苦瓜皂苷最佳提取工艺优化及其对α-葡萄糖苷酶的抑制活性

采用响应面法优化超声提取苦瓜皂苷的最佳工艺,并考察最佳提取工艺条件下提取物对α-葡萄糖苷酶的抑制活性。试验结果表明,超声提取苦瓜皂苷的最佳工艺条件为固液比1∶15（g/mL）、乙醇浓度75% 、超声时间95 min、提取温度50℃,在该条件下苦瓜皂苷的提取率可达2.21% ,其对α-葡萄糖苷酶抑制的IC50值为5.48 mg/mL。     

超临界-CO2 提取苦瓜有效成分的研究

采用U11(1110)均匀设计试验优选超临界-CO2 提取苦瓜总皂苷和黄酮的最佳工艺条件。分别以苦瓜中总皂苷和黄酮含量为指标探讨萃取压力、温度、萃取时间和夹带剂(无水乙醇)用量等因素在不同水平下对苦瓜皂苷和黄酮提取工艺的影响,确定苦瓜皂苷和黄酮超临界-CO2 流体萃取最佳工艺参数。苦瓜皂苷的最佳萃取条件为萃取压力25.5MPa、温度42.5℃、夹带剂用量180mL;苦瓜黄酮的最佳萃取条件是压力27.5MPa、温度39.5℃、夹带剂用量226mL。萃取时间均为3h,采用一级分离,分离温度均为35℃。     

苦瓜总皂苷提取工艺的研究

优选水浴振荡提取方法,以苦瓜总皂苷含量为考察指标,研究了提取溶剂浓度、提取温度、固液比、提取时间、提取次数等因素对总皂苷含量的影响。通过正交实验,确定苦瓜总皂苷提取的最佳工艺条件为:提取温度60℃,固液比1∶14,乙醇浓度70%,提取时间3.0h,提取次数2次。     

苦瓜皂苷的制备及体外抗氧化活性研究

为优化苦瓜中皂苷的提取条件及其抗氧化活性,以皂苷得率为考察指标,研究了提取温度、时间、乙醇浓度和料液比对苦瓜皂苷提取的影响,并采用正交试验确定最佳条件;以苦瓜皂苷对超氧自由基、羟基自由基的清除率作为考查指标,研究苦瓜皂苷的体外抗氧化活性。确定了最佳提取工艺条件为：最佳提取乙醇浓度为70％,料液比为1:15,温度55℃,提取时间2.5h。0.4mg/mL苦瓜皂苷对超氧自由基的清除率达到92.5％,对羟基自由基(·OH)的清除率达到78.9％     

大蒜多糖及皂苷的多指标优化提取工艺研究

目的:制备大蒜多糖和大蒜皂苷。方法:采用水提醇沉超声法,选取醇提浓度、温度、时间、超声功率4个因素,运用正交设计筛选大蒜多糖的最佳提取工艺。采用苯酚-硫酸法对大蒜多糖进行含量测定,茴香醛—硫酸法对大蒜皂苷进行含量测定。结果:通过上述方法优化多糖和皂苷的制备工艺为50%乙醇处理,超声时间2 h,提取温度20℃,超声功率40%条件下提取效果最佳,多糖收率为28%,多糖含量可达95%,皂苷收率为0.7%,皂苷含量为35%。结论:优化工艺条件提取大蒜多糖和皂苷产量和纯度高,简单可行。     

超声辅助溶剂法提取肉桂总皂苷工艺的研究

采用超声辅助溶剂法提取肉桂总皂苷.以肉桂总皂苷含量为考察标准,研究了超声温度、超声功率、超声时间这三个因素对总皂苷含量的影响.选用L9(34)正交表进行正交试验,确定肉桂总皂苷超声提取的最佳工艺条件为:超声温度60℃,超声功率70%,超声时间40min.验证实验测得肉桂总皂苷含量为4.393%,传统溶剂法提取的肉桂总皂苷含量为3.407%,结果表明超声辅助溶剂法的提取效果优于普通溶剂法,同时也缩短了提取时间.     

舞花姜根总皂苷的提取工艺及其抗氧化活性

研究舞花姜根中总皂苷的超声提取最佳工艺条件,并评价提取总皂苷的抗氧化活性。在单因素实验基础上,采用3因素3水平响应面实验优化超声提取条件。结果表明:舞花姜根总皂苷的最佳提取工艺参数为:料液比1:30 (g/mL),样品粒度40目,超声提取时间51 min。按此工艺对不同产地舞花姜根总皂苷进行提取,发现务川县和三都县的总皂苷含量相对较高且稳定,含量分别为16.88 mg/g和16.92 mg/g。利用DPPH、ABTS进行抗氧化分析,得出舞花姜根提取物浓度与抗氧化活性呈正比;不同产地的舞花姜根总皂苷提取物对自由基清除率不同;且清除率强弱与舞花姜根中提取的总皂苷含量呈正相关,验证了其抗氧化能力与总皂苷含量有关。     

苦瓜皂苷提取及纯化工艺的研究

用溶剂法从苦瓜干粉中提取苦瓜皂苷并用大孔吸附树脂对苦瓜皂苷进行了纯化研究。结果表明苦瓜皂苷最佳提取参数为:乙醇浓度70%、提取时间3 h、提取温度70℃、料液比1∶20(g/m L)。AB-8大孔吸附树脂最佳纯化工艺条件为:吸附流速4%BV/min,80%的乙醇洗脱流速为3%BV/min。得苦瓜皂苷提取率为4.8%,其纯度可达到46.5%。     

辽东楤木叶片皂苷超声提取工艺优化研究

以辽东楤木叶片为试材,采用超声波提取法,以乙醇为提取溶剂提取并测定楤木皂苷含量。在单因素实验的基础上进行正交实验,研究叶片中楤木皂苷的最佳提取工艺。结果表明,叶片楤木皂苷的最佳提取工艺为乙醇浓度70%、溶剂倍量40、提取温度70℃、提取时间75min。采用最佳的超声提取工艺测定叶片中楤木皂苷含量为92.77mg/g。经优化的超声提取工艺操作简单、提取时间短、提取效率高且结果稳定。     

微波辅助萃取苦瓜总皂苷工艺研究

为优选微波辅助萃取方法,以苦瓜总皂苷含量为考察指标,研究萃取溶剂浓度、萃取温度、料液比、萃取时间等因素对总皂苷含量的影响.通过正交试验确定苦瓜总皂苷萃取的最佳工艺条件为:萃取温度70℃.料液比1:24,乙醇体积分数60%,萃取12 min.此时测得的总皂苷含量为3.532%,优于正交试验的较优组.将微波辅助萃取法与水浴振荡法和超声提取法进行比较,结果表明,微波辅助萃取法不但大大缩短了萃取时间.而且提高了萃取率.对萃取物用化学法、红外光谱法检测,结果其为三萜类皂苷.通过红外光谱检测和HPLC分析.肉桂皂苷是多种同分异构体的混合物.     

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.