酸法提取海带多糖的效果评价及工艺优化

为了探究不同酸以及水提取海带多糖的差异,本文以多糖得率和胆酸盐吸附率为优选指标,对柠檬酸、硫酸、盐酸、磷酸以及水等提取溶剂提取海带多糖进行了比较,确定了柠檬酸提取海带多糖的效果最好。通过单因素试验研究了pH、提取时间、提取温度、提取液料比对海带多糖得率以及胆酸盐吸附率的影响,然后利用正交试验优化了柠檬酸提取海带多糖的条件。结果表明,影响海带多糖得率及胆酸盐吸附率的主要因素为pH,其次为提取料液比、提取时间、提取温度。最佳的提取工艺参数为:时间2h,液料比25/1mL/g,温度100℃,pH 2.0,此时多糖得率最高,为12.95%,胆酸盐吸附率可达52.64%。     

怀地黄和怀山药混合提取多糖工艺优化

对怀地黄和怀山药混合提取多糖的工艺参数进行研究。通过考察提取温度、固液比、提取液pH、浸提液与乙醇添加量对怀地黄和怀山药混合提取多糖的影响,采用L(933)正交试验,以多糖含量作为指标,确定混合提取多糖的最佳温度、pH、固液比。结果:怀地黄和怀山药混合提取多糖的最佳工艺参数为,浸提温度65℃、浸提液pH 5.0、固液比为1∶20(g/mL)、浸提液浓缩比为4∶1,沉降剂乙醇添加量6倍于浸提液体积,混合提取多糖率为44.78%。     

淫羊藿叶多糖的超声辅助提取工艺研究

通过单因素以及正交试验进行水浴及超声辅助提取淫羊藿叶多糖的工艺优化,用硫酸-葸酮比色法测量淫羊藿叶多糖的含量,并对两种工艺的提取结果进行比较.研究结果表明,水浴提取淫羊藿叶多糖的最佳工艺为料液比1∶80、提取时间60min、提取温度80℃、提取液的pH为8.0.超声辅助提取淫羊藿叶多糖的最佳工艺为料液比1∶60、超声强度100W、超声处理时间10min、提取液的pH值7.0.超声辅助提取淫羊藿叶多糖的得率比水浴提取的提高了68.7％,超声辅助提取淫羊藿叶多糖明显优于水浴提取法.     

半枝莲多糖提取工艺优化

以半枝莲为原料,多糖得率为技术指标,研究超声波协同复合酶法提取半枝莲多糖的工艺,分别对pH、酶量、料液比、超声时间、酶解温度进行单因素试验,然后进行正交试验优化.试验确定的最佳工艺条件为pH 4.5、复合酶用量0.025 g、料液比1∶60(m∶V)、超声时间15 min、酶解温度50℃,该条件下多糖得率为2.166％.用超声波协同复合酶法提取半枝莲多糖具有得率高、省时、有效成分破坏少及提取结果稳定等特点.     

猴头菇多糖的提取工艺

采用单因素分组实验和正交试验的方法,对猴头菇中的多糖提取工艺进行研究,考察了提取温度、料液比、pH和提取时间对多糖的影响,确定最佳的工艺参数为提取温度为80℃、料液比1∶25(g/mL)、pH5.5、提取时间为3 h。采取最佳工艺条件进行提取,最大提取率可达到4.5%。     

采用微波技术提取海带多糖的工艺研究

在单因素试验的基础上，采用正交试验，研究了乙醇用量、微波功率、浸提时间、固液比、pH值等因素对海带多糖提取量的规律，得出了海带多糖提取工艺的最佳参数组合为：以水为提取剂，微波功率为400W，提取时间为7min，固液比为1：90（g／mL），pH值为8．0。在此条件下海带多糖的提取量为71.66mg／g。     

玉米花粉多糖的提取工艺优化

玉米花粉多糖是从玉米花粉中提取出来的一种具有较高生物活性的水溶性多糖。通过对玉米花粉多糖提取温度、时间、料液比及提取液的pH值等因素的实验结果分析,发现影响最显著的因素是pH值,其次是提取时间的影响,温度,料液比的影响最为微弱。从而得出的最佳提取条件组合是：pH值10,时间3h,温度60℃,料液比1∶5。且最佳提取次数为2次。     

响应面分析法优化向日葵盘中果胶的提取工艺研究

通过响应面分析法对向日葵盘果胶的提取工艺进行优化.利用响应面实验设计考察提取温度、提取时间、料液比和pH值4因素对果胶提取量的影响.研究发现：提取时间、温度和pH值对提取量有显著影响,向日葵盘果胶的最佳提取条件是：提取温度为79℃、提取时间为80 min、料液比25∶1、pH值3.20;每5 g向日葵盘中果胶最大提取量为0.522 g.     

海带多糖的提取工艺

采取热水浸提法探讨海带中可溶性粗多糖的提取工艺,研究提取温度、提取时间、料液比和海带目数4个因素对多糖提取的影响.通过单因素试验和正交试验得到海带多糖提取最佳工艺提取组合为A2B1C2D3,提取温度70℃,提取时间4.5 h,料液比1:40(g/mL),海带目数60目,此时多糖提取量可以达到172.34 mg/g,多糖提取率达到7.90％.     

复合酶协同超高压法提取黑木耳多糖的工艺优化

该试验研究复合酶协同超高压法提取黑木耳多糖最佳工艺条件。以黑木耳多糖得率为指标,采用单因素试验和正交试验,确定最佳提取工艺参数。结果表明,复合酶提取最佳工艺参数为酶解时间50 min,复合酶（纤维素酶∶木瓜蛋白酶=1∶1,质量比）添加量3%,酶解温度50℃,酶解pH值6.5。在此条件下,黑木耳多糖得率为9.26%。经复合酶法优化后,再进行超高压法提取,最佳工艺参数为保压时间8 min,提取温度50℃,压力400 MPa,料液比1∶30（g/mL）。在此条件下,黑木耳多糖得率为12.23%。     

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.     

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.     

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.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.