分阶段酶解法与膜处理结合制备杨梅汁工艺研究

采用蛋白酶-果胶酶分阶段酶解与膜过滤相结合澄清杨梅果汁。根据酶解条件对澄清效果的影响,探究最优的酶解工艺。通过单因素和正交试验确定最优酶解工艺为蛋白酶添加量0.1 g/L,蛋白酶酶解阶段温度65℃,果胶酶添加量1 g/L,果胶酶酶解阶段温度50℃,可得到透光率高达89.63%的杨梅汁。之后再通过膜过滤进一步澄清果汁,得到透光率高达95.27%的杨梅汁。     

酶解技术在澄清型薏米汁生产中的应用

研究了酶解技术在澄清型薏米汁中的应用.在单因素试验的基础上,采用正交L9(34)试验方案,对薏米淀粉的水解工艺参数进行优化.研究结果表明:当澄清型薏米汁中薏米的用量为2.5%时,薏米淀粉糖化的最佳酶解工艺条件是:温度为55℃左右,pH为6.6左右,酶添加量为300U/g薏米;在此工艺条件下,可生产出品质优良、稳定性好的澄清型薏米汁.     

响应面法优化青柠汁的果胶酶澄清工艺

以青柠为主要原料,利用响应面法对青柠汁的果胶酶澄清的主要工艺参数进行优化。在单因素实验基础上选取实验因素和水平,采用Box-Benhnken试验设计,以透光率为响应值,考察了果胶酶添加量、酶解p H、澄清时间及澄清温度对青柠汁澄清效果的影响,并建立了数学模型。结果表明,果胶酶澄清青柠汁工艺的最佳参数为果胶酶添加量0.09g/100m L,酶解p H4.44,澄清时间1.39h,澄清温度49.61℃,在此条件下,青柠汁透光率可达93.36%,与预测值93.18%接近,说明根据Box-Benhnken模型并采用响应面分析法得到的果胶酶澄清青柠汁优化工艺可行。     

采用星点设计-效应面优化五汁饮的制备工艺

为优化五汁饮的制备工艺,以感官评定为指标,在单因素试验基础上采用星点设计-效应面优化法(CCDRSM)优化最佳配比工艺。同时在配比工艺基础上,以透光度为指标,考察果胶酶添加量、酶解时间和酶解温度对五汁饮澄清效果的影响。结果表明:得到的最佳配比工艺为:鲜藕20 g、鲜荸荠30 g、鲜麦冬5 g、鲜梨70 g、鲜芦根8 g。最佳澄清工艺为:果胶酶添加量0.20%,酶解时间150 min,酶解温度55℃。优选的制备工艺稳定、可行,为五汁饮的进一步开发奠定基础。     

"米邦塔"仙人掌汁的营养特性及酶法澄清研究

对仙人掌汁营养成分及果胶酶法澄清仙人掌汁的工艺条件进行研究。结果表明，仙人掌汁中高钾低钠，钾钠比1314：1，SOD活力103．97U／mL，多糖1．96％，由成分分析可知，仙人掌汁是一种集多功能成分于一身的营养物质；采用响应面分析确定果胶酶澄清汁液时的最佳酶解工艺备件：酶加量0．14g／L、酶解时间1．8h、CaCl2添加量0．215g／L、酶解温度50℃、反应液pH4．5，所得汁的透光率达到94．2％。     

果胶酶提高‘宁海白’枇杷果浆出汁率的工艺优化

为提高“宁海白”枇杷果浆的出汁率,通过果胶酶的酶解,在单因素的基础上,进行Box-Benhnken响应面优化实验.结果表明,酶解的最佳工艺为酶添加量0.1 1g/kg、酶解时间3.2h、酶解温度为41.7℃.在此基础上进行验证实验,得到出汁率为78.94％,与预测值80.15％接近,响应模型可靠,该工艺可以应用于“宁海白”枇杷果汁的实际生产.     

果胶酶澄清南酸枣汁的工艺优化

利用果胶酶对南酸枣汁进行澄清处理实验 主要以透光率来检测其澄清效果,对几个影响因素(果胶酶添加量、酶解温度、酶解时间)进行了单因素实验,在单因素实验的基础上,通过正交实验,确定果胶酶对南酸枣汁澄清的最佳工艺条件是:果胶酶添加量为0.06％,酶解温度为40℃,酶解时间为100min在此条件下得到的南酸枣澄清汁的透光率达77.5％,其果胶物质基本被降解.     

澄清型香蕉汁加工工艺的研究

以完全黄熟的鲜香蕉为原料,采用正交实验,研究了澄清型香蕉汁的酶解工艺条件及滋味调配。结果表明:用果胶酶酶解香蕉汁有明显的澄清效果,酶解香蕉汁的优化工艺条件为果胶酶用量0.03%、酶解温度45℃、酶解时间2.0h;在打浆时加酸量为0.5%的条件下,酶解后的香蕉汁的最佳滋味配方为调糖度至15°Brix、抗坏血酸添加量0.02%、无需二次加酸。     

草莓澄清汁的加工技术研究

本文采用复合果胶酶酶解的方法,研究了草莓澄清汁的加工工艺,得到草莓澄清汁最佳的酶解工艺条件为:复合果胶酶添加量0．015%,酶解时间90min,酶解温度35℃,此时草莓的出汁率为81．10%,透光率可达96．1%。     

人参果果酒的研制

以人参果为原料研制人参果果酒.对人参果护色、酶解后取汁,添加酵母进行酒精发酵,并进行澄清等工艺制得人参果果酒.通过正交试验确定酒精发酵的工艺条件为发酵温度24℃,发酵时间8d,酵母液添加量为4％;防褐变处理采用0.4％VC效果最佳;澄清采用皂土0.2％和明胶0.02％效果最佳.采用本方法可酿制出澄清透明、风味醇正的人参果果酒.     

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