自组装多肽水凝胶对百里香精油的控释作用、抑菌和抗氧化效果的延长作用

为实现百里香精油的控制释放并延长其抑菌和抗氧化效果,本实验利用N-芴甲氧羰基-L-苯丙氨酸(N-FMoc-L-phenylalanine,Fmoc-F)水凝胶包埋百里香精油,对比包埋前后Fmoc-F水凝胶的结构、形态等特征,研究其对百里香精油的包埋机制、控释作用及包埋后Fmoc-F对百里香精油抑菌和抗氧化效果的延长作用。结果表明:百里香精油的加入可以加速Fmoc-F/百里香精油水凝胶(50 s)的形成,并且显著提高胶体的储能模量;Fmoc-F及Fmoc-F/百里香精油水凝胶主要通过氢键作用形成胶体,其微观结构为纤维状网络结构,且百里香精油可以使Fmoc-F水凝胶的网络结构更紧密均匀,从而提高其胶体的储能模量。Fmoc-F水凝胶对百里香精油的包埋率达93.13%。通过抑菌实验和抗氧化实验发现,在环境p H≥6.5时,Fmoc-F水凝胶可通过包埋有效抑制百里香精油的挥发,而随着环境p H值的降低,Fmoc-F水凝胶会缓慢分解,释放百里香精油,起到对百里香精油抑菌和抗氧化效果的延长作用。     

丁香精油—壳聚糖纳米胶囊的制备及表征

为提高丁香精油在生产加工过程中的稳定性,降低其对食品感官品质的不良影响,采用离子凝胶法,以壳聚糖为壁材制备丁香精油—壳聚糖纳米胶囊,研究制备条件对纳米胶囊包埋率及粒径的影响并优化工艺,采用多种方法对所制备纳米胶囊的性能进行检测分析。结果表明:在最优制备条件下,即壳聚糖溶液pH值4.5、丁香精油与壳聚糖质量比0.81.0、壳聚糖与三聚磷酸钠质量比51,所制备纳米胶囊包埋率为40.2%,平均粒径为175nm。利用纳米胶囊技术对丁香精油进行包埋可有效提高丁香精油在食品加工中的稳定性,扩大其在食品工业中的应用范围。     

丁香精油微胶囊工艺优化及其对冰温猪肉保鲜效果的影响

为克服丁香精油在保鲜应用中易挥发、难溶于水的缺点,采用复凝聚法制备丁香精油微胶囊,以包埋率为评价指标,采用Box-Behnken中心组合试验和响应面分析法优化包埋工艺,并将丁香精油微胶囊应用于冰温猪肉的保鲜。结果表明,所得回归模型具有高度显著性(p<0.0001),方程对试验拟合较好,在CaCl₂浓度12 g/L,壁芯比7:1 (m/m),复合壁材比(海藻酸钠-壳聚糖)0.8:1 (m/m),包埋时间47 min的条件下,制得的丁香精油微胶囊包埋率最高为84.20%,与预测包埋率相对误差小于5%;用该条件制备的丁香精油微胶囊处理冷却猪肉,冰温下对照组猪肉可保鲜9 d,空芯组可保鲜21 d,精油组可保鲜27 d,表明丁香精油微胶囊可显著延长冰温猪肉的保鲜期(p<0.05)。     

自组装多肽水凝胶包埋大蒜精油的控释研究

研究Fmoc–F自组装多肽水凝胶对大蒜精油的包埋作用、控释特性和稳定作用。结果表明:该水凝胶对大蒜精油的包埋率可达到97.07%;当p H≥6.5时,包埋大蒜精油后的水凝胶结构分解率不高于12.17%,可提高大蒜精油的稳定性;当5p H6.5时,凝胶结构部分分解;当p H≤5.0时,凝胶结构迅速分解,快速释放大蒜精油抑制大肠杆菌的生长;感官评价表明Fmoc–F水凝胶可显著掩盖大蒜精油的不良气味。     

不同壁材丁香精油微胶囊保鲜剂性能研究

采用饱和水溶液法,以β-环糊精和壳聚糖为壁材,丁香精油为芯材与壁芯比为4∶1制备3种丁香精油微胶囊保鲜剂,并对三种组合壁材微胶囊保鲜剂的表面形态、光照稳定性、包埋率、缓释效果以及抑菌效果进行测定,结果表明β-环糊精丁香精油微胶囊的包埋率最高,为67%;β-环糊精-壳聚糖丁香精油微胶囊1的光照稳定性最好,丁香精油损失率仅为32.67%;β-环糊精-壳聚糖丁香精油微胶囊1的缓释效果最好;β-环糊精-壳聚糖丁香精油微胶囊1的抑菌圈直径最大(38.5±0.40 mm)。综合考量得β-环糊精-壳聚糖1为壁材制得的丁香精油微胶囊性能最好。     

燕麦蛋白-结冷胶冷诱导凝胶微观结构与控释特性的关联性研究

热变性后的燕麦蛋白(oat protein isolate,OPI)与结冷胶(gellan gum,GG)通过添加不同浓度的葡糖酸-δ-内酯(glucono-delta-lactone,GDL)形成OPI-GG冷诱导凝胶,通过质构分析、扫描电子显微镜、激光共聚焦显微镜以及傅里叶红外光谱,研究不同条件下形成的凝胶微结构以及分子构象的变化,探究不同凝胶微结构与凝胶控释特性的关联性。结果表明,在GG添加量为0.1%、pH 5时,凝胶硬度最大,随着GG浓度升高,凝胶硬度逐渐变弱。通过扫描电镜和激光共聚焦的观察可知OPI-GG凝胶可形成两种网络微结构,在pH 4和pH 5时,OPI与GG之间由于静电引力使其相互作用力增强,形成致密且均匀的单网络微结构;在pH 6和pH 7时,OPI与GG由于静电斥力的作用产生相分离,从而形成双网络结构。具有不同微结构的OPI-GG凝胶可作为基质包埋核黄素,双网络结构的凝胶可有效提高核黄素的包埋率(75%),其在pH 1.2磷酸缓冲溶液(phosphate buffer saline,PBS)中浸泡2 h后核黄素的释放率为33%;致密的单网络结构OPI-GG凝胶包埋率为61%,在pH1.2 PBS中可有效阻止核黄素的释放,其释放率为18%,并在pH 7.4 PBS中使核黄素逐步释放,8 h后释放率为53%。该研究结果表明,在中性条件下制备的OPI-GG双网络结构冷凝胶具有较好的核黄素包埋能力,在酸性条件下制备的OPI-GG单网络冷凝胶具有较好的控释能力,因此,不同微结构的OPI-GG冷凝胶具有作为营养素包埋和递送体系的潜力。     

丁香精油抑菌及抗氧化作用研究

利用超临界CO2萃取法从丁香中提取精油,研究测定了丁香精油对各种供试菌种的抑菌圈直径,加热处理及pH对丁香精油抑菌效果的影响,同时研究了丁香精油的抗氧化效果。结果表明:丁香精油对各供试菌种的抑菌圈直径在18.0～38.2mm之间,表明丁香精油对G+和G-细菌、霉菌和酵母均有很强的抑制作用;丁香精油的抑菌效果随pH的降低而增强;121℃/15min加热处理对丁香精油的抑菌效果无明显影响;丁香精油还具有一定的抗氧化性能。     

微波法和水蒸气蒸馏法提取丁香精油的研究

以丁香为原料,分别采用微波法和水蒸气蒸馏法提取精油,探讨微波萃取对丁香精油提取率和精油品质的影响。以丁香精油提取率为指标,通过正交试验优化微波提取条件,采用气相色谱-质谱(GC-MS)法鉴定其化学成分,并与水蒸气蒸馏法提取的精油进行比较。结果表明,微波萃取丁香精油的最佳工艺参数为微波功率300 W、料液比1∶4(m∶V)、微波时间25s、提取次数4,该条件下精油的提取率可达到20.65%,远远高于水蒸气蒸馏法的11.33%;从该精油中鉴定出19种成分,其中3种丁香精油有效成分的得率分别为丁香酚13.2%、石竹烯4.4%、乙酰基丁香酚2.2%,石竹烯和乙酰基丁香酚得率分别是水蒸气蒸馏精油的2.8倍和2倍。微波萃取是丁香精油较有效的提取方式。     

丁香精油抑菌及抗氧化作用研究

利用超临界CO2萃取法从丁香中提取精油,研究测定了丁香精油对各种供试菌种的抑菌圈直径,加热处理及pH对丁香精油抑菌效果的影响,同时研究了丁香精油的抗氧化效果。结果表明:丁香精油对各供试菌种的抑菌圈直径在18.0～38.2mm之间,表明丁香精油对G+和G-细菌、霉菌和酵母均有很强的抑制作用;丁香精油的抑菌效果随pH的降低而增强;121℃/15min加热处理对丁香精油的抑菌效果无明显影响;丁香精油还具有一定的抗氧化性能。      

反向凝胶法制备孜然精油微胶囊的工艺优化及其释放

运用了反向凝胶法,以海藻酸盐为壁材,孜然精油为芯材制备孜然精油微胶囊,研究反向凝胶法制备孜然精油微胶囊对孜然精油的包埋效果以及孜然精油微胶囊释放效果。结果表明:运用反向凝胶法制备的孜然精油微胶囊包埋率达到了85.09%;微胶囊具有相对圆整的外貌特征,约76%的孜然精油微胶囊粒径分布在500～800μm之间,呈正态分布;通过控制吐温80添加,可以有效控制孜然精油微胶囊的膜厚度,从而间接控制微胶囊的缓慢释放。     

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