UHT灭菌乳在贮藏期内的品质变化

选择了市售塑料袋装UHT灭菌乳(保质期为30 d),研究了其在4℃冷藏避光、4℃冷藏光照、25℃室温避光、25℃室温光照、37℃避光,37℃光照6种贮藏条件下,贮藏期内主要理化指标和微生物指标的变化.结果表明,在整个贮藏期内.UHT灭菌乳的酸度持续增加,10～15 d酸度增长幅度最大,37℃条件下,最大酸度可达到22.14°T;在6种贮藏条件下蛋白质量分数均相对稳定;在贮藏的前10 d,试验样品细菌总数均小于1 mL-1,之后持续增长;光照与否,各取样点维生素C质量浓度差异显著.     

不同贮藏温度对酸乳中乳酸菌活菌数以及品质影响的研究

目的:探究不同贮藏温度对酸乳中乳酸菌活菌数以及酸乳品质的影响。方法:每2天分别测定于常温、4、-10、-20℃条件下贮藏酸乳的乳酸菌的菌落总数、滴定酸度、p H、持水力、质构以及感官。结果:常温条件下贮藏的酸乳在5~7 d内乳酸菌菌落总数、滴定酸度、质构以及感官评分均有提升,随后菌落总数、滴定酸度、持水力、质构以及感官评分均迅速下降;4℃条件下贮藏的酸乳在17 d内乳酸菌总数、滴定酸度、质构以及感官评分均呈上升趋势,持水力变化不大;-10、-20℃条件下贮藏的酸乳各项指标均呈下降趋势。结论:酸乳在4℃条件下贮藏时,乳酸菌生长情况以及酸乳品质最佳,可有效延长酸乳货架期。     

酱香型白酒高温大曲储存过程中微生物群落演替与理化因子相关性研究

目的：本研究分析了酱香型白酒高温大曲在储存过程中（0～150 d）的理化特性和微生物的变化过程，以期了解大曲的老化成熟规律。方法：该研究基于传统可培养方法和高通量测序技术分析大曲在储存过程中微生物群落结构演替规律，结合相关性分析理化因子和微生物之间的关系。结果：储存过程中的可培养微生物的数量呈现先增加后下降的趋势；温度和糖化力指标呈先上升后下降的趋势，水分、酸度随着存储时间的增加呈现下降的趋势。储存过程中的主要优势细菌属为Kroppenstedtia、Lactobacillus、Staphylococcus、Enterobacter；主要优势真菌属为Thermomyces、Trichomonascus、Byssochlamys。微生物群落与理化指标间存在复杂的作用关系，Bacillus、Kroppenstedtia、Aspergillus、Trichomonascus与温度呈正相关关系；Byssochlamys、Dipodascus与温度、水分、酸度、液化力呈正相关关系；Thermomyces与温度、水分、酸度呈负相关关系。结论：本研究揭示了酱香型高温大曲在储存过程中微生物群落组成情况...     

凝固型酸奶在贮藏过程中的微生物菌相演变研究

通过对不同温度下贮藏的凝固型酸奶中乳酸菌、杂菌、pH值和酸度的变化进行分析,阐述温度对酸奶贮藏过程中微生物菌相演变的影响。结果表明:在0-5℃贮藏30d后酸奶中的乳酸菌数8.2×108cfu·mL-1下降到7.9×107cfu·mL-1,杂菌数由30cfu·mL-1增加到5.8×105cfu·mL-1,pH值缓慢下降,酸度缓慢增加。0-5℃是最佳的贮藏温度,建议贮藏期限以2周为宜。     

木糖醇酸奶发酵、贮藏期间质量变化的研究

为了确定木糖醇酸奶的保质期,本实验对该种酸奶在发酵过程和贮藏期间的质量变化进行了研究。结果表明,木糖醇酸奶在发酵过程中酸度和电导率随着发酵时间的延长而升高,pH值下降。贮藏期间其酸度随着贮藏时间的延长而升高,pH值下降;乳酸菌数、黏度和感官评分在贮藏3d时最高,以后逐渐下降,贮藏期限为9d,最佳饮用时间为3d。     

贮藏温度对无核黄皮保鲜期和品质的影响

研究确定无核黄皮的最佳贮藏保鲜温度,为其贮运保鲜提供理论和技术基础。方法 无核黄皮经采收分拣后, 分别贮藏于不同的环境温度下,观测贮藏期间果实外观整体感观质量、色泽及主要生理和品质指标的变化。结果 较低温3~5 ℃、低温8~10 ℃下无核黄皮的总感官品质下降慢,贮藏保鲜期较长,分别达13 d和11 d,而中低温13~15 ℃下缩短至9 d,室温23~25 ℃则只有3 d。低温贮藏降低果实的呼吸和乙烯产生速率,减缓果面色泽劣变,并减缓可溶性固形物、可滴定酸和维生素C的变化,从而保持新鲜品质营养。结论 低温贮藏能有效减缓无核黄皮内外观品质的下降,温度越低,贮藏保鲜期越长。8~10 ℃是无核黄皮的最佳低温保鲜温度范围,此温度下的贮藏保鲜期为11 d。     

直投式发酵剂(DVS)发酵牛乳冷藏过程中生物化学变化规律的研究

为测定本实验室自制直投式酸奶发酵剂的发酵性能，通过对其发酵的牛乳在冷藏过程中的主要生物化学指标的测定结果表明，该发酵乳在冷藏0～24d过程中，脂肪、蛋白质的含量无规律性变化；在0～15d过程中乳酸含量及酸度逐渐增加，乙醛质量分数、乳糖含量、pH4值及己糖激酶活性逐渐降低。该直投式酸奶发酵剂所发酵牛乳的保质期为15d，冷藏0d的50mL酸乳中蛋白质质量浓度为为605g／dL，脂肪质量浓度为262g／dL，该发酵剂发酵性能优良，已达到相应酸乳生产标准。     

不同温度对超高压处理鲜榨生菜汁贮藏稳定性的影响

为探究不同冷藏温度（0、4、8 ℃）下超高压（ultra-high pressure，UHP）（600 MPa、2 min）处理鲜榨生菜汁（fresh lettuce juice，FLJ）的贮藏稳定性，分别在0、5、10、15、20、25、30 d取样，测定微生物指标、理化指标、色泽、叶绿素、物性指标和稳定性指数等，并分析其变化规律。结果表明，UHP处理后FLJ于0、4、8 ℃贮藏30 d期间总好氧菌数量小于100 CFU/mL，霉菌和酵母菌数量小于10 CFU/mL，均在国家标准（GB 4789.2—2016《食品安全国家标准 食品微生物学检验 菌落总数测定》和GB 4789.15—2016《品安全国家标准 食品微生物学检验 霉菌和酵母菌计数》）限量范围内。与初始相比，0、4、8 ℃贮藏30 d，FLJ色泽由绿色变为棕褐色，总叶绿素含量分别下降18.96%、46.84%、67.07%；4、8 ℃贮藏30 d FLJ的pH值分别降低至4.66±0.08、4.37±0.08；0、4、8 ℃贮藏30 d FLJ的总可溶性固形物含量变化不明显；固形物体积、粒径、表观黏度均增大，稳定性和浑浊度降低。随着贮藏温度上升，FLJ各项参数的变化速率加快，其中0 ℃贮藏变化趋势最为平缓。综合考量FLJ的色泽、理化和稳定性指标，0 ℃可作为FLJ的最佳贮藏温度，4 ℃和8 ℃贮藏货架期分别可达15 d和10 d，本实验可为鲜榨蔬菜汁加工和贮藏提供技术参考。     

基于营养均衡设计的低温乳化肠在贮藏期间品质及微生物的变化

针对基于营养均衡设计的低温乳化肠中,其高不饱和脂肪酸、高碳水化合物、富含维生素的状况,本文以品质(感官评定、质构、色差、脂肪氧化情况)及微生物(菌落总数、大肠菌群)变化为指标,研究营养均衡设计的低温乳化肠在贮藏期间品质及微生物的变化规律,从而进一步指导工业生产结果表明,在常温25℃贮藏的此类产品,存放3d以后,产品的感官品质显著下降、菌落总数严重超标;在0～4℃贮藏的产品42d内菌落总数、大肠菌群均未超标,脂肪氧化情况并不显著(p＞0.05),但产品在35d后褪色(p＜0.05),硬度、咀嚼性增大(p＜0.05),感官品质不理想,失去食用价值.     

西藏地区牦牛乳理化和微生物指标的检测分析

研究了西藏地区牦牛乳的理化指标和微生物指标。从西藏3个不同地区共取48份牦牛乳样品．通过理化和微生物指标的检测及其统计分析，研究发现牦牛乳的营养成分为：脂肪7．14％（体积分数）、粗蛋白5．06％（质量分数）、干物质18．45％（质量分数）、乳糖5．00％（质量分数）和灰分0．81％（质量分数），并且不同地区各成分的质量分数也不同。牦牛乳的微生物检测结果为（对数值）：细菌5．63mL^-1，芽孢菌1．76mL^-1，乳酸菌5．19mL，真菌3．03mL^-1，肠道菌3．27mL^-1，大肠杆菌2．09mL^-1和金黄色葡萄球菌3．52mL^-1，并且存在明显的地区差异性。     

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.     

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