鹧鸪茶提取物抑菌活性研究及其成分分析

为了研究鹧鸪茶提取物的抑菌活性及其物质基础,采用滤纸片法,以抑菌圈大小为评价指标,对鹧鸪茶提取物的抑菌性能进行测试,确定抑菌活性后,采用溶剂萃取法和离子沉淀法对鹧鸪茶提取物进行精制,并通过UV、GC、HPLC等方法分析鹧鸪茶提取物抑菌活性的物质基础。结果发现鹧鸪茶提取物对枯草芽孢杆菌、大肠杆菌、金黄色葡萄球菌和酵母菌的抑菌作用较为明显,对其物质成分进行分析发现,鹧鸪茶提取物与茶多酚对照品存在共有色谱峰,茶多酚可能为鹧鸪茶提取物抑菌活性的物质基础之一。     

海南不同地区鹧鸪茶挥发性成分HS-SPME-GC/MS分析与评价

探讨海南鹧鸪茶中挥发性成分的含量及组成,解析地区间存在差异的特征性标志化合物,为鹧鸪茶的产地追溯及风味品质提升提供理论支撑。以20个地区的鹧鸪茶为研究对象,采用顶空固相微萃取-气相色谱质谱联用法(headspace solid-phase microextraction/gas chromatography-mass spectrometer,HS-SPME/GC-MS)检测,结合主成分分析(principal component analysis,PCA)和系统聚类分析(hierarchical cluster analysis,HCA)对不同地区样品进行分类。结果表明:从20个地区鹧鸪茶中共鉴定出193种挥发性成分,主要以烯烃类化合物为主(62种),相对含量占54.87%～79.73%,其次为醛类(37种,1.61%～8.03%)、醇类(37种,1.30%～6.12%)、酮类(17种,0.38%～6.32%)碳氢类、酯类(12种,0.03%～0.43%)、酸类(8种,0.00%～0.70%)、呋喃类(7种,0.07%～1.29%)、酚类化合物(3种,0.00%～0.29%)等。PCA分析和聚类分析表明,除海南岛南部区域(分别是三亚、万宁、乐东、陵水、保亭)少数样品外,大部分样品在PCA的二维得分投影图上按特性各自聚为一类。表明鹧鸪茶中呈香物质丰富且多样,具有较高的研究价值,可为海南鹧鸪茶的鉴别与产地追溯提供理论参考。     

静享精致之美

手撕木姜野兔 原料:鲜活野兔1只鲜木姜末20克鲜花椒叶60克 白卤水1锅柠檬片、薄荷叶各少许 制法: 1.把野兔宰杀后去皮治净.白卤水烧开后,加入鲜花椒叶煮至出香味.     

速溶鹧鸪茶粉真空冷冻干燥工艺及品质分析

通过研究3种不同真空冷冻干燥工艺对速溶鹧鸪茶粉含水率、色泽、多酚含量、湿润性、分散性的影响,确定真空冷冻干燥工艺条件;以速溶普洱茶粉为辅料拼配,结合电子感官和人为感官评分筛选最佳配比,采用顶空固相微萃取-气质联用技术比较拼配前后风味差异。结果表明:预冻温度-20±2℃、预冻7 h,一次干燥温度80℃,干燥3 h,二次干燥温度55℃,干燥6 h,速溶粉各理化指标最佳;速溶鹧鸪茶粉与速溶普洱茶粉拼配比为7∶3,风味最佳。拼配后复合茶粉中醛类物质含量增加了0.34%,酸类物质含量减少了0.18%,滋味醇和,口感顺滑。该研究为鹧鸪茶综合利用及产品研发提供理论参考和技术支持。     

柠檬片热风干燥特性及品质研究

以切片厚度为3 mm的新鲜柠檬为原料,研究热风干燥温度(50、60、70、80℃)对柠檬片干燥特性和理化品质的影响。结果表明:热风温度是影响柠檬片干燥的重要因素,柠檬片的干燥过程是一个降速过程。随干燥温度的升高,干燥速率和水分有效扩散系数增大,干燥时间缩短;干燥过程中,水分有效扩散系数随水分含量降低而增大。同其他热风温度相比,70℃热风干燥处理时间相对较短,柠檬片具有较好的颜色品质,总类胡萝卜素、总酚的含量较高,DPPH·清除能力维持在一个较好的水平,适合对柠檬片进行干制。     

低能量复合鹧鸪茶凉茶饮料的开发与抗氧化活性评价

以鹧鸪茶与甜菊糖苷为原料开发一种低能量复合凉茶饮料。采用单因素与正交试验确定了海南特产低能量复合鹧鸪茶凉茶饮料配方;在此基础上,利用国标法、分光光度法和HPLC-MS法分别对所开发饮料产品的质量指标、抗氧化活性与酚类物质组成进行了分析测定。结果表明,通过正交试验可得到低能量复合鹧鸪茶凉茶饮料的最佳配方为:鹧鸪茶夏枯草配比9∶1 (g/g),蔗糖添加量4.0%,甜菊糖苷添加量0.010%,柠檬酸添加量为0.035%,经验证后感官评分39.8分。经茶饮料制备工艺所得产品符合《食品安全国家标准饮料》(GB 7101-2015),对DPPH自由基(EC_(50)值2.087μg/mL)、ABTS自由基(EC_(50)值1.445μg/mL)的清除能力低于市售绿茶(EC_(50)值1.067μg/mL,EC_(50)值0.051μg/mL)和凉茶(EC_(50)值0.259μg/mL,EC_(50)值0.030μg/mL),且还原能力稍弱;利用HPLC-MS分别从三种茶饮料产品中共鉴定出21个酚类成分,其中隐绿原酸、咖啡酸、对香豆酸、水杨酸、柚皮素、金丝桃苷、鞣花酸和芦丁这8种酚类物质从低能量复合鹧鸪茶凉茶饮料中分析发现。     

保健燕麦茶啤酒的工艺研究

阐述了保健燕麦茶啤酒的生产工艺流程及生产工艺要点,采用大麦芽60%,燕麦20%,糖浆20%的原料配比,并在85℃对茶水比为1:180进行20min的绿茶浸提,生产过程中浸提后茶汁添加量为5%,酒花添加量0.02%,添加时间初沸后20min。经过中试生产,保健型燕麦茶啤酒各项指标均符合GB。     

打造新鲜菜品的味道形象

蜜汁马蹄梨 原料：脆梨丁200克马蹄丁100克蜂蜜20克柠檬片5片白糖10克黑芝麻少许     

胶原蛋白速溶茶的研制

探讨以绿茶、猪皮为原料开发保健型胶原蛋白速溶茶的途径。利用单因素实验,对绿茶提取茶粉的条件、速溶茶的配方进行优化,获得制备胶原蛋白速溶茶的最佳工艺和关键技术。结果表明,茶粉最佳提取工艺为:用50%乙醇作提取剂,固液比1:20,浸提温度60～70℃,浓缩和干燥温度60～70℃。胶原蛋白速溶茶最佳配方为:按胶原蛋白12.9%、茶粉12.9%、植脂末9.7%、白砂糖64.5%,研制出了一种饮用方便、价格便宜、风味独特、营养保健的固体速溶茶饮品。     

鹧鸪茶多酚的提取及抗氧化性研究

以鹧鸪茶为原料,选取超声辅助浸提法提取多酚化合物,探讨了超声功率、浸提温度、料液比、浸提时间对多酚得率的影响。在单因素试验基础上,通过正交试验优化提取工艺。采用DPPH自由基法、ABTS自由基法和羟自由基法评价多酚提取物的抗氧化性。结果表明,鹧鸪茶多酚的最佳工艺条件为:超声功率300 W、浸提温度70℃、料液比1:25 (g/mL)、时间30 min,在此条件下,多酚得率为(10.72±0.52)%(以干重计,w/w)。鹧鸪茶多酚提取物具有较强清除DPPH自由基、ABTS自由基和羟自由基能力,其IC50值分别为(0.0054±0.0003)、(0.077±0.004)、(0.114±0.006)mg/mL,说明鹧鸪茶多酚具有较强的体外抗氧化活性。     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.     

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%.