洋葱有机硫化物的提取及抑菌性研究

对洋葱中有机硫化物的提取及其抑菌作用进行研究。通过单因素实验和响应面优化得到最佳的工艺条件:乙醇浓度72%、提取温度52℃、酶反应时间为30.5min、料液比为1∶5,提取所得有机硫化物含量值达到最大,为4.141mg/g。同时研究有机硫化物对金黄色葡萄球菌、枯草芽孢杆菌和蜡状芽孢杆菌的抑菌效果,结果表明粗提物浓度在0.414g/mL时抑制最为显著,对应的抑菌圈直径分别为1.10,1.15和1.05cm,最小抑菌浓度MIC分别为0.103,0.207,0.207g/mL。     

水法提取大蒜抑菌活性物质条件优化

为优化水法提取大蒜抑菌活性物质的工艺,研究料液比、浸提时间、浸提温度、pH对水法提取抑菌活性物质的影响,并采用正交试验法优化其工艺参数.利用GC-MS对大蒜水提液中的有效物质进行鉴定.试验结果表明,水法提取大蒜抑菌活性物质的最优条件是:料液比1:3,浸提温度30℃,漫提时间30min,pH6;大蒜水漫提液中主要的活性物质为S-甲基甲烷硫代亚磺酸酯、3-乙烯基-1,2-二硫杂-4-环己烯、3-乙烯基-1、2-二硫杂-5-环已烯、二烯丙基三硫醚等.     

超声波大蒜提取物抑菌性及挥发性成分分析

以乙醇为提取剂，采用超声波辅助提取大蒜，考察了不同条件下(乙醇浓度、超声波提取时间、温度、料液比)大蒜提取物对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌的抑菌作用。实验结果表明，不同条件下的大蒜提取物对3种细菌的抑制作用不同。在超声波提取时间25 min、乙醇浓度80%、温度25℃、料液比1∶10的条件下，大蒜提取物对大肠杆菌的抑制作用最大；在超声波提取时间10 min、乙醇浓度75%、温度30℃、料液比1∶20的条件下，大蒜提取物对金黄色葡萄球菌的抑制作用最大；在超声波提取时间30 min、乙醇浓度75%、温度20℃、料液比1∶30的条件下，大蒜提取物对枯草芽孢杆菌的抑制作用最大。采用气相色谱-质谱联用仪，对温度30℃、料液比1∶20、乙醇浓度75%、超声波提取时间30 min条件下大蒜浸出物中的挥发性成分进行测定，其成分多达27种以上，主要是酸、酯、酮、烯、硫等化合物，其中硫化物占总化合物成分的9%。该研究为大蒜的有关研究提供了一定参考。     

马齿苋总黄酮酶解提取工艺的优化

目的:研究纤维素酶酶解辅助提取马齿苋总黄酮的的最佳工艺.方法:通过正交试验研究马齿苋总黄酮的乙醇浸提提取工艺;通过四元二次回归正交试验进行纤维素酶酶解辅助提取马齿苋总黄酮的研究.结果:乙醇浸提马齿苋总黄酮的最佳方法是:料液比1:30,浸提时间60min、水浴温度60℃,乙醇浓度60%.酶解辅助提取马齿苋总黄酮的最佳工艺为:酶浓度1.9%、pH7.0、酶解温度47℃、酶解时间0.7h.结论:得到了纤维素酶总黄酮提取马齿苋总黄酮的最佳工艺,酶解辅助提取法显著优于乙醇浸提法.     

谷精草黄酮类化合物的提取工艺研究

以乙醇为浸提溶剂,从谷精草中提取黄酮类化合物,通过单因素实验和正交实验,考察乙醇浓度、料液比、浸提时间、浸提温度对谷精草黄酮提取率的影响.结果表明,各因素的影响程度依次为:乙醇浓度>浸提时间>浸提温度>料液比;提取的最佳工艺条件为:60%乙醇,料液比1:25,提取时间3h,浸提温度70℃,在此条件下,谷精草黄酮提取率为4.95%.     

从制备大蒜精油的废弃物中提取大蒜多糖的研究

对从水蒸汽蒸馏制备大蒜精油的废弃物中提取大蒜多糖的工艺进行了初步研究。利用生产大蒜油的废水提取大蒜多糖,得率可达到86%。向蒜渣中加入水,使料液比为1∶2,提取温度为95℃,提取40min,可提取蒜渣中残余多糖的93%。选择乙醇作为沉淀剂,可沉淀98%的大蒜多糖。利用提取精油后的废渣和废水提取大蒜多糖,既可以减少环境污染,又可以提高经济效益,有益于我国大蒜产业的健康、高效发展。     

不同方法对菠萝皮类黄酮提取工艺的研究

分别采用热回流提取法、纤维素酶提取法和超声波提取法进行提取,确定了不同提取方法的最佳提取条件(即乙醇热回流提取:乙醇浓度为80%、温度80℃、料液比为1:50;纤维素酶-乙醇提取:乙醇浓度70%、温度70℃、pH5.0、料液比为1:50;超声波提取:乙醇浓度60%、超声萃取温度70℃、浸提时间30 min、料液比为1:50及超声强度350 W)。并对上述3种方法进行比较,确定了菠萝皮类黄酮提取的最佳工艺为超声波提取最佳工艺条件。在此条件下,每克菠萝皮中类黄酮含量为21.3 mg,则类黄酮浸提率高达87.08%。     

正交试验法优化超声辅助提取大蒜多糖工艺

以大蒜为原料,采用超声波辅助法提取大蒜中的多糖,以多糖提取率为考察指标,在单因素试验基础上,通过L9(34)正交试验设计优化最佳提取工艺条件。结果表明:影响大蒜多糖提取率的主要因素是超声浸提温度与料液比,大蒜多糖超声辅助提取的最佳工艺条件为超声浸提温度50℃,超声浸提时间40min,超声功率350W,料液比1∶40(g/mL),此工艺条件下多糖提取率达25.12%。正交试验法优化得到的提取工艺稳定合理,可作为大蒜多糖提取的一种有效手段。     

大蒜有机硫化物提取工艺研究进展

大蒜(Allium sativum L.)为百合科葱属植物,不仅是备受欢迎的调味品,还是历史悠久的药用植物,是一种药食同源的两用佳品。大蒜鳞茎在加工的过程中会产生多种有机硫化物,这些有机硫化物是大蒜发挥其药理功效的主要活性成分,具有抑菌、抗氧化、抗肿瘤等多种药理活性。大蒜有机硫化物提取工艺的不同导致有机硫化物的组分略有差异,进一步影响了大蒜有机硫化物的生物活性。深入研究大蒜有机硫化物的提取工艺以及检测技术,为大蒜的开发和应用提供了理论依据。     

复合溶剂提取大蒜精油的工艺条件研究

以环已烷- 丙酮复合溶剂提取大蒜精油,对复合溶剂提取大蒜精油的工艺条件进行研究,探讨影响大蒜精油得率的因素条件：复合溶剂质量配比、料液质量比、浸提温度、浸提时间。单因素试验确定较好的因素水平,正交试验确定最佳提取工艺条件。结果表明,提取大蒜精油最佳工艺条件为：环已烷- 丙酮复合溶剂质量配比7:3,料液质量比1:6,浸提温度55℃,浸提时间6h。     

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