过氧化氢-茚三酮体系荧光光度法检测食品中的焦磷酸盐

摄入过多的焦磷酸盐会对人体健康产生严重影响，因此控制食品中焦磷酸盐的含量十分重要。在酸性介质中，Cu2+能催化过氧化氢-茚三酮体系间的氧化-还原反应而产生较强的荧光。当在该体系中加入少量焦磷酸盐后，Cu2+-H2O₂-茚三酮体系的荧光强度显著减弱。基于此，建立一种荧光光度法检测焦磷酸盐含量。考察过氧化氢浓度、茚三酮浓度、Cu2+浓度、反应时间及反应温度等条件对荧光强度的影响。结果表明，最优条件为过氧化氢浓度3.0×10-5 mol/L，茚三酮浓度2.0×10-3 mol/L，Cu2+浓度6.0×10-5 mol/L，反应时间40 min，反应温度30 ℃，在此条件下，减弱的荧光强度与焦磷酸盐浓度在3.0×10-7～8.0×10-6 mol/L范围内的对数值呈良好的线性相关。方法的检出限与相对标准偏差(RSD)分别为3.2×10-8 mol/L，4.9%(C=1.0×10-6 mol/L，n=11)。采用该方法测定虾仁与带鱼样品中焦磷酸盐含量并做加标回收试验，平均回收率在93.00%～97.80%范围，表明该方法可用于实际食品样品中焦磷酸盐含量的准确检测。     

同步荧光法分析红葡萄酒中微量白藜芦醇含量的研究

建立了一种应用同步荧光检测红葡萄酒中白藜芦醇的新方法,系统研究了检测条件对白藜芦醇荧光强度的影响。该方法的回归方程为Int(荧光强度)=19.70×Conc(浓度μg/mL)+13.98,相关系数r2=0.9987。白藜芦醇产生的荧光强度与浓度在0mol/L～1.96×10-5mol/L的范围内具有良好的线性关系,检测限为8.14×10-10mol/L。     

同步荧光法测定红葡萄酒中白藜芦醇含量

建立了一种应用同步荧光检测红葡萄酒中白藜芦醇的新方法,系统研究了检测条件对白藜芦醇荧光强度的影响。该方法的回归方程为Int(荧光强度)=19.70×Conc(浓度μg/mL)+13.98,相关系数r=0.9987。白藜芦醇产生的荧光强度与浓度在0～1.96×10-5mol/L的范围内具有良好的线性关系,检测限为8.14×10-10mol/L。     

荧光分析法测定沙棘叶中总黄酮的含量

采用荧光光度法测定沙棘叶中总黄酮的含量,根据黄酮类化合物的荧光性质,以芦丁为标样,研究了溶剂、pH值、表面活性剂及放置时间对荧光强度的影响。结果表明,在95%的乙醇中加入pH7的缓冲液,芦丁荧光强度最大,检测限为3．2×10~(-6)mol/L,线性回归方程y=0．6513x 55．166,相关系数为0．9968,荧光强度与浓度的线性范围在1．2×10~(-6)mol/L～4．8×10~(-6)mol/L,相对标准偏差为1．96%。     

花生红衣提取物中白藜芦醇的荧光光谱特性分析

建立了一种利用荧光分光光度计检测花生红衣提取物中白藜芦醇的新方法,探讨了白藜芦醇荧光光谱检测的最佳条件,其激发波长和发射波长分别是324.06nm和400.00nm。白藜芦醇产生的荧光强度与浓度在0～1.68×10-5mol/L的范围内具有良好的线性关系,检测限为8.14×10-10mol/L。     

分子荧光法快速定量测定干红葡萄酒中白藜芦醇的含量

建立了一种利用荧光分光光度计检测干红葡萄酒中白藜芦醇的新方法,探讨了白藜芦醇荧光光谱检测的最佳条件,其激发波长和发射波长分别是346.00nm和384.00nm。白藜芦醇产生的荧光强度与浓度在0～1.68×10-5mol/L的范围内具有良好的线性关系,检测限为8.14×10-10mol/L。     

流动注射-化学发光法测定双氧水的分解率

在铁氰化钾-亚铁氰化钾存在的氢氧化钠碱性介质中,双氧水可氧化鲁米诺产生化学发光,结合流动注射技术,建立了一种测定双氧水漂白过程中双氧水分解率的新方法.该方法测定双氧水的检出限为1.75×10~(-5)mol/L,线性范围为2.1×10~(-5)～1.7×10~(-2)mol/L.相对标准偏差为2.9％(5.8×10~(-3)mol/L,n=11).     

HPLC法测定乳制品中的苯甲酸和山梨酸含量

建立了高效液相色谱法测定乳制品中的苯甲酸和山梨酸含量的方法。采用色谱柱为WatersC18,V流动相醋酸铵(0.02mol/L)∶V甲醇=65∶35,pH=3,流速为1mL/min,检测波长为230nm。结果表明,苯甲酸的最低检出量为1.5×10-9g;回收率为99.93%;CV(变异系数)为0.22%;山梨酸的最低检出量为1×10-9g;回收率为99.81%;CV(变异系数)为0.18%。     

CdTe为荧光探针测定罗汉参中的混合氨基酸

制备一种新型量子点CdTe,建立一种以CdTe为荧光探针测定罗汉参中混合氨基酸的方法。向荧光量子点CdTe溶液中加入Co2+后其荧光强度降低,降低的程度在一定范围内与Co2+浓度成线性关系;加入氨基酸后,荧光强度又得到恢复,而量子点荧光的恢复强度与加入氨基酸的浓度呈线性关系。在混合氨基酸标准溶液2.0×10-8~5.5×10-7mol/L线性范围内,量子点荧光的恢复强度与混合氨基酸浓度的线性方程为y=1.04×106x+1.013,相关系数R2=0.9995。考察了不同缓冲溶液、pH、Co2+浓度等因素对体系造成的影响。结果表明,在pH=9.5的硼砂缓冲溶液中,2.0×10-5mol/L的Co2+能很好的猝灭CdTe荧光。应用于实际样品测定的相对标准偏差(n=5)为3.0%,加标回收率在98.3%~104.4%范围内,检出限为1.1×10-8mol/L。该方法简单、快速,实用性强。     

毛细管电泳-电化学检测测定荞麦中表儿茶素、芦丁、槲皮素的含量

用毛细管电泳-电化学检测的方法研究了荞麦中黄酮类物质:表儿茶素、芦丁、槲皮素的含量,研究了电极电位、缓冲液的pH值、分离电压及进样时间对电泳的影响,得到优化的测定条件。以直径为300μm的碳圆盘电极为检测电极,工作电极电位为0.95V(vs.SCE),在50mmol/L硼砂(pH8.5)运行缓冲液中,上述3组分在12min内完全分离。表儿茶素、芦丁、槲皮素线性范围分别为5×10-7￣1×10-4g/mL、1×10-6￣1×10-4g/mL、1×10-6￣1×10-4g/mL;检出限分别为1.83×10-7g/mL、2.9×10-8g/mL、1.00×10-7g/mL;3种标样7次平行进样的相对标准偏差(RSD)小于2.5%;回收率表儿茶素100.4%、芦丁98.1%、槲皮素100.1%(n=3)。该法灵敏可靠,结果令人满意。     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.