基于近红外光谱和随机森林方法鉴别蜂蜜真伪

目的建立蜂蜜样品真伪鉴别的近红外光谱快速检测方法,为今后蜂蜜检验工作提供可靠参考依据。方法采用积分球透反射模式采集样品近红外光谱数据,以Savitzky-Golay 1阶微分方法对原始光谱进行预处理,以随机森林方法建立光谱数据与蜂蜜真伪的定性判别模型。结果所建立的判别模型中训练样本判别正确率为100%,测试样本判别正确率为95%。结论近红外透反射光谱技术应用于蜂蜜真伪鉴别的可行性,同其他分析方法相比具有操作简单、速度快、效率高、无污染、费用低、无需复杂前处理等优点。     

麦卢卡蜂蜜特征标志物及其分析方法研究进展

麦卢卡蜂蜜是产自新西兰的医疗级蜂蜜,具有独特的非过氧化抗菌活性,抗菌活性与其特征标志物有密切联系。随着国外学者对麦卢卡蜂蜜中抗菌活性物质的深入研究,其中的抗菌活性物质被不断地发现和证实,目前已发现的麦卢卡蜂蜜的特征标志物包括甲基乙二醛、3,5-二甲氧基苯甲酸甲酯-4-双葡萄糖苷、3-苯基乳酸、2-甲氧基苯乙酮、2-甲氧基苯甲酸、4-羟苯基乳酸、Lepteridine等,这些化合物也已应用于麦卢卡蜂蜜的质量评价和真伪鉴别中。麦卢卡蜂蜜在我国进口蜂蜜中所占的比重越来越大,但国内对麦卢卡蜂蜜的研究起步较晚,本文针对与麦卢卡蜂蜜质量评价及真伪鉴别相关的特征标志物及其分析方法进行了综述,以期为麦卢卡蜂蜜的质量评价和真伪鉴别研究提供参考。     

近红外光谱技术定性鉴别蜂蜜品种及真伪的研究

提出了蜂蜜品种及真伪定性鉴别的新方法。在12000～4000cm-1范采集荆条蜜、槐花蜜、油菜蜜和掺假蜜的近红外光谱,结合一阶导、多元散射校正及变量标准化)三种方法对光谱进行预处理,以主成分分析结合马氏距离判别法,在不同谱区建立蜂蜜品种及真伪定性鉴别模型。研究发现6100～5700cm-1谱区为最佳建模波段,品种判别正确率达90%以上,真伪鉴别正确率为93.10%。     

近红外光谱技术在蜂蜜真实性鉴定中的应用

由于蜂蜜品种多,组分复杂,真假鉴定技术较难,用传统的分析技术评价蜂蜜质量具有一定的局限性.用具有快速稳定的近红外光谱技术鉴别蜂蜜真实性.对近红外光谱技术(IR)做了简要介绍,同时,详细阐述了该技术在蜂蜜成分、品种和产地来源、掺假鉴定中的应用.对该技术存在的缺陷及与其他技术联用前景进行了探讨,可为蜂蜜真伪鉴别提供新的方法和思路.     

蜂蜜的主要成分及其鉴别技术

蜂蜜是一种成分高度复杂的天然保健食品,富含很多对人体有益的营养物质,深受广大消费者青睐。蜂蜜成分易受蜜源种类、采蜜季节、贮藏时间等诸多因素影响。随着国内外消费者对蜂蜜需求的不断增大,蜂蜜质量问题频繁出现,如向蜂蜜中添加糖浆,以杂花蜜或劣质蜜充当优质的单花蜜等,严重影响蜂蜜市场的健康发展,如何科学检测蜂蜜品质是目前我国乃至国际蜂业发展中亟待解决的关键问题。本文针对蜂蜜中的主要化学成分,对现阶段国内外的蜂蜜真伪鉴别技术进行综述,以期为准确、快速鉴别蜂蜜真伪的研究和应用提供参考。     

利用聚丙烯酰胺凝胶电泳技术分析蜂蜜蛋白质行为

拟采用蛋白质电泳技术对蜂蜜的电泳行为进行分析,以探索蜂蜜蛋白质行为,为蜂蜜真伪鉴别开辟一条新途径,测定不同品种、不同产地的蜂蜜与掺假蜂蜜蛋白质含量以及SDS-PAGE电泳行为。结果表明：不同品种、不同产地的蜂蜜其蛋白质含量与电泳行为有明显的差异;掺假蜂蜜蛋白质含量明显低于真蜂蜜,但二者的SDS-PAGE谱图差别不大。     

蜂蜜常见的掺假类型及真伪鉴别方法的研究进展

本文简要介绍了蜂蜜中常见的掺假物质及掺假方式,主要对当前蜂蜜真伪鉴别的多种现代仪器方法研究进行了综述,并分析了各种方法的特点。并对今后蜂蜜掺假检测研究进行了展望,提出了建立标志物数据库、引入标准样品、多种检测技术联合使用等建议。     

基于HS-SPME-GC/MS指纹图谱及化学计量学的野坝子蜂蜜鉴别

为了实现野坝子蜂蜜的有效鉴别,收集了代表性产地大姚-滇中北部冷凉区、弥勒-滇中部半干旱区野坝子蜂蜜以及普通蜂蜜样品,采用HS-SPME-GC/MS分析,结合指纹图谱、主成分分析(PCA)、欧氏距离以及聚类分析等数据分析手段,均能实现对野坝子蜂蜜与普通蜂蜜的准确判别。同时,在指纹图谱所指认的15个共有峰基础上,筛选出反式氧化芳樟醇、顺式氧化芳樟醇、壬酸乙酯、脱氢芳樟醇和苯乙醇等5个峰峰面积构建了3个Fisher函数,能够快速有效地实现野坝子蜂蜜与普通蜂蜜的鉴别。此外,为了实现不同产地野坝子蜂蜜的识别及质量控制,对两个代表性野坝子蜂蜜产地野坝子蜂蜜成分,采用F检验进行分析,表明由于产地特征差异2个代表性产地野坝子蜂蜜成分差异明显,其中丁香醇C、间苯二甲醛、丁香醇D、月桂酸乙酯、α-异氟尔酮、苯甲酸乙酯、乙酸苯乙酯、异丁醇、2-甲基丁醇等9个成分可作为2个产地野坝子蜂蜜之间的主要差异成分。本研究为野坝子蜂蜜的真伪鉴别以及不同产地野坝子蜂蜜产地识别评价提供技术支持。     

不同花源蜂蜜蛋白质组分及提取方法的比较

比较中国不同花源蜂蜜蛋白质组分及提取方法的差异。以枣花蜜、荆条蜜、龙眼蜜、土蜂蜜、洋槐蜜和油菜蜜为研究对象,比较6种蜂蜜蛋白质电泳行为差异;采用超滤法和硫酸-钨酸钠沉淀法提取蜂蜜蛋白,分析2种蛋白质提取方法的适用性及分离效果。6种不同花源蜂蜜蛋白质相对分子质量集中在14. 4～97. 4 k Da,但蛋白质组成和含量在品种间差异明显,而枣花蜜、龙眼蜜和土蜂蜜在> 97. 4 k Da存在较多高分子质量蛋白;超滤法适合提取枣花蜜、荆条蜜、洋槐蜜和油菜蜜蛋白质,而龙眼蜜和土蜂蜜适合用硫酸-钨酸钠沉淀法分离,2种方法获得的6种蜂蜜蛋白在SDS-PAGE和RP-HPLC图谱中呈现明显的分子质量和疏水性差异。这为基于蛋白质差异构建蜂蜜花源鉴别技术奠定理论基础。     

利用非糖物质快速鉴别单花蜂蜜

本文利用非糖物质快速鉴别四种常见的单花蜂蜜(枸杞蜂蜜、荆条蜂蜜、枣花蜂蜜和洋槐蜂蜜)。利用固相萃取除糖提取蜂蜜非糖物质,并用高效液相色谱(HPLC)结合化学计量学进行蜂蜜花源的判定。发现了四种单花蜂蜜的非糖特征标志物。芦丁、丁香酸甲酯、阿魏酸的含量在四种蜂蜜中差异最大。对羟基苯甲酸和脱落酸在枸杞蜂蜜中平均含量分别为0.59μg/g和0.42μg/g,可作为枸杞蜂蜜的花源标志物;对香豆酸和肉桂酸在荆条蜂蜜中平均含量为0.08μg/g和0.05μg/g,可作为荆条蜂蜜的潜在花源标志物;阿魏酸、异阿魏酸是枣花蜂蜜的特征标志物,平均含量分别为0.40μg/g和0.76μg/g;洋槐蜂蜜的特征标志物是芦丁和丁香酸甲酯,平均含量为0.08μg/g和0.14μg/g。利用高效液相色谱指纹图谱结合化学计量学方法(主成分分析和判别分析),四种单花蜂蜜依据其花源被成功区分。本研究对蜂蜜真实性判定有重要参考价值,为后续蜂蜜真伪鉴别奠定基础。     

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.     

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

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）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

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.