蓝莓果渣花色苷提取工艺优化及抗氧化活性比较研究

以蓝莓干果渣为原料,酸化乙醇为溶剂,应用超声辅助法提取花色苷,利用pH示差法测定花色苷含量,通过单因素实验和响应面试验优化得出蓝莓干果渣花色苷提取工艺条件,比较相同干重的蓝莓干果渣、湿果渣采用超声辅助提取和无超声辅助工艺得到的提取液的总多酚、花色苷含量及抗氧化活性。结果表明,蓝莓干果渣最佳提取工艺为液料比(31:1)mL/g,乙醇浓度63%,pH2.6,超声功率500 W,提取时间20 min,在此条件下蓝莓果渣提取液中花色苷含量为498.84 mg/100 g。相同原料,超声辅助提取工艺提取液较无超声辅助提取工艺提取液的总多酚和花色苷含量多;相同工艺条件下,相同干重的湿果渣总多酚和花色苷含量较干果渣低,但却拥有更高的抗氧化活性。     

响应面法优化超声波辅助提取蓝莓叶多酚

以蓝莓叶粉末为材料,以超声波辅助乙醇提取蓝莓叶多酚,研究超声时间、超声功率、乙醇浓度、料液比对蓝莓叶多酚得率的影响,并采用响应面法优化了超声波辅助乙醇提取蓝莓叶多酚的工艺条件。结果表明:超声时间10 min,超声功率546 W,乙醇浓度64%,料液比1∶22(g/m L),蓝莓叶多酚得率为8.54%。超声波辅助提取法操作简便、得率高,是适合蓝莓叶多酚提取的一种工艺方法。     

蓝莓叶多酚减压提取工艺优化

采用减压提取蓝莓叶多酚,在单因素基础上采用正交实验对pH、提取时间、料液比、粒度进行优化,得到最佳提取条件为:真空度-0.07MPa,乙醇浓度60%,pH3.5,提取时间60min,料液比1∶50,物料粒度80～100目,在此条件下多酚提取率为81.47%,多酚纯度为45.32%,其中多酚纯度比常压提取高6.57%。采用ORAC法、TEAC法、DPPH法、亚硝酸盐法对蓝莓叶多酚抗氧化能力进行评价,结果表明:蓝莓叶多酚有很强的抗氧化能力,减压提取的蓝莓叶多酚比常压提取的蓝莓叶多酚具有更强的抗氧化能力。     

溶剂提取蓝莓果渣中总黄酮的研究

研究了从废弃的蓝莓果渣中提取总黄酮的工艺,采用紫外分光光度法测定其含量,实验结果表明:乙醇为最佳的提取溶剂,最佳提取奈件为:60%乙醇为提取溶剂,按照1:18的料液比例,在80℃条件下回流提取3h.经实验验证得出,此条件下蓝莓果渣的总黄酮提取率可达5.8%.     

响应面法优化蓝莓叶多酚提取工艺

采用乙醇提取蓝莓叶中多酚。在单因素试验的基础上,通过Plackett Burman试验筛选出对蓝莓叶多酚提取具有显著影响的因子:乙醇体积分数(P=0.0025)、提取温度(P=0.0091)、料液比(P=0.0236)、提取时间(P=0.0156);采用响应面法优化,得到最佳工艺条件为乙醇体积分数62.05%、提取温度67.54℃、料液比1:23.65、提取时间2.06h,在此条件下,多酚提取率为90.49%。同时,建立了醇提蓝莓叶多酚的二次数学模型,对蓝莓叶多酚提取具有良好的预测作用。     

微波辅助提取油橄榄果渣多酚

利用微波辅助技术对油橄榄加工果渣中多酚的提取工艺进行了研究,考察了提取方式、溶剂种类和浓度、料液比、微波提取功率、处理时间等因素对油橄榄果渣多酚提取含量的影响。结果表明:微波辅助提取油橄榄果渣多酚的提取量比常规溶剂提取方法提高18%～38%,适宜提取溶剂为乙醇。正交实验确定的优化工艺为:料液比1∶20(g∶mL)、微波功率300 W、处理时间3 min、乙醇体积分数60%,在此优化条件下,油橄榄果渣多酚含量可达1.02%。     

蓝莓果渣花青素的超声辅助提取工艺优化

以蓝莓果渣为原料,用酒石酸酸化乙醇提取花青素,同时应用超声波进行辅助提取,采用双波长pH示差法计算花青素提取率,利用响应面分析法对蓝莓果渣花青素的提取工艺条件进行优化。结果表明:其最佳提取条件为提取温度50℃,pH 3.0,酸化乙醇浓度65%,料液比1:70(g/mL),超声波提取功率500 W,提取时间20 min,蓝莓果渣花青素提取率实际值为83.638%,与预测值85.442%的偏差为2.111%。该试验设计操作简便合理,得率高,可预测性较好,为蓝莓果渣花青素提取提供了理论依据。     

超声波辅助提取桑葚果渣中多酚物质的工艺研究

研究了以乙醇为溶剂,用超声波辅助提取法提取桑椹果渣中总多酚物质的最佳工艺,主要考察了乙醇提取时乙醇浓度、料液比、振幅、超声时间对多酚提取率的影响。结果表明：超声波辅助法提取桑椹渣中多酚的最佳工艺条件为：料液比为1：70,超声时间为160s,乙醇浓度为60%,振幅90%;在此条件下从桑椹果渣中提取的总多酚浓度为73.3284mg/g。     

苹果渣多酚超声提取工艺研究

以新鲜苹果渣为原料,乙醇为提取溶剂,使用单因素结合正交试验的方法对超声波提取苹果渣多酚工艺条件进行优化。结果表明:苹果渣多酚最优提取工艺条件为:提取功率为600W,提取时间为25min,乙醇浓度为60%,料液比为1∶20,提取温度为45℃。在此条件下,苹果多酚的得率为2.05%。     

基于抗氧化活性分析的蓝莓多酚提取工艺

基于对蓝莓不同极性溶剂(水、正丁醇、甲醇、70%乙醇、乙酸乙酯)提取物以及甲醇提取、大孔树脂纯化后的乙酸乙酯、正丁醇和水萃取物抗氧化活性(DPPH和ABTS)的分析测定,优化并确定了蓝莓多酚的提取工艺。实验结果显示,蓝莓不同溶剂提取物对DPPH、ABTS自由基具有良好的清除能力,其活性成分主要集中在大极性的70%乙醇、甲醇和正丁醇部位,经过大孔树脂纯化后萃取得到蓝莓不同极性多酚抗氧化活性强弱顺序为:正丁醇水乙酸乙酯。蓝莓提取物和萃取物的抗氧化能力与多酚含量有显著的相关性,与花色苷含量无关。较大极性的提取和萃取溶剂有利于蓝莓强效多酚的获取。以抗氧化活性为导向的蓝莓多酚提取工艺为:蓝莓果实以含0.3%三氟乙酸的70%乙醇提取,提取液经LS-305大孔树脂吸附,先用0.3%三氟乙酸水溶液冲洗去杂,再用含0.3%三氟乙酸的甲醇溶液洗脱,洗脱液在40℃下减压浓缩除去甲醇后用水溶解,以乙酸乙酯萃取去杂,再以正丁醇萃取,萃取液在60℃下减压浓缩后冷冻干燥。     

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.     

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.     

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.