密蒙花黄色素的提取及其稳定性研究

研究了密蒙花中天然黄色素提取的最佳工艺条件及其在不同条件下的稳定性。采用单因素和正交实验研究黄色素的最优提取工艺条件;分析其在不同p H值、温度、光线条件以及与常见金属离子、氧化剂、还原剂、糖等物质共存时黄色素的稳定性。结果表明,最佳的提取条件为:乙醇体积分数是60%,提取温度为60℃,提取时间为2.5 h,液料比为1∶50。密蒙花黄色素在p H2~8时较稳定,对高温比较敏感,在日光下较不稳定;对还原剂较敏感,有一定的抗氧化能力;对金属离子K+、Na+、Ca2+、Mg2+、Zn2+、Al3+、Cu2+比较稳定,对Fe3+和Pb2+不稳定;葡萄糖、蔗糖、麦芽糖、苯甲酸钠等常用食品添加剂对黄色素的稳定性无明显影响。可为密蒙花黄色素作为食用色素提供科学依据。     

紫叶酢浆草色素的提取及性质研究

研究紫叶酢浆草色素的提取条件和理化性质,结果表明:用料液比13∶0(g/mL)、pH1(10%盐酸调)的95%乙醇作提取剂、在70℃恒温浸提40min,提取效率较好。紫叶酢浆草色素属花青素类色素,pH值对色素影响明显,在酸性条件下色泽稳定且具有热稳定性;光照能加快色素降解;金属离子Na+、Ca2+、A13+、Cu2+、Zn2+对色素色泽无影响,而Fe3+、Pb2+有不良影响;色素的抗氧化还原性能较差;蔗糖、葡葡糖和盐等添加剂对色素无影响。急性毒性试验中白鼠无异常表现。     

拐枣总黄酮稳定性研究

以拐枣为原料,利用醇提法提取拐枣总黄酮,研究拐枣总黄酮在不同温度、pH、还原剂、氧化剂、食品添加剂、金属离子条件下的稳定性。结果表明,拐枣总黄酮在80℃以下、pH 3-6时较为稳定;蔗糖、氧化剂和还原剂均对黄酮稳定性有影响,而抗坏血酸、柠檬酸、苯甲酸钠和葡萄糖对稳定性影响不大;金属离子中Na~+、K~+对拐枣总黄酮的影响很小,Mg~(2+)、Ca~(2+)、Cu~(2+)的影响稍大,而Al~(3+)、Fe~(3+)的影响较明显。     

拐枣总黄酮稳定性研究

以拐枣为原料,利用醇提法提取拐枣总黄酮,研究拐枣总黄酮在不同温度、pH、还原剂、氧化剂、食品添加剂、金属离子条件下的稳定性。结果表明,拐枣总黄酮在80℃以下、pH 3-6时较为稳定;蔗糖、氧化剂和还原剂均对黄酮稳定性有影响,而抗坏血酸、柠檬酸、苯甲酸钠和葡萄糖对稳定性影响不大;金属离子中Na~+、K~+对拐枣总黄酮的影响很小,Mg~(2+)、Ca~(2+)、Cu~(2+)的影响稍大,而Al~(3+)、Fe~(3+)的影响较明显。     

油桃皮红色素的提取及稳定性研究

研究了油桃皮红色素的提取条件和稳定性,结果表明,用料液比1:30(g:ml)、pH1的50%乙醇作提取剂、在50℃恒温浸提40min,提取效率较好。油桃皮红色素属花色素苷类色素,水溶性好,对光、热(80℃以内)的耐受性强。pH值对色素影响明显。金属离子Na+、Ca2+、A13+、Cu2+、Zn2+对色素色泽无影响,而Fe3+、Pb2+有不良影响。色素的抗氧化能力较差而耐还原性能较好。蔗糖、葡葡糖和盐等添加剂对色素无影响。     

陕西茵陈黄酮提取及抗氧化性能研究

以陕西茵陈为原料,采用超声波预处理-乙醇回流法提取菌陈黄酮,以乙醇体积分数、回流时间、回流温度和料液比为因素,茵陈黄酮得率为考察指标,确定茵陈黄酮的最佳提取工艺。研究了茵陈黄酮抗脂质过氧化能力和DPPH自由基清除能力,及温度、光照、p H、金属离子对茵陈黄酮抗氧化性能的影响。结果表明:茵陈黄酮最佳提取条件为乙醇体积分数50%、回流时间50 min、回流温度90℃、料液比1∶25,在此条件下茵陈黄酮得率为2.35%。温度和Na~+、K~+、Ca~(2+)、Cu~(2+)对茵陈黄酮抗氧化能力影响不大;Cd~(3+)、Cr~(3+)、Al~(3+)以及pH、光照对茵陈黄酮抗氧化能力影响显著。此外,茵陈黄酮对菜籽油具有一定的抗氧化能力,分别与V_C和柠檬酸协同作用时其抗氧化能力增强。     

菊花中黄色素的微波辅助提取工艺研究

以菊花为原料,在单因素实验基础上,通过正交试验确定了黄色素提取的最佳工艺条件。结果表明,微波提取菊花黄色素的最佳工艺条件为:辐射功率600W,辐射时间5min,料液比1∶80,辐射温度70℃。研究了菊花黄色素的稳定性实验,结果表明:对弱酸、弱碱、氧化剂、大部分金属离子稳定,但对还原剂和少数金属离子(Cu2+、Al3+、Ca2+)不稳定。     

荷叶总黄酮稳定性的研究

以干荷叶为原料,研究利用超声波提取法浸提荷叶总黄酮的稳定性,对荷叶总黄酮浸提液在不同温度、pH、光照、氧化剂、还原剂、金属离子等条件下的稳定性进行测定。结果表明,荷叶总黄酮在45℃以下、pH 6左右时较稳定;在光照条件下,荷叶总黄酮的稳定性不佳;还原剂和氧化剂使荷叶总黄酮的稳定性大幅下降;金属离子K~+和Na~+基本对荷叶总黄酮的稳定性没有影响,而其他金属离子Fe~(3+)、Mg~(2+)、Zn~(2+)、Cu~(2+)、Ca~(2+)、Mn~(2+)能明显隆低荷叶总黄酮的稳定性。     

柿子黄色素稳定性及抗氧化活性的研究

文章研究了pH、金属离子、热、光、氧化剂和还原剂等对柿子黄色素稳定性的影响。结果表明:柿子黄色素在酸性条件下不稳定而在碱性条件下稳定;低温和避光有利于维持柿子黄色素的稳定性;Fe3+对柿子黄色素产生极强破坏性而Cu2+具有护色作用,Ca2+,Mg2+,Al 3+,还原剂和低浓度的氧化剂对柿子黄色素的影响不明显。当柿子黄色素浓度达到3.0 mg/mL时,其对DPPH自由基、羟自由基(·OH)、超氧自由基(O2-·)、ABTS自由基、亚硝酸根离子的清除率分别为98.90%,97.56%,98.73%,90.84%,96.73%,其还原能力为OD700nm=2.985。以VC和茶多酚作为阳性对照,表明柿子黄色素具有较强的抗氧化能力。     

玉米蛋白粉天然黄色素稳定性研究

从玉米蛋白粉提取的天然黄色素是一种安全无毒食用色素。该实验主要研究黄色素稳定性及食品中常用几种食品添加剂对黄色素稳定性影响,结果表明:黄色素耐光性较差,有一定耐热性,食用植物油对其有很好保护作用,对Al~(3+)、Fe~(3+)、Cu~(2+)等离子极不稳定,对高浓度氧化剂稳定性较差,而对酸、碱、还原剂、含氧酸根、Fe~(2+)、Na~(2+)、K~+等离子较稳定;另外,木糖醇对黄色素有一定保护作用,维生素C和香兰素对黄色素也有较强保护作用,且香兰素保护作用明显优于维生素C。     

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