荞麦米多酚物质的提取及其抗氧化特性

为了获得乙醇提取荞麦米多酚物质的最佳工艺参数,以提取温度、时间、乙醇浓度及料液比为实验因子,以多酚物质得率为响应值,采用响应面设计进行实验。并对优化后荞麦米提取物粉末的抗氧化特性进行了分析。结果表明,影响荞麦米多酚物质得率因素强弱顺序依次为:料液比乙醇浓度提取温度提取时间,荞麦米多酚物质提取最优条件为提取温度56℃、提取时间6.0h、料液比1∶12g/m L、乙醇浓度65%。2mg/m L荞麦提取物对羟自由基在反应时间为20min时具最强清除活性,其清除率为26.88%;对DPPH·的清除在反应时间为30min时,清除率最高,为43.65%;在反应时间为10min时,3mg/m L荞麦提取物表现出最大的还原力,其值为2065.39。     

杏仁及杏仁皮多酚超声提取优化及抗氧化能力差异性研究

为获得杏仁及杏仁皮内多酚提取的最优方案,采用超声波处理样品,以料液比、超声温度、功率和时间为影响因素多酚得率为指标进行研究。结果表明:杏仁多酚超声提取最佳条件为料液比1∶10、超声温度50℃、超声功率400 W,超声时间60 min。而杏仁皮多酚超声提取最佳条件为料液比1∶10、超声温度60℃、超声功率400 W,超声时间60 min。采用还原力、OH、DPPH和ABTS自由基清除率四个抗氧化能力指标对杏仁及杏仁皮多酚的抗氧化能力进行差异性分析,以期为杏仁多酚这一功能性成分的开发提供参考依据。研究结果表明,杏仁多酚抗氧化能力大小与其含量成正比。甜杏仁多酚的还原力、OH和ABTS自由基清除率均高于苦杏仁多酚,而甜苦杏仁多酚的DPPH自由基清除率接近一致,且在0.024 mg/m L浓度时依次为25.4%和23.7%。甜苦杏仁皮多酚抗氧化能力差异不明显,其还原力、DPPH和ABTS自由基清除率三者基本一致,而在0.24 mg/m L浓度时,甜杏仁皮多酚的OH自由基清除率约为苦杏仁皮的2倍。总体来说,甜杏仁多酚的抗氧化能力优于苦杏仁多酚,潜在利用价值更高。     

纤维素酶辅助提取沉香叶黄酮及其抗氧化活性测定

以黄酮得率为评价指标,利用纤维素酶辅助乙醇提取法从沉香叶中提取黄酮,在单因素的基础上,选取乙醇浓度、温度、p H、底物质量浓度4因素,运用正交试验设计优化提取工艺;采用DPPH自由基法、ABTS自由基法测定沉香叶黄酮的抗氧化活性。结果表明,沉香叶黄酮的提取工艺为:乙醇浓度70%(v/v)、酶解温度55℃、酶解p H5、酶添加量200 U/g,底物质量浓度3 g/100 m L,酶解时间3 h,此条件下沉香叶黄酮的得率为3.86%(w/w);沉香叶黄酮提取物具有较强的清除DPPH自由基和ABTS自由基能力,其IC50值分别为0.17、0.18 mg/m L。     

藕皮多酚提取工艺优化及其体外抗氧化性研究

以藕皮为原料提取多酚,通过单因素试验分析乙醇浓度、料液比、提取温度、提取时间4个因素对莲藕皮多酚提取得率的影响,利用正交试验对提取工艺进行优化,并以抗坏血酸为对比以羟基自由基、DPPH自由基、超氧阴离子自由基的清除能力为指标,分析藕皮多酚提取物的体外抗氧化活性。结果表明:藕皮多酚提取优化工艺条件为:乙醇浓度为40%,料液比为1:30(g/mL),提取温度为90℃,提取时间2 h,该条件下藕皮多酚类物质的提取得率为(4.45±0.05)mg/g。藕皮多酚提取物对羟基自由基、DPPH自由基、超氧阴离子自由基消除率最高分别可达92.45%、82.11%、80.41%,证实藕皮多酚提取物具有很好的抗氧化能力。     

构树根皮活性成分乙醇提取工艺优化及其抗氧化活性分析

以构树根皮为原料,通过单因素实验考察不同因素对构树根皮总黄酮和多酚提取量的影响。运用DesignExpert 11软件设计响应面法优化构树根皮乙醇回流提取工艺,并进行工艺验证。最后对提取得到的构树根皮乙醇提取物进行DPPH·、ABTS+·、羟自由基清除能力和总还原能力的测定,评价其抗氧化活性。响应面分析表明,构树根皮总黄酮和多酚的最佳提取工艺为提取温度75℃、提取时间117 min、料液比1:16 g/mL、乙醇浓度70%。此条件下,构树根皮总黄酮和多酚提取量分别为23.93±0.30 mg/g和14.69±0.56 mg/g,与预测理论值接近。抗氧化实验表明,构树根皮乙醇提取物对DPPH·、ABTS+·和羟自由基的半数清除浓度（IC50）分别为5.256μg/mL、0.259 mg/mL和0.310 mg/mL,且清除能力与其浓度呈现一定的量效关系。当提取物浓度为1.0 mg/mL时,总还原能力达到1.484±0.062。此优化实验有效可行,构树根皮乙醇提取物具有较强的抗氧化活性。本研究为构树资源的综合利用提供了一定的理论依据。     

莲藕多酚的提取工艺优化及抗氧化活性评价

通过单因素实验确定了乙醇浓度、料液比、pH、温度和时间对莲藕多酚浸提得率的影响,并建立了乙醇浓度、料液比、pH和时间的四因素回归模型。基于响应面分析和实际应用考虑,确定莲藕多酚的超声波提取工艺条件为:乙醇浓度40%、料液比1∶22、pH3、时间72min,浸提得率预测值为0.22%,实际值为0.23%。在该条件下,莲藕多酚粗提物得率为1.12g/100g鲜重,其中多酚含量为19.73mg GAE/100mg干重。莲藕多酚粗提物的DPPH自由基清除IC50值为351.56μg/m L,ABTS自由基清除IC50值为308.80μg/m L,FRAP抗氧化能力为0.21mg TE/mg粗提物,作为天然抗氧化剂应用前景良好。     

紫粒小麦麸皮花色苷提取工艺优化及其抗氧化活性研究

以紫粒小麦麸皮为原料,研究其花色苷超声波辅助提取工艺及其体外抗氧化活性。选取超声辅助提取功率、提取温度、提取时间、料液比和乙醇浓度等为考察因素进行了提取工艺的单因素及正交实验。实验结果表明,乙醇浓度为60%、料液比1∶10(g/m L)、提取时间10 min、提取温度60℃、超声波功率160 W。在此条件下,花色苷得率为(1.82±0.23)mg/g,是普通浸提法的2.09倍。体外抗氧化实验显示:紫小麦麸皮花色苷提取物具有一定的清除DPPH自由基和ABTS自由基能力以及铁还原力,其花色苷含量与DPPH自由基、ABTS自由基清除率、铁还原力有显著的相关性(相关系数R2分别为0.9938,0.9737和0.9985),IC50值分别为7.81、12.20、5.18 mg/L。这一结果将为以紫小麦麸皮花色苷为原料的功能性食品的开发提供有益提示和理论基础。     

忧遁草茎中黄酮类化合物的提取工艺优化及比较

为筛选适合忧遁草茎中黄酮类化合物的提取方法,以得率为评价指标,在单因素基础上,通过正交试验优化纤维素酶法和有机溶剂浸提法提取忧遁草茎中的黄酮类化合物工艺;采用ABTS自由基法、DPPH自由基法和还原力法比较提取物的抗氧化性。结果表明,纤维素酶辅助提取忧遁草茎中黄酮类化合物的最佳工艺条件为:乙醇浓度80%(v/v)、温度55 ℃、pH5.0、底物质量浓度30 g/L、酶用量300 U/g、时间1.5 h;有机溶剂浸提的最佳工艺条件为:乙醇浓度80%(v/v)、温度55 ℃、料液比1:15 (g/mL)、时间2.5 h。纤维素酶辅助提取忧遁草茎中的黄酮类化合物得率为(1.32±0.11)%(w/w),高于有机溶剂浸提法的(1.05±0.08)%(w/w)。2种提取方法得到的黄酮化合物均具有较强的抗氧化性,其中纤维素酶辅助提取物清除ABTS自由基和DPPH自由基的半抑制浓度(IC50)值分别为(1.94±0.04)、(0.178±0.013)mg/mL,低于有机溶剂提取物的(2.76±0.05)、(0.200±0.015)mg/mL,说明酶法提取物的抗氧化性强于有机溶剂浸提法。忧遁草茎中黄酮类化合物提取采用纤维素酶辅助提取较为适宜。     

酶辅助提取沉香叶多酚及其抗氧化性研究

以沉香叶为原料,采用酶辅助有机溶剂浸提法提取沉香叶多酚,探讨了酶种类、乙醇浓度、酶解温度、酶解pH值、酶添加量、底物质量浓度及酶解时间对多酚得率的影响,在单因素基础上,运用正交试验优化提取工艺;采用清除自由基法评价多酚提取物的抗氧化性。结果表明,纤维素酶辅助乙醇法提取沉香叶多酚的效果最好,最佳提取条件为:乙醇浓度60%(v/v),酶解温度50℃,酶解pH5,酶添加量200 U/g、底物质量浓度5 g/100 mL,时间2 h,此条件下多酚的得率为4.96%(w/w);沉香叶多酚提取物具有较强的抗氧化性,清除ABTS自由基、DPPH自由基和·OH自由基的半数有效浓度(EC_(50))值分别为(0.025±0.002)、(0.106±0.006)、(0.12±0.001)mg/mL。     

桦褐孔菌抗氧化物质的提取工艺优化及其活性

通过响应面分析对桦褐孔菌抗氧化活性成分的提取工艺进行了优化,并对提取物的铁离子还原能力(FRAP)、DPPH自由基清除能力进行了评价。结果表明,最佳提取工艺为料液比1∶20(g/m L),乙醇浓度65%,提取温度85℃,提取时间2.5 h。根据最佳提取工艺,得到桦褐孔菌抗氧化活性成分提取物得率为21.6%,其多酚含量为12.04 mg/g,铁离子还原能力测试(FRAP)值为1.42 mmol/g样品,提取物浓度为400μg/m L时DPPH自由基清除率为78.05%。加热实验表明,桦褐孔菌提取物具有一定的热稳定性。     

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.     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.