壳聚糖在红枣汁澄清中的应用

在采用壳聚糖澄清红枣汁中，研究了壳聚糖用量、温度、pH对澄清效果的影响。结果表明：壳聚糖澄清枣汁透光率可达98％以上，清汁与原汁相比，VC含量、可溶性固形物含量稍有下降。总糖含量变化不明显，其澄清优化工艺条件是壳聚糖用量3％(1％壳聚糖醋酸溶液)、温度45℃、pH3．5。     

壳聚糖澄清芦荟、葡萄、枣、姜复合汁

用壳聚糖为澄清剂,对芦荟、葡萄、大枣、大姜复合汁进行澄清试验.研究壳聚糖用量、温度、澄清时间、pH等工艺条件与复合汁透光率的关系.通过正交试验筛选出壳聚糖澄清该复合汁的最佳工艺条件为:壳聚糖用量0.3g/L、温度40 ℃,pH 6、反应时间30 min.澄清后,果汁透光率达98%,由此可见,壳聚糖是一种良好的芦荟、葡萄、大枣、大姜复合汁澄清剂.     

猕猴桃澄清果汁加工工艺研究

利用壳聚糖聚阳离子电解质的特性澄清猕猴桃汁,选择壳聚糖脱乙酰度、壳聚糖加入量、果汁pH、加入壳聚糖后47℃果汁保温时间与澄清果汁的透光率的关系进行单因素实验,并在单因素实验基础上用拟因子正交实验设计,找出了澄清猕猴桃原汁的最优条件为:用脱乙酰度80%的壳聚糖,加入量为0.4g/L,加入壳聚糖后果汁于40℃保温40min,果汁pH为自然pH值,壳聚糖澄清猕猴桃汁之后离心时间为30min;影响澄清猕猴桃汁的显著因素为壳聚糖的脱乙酰度、加入壳聚糖后果汁的保温时间和离心时间。     

壳聚糖对枇杷汁的澄清效应

单因素与正交实验相结合,探讨壳聚糖对枇杷汁的澄清效应与最佳工艺。结果表明:壳聚糖用量为0.6~0.9 g/L,澄清时间为70~90 min,p H值2.5~4.5,枇杷汁温度为32~45℃的条件下,壳聚糖对枇杷汁澄清处理的透光率可达90%以上;壳聚糖用量0.70g/L+澄清时间80min+温度40℃为壳聚糖对枇杷汁澄清处理的最佳工艺参数,枇杷汁透光率为95.9%。     

果胶酶澄清蜜瓜汁过程中甲醇含量的变化

目的：在优化果胶酶处理蜜瓜汁工艺过程中考察蜜瓜汁澄清效果与甲醇含量的关系。方法：以蜜瓜汁透光率和甲醇含量为指标，通过单因素与正交试验，研究果胶酶加入量、蜜瓜汁pH值、作用时间、处理温度对蜜瓜汁澄清效果和甲醇含量的影响。结果：对蜜瓜汁澄清效果和甲醇含量影响的因素顺序为蜜瓜汁pH值＞果胶酶加入量＞作用时间＞处理温度，蜜瓜汁最优澄清效果和甲醇最高含量的条件均为果胶酶加入量0.04 g/100 mL、蜜瓜汁pH值4.0、作用时间120 min、处理温度35 ℃。在该工艺条件下，甲醇含量为423.79 mg/L、蜜瓜汁透光率为95.71%。结论：蜜瓜汁中甲醇含量与蜜瓜汁的澄清效果呈正相关，蜜瓜汁的透光率愈高，果胶分解愈完全，甲醇含量越高。     

红枣澄清汁加工工艺的研究

为了制备澄清透明且营养丰富的红枣汁,将干红枣经果胶酶解浸提,得到红枣汁。采用果胶酶和壳聚糖分别对红枣汁进行澄清处理,以透光率为指标,比较两种方法的澄清效果。对两种澄清方法进行正交试验的极差分析和方差分析,结果表明,壳聚糖的澄清效果更好。确定了壳聚糖澄清红枣汁的最佳工艺条件为:壳聚糖添加量为0.02%,50℃下澄清1h,所得澄清汁的透光率达到95.6%。清汁与原汁相比,汁液清澈透明、色泽自然。总糖含量提高,总酸含量无明显变化。     

活性炭负载壳聚糖对苹果汁的澄清效果研究

以透光率为指标,以壳聚糖澄清和活性炭澄清为对照,探讨活性炭负载壳聚糖澄清剂在不同添加量、温度、时间和pH条件下对苹量汁的澄清效果影响,并采用Box-Behnken中心组合设计法进行澄清工艺条件的响应面优化。试验结果表明：经活性炭负载的壳聚糖澄清剂对苹果汁有较好的澄清效果,且明显优于对照组;建立的响应面模型能较好地预测透光率随澄清条件的变化规律,且在最优澄清条件负载澄清剂用量12 g,澄清时间9.6 min,澄清温度55℃,pH 2.56下的透光率为96.47%。     

壳聚糖在甘薯饮料澄清中的应用

将经过一定预处理的甘薯汁用壳聚糖进行澄清处理,通过正交试验研究确定最佳澄清条件.结果表明采用壳聚糖用量0.6g/L、pH值3.0、时间2.5h、温度60℃的澄清条件效果最佳,透光率可达99%;澄清甘薯汁经调配制得风味佳且澄清透亮稳定性好的甘薯饮料.     

红枣汁的澄清工艺研究

将红枣浸提原汁分别采用果胶酶和壳聚糖进行澄清处理,并对2种澄清剂的澄清效果进行比较,确定较好的澄清剂及其澄清工艺条件。试验表明,壳聚糖的澄清效果较好,确定壳聚糖澄清红枣汁的最佳工艺条件为:壳聚糖添加量0.4g/L、50℃下澄清30min,所得澄清汁透光率达到95%以上,枣汁清澈透明、色泽自然、枣香浓郁。     

籽瓜原汁澄清工艺优化

利用籽瓜副产物制备籽瓜原汁,对籽瓜原汁澄清工艺进行研究。由单因素和响应面试验结果得出:采用复合酶较单一酶澄清籽瓜原汁能有效提高其透光率。复合酶加工籽瓜原汁澄清汁最佳工艺条件为:果胶酶添加量0.05%、纤维素酶添加量0.07%、时间1 h、温度51℃,在此条件下,得到籽瓜清汁透光率98.8%。     

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