草莓汁澄清工艺研究

草莓汁的澄清是草莓汁加工工艺的重要环节,澄清效果会影响草莓汁的品质和货架期。以红颜草莓为原料,首先采用单因素及正交试验对果胶酶、壳聚糖澄清草莓汁的条件进行了优化,确定了果胶酶、壳聚糖澄清草莓汁的最佳作用条件,再使用果胶酶-壳聚糖复合法澄清草莓汁。结果表明,果胶酶最佳用量为0.015 g/L,壳聚糖处理草莓汁的最佳工艺条件为壳聚糖添加量0.6 g/L,水浴时间25 min,水浴温度55 ℃,草莓汁pH值3.3。采用果胶酶-壳聚糖（果胶酶0.015 g/L和壳聚糖0.6 g/L）复合法澄清草莓汁,透光率为97.3%,澄清效果优于单一澄清法,因此果胶酶-壳聚糖复合澄清法可作为一种良好澄清方法使用。     

不同澄清方式对石榴果汁澄清效果的比较

研究以果汁透光率为指标,比较膨润土、果胶酶、壳聚糖三种澄清方式对石榴果汁澄清效果,结果表明,果胶酶澄清效果最好,壳聚糖次之,膨润土最差,果胶酶澄清后的果汁稳定性最好,壳聚糖和膨润土澄清后的果汁稳定性较差。通过比较三种澄清方式对石榴果汁中主要物质含量的影响发现,果胶酶对果汁中的蛋白质、果胶及酚类物质去除能力最高,壳聚糖次之,膨润土最差。通过比较三种澄清方式对果汁色差的影响发现,果胶酶处理后的果汁L值最大,壳聚糖次之,膨润土最小。通过正交试验优化石榴果汁澄清工艺,结果表明,当果胶酶用量为0.08%,酶解时间为1.5 h,酶解温度为50℃时,果汁澄清效果最好。     

几种澄清剂对荔枝提取液中多糖含量影响

在荔枝提取液澄清过程中,分别就果胶酶、纤维素酶、101澄清剂、壳聚糖、果胶酶和纤维素酶合用及果胶酶、纤维素酶和壳聚糖联合处理时对其中多糖的影响进行了研究,结果表明,这几种澄清方法对荔枝提取液中多糖都有不同程度的影响,在各处理的最佳澄清条件下,即果胶酶用量在6mL/L时,多糖损失率为12.2%;纤维素酶用量在10mL/L时,多糖损失率在7%;101澄清剂及助剂都采用9mL/L添加量时,多糖损失率为7.3%;壳聚糖用量为15mL/L时,多糖损失率为9.9%;果胶酶和纤维素酶用量分别是4mL/L、13mL/L,多糖损失率为10.6%;果胶酶和纤维素酶使用浓度分别是4mL/L、13mL/L,壳聚糖使用浓度是15mL/L时,多糖损失率为12.8%。     

不同澄清剂对发酵木瓜酒澄清效果的研究

研究了皂土、壳聚糖、果胶酶澄清发酵木瓜酒的工艺,结果表明,三种澄清剂对发酵木瓜酒均具有不同程度的影响,皂土的澄清效果最佳;通过正交实验确定三种澄清剂的最佳配比为皂土用量1.5%,壳聚糖用量0.1%,果胶酶用量0.15%,在此条件下,透光率可达到98.8%。     

果胶酶和壳聚糖对无核黄皮发酵酒澄清效果的比较研究

研究了果胶酶和壳聚糖对无核黄皮发酵酒的澄清效果,并通过正交试验及综合评比分析,确定了最佳澄清剂和工艺条件,即壳聚糖法:壳聚糖用量1.0 g/L,pH值为3.0,温度30℃,澄清时间24h.澄清后的发酵酒澄清透明,稳定性增加.     

红柠檬果汁澄清工艺的优化

选用红柠檬作为研究对象,以透光率为指标来研究果胶酶、复合酶、壳聚糖、膨润土和硅藻土这5种澄清剂对红柠檬汁的澄清效果,并探讨其中澄清效果较好的澄清剂对澄清后果汁品质的影响。通过单因素试验和Box-Behnken试验设计对红柠檬汁澄清工艺进行优化。结果表明,膨润土和硅藻土对红柠檬汁几乎没有澄清作用,果胶酶、复合酶和壳聚糖澄清效果都比较好。综合经济、方便和澄清后红柠檬汁品质3个方面考虑,最后选择果胶酶作为红柠檬汁的澄清剂。利用响应面优化试验得到了澄清型红柠檬汁的最优工艺,其条件为果胶酶用量0.22 g/100mL、处理温度50.3℃、pH 4.3和时间62 min,在此条件下,红柠檬汁透光率为93.8%。     

慕萨莱思葡萄酒澄清工艺研究

选用食用明胶、壳聚糖、果胶酶、木瓜蛋白酶、蛋清5种澄清剂,对慕萨莱思葡萄酒进行单一及复合澄清剂处理,研究慕萨莱思葡萄酒在不同澄清剂下澄清度和色度的变化规律.结果表明,壳聚糖澄清效果最好,但脱色严重.果胶酶澄清处理后色度最接近原酒色度.因此选用果胶酶-壳聚糖复合澄清剂,经过正交试验得出壳聚糖添加量为0.024％,果胶酶添加量为0.08％,澄清时间为4h,水浴温度为40℃,该条件下澄清度为92.4％,色度为0.152.     

不同澄清剂对红枣汁的澄清效果的工艺研究

以新疆大红枣为原料,利用果胶酶酶解技术和壳聚糖的电解质作用对红枣汁的澄清效果进行研究,根据处理时间、处理温度、料液比及pH值的不同进行试验,利用单因素试验方法,分别研究果胶酶、壳聚糖对红枣汁澄清效果的影响,再进行果胶酶和壳聚糖的正交试验以确定最佳的工艺条件。试验结果表明:果胶酶添加量7 m L,温度50℃,时间2 h,固液比为1∶5(g/mL)澄清效果最佳。壳聚糖添加量0.02 g,温度50℃,时间30 min,pH值为3澄清效果最佳。     

发酵型枸杞酒澄清技术研究

针对枸杞酒本身的特有成分，研究了果胶酶酶解、果胶酶与明胶复合处理、壳聚糖澄清三种方法对发酵型枸杞红酒的澄清效果。试验结果表明，采用壳聚糖的澄清效果最为理想，其澄清速度快，用量少，生产成本低。产品在贮藏期间稳定，风味好。     

果胶酶对百香果醋澄清作用的研究

以果胶酶作为澄清剂对百香果醋进行澄清处理,研究了酶用量、酶解温度和时间对澄清效果的影响.根据果胶酶对百香果醋澄清的单因素试验结果,采用正交试验对果胶酶用量、酶解温度和酶解时间等工艺参数进行优化,确定了适宜的反应条件为:果胶酶用量120mg/kg、温度45℃、反应时间150min.利用果胶酶澄清百香果醋能较好地避免二次混浊现象.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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