采用美拉德反应提高黄鲫蛋白抗菌肽的抑菌活性

以黄鲫蛋白抗菌肽(HAHp)为底物,通过美拉德反应提高其抑菌活性.以大肠杆菌为指示菌,在100℃水浴加热条件下,比较 HAHp-葡萄糖、HAHp-蔗糖、HAHp-麦芽糖和 HAHp-乳糖的美拉德反应物抑菌活性;选用葡萄糖为添加糖,测定 HAHp-葡萄糖美拉德反应初始 pH 值、加糖量、加热温度和加热时间对美拉德反应物的抑菌活性影响.结果表明:提高反应初始 pH 值(大于 pH6.0)会降低 HAHp 美拉德产物的抑菌活性,选择葡萄糖适宜加入量,控制加热温度和时间可以提高 HAHp-葡萄糖美拉德反应物对大肠杆菌的抑菌活性     

热处理对牛乳美拉德反应程度及挥发性成分的影响

以原料乳及不同热处理程度的15 种牛乳样品为研究对象，通过分析典型美拉德产物糠氨酸和5-羟甲基糠醛的含量以反映不同热处理牛乳的美拉德反应程度，同时采用顶空固相微萃取-气相色谱-质谱（headspace solid-phase microextraction-gas chromatography-mass spectrometry，SPME-GC-MS）和电子鼻解析不同热处理的牛乳中挥发性成分的变化规律。结果表明：热处理程度越大，美拉德反应越剧烈，美拉德产物糠氨酸和5-羟甲基糠醛的含量在热处理温度高于120 ℃或热处理时间高于15 s时急剧增加。电子鼻通过主成分分析可知，热处理时间相同时，不同热处理温度的牛乳样品间气味差异显著。SPME-GC-MS结果表明：120 ℃/5 s和120 ℃/15 s热处理的牛乳风味相近，且热处理强度越大，风味物质种类增加越多，其中醛类、酮类和酯类相对含量增加明显，部分酸类相对含量明显减少。本实验明确不同热处理方式对牛乳美拉德反应程度及其对牛乳风味的影响，具实际生产指导意义。     

美拉德反应中间体对卷烟评吸品质的影响及其风味受控形成研究

完全美拉德反应产物(MRPs)是构成烟草特征香味的重要来源,但普遍存在易逸失、不稳定的问题。以果糖为原料,制备了6种Heyns重排产物(HRP)类美拉德反应中间体,通过卷烟感官评吸筛选发现,果糖和苯丙氨酸反应得到的中间体2-脱氧-2-L-苯丙氨酸-D-葡萄糖具有最理想的加香效果。比较了苯丙氨酸—果糖的完全美拉德反应产物溶液和相应中间体HRP溶液的后续热加工稳定性,随着热处理时间延长,完全美拉德反应产物的香气降低了74.7%,而中间体HRP溶液挥发性风味成分增加为未加热的12.1倍,具有加工风味受控形成的特点,从而很好地克服了完全美拉德反应产物在食品、烟草加工过程中的加香缺陷。     

黄鲫蛋白抗菌肽—葡萄糖美拉德反应物的抑菌性实验研究

利用响应面分析法优化黄鲫蛋白抗菌肽-葡萄糖美拉德反应条件,提高产物的抑菌活性。以大肠杆菌为指示菌,在黄鲫蛋白抗菌肽初始反应pH为5.58条件下,进行葡萄糖添加量、加热温度和加热时间三因素三水平Box-Benhnken响应面分析实验,得出黄鲫蛋白抗菌肽-葡萄糖美拉德反应最优条件为葡萄糖添加量0.25%(w/v)、加热温度100℃、加热时间60 min。在最优反应条件下,黄鲫蛋白抗菌肽-葡萄糖美拉德反应物对大肠杆菌的抑菌圈直径为28.9 mm,与理论值28.4 mm接近。     

影响褐色益生菌乳饮料颜色的因素

美拉德反应是褐色乳饮料独特风味物质的主要来源。试验中使用色度仪测量产品黄蓝值,比较黄褐色产物的量,进而判断比较美拉德反应程度。通过单因素试验与正交试验分析了热处理时间、果葡糖浆添加量、无乳糖乳粉添加量对美拉德反应的影响,确定了形成乳饮料良好色泽风味的美拉德反应的优化条件为:热处理时间90min,果葡糖浆添加量9%,无乳糖脱脂乳粉添加量2%。     

利用美拉德反应生产天然肉味香料及其风味成分分析

通过模拟美拉德反应体系,研究了氨基酸添加量、葡萄糖添加量、pH、反应温度以及反应时间对美拉德反应产物风味的影响,确定最佳配方及反应条件为L-胱氨酸和L-半胱氨酸添加量为1%、葡萄糖添加量3%、pH6.5、反应温度为110℃、反应时间1.5h。在确定的最佳配方及反应条件下制取肉味香精,并检测产物风味成分,美拉德反应产物主要为醇类、酯类、酮类、醛类、羧酸类、杂环类等化合物,其中杂环类化合物以吡咯类、噻吩类、呋喃类、吲哚类等为主。     

HPLC法检测分析温度对中药口服液品质的影响

运用高效液相色谱法（HPLC）比较分析了正常、异常中药（TCM）口服液中美拉德反应产物组成及其对中药口服液质量的影响。结果表明,异常样品的还原糖、蛋白质含量、美拉德反应中间产物糠氨酸、糠醛、5-羟甲基糠醛和丙烯酰胺以及氨基酸含量如赖氨酸、甘氨酸、亮氨酸等均比正常样品偏高。采用不同温度处理提取的类黑素的黑化程度随加热温度的升高而增强。美拉德反应程度随样品烘干温度的升高而增加,高温处理不利于中药口服液样品的安全性。     

热处理对牛骨酶解液美拉德反应产物呈味物质及挥发性成分的影响

探讨不同热处理条件(温度110,115,120,125,130 ℃和时间25,40,55,70,85 min)对牛骨酶解液美拉德反应产物(EBBH-MRP)呈味特性及挥发性风味成分的影响。结果表明:热处理温度低于130 ℃时,总游离氨基酸含量降低,这与鲜味氨基酸和苦味氨基酸变化趋势一致。风味核苷酸含量随温度上升呈增加趋势。在不同温度下,共检测到63种挥发性风味物质,包括醛类、酮类、醇类、酸类和杂环类化合物。当热处理时间超过40 min时,总游离氨基酸含量不断增加,风味核苷酸含量也缓慢增加。随着热处理时间的延长,挥发性风味物质种类减少,共检测到54种。醛类、酮类含量随时间的延长而明显增加,至70 min,其含量保持相对稳定。结论:适当的热处理条件可以提升EBBH-MRP的呈味及风味特性。     

加热对美拉德反应产物主要成分及其抗氧化活性的影响

通过高压反应釜模拟烘焙产品中的酪蛋白与葡萄糖之间的美拉德反应,探究温度和时间对美拉德反应产物及其抗氧化活性的影响。结果表明：温度是影响美拉德反应产物及其抗氧化活性的重要因素,而时间影响较小。高温有利于生成更多的无色中间产物和类黑精产物,增加葡萄糖与蛋白质的消耗量,促进美拉德反应的进行,提高美拉德反应产物的抗氧化活性。但高温提高了5-羟甲基糠醛(5-HMF)含量。     

复合酶解及美拉德反应制备鱿鱼调味品

目的以阿根廷鱿鱼为研究对象,采用酶解法结合美拉德反应制备海鲜调味剂。方法以感官评定为主要指标,确定风味蛋白酶、中性蛋白酶、木瓜蛋白酶3种蛋白酶的用量。通过正交试验确定3种酶的最佳质量配比,并将复配酶作为接下来的实验用酶。在单因素试验的基础上进行正交试验优化酶解工艺。美拉德反应以质量配比1:1:1的D-木糖、D-葡萄糖、蔗糖作为实验用糖。通过单因素试验探讨不同pH、反应温度、反应时间和加糖量对美拉德反应产物的感官评定的影响。结果最佳酶解工艺条件为:pH 6.8,酶解温度50℃,底物浓度15%,加酶量0.30%,酶解时间4 h。美拉德反应最佳反应条件为:pH 8.0、反应温度110℃、反应时间60 min、加糖量1.0%。将最佳反应条件下的美拉德反应产物在4500 r/min,20 min条件下离心取上清液后,浓缩为原体积的25%,最后进行冷冻干燥得到浅棕色的具有鱿鱼特征香味的海鲜调味品。结论利用复合酶和美拉德反应制备鱿鱼调味品具有广阔的应用前景,有利于充分发掘鱿鱼的利用价值,拓宽消费者选择空间,丰富调味品市场。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press