红枣及红景天色素的提取及稳定性的比较研究

对红景天及红枣色素的提取方法和色素的基本性质进行了研究比较。结果表明,红景天色素以95%(pH=3)的乙醇水溶液提取时效果最佳,色素的最大吸收峰在314nm处;红枣色素以50%(pH=3)的乙醇水溶液提取时效果最好,色素的最大吸收峰在320nm处;日光、温度和大多数金属离子Ca2 、Mg2 、Mn2 、Zn2 等对这2种色素的稳定性都无太大的影响,但是Na 、Fe2 、K 对红景天色素有增色的趋势,Fe2 对红枣色素有增色的趋势。这2种色素的耐糖性和耐光性都很好。红景天色素在酸性条件下pH稳定性好,但在碱性环境下pH稳定性较差,而红枣色素的pH稳定性在无论在酸性或在碱性条件下都稳定。     

红枣色素的提取及稳定性的研究

本文对红枣色素的提取方法和色素的基本性质进行了研究。通过研究发现，所选用的16种不同的提取溶液当中，红枣色素在以50％（pH3）的乙醇水溶液提取时，效果最好，色素的最大吸收峰在320nm处；日光、温度、和大多数金属离予，对这种色素的稳定性无太大的影响，这种色素的耐糖性和耐光性很好。红枣色素的pH稳定性无论在酸性或在碱性条件下都很稳定。红枣色素稳定性不受人体所需的微量元素Ca^2＋、Na^＋、Fe^2＋、K^＋、Mg^2＋、Mn^2＋、Zn^2＋和Fe^3＋的影响。温度变化（20～100℃）也对色素稳定性几乎无影响。根据研究结果可以初步确定，红枣色素具备了作为天然色素使用的最基本的性能，可开发利用。     

茼蒿色素的提取工艺及稳定性研究

对茼蒿天然色素的提取方法及稳定性进行研究.通过不同溶剂提取效率比较,确定水为最佳提取溶剂.对水提取茼蒿色素的温度、pH值、料液比和时间进行单因子试验与正交设计试验,确定最佳提取工艺条件为pH5.0,温度50℃,料液比1:20,提取时间5 h.茼蒿色素的稳定性研究表明,其耐高温、耐光性较好,在酸性条件下较为稳定,在碱性条件下变色:不同金属离子对色素稳定性影响不大,糖类食品添加剂和氧化还原剂对色素稳定性有较大影响.     

“黑美人”土豆色素稳定性的研究

为了研究黑美人土豆色素的理化性质和稳定性,用0.1%HCl-乙醇溶液在恒温振荡条件下提取黑美人土豆色素,用分光光度计法测定该色素在不同环境下最大吸收波长处吸光度的变化,结果表明:该色素属于水溶性花色苷类色素,pH值对黑美人土豆色素稳定性的影响明显,酸性条件下该色素较稳定;金属离子Al3+对色素有增色作用,Na+、K+、Ca2+、Mg2+、Zn2+对色素稳定性基本无影响,而Cu2+、Fe3+则对色素稳定性有明显的不良影响;该色素耐辐射能力强,不耐自然光、高热,耐氧化性极差;低质量分数的蔗糖、VC和β-环糊精对色素稳定性影响不大;一定质量分数的柠檬酸具有增色作用,而山梨酸钾对色素稳定性有一定影响。通过初步研究,发现该色素有一定的开发利用价值,可作为食品添加剂广泛使用。     

紫茉莉红色素的提取及其稳定性研究

为生产各种食用品、化妆品、医药药品等色素新产品提供重要原料，研究了紫茉莉红色素的提取条件和稳定性。以乙醇作提取剂，用紫外分析法研究色素的稳定性。研究结果为：乙醇提取的适宜工艺条件是以pH=3的65％乙醇溶液，原料与乙醇的质量与体积比为1：10，在室温下浸提24h。色素在440nm有最大吸收峰，该色素水溶性较好，在pH值1-9时具有良好的稳定性，热稳定性也较好。蔗糖、葡葡糖和盐等食品添加剂对色素无影响，但淀粉对其影响较大，耐光性较差。影响明显的氧化剂有（NH4）2S2O8、还原剂有抗坏血酸，金属离子对其影响较大。     

油桃果皮红色素的微波提取工艺及特性研究

对油桃皮红色素的微波提取及理化特性进行了研究,结果表明,该色素为水溶性多酚类花色素,在不同的pH环境下显示不同的颜色;其耐热性、耐光性、耐酸、耐糖、耐还原性较好;但耐氧化性、耐碱性较差;Fe3 对色素有破坏性。研究还表明,该色素的提取宜在酸性介质中进行,酸性条件下其综合稳定性较优,有较高的利用价值。     

甘蔗皮色素的提取工艺及稳定性研究

本实验以甘蔗皮为原料,通过正交试验优化得到甘蔗皮色素最佳提取条件:乙醇浓度为80%,提取温度为50℃,提取时间为60min,料液比为1∶40。在此基础上研究pH、光照、温度、金属离子、H_2O_2、抗坏血酸、食盐、蔗糖、葡萄糖、苯甲酸钠对甘蔗皮色素稳定性的影响。甘蔗皮色素在pH7、避光、较低温度等条件下稳定性较好;甘蔗皮色素的耐氧化性和耐还原性都较差;低浓度食盐、蔗糖、葡萄糖对甘蔗皮色素影响较小,Fe~(3+)、Cu~(2+)导致甘蔗皮色素的吸光度明显降低,高浓度食盐、蔗糖、苯钾酸钠、Fe~(2+)对甘蔗皮色素略有增色的效果。     

马铃薯紫色素的提取及稳定性研究

对马铃薯紫色素的提取及其理化稳定性进行了研究.通过正交实验得到马铃薯紫色素的最佳提取条件为:温度为30℃、时间为60min、料液比为1:20、溶剂为80%乙醇.在对其稳定性进行研究时发现:马铃薯紫色素对温度特别敏感,小于30℃的情况下相对比较稳定;在pH=6左右的条件下稳定;光照会破坏色素的稳定性;葡萄糖和蔗糖对色素的影响不是很大;该色素的抗氧化还原性不是很好,特别是耐氧化性较差.金属离子对色素稳定性的影响主要表现为:Fe3+对色素的影响最大,其次是Cu2+对色素有一定的影响,K+和Al3+对色素的影响不大.     

藤稔葡萄的色素提取及稳定性研究

以新鲜的藤稔葡萄为原料,探讨藤稔葡萄天然色素的提取工艺,并通过正交实验得出藤稔葡萄色素的最佳提取条件,藤稔葡萄色素提取的最佳工艺条件是80%的乙醇作提取剂、pH为2、提取温度为70℃、料液比为1:7.同时研究了藤稔葡萄色素的稳定性,结果表明,藤稔葡萄色素在pH2～6时相对稳定,耐热性较好,耐光性也较好.金属离子对色素稳定性有一定的影响,其中Cu2 、Fe3 、Fe2 对色素的色泽有较大的破坏作用,但Mg2 对藤稔葡萄色素有稳定作用.氧化剂H2O2和还原剂Na2SO3对色素有一定的破坏作用.     

三种紫甘薯色素性质及稳定性研究

紫甘薯美国黑薯、花心薯和德国黑薯水溶性色素吸收最大吸收波长分别为538.5nm、525nm和532nm。三种紫甘薯色素在酸性条件下呈深红色,性质稳定,通过对三种紫甘薯色素稳定性研究发现,pH对色素稳定性有很大影响,在pH为3时温度和光照对色素基本不产生影响,三种紫甘薯色素有良好耐热性和耐光性。     

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