假丝酵母的添加对高盐稀态酱油有机酸含量影响

目的:研究不同时间添加假丝酵母菌对高盐稀态酱油有机酸含量的影响。方法:高盐稀态酱油在发酵的第15天、30天和45天添加假丝酵母,监测发酵过程中pH值、总酸含量以及有机酸的含量和种类,最终通过风味物质种类和可溶性无盐固形物含量的测定比较酱油的品质。结果:发酵结束后,总酸含量依次为30 d+C15 d+C45 d+C空白,其中有机酸含量依次为空白30 d+C15 d+C45 d+C;气相色谱-质谱检测风味物质种类以及可溶性无盐固形物含量依次为空白30 d+C 15 d+C45 d+C;45 d+C组酱油品质最高,风味物质种类达到73种,可溶性无盐固形物含量达到15.72 g/dL。结论:第45天添加假丝酵母的HLFSS品质最佳;假丝酵母通过增加有机酸含量提高HLFSS品质;假丝酵母添加后HLFSS的品质评价可利用有机酸含量作为依据。     

盐度对紫甘蓝酸菜发酵过程中挥发性风味物质及理化指标的影响

为考察不同盐度(1%,3%,5%,10%)对紫甘蓝酸菜发酵过程中挥发性风味物质及理化指标的影响,利用顶空固相微萃取-气相色谱-质谱联用(HS-SPME/GC-MS)方法分析挥发性风味物质的差异性,比较在发酵过程中,其感官得分、pH、总酸、亚硝酸盐、氨基酸态氮、还原糖含量及乳酸菌数的差异。结果表明:盐度对紫甘蓝酸菜的感官得分及理化指标中的pH、总酸、氨基酸态氮、还原糖含量及乳酸菌数有显著影响(P<0.05)。盐度过高(＞5%)不利于紫甘蓝酸菜的发酵及感官品质,其中3%盐度发酵酸菜的感官综合得分最高。HS-SPME/GC-MS分析结果表明,发酵末期(60 d),3%盐度发酵的酸菜的风味物质总含量最高;其中,部分烯烃类、醇类、醛类、酮类、异硫氰酸酯类及腈类等风味物质的含量显著高于其它盐度的酸菜(P<0.05),随着盐度的增加,这些风味物质相应减少。结合OAV值分析得到酸菜中21种关键挥发性风味物质,其在较高的盐度(＞5%)下对应的OAV值显著降低(P<0.05);通过PCA可知,发酵中期(30 d)和末期(60 d),不同盐度发酵的酸菜间风味物质组成差异较大,其中3%盐度的风味物质组成更为丰富;Pearson相关性分析表明,盐度与总酸、氨基酸态氮含量、乳酸菌数、感官综合得分及大部分挥发性风味物质之间呈负相关,其中与总酸呈显著负相关(P<0.05),而与pH值、还原糖含量呈正相关。结论:相比其它盐度的酸菜,3%盐度发酵的紫甘蓝酸菜风味品质较好,可直接用于紫甘蓝的发酵工艺,对紫甘蓝酸菜的生产具有一定的指导意义。     

东北酸菜不同发酵时间有机酸变化及其对产品酸感的影响

采用高效液相色谱法(high performance liquid chromatography,HPLC)和暂时性感官支配分析法(temporal dominance of sensations,TDS)研究东北酸菜有机酸变化及其对产品酸感的影响。HPLC检测结果表明:在0～120 d发酵过程中能检测到9种有机酸,其中乳酸、柠檬酸、乙酸、草酸、苹果酸、琥珀酸及酒石酸含量随发酵时间的增加而增加,发酵120 d时还检测到了丙酸和戊酸;TDS评价结果表明,发酵90 d样品相比其它发酵时间样品酸感更加柔和适中,说明其各种有机酸含量及比例适宜。因此,90 d为东北酸菜最适发酵期;相关性分析表明乳酸在东北酸菜酸感形成中起主导作用,柠檬酸、乙酸、草酸、苹果酸、琥珀酸及酒石酸则起到辅助作用。这些有机酸含量及比例合适时对东北酸菜柔和酸感起到促进作用;含量及比例不合适时会破坏柔和酸感。丙酸和戊酸的存在则会导致尖酸酸感。     

发酵及贮藏期影响酸菜品质的因素

该研究以东北大宗蔬菜品种——大白菜为原料,釆用北方地区传统的工艺发酵方法及人工接种发酵方法制作酸菜,考察发酵期的发酵方法和加盐量及贮藏期的贮藏温度和光照条件对酸菜中亚硝酸盐含量、总酸含量及感官指标的影响。结果显示,人工接种发酵的酸菜亚硝酸盐含量低于自然发酵,总酸含量及感官评价结果相近;发酵期食盐的添加量不超过2%,酸菜的品质较优;贮藏期的温度低于20℃,有利于酸菜的储存;避光贮藏酸菜为最佳储存条件。     

乳酸菌发酵对富源酸菜品质及安全性的影响

采用液态发酵方式,比较乳酸菌发酵和自然发酵的富源酸菜在整个贮藏过程中不同时段的感官、理化指标和微生物变化的规律,评价两种发酵方式对富源酸菜品质及安全性的影响。试验结果表明:与自然发酵相比,乳酸菌发酵的富源酸菜感官品质更优;亚硝酸盐含量较低且亚硝峰值出现得较早、pH值较低、总酸含量较高;乳酸菌活菌数量更多,菌落总数、霉菌和酵母菌数量都较少;大肠杆菌未检出。说明乳酸菌发酵制作的富源酸菜在品质及安全性方面都优于自然发酵的富源酸菜。     

四川泡菜和东北酸菜在发酵过程中的物质成分变化

为研究工艺对发酵蔬菜品质的影响,以四川泡菜和东北酸菜为研究对象,分析在发酵过程中盐度、pH值、总酸、有机酸、游离氨基酸、质构及亚硝酸盐等物质成分的变化规律。结果表明,四川泡菜和东北酸菜在发酵过程中盐度都先逐渐升高后趋于稳定,pH值都逐渐下降,总酸含量均逐渐升高,发酵产生了大量乳酸和少量乙酸,但四川泡菜产酸更快;游离氨基酸均以丙氨酸、脯氨酸和丝氨酸为主,其硬度、弹性、咀嚼性均随着发酵时间延长而逐渐降低,亚硝酸盐都在第5天达到峰值,但远低于限量标准20mg/kg。四川泡菜和东北酸菜在发酵过程中具有相似的变化规律,但含量各有差异,表明发酵蔬菜之间具有共性和个性。     

贮藏条件对红薯叶酸菜品质的影响

目的:探寻乳酸菌发酵红薯叶酸菜的贮藏条件及贮藏期间品质变化规律。方法:真空包装后以常温25℃、低温4℃、80℃—15 min巴氏杀菌后4℃、85℃-10 min巴氏杀菌后4℃贮藏,比较4个条件下红薯叶酸菜pH值、乳酸含量、亚硝酸盐含量、菌落数、色差值及感官评分。结果:25℃下贮藏亮度下降最快,第60天色泽明显变深;4℃下贮藏第30天的酵母菌数量最多,第45天的乳酸菌数量最多;80℃-15 min杀菌后贮藏第90天的大肠杆菌数量最少,感官评分达到食用临界值;85℃-10 min杀菌后贮藏第75天的总菌数量最少,感官评分及格。pH值与亚硝酸盐含量呈极显著负相关,与L值、感官评分呈极显著正相关;乳酸菌数与酵母菌、大肠杆菌、总菌数呈极显著正相关,其中感官评分在第一主成分中的载荷量最大。结论:80℃-15 min杀菌后4℃贮藏,其主要微生物为乳酸菌,其他指标均符合安全标准,感官品质稳定,更适合作为酸菜的贮藏条件,贮藏期可达90 d。     

发酵条件对芋头叶柄酸菜品质的影响

为提高芋头叶柄酸菜品质,降低其中亚硝酸盐含量,研究不同自然发酵条件对芋头叶柄酸菜感官品质、营养品质和有害成分的影响。结果表明,原料的含水量、食盐浓度、发酵温度和发酵时间对酸菜的总酸含量、还原糖含量和亚硝酸盐含量均有不同程度的影响,其中原料水分含量70%,食盐浓度4%,室温(28±2℃)条件下发酵32 d时总酸含量为67.84 g/kg,还原糖含量为22.21 mg/g,亚硝酸盐含量为1.61 mg/kg。该试验以玻璃瓶代替传统的大缸为发酵容器,制作的酸菜感官品质和营养品质较佳,亚硝酸盐含量极低,能得到可安全放心食用的酸菜产品。     

混和乳酸菌发酵对酸菜品质的影响

以3种乳酸菌为研究目标,研究接种3种乳酸菌对酸菜品质的影响。发酵接种的是混菌培养的副干酪乳杆菌、布氏乳杆菌和凝结芽孢杆菌。在发酵过程中,接种混菌后的酸菜亚硝酸盐的浓度明显低于自然发酵酸菜的浓度;氨基酸含量、维生素C含量、L-乳酸含量都有所增加,通过食品专业人员对酸菜感官品质的评分,酸菜的感官品质无论是在色泽、香气还是滋味和脆性都优于自然发酵的酸菜。因此接种3种乳酸菌有助于提高酸菜的发酵品质。     

不同乳酸菌发酵对酸菜的风味物质形成及品质指标的影响

为研究不同乳酸菌对于酸菜发酵效果的影响,以白菜为原料,采用植物乳杆菌（Lactobacillus plantarum）、干酪乳杆菌（Lactobacillus casei）和肠膜明串珠菌（Leuconostoc mesenteroides）作为发酵剂进行酸菜发酵,并分析不同乳酸菌发酵体系中的理化指标、感官指标和挥发性风味物质。结果表明,在发酵30 d时,肠膜明串珠菌（L. mesenteroides）发酵酸菜中pH值（3.28）和还原糖含量（2.14 g/L）最低,总酸含量（8.69 g/L）最高,但亚硝酸盐含量无显著差异（P＞0.05）。肠膜明串珠菌（L. mesenteroides）发酵酸菜中乳酸（7.59 g/L）和柠檬酸（1.84 g/L）含量最高,且乳酸占总有机酸的65%。3种乳酸菌发酵酸菜中共检出挥发性风味物质65种,主要包括醛类13种、酯类12种、酸类12种、醇类7种、异硫氰酸酯类5种和酮类4种。主成分分析（PCA）结果表明,不同乳酸菌发酵酸菜的挥发性物质种类和含量差异显著。     

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