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1.
采用溶胶-凝胶和浸渍法制备了SO2-4/TiO2-SiO2固体酸催化剂,利用其对大豆油脱臭馏出物进行甲酯化。研究了TiO2-SiO2载体焙烧温度、浸渍用硫酸浓度、浸渍时间对催化剂活性的影响,以及催化剂用量、醇油比、反应温度和反应时间对酯化率的影响。得到了最佳反应条件为载体焙烧温度550℃,浸渍用硫酸浓度2.5 mol/L,浸渍时间12 h,催化剂用量5%(以大豆油脱臭馏出物质量计),醇油比1.5∶1(甲醇与大豆油脱臭馏出物体积质量比),反应温度65℃,反应时间4 h。在最佳条件下,酯化率达到96.5%。 相似文献
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以MgO为载体,采用等体积浸渍法制备固体碱催化剂Na2SiO3/MgO。通过X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)分别对催化剂和产物进行表征。通过单因素试验和正交试验优化了大豆油制备生物柴油的工艺条件。结果表明:当Na2SiO3/MgO中的Na2SiO3负载量为20%(以MgO质量计)、醇油摩尔比为10∶1、催化剂用量4%(以大豆油质量计)、反应温度55℃、反应时间3h时,生物柴油的产率可以达到98.77%。XRD表征结果表明,当Na2SiO3的负载量为20%时,Na2SiO3以单层分散的形式附着在载体MgO表面,且没有形成新的晶体。FT-IR表征结果表明,所合成产物分子的官能团结构与目的产物相符。 相似文献
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《粮食与油脂》2021,(2)
采用浸渍法制备了固体碱K_2CO_3/SBA-15催化剂,通过单因素试验考察了焙烧温度、焙烧时间、K_2CO_3负载量、催化剂用量和反应时间对利用大豆油制备生物柴油产率的影响。通过X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等方法对催化剂进行了表征。结果表明:催化剂通过焙烧产生了新的活性中心K_2O; K_2CO_3/SBA-15催化剂能够很好地保持SBA-15原有的二维六方相有序介孔结构。对催化剂性能进行测试表明:当催化剂的焙烧温度为500℃、焙烧时间为3 h、K_2CO_3负载量为40%、催化剂用量为大豆油质量的3%、反应时间为4 h时,生物柴油的产率最高,为88.6%。 相似文献
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大豆油主要成分为亚油酸(51%~57%),油酸(32%~36%),棕榈酸(2.4%~2.8%),硬脂酸(4.4%~4.6%)。环氧大豆油是以食用大豆色拉油为主要原料,在催化剂存在下,用双氧水与大豆油作用而制得。环氧大豆油在常温下为浅黄色粘稠油状液体,无毒、无 相似文献
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Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates 总被引:2,自引:0,他引:2
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. 相似文献
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Anne Theobald Catherine Simoneau Philippe Hannaert Patrizia Roncari Anna Roncari Thomas Rudolph Elke Anklam 《Food Additives & Contaminants》2000,17(10):881-887
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. 相似文献
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A. Boenke 《Food Additives & Contaminants》2001,18(12):1135-1140
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. 相似文献
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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。 相似文献
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Microbiology of food taints 总被引:2,自引:0,他引:2
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. 相似文献
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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 相似文献
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Jesus Simal-Gandara Miguel Sarria-Vidal Rinus Rijk 《Food Additives & Contaminants》2000,17(9):815-819
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. 相似文献
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H. J. Van Den Top A. Boenke P. A. Burdaspal
J. Bustos
H. P. Van Egmond T. Legarda
A. Mesego A. Mouri o W. E. Paulsch C. Salgado 《Food Additives & Contaminants》2000,17(6):419-433
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. 相似文献
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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 下载免费PDF全文
《造纸信息》2014,(8):80-80
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)" 相似文献
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1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China 下载免费PDF全文
《造纸信息》2014,(8)
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. 相似文献