响应面优化牡丹籽壳总黄酮超声波提取工艺及抗氧化活性研究

采用超声波法提取牡丹籽壳中总黄酮。通过单因素试验分别考察乙醇体积分数、料液比、超声功率、超声时间、提取温度对总黄酮得率的影响,在此基础上采用响应面法优化超声波提取工艺条件。以抗氧化剂V_C为对照,采用DPPH法测定牡丹籽壳总黄酮的体外抗氧化活性。结果表明:超声波提取牡丹籽壳总黄酮最佳工艺条件为乙醇体积分数60%、料液比1∶50、超声功率250 W、超声时间50 min、提取温度40℃,在此条件下牡丹籽壳总黄酮得率为13.66%;牡丹籽壳总黄酮对DPPH自由基的清除能力优于V_C,且其抗氧化活性与质量浓度呈一定的量效关系。     

甘草总黄酮的超声波法提取工艺研究

以人工种植的甘草切片为主要原料,以乙醇为主要提取剂,对超声辅助提取法提取甘草总黄酮工艺进行研究,确定超声波法提取甘草总黄酮的最佳工艺。结果表明,影响甘草总黄酮提取率的因素主次依次是:超声温度>乙醇浓度>料液比>超声时间;超声波法提取甘草总黄酮的最佳工艺条件为:超声温度45℃,超声时间75min,乙醇浓度75%,料液比1∶12,在此参数下,甘草总黄酮的提取率最高,达到1.79%。     

超声波辅助提取菊花总黄酮的工艺研究

用超声波提取技术提取菊花中黄酮,在单因素提取基础上,采取正交优化试验,探讨乙醇浓度、料液比、提取温度和提取时间对菊花总黄酮提取工艺的影响,结果表明,影响菊花黄酮超声提取的主要因素为乙醇浓度,其次为提取时间、提取温度和料液比.最佳提取工艺条件为乙醇浓度60%,料液比1:40,提取温度40%℃,提取时间50min,测得菊花总黄酮为3.97%.     

超声波提取海红果中总黄酮工艺研究

以海红果为原料,在单因素实验基础上采用二次通用旋转回归组合设计研究了超声波提取海红果中总黄酮的最佳工艺参数。结果表明:4个参试因素对海红果中总黄酮的提取率影响大小顺序为:乙醇浓度>超声波时间>提取温度>料液比,其最佳提取工艺条件为乙醇浓度70%,料液比1∶50,提取温度40℃,超声波时间30min,在此条件下,海红果总黄酮提取率高达0.3100%。     

超声波提取菟丝子总黄酮的工艺研究

在超声波单因素提取的基础上,采取L16(45)正交优化试验,探讨乙醇浓度、提取时间、提取温度和料液比对菟丝子总黄酮提取工艺的影响,结果表明影响菟丝子黄酮超声提取的主要因素为乙醇浓度,其次为提取时间、提取温度和料液比.最佳提取工艺条件为:乙醇浓度70%,料液比1:30,提取温度40℃、提取时间40 min.在该条件下测得菟丝子总黄酮的含量为3.46%.     

紫苏叶中总黄酮的超声波辅助提取工艺优化

以总黄酮提取率为指标,通过单因素试验考察液料比、超声时间、乙醇浓度、提取温度对紫苏叶总黄酮提取率的影响,采用响应面分析法对超声波辅助乙醇提取紫苏叶中总黄酮的工艺进行优化。结果表明,紫苏叶总黄酮最佳提取条件为:液料比29∶1(V∶m)、超声时间40min、乙醇浓度45%、提取温度51℃,该条件下紫苏叶中总黄酮的实际提取率为5.41%。     

超声波法辅助提取香蕉皮中黄酮的工艺研究

以乙醇为提取剂,采用超声波辅助法研究香蕉皮中总黄酮的提取工艺。通过单因素和正交试验研究,结果表明,影响总黄酮提取效果的主要因素是乙醇浓度,其次是提取温度和料液比,最佳提取工艺条件为:乙醇浓度为60%,超声功率为400 W,超声温度60℃,料液比1∶30(g/mL),超声时间30 min。     

超声提取砂糖橘落果总黄酮及其抗氧化活性研究

以砂糖橘落果为原料，采用超声辅助法提取落果中的总黄酮，并研究其抗氧化活性。以DPPH自由基、羟基自由基清除率及总还原力评价总黄酮的抗氧化活性为指标，在乙醇浓度、料液比、超声时间、超声温度的单因素实验基础上，利用正交实验进行提取工艺优化。结果表明，超声提取砂糖橘落果中总黄酮最佳工艺为乙醇浓度50%、料液比1:50 g/mL、超声时间60 min、超声温度70℃，在该条件下总黄酮的提取率达到2.61%，此时砂糖橘落果总黄酮对DPPH自由基、羟基自由基的最高清除率达88.89%和80.77%，具有很强的抗氧化能力。该结果可为深入研究和开发砂糖橘落果总黄酮提供理论支持。     

超声波辅助提取大新苦丁茶中总黄酮的工艺研究

以广西大新县苦丁茶作为原材料,采用超声波辅助提取总黄酮,以芦丁为对照品,用分光光度法检测总黄酮含量。通过单因素试验讨论料液比、乙醇浓度、超声时间、超声温度4个因素对总黄酮提取率的影响,通过正交试验确定最佳提取工艺。试验结果显示：超声波辅助提取法的最佳提取条件为料液比1∶25（g/mL）、乙醇浓度70%、超声时间15 min、超声温度50℃,此时总黄酮的提取率为0.772%。     

双水相-超声波提取榴莲果皮总黄酮的工艺研究

在乙醇-硫酸铵双水相中,采用超声波法提取了榴莲皮中的总黄酮。考查了乙醇浓度、硫酸铵用量、料液比、超声功率、超声时间、提取温度对总黄酮提取率的影响。通过L9(34)正交试验设计,确立了榴莲果皮中总黄酮提取最佳工艺条件为:60%乙醇浓度,料液比为1:25,超声波功率280W,超声时间50 min,提取温度70℃。按照最优条件提取,总黄酮得率达3.26%。     

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.     

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.     

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.     

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.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.