红肉中血红素的肠道致癌作用机理与预防措施的研究进展

血红素是一种铁卟啉化合物,其分子结构为一个大型疏水性四聚吡咯环连接两个垂直于卟啉环的丙酸侧链。近年来许多研究发现血红素是红肉及其加工制品诱发肠道癌症的一个重要因素,本文对其诱发结直肠癌的作用机理进行综述,即它可以诱导细胞毒性,催化脂质过氧化以及亚硝基化合物的形成,并导致肠道菌群紊乱,从而诱发肠道炎症和癌变。后续列出部分预防措施,如适量摄入钙、叶绿素、亚硝酸盐替代剂、抗氧化剂、益生元等能够缓解血红素的致癌作用。     

摄入过量血红素铁易导致心脏病

以前曾有多项研究认定,食用过多红肉会增加患心脏病的风险。最近一项新的研究对这一结论给出了更明确的解释,红肉之所以会增加患心脏病的风险,是与红肉中的血红素铁有关。因为摄入过量的血红素铁,会导致致命的冠状动脉硬化。     

Fur过表达对大肠杆菌血红素合成的影响

为了阐明铁摄取调节子基因fur对大肠杆菌血红素合成的影响,对fur基因进行了同源过表达,考察了菌体生长、铁离子浓度及血红素合成变化,并分析了血红素合成途径关键基因的表达水平。结果表明,原始菌株在限铁条件下的血红素量比在非限铁条件下的血红素量下降2.54倍;fur过表达对菌体的生长有抑制作用,胞内的铁离子减少;非限铁条件下,过表达菌株Eco/pEF的血红素量比原始菌株下降了3.55倍;而过表达菌株Eco/pEF在限铁条件下的血红素量比在非限铁条件下的血红素量增加3.10倍。fur过表达引起hemA下调,而gltX、hemB、hemC分别上调4.93倍、4.61倍和9.39倍;菌株Eco/pEF在限铁条件下hemB与hemG分别上调了5.59倍和4.49倍。虽然fur过表达使血红素合成途径基因表达水平上调,但并未导致血红素大量合成。该结果为通过铁离子摄取调控胞内血红素的水平提供了新的理论支持。     

红肉与加工肉制品致癌风险及风险评估研究进展

红肉及加工肉制品的致癌之说成为世界性的热点话题。本文介绍了近年来许多研究者关于红肉及加工肉制品与结/直肠癌、乳腺癌、前列腺癌、胃癌、肝癌等的相关性研究调查结果,发现存在不一致的结论。揭示了用于评价红肉及加工肉制品的健康危险度衡量法的不足之处,总结并介绍红肉及加工肉制品中N-羟乙酰神经氨酸、4-羟基-2-壬烯醛、杂环胺、多环芳烃和血红素铁等需要注意的风险物质,指导人们理性看待国际癌症研究机构关于红肉及加工肉制品发出的致癌警告,平衡膳食,取其利而避其害。     

过量摄取植物中的铁元素易患帕金森氏症

意大利研究人员在最新出版的《美国流行病学杂志》上报告说,通过食用植物类食物摄入过多铁元素的人更易患帕金森氏症。 意大利巴里大学研究人员对47406名男性和79947名女性进行了长达16年的跟踪研究,发现通过食用植物类食物摄入较多非血红素铁（专指植物中的铁元素,非肉类中的铁元素）的人患帕金森氏症的风险大大高于摄入非血红素铁量低的人。     

过量摄入红肉及加工肉类对人体致癌风险的研究进展

世界癌症研究基金会(International Agency for Research on Cancer,IARC)报告指出,过多摄入红肉会增加患癌症的风险,但是否有足够令人信服的证据证明呢?本文对近年来有关红肉摄入对人类患肺癌、前列腺癌、乳腺癌、结/直肠癌、膀胱癌、食道癌和胃癌的风险等国外文章进行综述。研究表明,没有人体量-效关系实验等证据证明癌症与食用红肉和加工肉有直接关系,但大量摄入红肉、高温及炸制红肉,患某些癌症的风险会相对增加,还伴随着其他致癌因素,如吸烟、酗酒、癌症家族史、遗传变异等。此结果是否适应我国人群,尚有待进一步研究确证。预防癌症的有效途径为降低或控制红肉过量摄入,采用科学的烹饪和加工方法,戒烟及少饮酒,多摄入新鲜蔬菜、水果等平衡膳食。     

基于转录组学技术探究新琼四糖对过度疲劳性肠道损伤的保护作用

目的:运用转录组学探究新琼四糖对过度疲劳性肠道损伤的保护作用。方法:雄性BALB/c小鼠被随机分为正常组、力竭运动组、阳性对照低聚果糖组和新琼四糖干预组,连续喂养16 d后,取小鼠结肠组织,应用RNA-seq技术对结肠组织RNA进行完全测序,并对测序结果进行分析。结果:过度疲劳引起小鼠结肠肿瘤标志物Zfp521和Zmynd8等锌指蛋白表达量极显著增加(P0.01)、抑癌因子Casz1、Zfp346等的表达显著降低(P0.05),新琼四糖可缓解过度疲劳造成的肠道损伤,下调肿瘤相关锌指蛋白的表达,上调抑癌锌指蛋白的表达。结论:新琼四糖可保护肠道、缓解过度疲劳引发的肠道损伤、预防肿瘤的发生。     

血红素氧合酶-1介导海参蛋白肽对脂多糖诱导RAW264.7巨噬细胞炎症反应的抑制作用

为研究海参蛋白肽对脂多糖(LPS)诱导小鼠RAW264.7巨噬细胞炎症反应的抑制作用及作用机制,本研究利用LPS刺激RAW264.7巨噬细胞建立炎症模型,采用Griess法测定细胞一氧化氮(NO)含量,实时荧光定量PCR测定细胞内诱导型一氧化氮合酶(i NOS)、肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)、白介素-6(IL-6)以及血红素氧合酶-1(HO-1)m RNA表达。结果表明,海参蛋白肽以浓度依赖效应显著抑制LPS诱导RAW264.7巨噬细胞NO生成以及TNF-α、IL-1β、IL-6和i NOS m RNA表达(p0.05),显著提高细胞内HO-1 m RNA表达(p0.05)。HO-1抑制剂锌原卟啉Ⅸ(Zn PP-Ⅸ)部分逆转海参蛋白肽对LPS诱导RAW264.7巨噬细胞炎症反应的抑制作用。具有抗炎活性的海参蛋白肽富含甘氨酸、谷氨酸和天冬氨酸,分子量180~1000 u的组分为72.12%。这些结果说明海参蛋白肽通过上调细胞HO-1 m RNA表达发挥抑制LPS诱导RAW264.7巨噬细胞炎症反应的作用。     

小麦麸皮阿拉伯木聚糖的免疫调节作用

该研究以小麦麸皮阿拉伯木聚糖（AX）为研究对象,探讨其对小鼠腹腔巨噬细胞的免疫调节作用及机制。用不同浓度的AX处理小鼠腹腔巨噬细胞,检测AX对小鼠腹腔巨噬细胞活力及NO释放量的影响,用AX处理小鼠腹腔巨噬细胞0、1、3、6 h,检测AX对小鼠腹腔巨噬免疫关联基因及MAPK、Akt通路相关蛋白表达的影响。结果显示6.25和12.5 μg/mL的AX对小鼠腹腔巨噬细胞没有显著毒性,细胞的存活率分别为90.42%和89.99%（p>0.05）。当浓度高于12.5 μg/mL时,细胞存活率显著降低（p<0.05）;与对照组相比,AX（6.25~200 μg/mL）能显著增加小鼠腹腔巨噬细胞NO的释放量（p<0.05）;同时可以促进免疫关联基因（1L-1β、IL-6、TNF-α、iNOS、COX-2、Nfkbia）mRNA的表达,进一步研究发现AX可以增加MAPK和Akt信号通路蛋白（ERK1/2、JNK、p38 MAPK、Akt）的磷酸化水平。上述研究结果表明,AX可以通过活化小鼠腹腔巨噬细胞,增加NO的产生,促进免疫关联基因mRNA的表达,激活MAPK和Akt信号通路,来调节免疫。     

红肉及加工肉制品与结直肠癌风险关系的研究进展

近年来我国结直肠癌的发病率和死亡率逐年上升。据研究,结直肠癌发生率的升高可能与红肉及加工肉制品消费的增长具有一定相关性,但该关联性一直存在争议。为此,本文分析了现阶段研究红肉及加工肉制品与结直肠癌相关性的方法及其局限性,并综述了与红肉及加工肉制品相关的潜在结直肠癌致病因素,为确定结直肠癌及其他癌症与红肉及加工肉制品之间的关系提供了新的思路。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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