5％(质量分数),水解度为18.1％,该条件具有生产应用前景.     

海参体壁酸溶性胶原提取及氨基酸组成分析

以海参体壁为原料,采用乙酸溶剂法提取酸溶性胶原。以酸溶性胶原得率为指标,通过均匀设计试验确定了乙酸溶剂法提取酸溶性胶原的优化条件:温度为4℃,乙酸浓度为0.5 mol/L,料液比为1∶1 000,提取时间为72 h,在此条件下酸溶性胶原的得率可达到胶原纤维原料的7.35%(质量分数)。氨基酸组成分析表明,海参体壁酸溶性胶原的甘氨酸(Gly)含量为33.6%,羟脯氨酸(Hyp)含量为7.04%。     

响应面法优化菜籽粕中植酸提取工艺研究

利用低浓度(体积分数)的醋酸溶液,在单因素试验的基础上选择了醋酸浓度、提取温度和提取时间进行响应面分析,以提取液中植酸含量(质量分数)为响应值,建立了植酸提取的二次多项式数学模型,确定了植酸提取的最佳工艺条件为:醋酸浓度4.4%,提取温度41℃,提取时间2h,得到提取液中植酸含量为1.64%。     

酶法提取牛腱胶原的研究

以牛肌腱为原料,通过酶法来提取Ⅰ型胶原,找出其最佳工艺条件,并对所提取的胶原进行了性能表征。酶法水解的最佳条件:进口胃蛋白酶用量的质量分数1 % ,pH值2 .5及4℃条件下水解作用3 0h。研究结果提示:酶解法是比较理想的提取方法,不仅提取产率高,而且提取的胶原样品的分子质量高(1 0万Dal以上)且分布窄,可初步判定其基本维持了天然胶原的三股螺旋结构,适合作为生物医用材料的原料。     

超声波处理玉米芯制备低聚木糖的条件优化

考察了试验室规模下超声波处理玉米芯提取木聚糖经酶水解制备低聚木糖的影响因素,通过单因素试验和正交试验,优化了提取和水解条件。结果表明:以质量分数5%Na OH溶液为提取剂,超声功率为180 W,超声温度为60℃的条件下提取45 min,木聚糖产率可达到33.18%。所得提取液经脱色,调p H,调木聚糖底物浓度后酶水解制备低聚木糖。最佳酶解条件为:木聚糖底物质量浓度10 mg/m L,加酶量质量分数1.5%(相对于玉米芯干物料),酶水解时间为8 h的条件下,水解液中还原糖的质量浓度达到6.89 mg/m L。     

番茄皮渣中番茄红素和多糖的提取

以番茄皮渣为原料,采用酶辅助双水相法提取番茄红素和多糖。考察溶剂与盐质量分数、混合酶的组成、酶质量分数、pH、酶解温度及酶解时间对有效成分得率的影响,并采用响应面法对工艺条件进行优化。结果表明:当双水相体系组成为31%乙醇-16%K2HPO4,果胶酶-菠萝蛋白酶为1∶1,酶质量分数为2.0%,在pH 6.0,50℃条件下酶解119 min时,番茄红素和多糖提取得率最高,分别为15.69 mg/100 g和77.16 mg/g。响应面法结果显示,酶质量分数对番茄红素和多糖的提取影响最为显著,其提取结果与预测值相符。与传统溶剂法相比,酶辅助双水相提取法溶剂用量少,提取温度低,提取物具有较好的抗氧化活性。     

鱼鳞胶原多肽的制备研究

利用单因素实验优化热水法提取鱼鳞胶原蛋白工艺,使用正交实验优化胶原多肽酶解工艺。最佳提取工艺为:温度70℃,时间6h,料液比1∶20,胶原蛋白的得率为32.55%;酶解最佳工艺为:pH9.5,温度55℃,时间2.0h,酶量0.3%,最大水解度达23.17%;用氨基酸自动分析仪和凝胶渗透色谱法测定胶原多肽氨基酸分布情况和分子质量,结果表明:氨基酸组成符合胶原蛋白特征,胶原多肽分子质量大部分在1000u以内。     

牛跟腱胶原与草鱼皮胶原的结构表征及自组装行为比较

以牛跟腱和草鱼皮为原料，采用“酸-酶”结合法提取I型胶原，研究两种胶原的结构特性及其自组装行为差异。结果表明：牛跟腱胶原和草鱼皮胶原均具有I型胶原的典型结构特点，具有相似的相对分子质量和二级结构，但氨基酸含量有所差异，其中牛跟腱胶原亚氨基酸（脯氨酸+胫脯氨酸）含量要高于草鱼皮胶原。胶原的自组装结果表明，当胶原质量浓度为2 mg/m L、温度为37℃时胶原自组装速率最高。而当温度过高（>42℃）时，相比牛跟腱胶原，草鱼皮胶原的组装受到更大地抑制，这可能归因于牛跟腱胶原中更多的亚氨基酸含量赋予了其更好的热稳定性。此外，增大胶原浓度可以提升胶原凝胶的存储模量，整体而言，牛跟腱胶原凝胶的存储模量优于草鱼皮胶原凝胶。     

Bacillus cereus胞外胶原蛋白酶水解牛骨胶原蛋白的动力学

针对从细菌蜡样芽孢杆菌(Bacillus cereus)MBL13中提取得到的胶原蛋白酶酶解牛骨胶原蛋白的动力学性质进行研究。考察底物质量浓度、时间、温度、酶质量浓度、pH值5个因素对酶解水解度的影响,优化酶解的条件;并对酶解过程的动力学进行分析。结果表明:最佳的酶解工艺参数为底物质量浓度30g/L、时间6h、温度45℃、初始酶液质量浓度为0.35g/100mL、pH8.0。在此基础上推导出酶解动力学方程为:V=9.3633[S]/(114.785+[S])。并在波长230nm和570nm处对酶解过程动态变化进行测定,表明胶原多肽含量不断增加的动态变化。     

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.