黑木耳多糖的提取工艺

研究黑木耳多糖的提取工艺,以多糖得率为考察指标,在单因素试验结果的基础上,进行正交试验设计,考察液料比、时间、温度对多糖得率的影响.结果表明,温度是影响粗多糖得率的重要因素,水提法的最佳工艺为:液料比70(mL:g),提取时间4h,温度100 ℃,提取2次,pH为7.0.此条件下黑木耳多糖得率为32.24%,多糖含量为64.23%.     

球等鞭金藻胞内和胞外多糖的提取工艺

采用热水浸提法,通过一系列单因素试验,研究提取时间、提取pH 值、提取温度和液料比对球等鞭金藻胞内和胞外多糖提取的影响。在此基础上,通过正交试验进一步优化胞内和胞外多糖的提取工艺。最后,采用适宜提取工艺制备胞内和胞外粗多糖样品,并测定该样品中蛋白质和多糖含量。单因素试验结果表明,提取时间、提取pH 值和提取温度均能显著影响胞内和胞外多糖的提取。对胞内粗多糖提取率而言,提取时间180min、提取pH9 和提取温度70℃为最适宜的提取条件;当提取时间300min、提取pH10 和提取温度80℃时,更利于胞外粗多糖的提取。液料比对胞内和胞外粗多糖提取的影响较小,20:1(mL/g)为多糖提取合适的液料比;正交试验结果表明,胞内(胞外)多糖的适宜提取工艺为提取时间、提取pH 值、提取温度和液料比分别为180min(240min)、pH8(9)、70℃和15:1。粗多糖样品的蛋白质和多糖含量分别为1.18%(0.82%)和 22.1%(18.6%),很低的蛋白质含量和较高的多糖含量表明采用该提取工艺获得的粗多糖样品纯度较高,利于样品的后续分离纯化。     

复合酶法提取红雪茶粗多糖工艺优化研究

为了获得复合酶法提取红雪茶粗多糖的最佳工艺,采用单因素实验和正交实验,研究了不同料液比、pH、酶解温度、提取时间和不同复合酶配比对红雪茶粗多糖提取率的影响;在此基础上采用L9(34)正交实验研究了各影响因素对红雪茶粗多糖提取率的影响,结果表明复合酶最佳配比为纤维素酶2.0%,果胶酶2.0%,木瓜蛋白酶0.5%;影响红雪茶粗多糖提取率的四个因素的主次顺序为:料液比>酶解温度>pH>酶解时间;最佳提取工艺条件是料液比1:40,pH4.5,酶解温度40℃,酶解时间80min,在此条件下红雪茶多糖提取率达8.91%。本研究确定了复合酶法提取红雪茶多糖的最佳工艺。     

活性炭负载壳聚糖对苹果汁的澄清效果研究

以透光率为指标,以壳聚糖澄清和活性炭澄清为对照,探讨活性炭负载壳聚糖澄清剂在不同添加量、温度、时间和pH条件下对苹量汁的澄清效果影响,并采用Box-Behnken中心组合设计法进行澄清工艺条件的响应面优化。试验结果表明：经活性炭负载的壳聚糖澄清剂对苹果汁有较好的澄清效果,且明显优于对照组;建立的响应面模型能较好地预测透光率随澄清条件的变化规律,且在最优澄清条件负载澄清剂用量12 g,澄清时间9.6 min,澄清温度55℃,pH 2.56下的透光率为96.47%。     

银杏外种皮粗多糖提取工艺研究

目的:研究银杏外种皮中粗多糖的水提最优工艺。方法:采用苯酚-硫酸法测定多糖含量,以多糖提取率为考察指标,在单因素试验结果的基础上,进行正交试验设计,考察料液比、温度、时间等因素对提取率的影响。结果:温度是影响粗多糖提取率的重要因素。水提法最优工艺条件为温度100℃、时间1h、料液比1:12、提取次数3次,此条件下多糖提取率达95.09%,粗多糖得率为23%。结论:该提取工艺的多糖提取率高,可用于银杏外种皮中粗多糖的提取。     

超声辅助提取对大枣粗多糖体外抗凝血活性及得率的影响

为了在提高大枣粗多糖得率的同时保持其抗凝血活性,采用超声辅助提取大枣粗多糖;设计单因素和响应面优化试验探讨温度、pH值、超声功率、超声时间以及料液比对大枣粗多糖体外抗凝血活性和得率的影响。试验结果表明最佳提取工艺是:超声温度69℃,pH 7.15,超声功率80 W,料液比为1∶10(g/mL),超声时间30min。在此条件下大枣多糖既能保持良好的体外抗凝血活性,又具有较高的得率。     

红松松塔多糖活性炭法脱色工艺的研究

摸索红松松塔粗多糖脱色工艺条件,为松塔粗多糖的纯化提供理论依据.实验采用活性炭法对红松松塔多糖进行脱色研究,利用单因素和正交试验研究了活性炭浓度、脱色温度、脱色时间和pH值对松塔粗多糖脱色工艺的影响.研究结果,表明活性炭法最佳脱色工艺条件为活性炭浓度1.5％、时间60min、温度50℃和pH值3.本研究为红松松塔多糖的进一步纯化提供了科学依据,为松塔的开发利用奠定理论基础.     

壳聚糖影响苹果汁澄清条件的探讨

目的考察壳聚糖澄清苹果汁的效果,探讨影响澄清工艺的因素,确定壳聚糖澄清果汁的最佳条件。方法以澄清果汁720 nm处的透光度评价各条件,比较各因素的较优水平。结果温度40℃,壳聚糖用量0.15 g/L,时间1 h,pH3时壳聚糖澄清苹果汁的效果最佳,果汁的营养成分和风味不受影响。结论壳聚糖可用于果汁澄清工艺。     

壳聚糖影响苹果汁澄清条件的探讨

目的考察壳聚糖澄清苹果汁的效果,探讨影响澄清工艺的因素,确定壳聚糖澄清果汁的最佳条件。方法以澄清果汁720nm处的透光度评价各条件,比较各因素的较优水平。结果温度40℃,壳聚糖用量0．15g／L,时间1h,pH3时壳聚糖澄清苹果汁的效果最佳,果汁的营养成分和风味不受影响。结论壳聚糖可用于果汁澄清工艺。     

浓缩苹果汁加工中酶作用及贮藏稳定性研究

以红富士苹果浓缩汁为材料,采用单因素试验,研究果胶酶和α- 淀粉酶对还原糖、总酸、可溶性固形物等几个指标的影响,同时找出适合浓缩苹果汁澄清的果胶酶和α- 淀粉酶的酶用量、温度和时间。实验结果表明,在酶用量0.1%、温度50℃、时间1.5h 的条件下,浓缩苹果汁的澄清效果较明显。将加入果胶酶和α- 淀粉酶的浓缩苹果汁置于4℃和26℃条件下贮藏,测定其在贮藏过程中还原糖含量、总酸含量、pH 值和透光率等指标的变化。结果表明,在4 ℃贮藏条件下,随着贮藏时间的延长,还原糖含量、总酸含量、pH 值、透光率变化幅度较小,果汁营养成分保持较好,适宜贮藏。     

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.