超声辅助提取发酵豆渣蛋白工艺研究

以豆渣为原料,首先采用黑曲霉（Aspergillus niger）发酵豆渣,然后分别应用超声辅助碱溶酸沉法和单一碱溶酸沉法提取已发酵豆渣中的蛋白质。单因素和正交试验结果表明：超声辅助碱溶酸沉法豆渣蛋白提取率明显升高,提取时间也大大缩短;最佳工艺参数为碱提温度55 ℃,提取时间90 min,碱液浓度0.3 mol/L,超声功率300 W,料液比1∶24（g∶mL）。在此最佳条件下,豆渣蛋白提取率是83.84%。     

黑蚂蚁中黑色素的提取及性能初步研究

黑色素是一种存在于各种生物体中的优良的活性成分。为研究影响提取工艺的主要因素,以黑蚂蚁为原料,采用碱溶酸沉法提取黑色素。通过紫外、红外鉴定初步鉴定黑色素,并分析黑蚂蚁黑色素的总酚含量及抗氧化、消除自由基的能力。结果表明,碱提酸沉法提取黑色素过程中水解蛋白对黑色素提取率影响较大。进一步研究发现,当盐酸浓度为6 mol/L、料液比为1︰30 g/m L、水解温度为60℃、水解时间为3 h时,得到的黑色素提取率为5.2%。黑蚂蚁中黑色素磷酸缓冲液在212 nm处有最大吸收峰,IR显示有与文献报道黑色素相吻合的红外特征吸收;与同浓度的抗坏血酸相比,它的抗氧化能力较弱。     

糖化酶纯化棉籽分离蛋白的工艺研究

以脱酚棉籽为原料,对比碱溶酸沉法和酶水解-超声波辅助碱溶酸沉法对棉籽蛋白提取率的影响发现,酶解和超声辅助可以显著增加碱溶酸沉的蛋白提取率。在酶水解-超声波辅助碱溶酸沉提取蛋白的基础上,利用糖化酶纯化所提取的蛋白粗品,并在单因素试验的基础上采用正交试验优化棉籽蛋白纯化工艺,得到高纯棉籽蛋白制备的最佳工艺条件为:酶解温度60℃,酶解pH 4.5,酶解时间120 min,糖化酶用量0.4%,液料比9︰1(mL/g)。验证试验表明,利用该工艺两次纯化棉籽蛋白所得的纯化产品蛋白质含量可达93.10%。采用SDS-PAGE对纯化后的棉籽分离蛋白亚基相对分子质量分布进行分析,结果表明,纯化产品中蛋白质亚基相对分子质量主要为55.1 k Da与47.5 k Da。该研究可为棉籽蛋白在食品工业中的应用提供理论参考。     

微波辅助-碱溶酸沉法提取豌豆分离蛋白

考察微波辅助碱溶酸沉法提取豌豆分离蛋白的主要影响因素。同时采用微波改进的提取工艺与传统工艺进行比较,微波辅助提取工艺后蛋白质的提取率明显要高于传统工艺。传统的碱溶酸沉工艺提取豌豆分离蛋白的最佳工艺为:料液比1:25、提取时间50min、pH值9.0、提取温度40℃。在此提取条件下豌豆分离蛋白的含量为17.30g/100g。微波辅助提取豌豆分离蛋白质的最佳工艺为:微波时间6min、微波功率300W、料液比1:20,在此提取条件下,蛋白质的含量可以达到19.44g/100g。     

不同提取方法对沙棘蛋白品质的影响

文章系统研究了不同提取工艺对沙棘蛋白组成及α-淀粉酶抑制活性的影响。分别采用水提、盐提、碱溶酸沉、先醇提后碱溶酸沉、先碱溶酸沉后醇提这5种工艺提取沙棘蛋白,比较了沙棘蛋白的蛋白质含量、蛋白提取率、色泽、α-淀粉酶抑制活性、氨基酸组成和重金属含量,确定了提取沙棘蛋白的最优工艺。研究结果表明,最佳提取工艺为先醇提后碱溶酸沉,该工艺提取得到的沙棘蛋白的蛋白质含量为(77.86±2.34)%,蛋白质提取率为(73.18±1.8)%,氨基酸组成完全,且当浓度为1mg/mL时,α-淀粉酶抑制活性可以达到85%,80℃热处理不会影响其抑制活性;重金属含量检测表明,该蛋白中重金属含量均低于国家安全标准,可以用于食品工业生产。该研究可为沙棘蛋白的深加工与利用提供理论基础。     

响应面法优化山毛豆蛋白质提取工艺

通过响应面法优化山毛豆蛋白质碱溶酸沉法提取工艺。结果表明,碱溶酸沉法提取山毛豆蛋白质的优化工艺为碱溶pH=11.0、料液比为1∶36(g/mL)、提取温度40℃、提取时间143 min、酸沉pH=4.0;在此条件下山毛豆蛋白质的提取率为83.42%。     

豆制品废水中蛋白质提取与纯化工艺研究

用碱溶酸沉法纯化蛋白质粗品,通过单因素试验和正交试验优化提取工艺。试验得到:在碱溶pH9.0,料液比1∶20(g/mL),提取温度40℃,提取时间1.5h,酸沉pH为3.7的条件下,以10 000 r/min离心蛋白质沉淀率达到89.8%。蛋白质得率为75.5%,纯化后蛋白质纯度达到90.5%,灰分含量为3.76%。     

冠突散囊菌胞外黑色素碱法提取工艺的研究

以碱性溶液为提取剂,运用单因素试验及响应面法对马铃薯液态培养基培养冠突散囊菌（Eurotium cristatum）所产的胞外黑色素的提取工艺条件进行优化,得到最优提取条件。单因素试验以NaOH溶液浓度、提取温度、色素酸沉pH值和料液比（发酵液∶NaOH溶液）为评价因素,黑色素提取量为响应值,并在此基础上建立4因素3水平响应面试验。结果表明,冠突散囊菌胞外黑色素的最佳提取工艺参数为：NaOH浓度1 mol/L,提取温度74 ℃,色素酸沉pH值2.5,料液比为1∶1.4（V∶V）。在该优化条件下,提取的黑色素含量最高,为3.982 mg/mL。     

莲子心总黄酮不同提取方法的比较与分析

以莲子心总黄酮提取率、干浸膏得率为指标,对碱溶酸沉法、水提法、常规醇提法、超声波辅助醇提法、微波辅助醇提法提取莲子心黄酮进行比较研究与分析,优化莲子心黄酮的提取工艺。考察5种提取方法对考察指标的影响,并计算综合评价指标Y值。Y值的大小顺序依次为微波辅助醇提法超声波辅助醇提法常规醇提法水提法碱溶酸沉法。莲子心总黄酮的提取以微波辅助醇提法为佳。     

尤曼桉中芦丁的提取方法研究

本文首次报道了尤曼桉(EucalyptusYoumanii)芦丁的提取方法和工艺条件。采用正交试验设计分别以碱溶酸沉法、乙醇回流法、热水法提取尤曼桉叶芦丁。碱溶酸沉法的工艺条件为固液比1:10,提取时间10min,pH8,提取两次,热水纯化;乙醇回流法提取尤曼桉芦丁的工艺条件为乙醇浓度75%,提取温度75℃,提取时间3h,碳酸氢纳用量10%,固液比1:20,热水纯化;热水提取尤曼桉芦丁的工艺条件为固液比1:30,时间30min,粒度100目,提取两次,热乙醇纯化。三种提取方法以碱溶酸沉法较优。     

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