超声波辅助纤维素酶提取核桃壳多糖及其抗氧化活性研究

采用单因素试验和正交试验对核桃壳多糖的超声波辅助纤维素酶提取工艺条件进行优化,并对核桃壳多糖的抗氧化活性进行研究。结果表明,超声波辅助纤维素酶提取核桃壳多糖的最优工艺条件为:料液比1∶20,纤维素酶添加量1. 75%,提取温度45℃,提取时间90 min,超声波功率750W。在最优条件下,核桃壳多糖提取率为2. 20%。核桃壳多糖对DPPH自由基、羟基自由基、超氧阴离子自由基均表现出较好的清除能力,且在一定范围内对三者的清除作用呈现良好的量效关系。     

超声波辅助提取霍山石斛多糖及其抗氧化活性研究

以霍山石斛为原料,利用超声波辅助法提取霍山石斛多糖,采用Box-Behnken设计和响应面分析对提取条件进行优化,同时比较了超声波辅助提取工艺和热水浸提工艺所得霍山石斛多糖的还原力和ABTS自由基清除率。结果表明,超声波辅助提取霍山石斛多糖的最优工艺条件为:液料比30:1,浸提温度81℃,浸提时间120 min,超声功率423 W,超声时间8 min,在此优化条件下多糖平均得率为19.96 mg/g,是传统热水浸提工艺的1.70倍。体外抗氧化结果显示,超声波辅助提取工艺所得霍山石斛多糖还原力和ABTS自由基清除率均优于热水浸提的多糖。该试验结果为后续霍山石斛多糖的提取和抗氧化活性研究提供了实验依据和技术支持。     

笋壳多糖的微波-超声波联合辅助提取工艺优化及其抗氧化活性

目的：通过微波-超声波联合辅助提取法优化笋壳多糖提取工艺,并研究其抗氧化活性。方法：考察提取时间、料液比、微波功率、超声波功率、提取次数对笋壳多糖含量的影响,在单因素试验基础上做L9（34）正交试验优化提取工艺参数,通过测定笋壳多糖清除羟自由基、超氧阴离子自由基、1,1-二苯基-2-苦基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基的能力来评价其抗氧化活性,并同传统热水浸提法进行比较。结果：微波-超声波联合辅助提取最优工艺条件为提取时间30 min、料液比1∶30（g/mL）、微波功率200 W、超声波功率750 W,笋壳多糖得率为2.76%,粗多糖中多糖含量为37.63%;清除羟自由基、DPPH自由基和超氧阴离子自由基的半抑制浓度分别为0.17、0.43 mg/mL和大于16 mg/mL。微波-超声波联合辅助提取法的各项指标均优于热水浸提法。结论：微波-超声波联合辅助提取笋壳多糖比传统热水浸提具有耗时短、效率高等优点,笋壳水溶性多糖具有显著体外抗氧化活性。     

超声辅助提取苦荞芽多酚及其抗氧化活性分析

优化了超声波辅助提取苦荞芽中多酚类物质的工艺条件,并采用ABTS和DPPH自由基清除率法检测了苦荞芽多酚提取物的抗氧化活性。研究结果表明,苦荞芽多酚的最佳提取条件为:甲醇体积分数60%、超声时间30 min、超声温度50℃、料液比1:50 g/mL,在该条件下苦荞芽多酚的提取量可达72.82 mg/g。抗氧化活性测定结果表明,苦荞芽多酚提取物对ABTS自由基和DPPH自由基均有较强的清除能力,其半抑制浓度(IC50)值分别为119.26、205.24μg/mL。     

香荔核多糖超声波辅助提取工艺的响应面优化及抗氧化性研究

以香荔核为原料,参照单因素试验结果,以多糖提取率为响应值,采用响应面法优化香荔核多糖的超声波辅助提取工艺,并通过测定香荔核多糖对羟基自由基、超氧阴离子自由基的清除能力及总还原力对其抗氧化活性进行评价。试验表明,超声波辅助热水浸提法提取香荔核多糖的最佳工艺:提取温度58℃,液料比为24∶1(mL/g),超声功率为620 W,超声时间20 min,此条件下,多糖的实测平均提取率为10.04%,与回归模型预测值10.72%相当。当多糖浓度为0.5 mg/mL时,对羟基自由基、超氧阴离子自由基的清除率达到74.44%、86.52%,总还原力为0.596,说明香荔核多糖具有较强的抗氧化能力,且其抗氧化活性与多糖浓度成正向线性关系。     

海芦笋多糖超声波辅助提取工艺及抗氧化活性研究

研究海芦笋多糖的超声波辅助提取工艺条件及体外抗氧化活性。通过单因素和正交试验确定超声波辅助提取工艺,利用羟自由基抑制试验判断海芦笋多糖的抗氧化功能。结果表明:海芦笋多糖的最优提取条件为料液(水)比1:15(m:V)、超声波处理时间15min、浸提温度70℃、浸提时间2h,该工艺下粗多糖提取率为6.12%,与传统浸提相比,提取效率明显提高;海芦笋多糖对羟自由基.OH有明显的清除作用,且作用效果随着浓度的增加而增强,对羟自由基的半数抑制率(IC50)为0.578mg/mL。     

超声波辅助提取猴头菇多糖及其抗氧化活性研究

采用超声波辅助提取猴头菇中的多糖,通过单因素试验和正交试验对提取条件进行优化。结果表明,超声波辅助提取猴头菇多糖的最佳工艺条件为:超声波功率300W、超声时间15min、液料比15mL/g、超声2次,在此条件下猴头菇多糖的提取率为16.96%。同时,猴头菇多糖体外抗氧化试验表明,猴头菇多糖对·OH和DPPH自由基均有较好的清除效果。当猴头菇含量为0.10mg/mL时,其对·OH的清除率可达60%,当含量为15mg/mL时,其对DPPH自由基的清除率可达到80%,但几乎没有还原能力。     

超声波辅助提取野胡萝卜多糖工艺优化及其体外抗氧化性

以野胡萝卜为试材,采用超声波辅助方法提取其多糖,在单因素试验的基础上,利用正交试验优化超声波辅助提取野胡萝卜多糖工艺,同时探究其体外抗氧化活性。结果表明,最佳提取工艺工艺参数为:超声功率550 W、料液比1:40(g/mL)、超声时间30 min、超声温度40℃,在此条件下,野胡萝卜多糖的平均提取率为6.86%。超声波辅助提取的野胡萝卜多糖具有较强的抗氧化活性,对羟基自由基(·OH)、1,1-二苯基-2-三硝基苯肼自由基(DPPH·)和超氧阴离子自由基(O_2~-·)的清除作用明显,且其质量浓度与抗氧性活性呈现一定的量效关系,是一种良好的天然抗氧化剂。     

响应面法优化白灵菇多糖超声辅助提取工艺及其体外抗氧化性

利用响应面法优化超声波处理辅助提取白灵菇多糖工艺,并研究其体外抗氧化活性。在单因素实验的基础上,根据Box-Behnken实验设计对超声波处理时间、提取温度和液料比进行分析与优化,确定了超声波辅助提取的最佳工艺参数:提取温度56℃、超声波处理时间45 min、提取的液料比为41∶1,在此条件下进行2次提取,得到白灵菇多糖得率为12.26%,相比于传统热水提取法(提取温度77℃、提取时间189.6 min、液料比46∶1、提取次数为2次)多糖得率提高了44.41%。白灵菇多糖体外抗氧化活性实验表明:超声波辅助提取法得到的白灵菇多糖在质量浓度4 mg/m L时,清除羟基自由基的能力和DPPH自由基的能力分别为98.39%和60.8%。     

超声波辅助提取黑苦荞黄酮类化合物及其抗氧化活性研究

以黑苦荞为原料,通过单因素和正交实验优化超声波辅助提取黑苦荞中黄酮类化合物的工艺,并且研究黄酮类化合物的体外抗氧化活性。结果表明,从黑苦荞中提取黄酮类化合物的最佳工艺条件为:提取温度60℃、超声波功率400 W、乙醇体积分数80%、料液比1∶15,在此条件下提取率达到4.58%;抗氧化活性实验表明,在一定浓度(10⁴0μg/mL)范围内,黑苦荞黄酮类化合物对羟自由基、超氧阴离子自由基和DPPH自由基均有一定的清除作用,但不如Vc的清除效果好。     

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