黑果枸杞花青素的制备与纯化研究

目的以黑果枸杞为原料,研究黑果枸杞花青素提取的最佳工艺条件及其纯化工艺,并对纯化效果进行检验。方法采用单因素和正交实验,以乙醇为提取溶剂,对花青素进行提取,对提取温度、提取时间、料液比和乙醇浓度等参数进行优化;将提取液离心并蒸发浓缩后用大孔树脂进行纯化,对纯化工艺进行研究,确定最佳纯化工艺。结果确定黑果枸杞花青素的最佳提取工艺为:以pH3.0的75%乙醇溶液为提取溶剂,提取温度为40℃,提取时间为2 h,料液比为1:40。在pH3.0,温度低于50℃,流速为1 mL/min的条件下,大孔树脂对黑果枸杞花青素的最大吸附量达61.21 mg/mL,花青素回收率为44.35%,花青素含量为118mg/g,是纯化前的10.91倍,通过冷冻干燥洗脱液得到外观呈黑紫色的花青素产品。结论确定了黑果枸杞花青素乙醇浸提法的最佳工艺条件,证明了AB-8大孔树脂具有良好的吸附能力和选择吸附性。     

均匀设计优化黑果枸杞色素纯化工艺研究

利用均匀实验设计法,考察了树脂径高比、料液浓度和pH对大孔树脂吸附色素的影响及洗脱剂速度、乙醇浓度和pH对大孔树脂解析色素的影响,优化出AB-8大孔树脂对黑果枸杞色素纯化的动态吸附最佳条件为:原料液浓度(以吸光度计)0.307 A,树脂径高比1∶25,原料液pH 3.0,动态解析最佳条件为:解析液pH4.0,解析液浓度95%,解析液流速0.76 mL/min。在此工艺条件下纯化的黑果枸杞色素,糖含量仅为2.30%,总酸含量仅为0.18%,黄酮含量为29.90%,产品的色阶为23.2,证明AB-8大孔树脂在此工艺条件下能较好的纯化黑果枸杞色素。     

大孔树脂分离纯化黑果枸杞总黄酮的研究

目的：研究大孔树脂分离纯化黑果枸杞总黄酮的工艺条件及参数。方法：利用单因素试验和多因素正交试验研究大孔树脂分离纯化黑果枸杞总黄酮的最佳工艺条件。结果：AB-8 型大孔树脂分离纯化黑果枸杞总黄酮的最佳工艺条件为：上样液浓度0.200mg/ml,流速2ml/min,pH5;以95% 的乙醇洗脱,流速4ml/min,用量为5 倍柱床体积。AB-8 树脂的饱和吸附量为0.64691mg/g 树脂,重复利用9 次吸附量仍然很好。采用该工艺分离纯化黑果枸杞总黄酮含量达28%。结论：AB-8 树脂分离纯化黑果枸杞总黄酮效果较好,工艺的重复性和稳定性良好,适合于工业化生产。     

野生黑果枸杞花青素提取工艺优化及地区差异性

采用响应面法优化野生黑果枸杞花青素提取工艺。以野生黑果枸杞为实验材料,在单因素实验基础上,以乙醇浓度、提取温度、提取时间和液料比为自变量,花青素提取量为响应值,通过Box-Behnken实验设计方案确定最佳提取工艺条件。结果表明,野生黑果枸杞花青素最佳提取条件为:乙醇浓度79%,提取温度37℃,提取时间68 min,料液比1:21(g/mL)。在此条件下,花青素提取量为(2.71±0.04)%。同时发现不同地区野生黑果枸杞花青素含量之间存在明显差异性,其中内蒙古额吉纳旗西部野生黑果枸杞中花青素含量最高,达2.71%,其次为内蒙古阿拉善右旗阿拉腾敖包,其花青素含量为2.57%。     

黑枸杞中抗氧化物质的提取及花青素含量分析

通过单因素试验和正交试验,确定黑枸杞中抗氧化物质的最佳提取工艺条件。结果表明影响提取效果的主次因素为:提取时间提取温度提取剂料液比;最佳提取工艺条件为:超声提取、料液比1:25(g/mL)、温度50℃、溶剂60%乙醇、时间25 min。以维生素C作为标准物质,对黑枸杞的总抗氧化性进行评价。采用pH示差法测定黑枸杞中花青素含量。     

太空莲叶原花青素的提取及分离纯化

利用响应面法优化太空莲叶中原花青素的提取工艺,并采用大孔树脂对原花青素进行分离纯化。结果表明,最佳提取工艺条件为:料液比为20:1、乙醇浓度为55%、提取温度为80℃、提取溶剂pH为3.0、提取时间为90 min、提取次数为2次,太空莲叶中原花青素提取率达到93.26%。提取液经大孔树脂HPD-400吸附解吸,解吸液经减压浓缩,真空干燥,得到棕红色粉末,其原花青素含量达95.32%,为从太空莲叶中分离纯化原花青素提供参考。     

Box-Behnken设计响应面法优化黑果枸杞总黄酮纯化工艺

目的应用Box-Behnken设计响应面法优化黑果枸杞总黄酮纯化工艺条件及相关参数。方法考察6种大孔吸附树脂静态、动态吸附和解吸性能,用单因素试验分别对上样浓度、上样体积、上样pH、洗脱液浓度、洗脱液体积和洗脱流速进行考察,以黑果枸杞总黄酮纯化后含量为指标,再从6个单因素中选出对解吸附试验影响最显著的3个因素进行三因素三水平Box-Behnken设计响应面实验。结果 NKA-9型大孔树脂为纯化黑果枸杞总黄酮的最佳树脂,最佳纯化工艺条件为总黄酮提取液浓度为4mg/mL,pH为4.0,按5BV进行上样,再用3VB的80%乙醇在2mL/min流速下进行洗脱,黑果枸杞总黄酮含量可以从4.54%提高到43.19%。结论此工艺对黑果枸杞总黄酮的纯化效果较好,工艺简单且稳定性良好,适用于工业化生产。     

黑果枸杞花色苷的提取、纯化及降解动力学研究

以花色苷提取量为主要考察指标,通过单因素和正交试验优化冻干黑果枸杞花色苷提取工艺,并在此条件下研究花色苷纯化工艺及其降解动力学,探讨不同温度、pH下花色苷提取量的变化。结果表明,提取最佳工艺条件为：料液比1:25(g:mL)、乙醇浓度60%、pH4、提取时间2 h,此条件下花色苷提取量达36.507±0.325 mg/g。研究显示AB-8大孔树脂纯化黑果枸杞花色苷效果最好,对花色苷吸附量和解吸量的影响效果最佳,其最佳条件为：上样液浓度200 mg/100 g,解吸乙醇浓度80%,上样流速2 mL/min,洗脱流速2 mL/min,上样体积为5 BV,纯化率为90.02%。降解动力学研究结果表明：相同pH下,随着温度升高花色苷的降解速率增大、半衰期减少;此外,花色苷在酸性环境中较稳定,在碱性环境下易降解,当pH为3,50℃时花色苷稳定性最好,t1/2最大为38.5 h,Ea最大为41.89 kJ/mol。因此黑果枸杞花色苷提取量与其提取、纯化及温度、pH的工艺条件密切相关,本研究为黑果枸杞花色苷的提取及饮品开发提供技术支撑。     

大孔树脂纯化黑果腺肋花楸多酚的工艺优化

以黑果腺肋花楸为原料,采用大孔树脂纯化黑果腺肋花楸中多酚类物质。通过对比6 种大孔树脂对黑果腺肋花楸多酚吸附-解吸效果,筛选出XAD-7大孔树脂作为最佳纯化材料,并通过单因素试验确定XAD-7大孔树脂纯化黑果腺肋花楸多酚的静态吸附-解吸最佳工艺条件为：吸附时间4 h、解吸时间2 h、上样液质量浓度3.6 mg/mL、上样液pH 4、乙醇体积分数95%、乙醇溶液pH 7;其对黑果腺肋花楸多酚动态吸附-解吸最佳工艺条件为：上样流速2 mL/min、上样量560 mL、蒸馏水洗脱用量350 mL、洗脱流速2 mL/min、洗脱体积300 mL。在此条件下,黑果腺肋花楸多酚纯度由11.62%提高到64.37%,表明XAD-7大孔树脂对于黑果腺肋花楸多酚具有较好的纯化效果。     

BBD-响应面法优化黑果枸杞色素的渗漉法提取工艺及其纯化工艺研究

目的:采用BBD-响应面法优化黑果枸杞色素的渗漉法提取工艺,并对其纯化工艺进行研究。方法:采用单因素实验结合BBD-响应面法,对影响渗漉法提取的3个主要因素乙醇浓度、渗漉速度、溶剂倍数进行了优化。通过筛选出吸附性能最好的大孔树脂,对影响其吸附与解析的因素:上样液浓度、上样液pH值、径高比、上样流速、水洗用量、洗脱剂浓度、洗脱剂pH值、洗脱剂流速进行考察,并对色素色价和产率进行测定。结果:最佳工艺是采用pH3.0,20倍量79%乙醇,以1 mL/min的流速进行渗漉提取。采用X-5大孔树脂纯化色素,径高比1:15、色素液浓度0.02 g/mL,上样液pH3.0、上样量90 mL,流速3 mL/min为最佳吸附条件;以5 BV的95%乙醇在pH2.0、流速3 mL/min的条件下洗脱效果最佳,纯化色素产率可达7.33%,色价为21.7,重复性较好,适合于工业化生产。结论:该工艺操作简单、重复性好,节约成本,可为色素大工业生产提供参考。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.