赖氨酸/葡萄糖美拉德反应产物对丙烯酰胺生成的抑制作用

建立天冬酰胺/葡萄糖模式反应体系,运用高效液相色谱法、自由基清除法等手段研究赖氨酸/葡萄糖美拉德反应产物对该模式体系中丙烯酰胺生成量及体系抗氧化性的影响。结果显示:高、低分子量的赖氨酸/葡萄糖美拉德反应产物(H-LGP和L-LGP)均能显著降低模式反应体系中的丙烯酰胺生成量,其中H-LGP和L-LGP的添加量为10 mg/mL时,对丙烯酰胺生成的抑制率最大,分别为32.0%和31.4%。H-LGP和L-LGP(均为10mg/mL)的添加还可显著提高反应体系清除自由基DPPH和ABTS的能力。结论:赖氨酸/葡萄糖美拉德反应产物(LGP)能够显著抑制天冬酰胺/葡萄糖模式反应体系中丙烯酰胺的生成,且高浓度的LGP能够显著提高反应体系的抗氧化性。     

Asn/Glc模拟体系中丙烯酰胺形成规律的研究

美拉德反应目前被认为是形成丙烯酰胺的重要途径。本文对葡萄糖和天冬酰胺模拟体系中丙烯酰胺的形成规律进行研究。结果表明,反应温度和时间对丙烯酰胺的产生量具有很大的影响,即随着温度和时间的增加,丙烯酰胺的产生量也相应增加;研究还发现,丙烯酰胺与天冬酰胺、吸光度之间呈线性关系,与葡萄糖、果糖也呈一定的相关性。     

抗氧化剂对美拉德反应产物中荧光物质的影响

采用葡萄糖分别与天冬酰胺和甘氨酸在160℃下反应建立美拉德反应的模拟体系,通过在激发波长419nm,发射波长507nm测定荧光强度,探讨了4种抗氧化剂BHA、BHT、TBHQ、Vc对美拉德反应产物中荧光物质的影响。结果表明,添加4种抗氧化剂后MRPs的荧光物质强度都有所增加,并且甘氨酸-葡萄糖体系的荧光强度大于天冬酰胺-葡萄糖体系。添加不同浓度的抗氧化剂会影响其荧光强度,影响其荧光物质的含量。     

土耳其科学家研究多酚类成分对美拉德模型中呋喃及丙烯酰胺形成的影响

据sciencedirect数据库消息,2013年8月土耳其研究人员在《食品化学》（Food Chemistry）杂志刊登一项多酚成分对美拉德模型中呋喃、丙烯酰胺形成的影响及储藏过程中总呋喃含量影响的研究。本研究采用葡萄糖-甘氨酸及果糖-天冬酰胺体系作为美拉德反应模型,分别研究咖啡酸、绿原酸、ECE（欧洲蔓越莓多酚提取物）、鞣花酸、表儿茶酸、橄榄苦苷、PPE（石榴皮多酚提取物）、OMWWE（橄榄多酚提取物）、安石榴苷、对羟苯基乙醇对美拉德模型及饼干焙烤过程中呋喃、丙烯酰胺形成影响。     

葡萄糖/天冬酰胺模拟体系中丙烯酰胺的产生及其机理研究

油炸食品中丙烯酰胺的发现引起了科学家们的广泛重视。美拉德反应是形成丙烯酰胺的重要途径。为了进一步证实其形成机理,进行了葡萄糖和天冬酰胺模拟体系的研究。采用高效液相色谱-紫外检测器分析模拟体系中的丙烯酰胺,结果表明:不同的加热温度和加热时间对丙烯酰胺的产生量影响显著,且随着反应温度的升高和反应时间的延长,整个反应体系的颜色逐渐加深,丙烯酰胺的产生量也逐渐增多。     

阿魏酸与咖啡酸对丙烯酰胺形成及消减的影响

探讨阿魏酸与咖啡酸在美拉德模拟体系中对丙烯酰胺形成和消减的影响。结果表明:在天冬酰胺/葡萄糖模拟反应体系中,阿魏酸与咖啡酸的添加量为250 mmol/L和25mmol/L时可抑制丙烯酰胺的形成,而二者浓度低于2.5mmol/L时则促进丙烯酰胺的形成。将阿魏酸与咖啡酸分别与丙烯酰胺单独高温处理,发现2种酚酸对丙烯酰胺都具有消减效果,但效果不明显,因此判定阿魏酸与咖啡酸对美拉德模拟体系中丙烯酰胺含量的影响主要作用于丙烯酰胺的形成阶段。另外,酸性条件下,醌型酚酸比酚型酚酸对丙烯酰胺的消减作用更大,而在中性条件下,酚型酚酸的消减作用更强。     

抗氧化剂对美拉德反应的影响

采用葡萄糖分别与天冬酰胺和甘氨酸在160℃下反应建立美拉德反应的模拟体系,通过HPLC分析和褐变程度的测定,探讨了4种抗氧化剂BHA、BHT、TBHQ、Vc对美拉德反应的影响。结果表明,添加抗氧化剂对其HPLC色谱峰的出峰数、峰面积都有较大影响。相同条件下,添加抗氧化剂对甘氨酸-葡萄糖体系影响较大。     

牛磺酸对富含淀粉食品中丙烯酰胺的抑制作用

运用天冬酰胺/葡萄糖模式反应体系研究了牛磺酸对富含淀粉的食品中丙烯酰胺生成的影响及其抑制机理。试验结果显示:牛磺酸能够显著抑制天冬酰胺/葡萄糖反应体系中丙烯酰胺的生成,且抑制率与浓度呈剂量关系。运用LC-QTOF分析得到2种主要的反应产物:丙烯酰胺-牛磺酸加合物和丙烯酰胺二聚体-牛磺酸加合物。此外,牛磺酸与葡萄糖共存于同一体系中加热时,葡萄糖的含量显著下降,说明牛磺酸可与葡萄糖发生反应。通过模式反应体系证明:牛磺酸能够显著降低富含淀粉食品中的丙烯酰胺含量;抑制机理主要是牛磺酸与丙烯酰胺直接发生反应,反应产物为丙烯酰胺-牛磺酸加合物和丙烯酰胺二聚体-牛磺酸加合物,从而除去体系中已经生成的丙烯酰胺。此外,牛磺酸能够与葡萄糖发生美拉德反应,从而与天冬酰胺竞争消耗体系中的葡萄糖,减少了食品中的丙烯酰胺含量。     

Glu-Asn食品模拟体系中丙烯酰胺的形成规律

以葡萄糖和天冬酰胺为主要反应物,建立美拉德模拟体系,研究不同的反应条件和不同种类的糖对模拟体系中丙烯酰胺生成的作用规律。结果表明:温度是丙烯酰胺形成的重要因素。在120~180℃条件下丙烯酰胺含量与温度呈正相关的趋势,200℃时丙烯酰胺含量呈先上升后下降的趋势;模拟体系的初始p H值小于8时,丙烯酰胺含量随p H值升高而增加,当p H=8时其达到最大值,继续升高p H值,丙烯酰胺含量开始下降,说明高p H值条件不利于丙烯酰胺的生成;Glc/Asn物质的量比接近1∶1时反应生成的丙烯酰胺最多,且天冬酰胺过量引起的影响要小于葡萄糖过量引起的影响;半乳糖、果糖和蔗糖对丙烯酰胺的生成起促进作用,甘露醇、赤藓糖醇、山梨醇、β-环糊精对丙烯酰胺的抑制作用较为明显,前三者均有各自的最佳抑制浓度。丙烯酰胺抑制率与β-环糊精加入量呈正相关趋势。β-葡聚糖的浓度对丙烯酰胺最终形成几乎没有影响。     

脉冲电场强化天冬酰胺- 果糖体系的研究

应用脉冲电场强化天冬酰胺- 果糖模式美拉德反应,对反应后天冬酰胺- 果糖模式美拉德反应体系的pH 值、紫外特征吸收(A294nm)、褐变程度(A420nm)、反应过程中天冬酰胺和果糖含量以及抗氧化活性进行分析,同时采用高效液相色谱(HPLC)检测产物中丙烯酰胺和5- 羟甲基糠醛(HMF)的含量。结果表明：脉冲电场能显著促进天冬酰胺-果糖模式美拉德反应,体系褐变程度、抗氧化活性与反应时间及电场强度均呈正相关,反应产物中未发现丙烯酰胺和HMF。     

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