基于Design-Expert 软件设计优化大蒜多糖提取工艺

主要研究大蒜多糖提取的4种影响因素及其交互作用对大蒜多糖提取率的影响,借助于Design-Expert软件设计,优化大蒜多糖提取工艺条件,以期为开发利用大蒜多糖提供参考。采用水煮醇沉法提取大蒜多糖,以苯酚-硫酸法检测其含量,分别考察浸提时间、料液比、浸提温度及浸提次数对大蒜多糖得率的影响。在单因素试验的基础上,利用Design-Expert软件进行四因素三水平Box-Behnken试验设计,建立了大蒜多糖提取率和各因素之间的数学模型。结果表明,提取温度、液料比、提取时间和提取次数的一次项,个别交互项及其二次项对大蒜多糖得率的影响显著,而液料比与提取时间,液料比与提取次数的交互项作用不明显。大蒜多糖提取最优条件最终确定为:提取温度81℃,液料比14∶1(m L/g),提取时间84 min,提取次数2次。     

黄鸡枞子实体多糖提取工艺优化研究

以多糖得率为评价指标,采用水提醇沉法对黄鸡枞多糖的提取工艺条件进行优化,选用单因素试验和正交试验法,考察料液比、提取温度、浸提时间3个因素对该菌多糖得率的影响。结果表明,影响黄鸡枞水溶性多糖提取率的主要因素依次为料液比提取温度浸提时间,通过正交试验确定该菌多糖的最佳提取条件为料液比1∶30,浸提温度60℃,浸提时间2 h,在此条件下,其多糖得率可达4.7%,为改善黄鸡枞多糖的提取方法提供了试验基础。     

响应面分析法优化莲花蜂花粉多糖提取工艺研究

为研究水提法提取莲花蜂花粉多糖的条件,在单因素试验的基础上,根据Box-Behnken 试验设计原理,选取料液比、浸提时间和浸提温度三因素三水平进行响应面分析,建立多糖提取率的二次回归方程,得到提取工艺的优化组合条件。结果表明：料液比、浸提时间和浸提温度对莲花蜂花粉多糖提取率都有显著影响,当提取工艺条件为料液比1:9.4(g/mL)、浸提时间2.4h、浸提温度81.6℃、浸提2 次时,莲花蜂花粉多糖提取率预测值为1.2201%、验证值为1.2317%。     

复合酶法提取石榴皮多糖的工艺研究

对复合酶(纤维素酶、果胶酶和木瓜蛋白酶)提取石榴皮多糖的工艺条件进行研究。以陕西临潼石榴皮为材料,运用正交试验法确定了复合酶的最佳加入量配比。比较了酶解时间、温度、pH以及液料比对多糖得率的影响,通过正交试验确定了最佳酶法提取条件。结果表明复合酶的最佳加入量配比为:纤维素酶120 U/g,果胶酶150 U/g,木瓜蛋白酶90 U/g;提取因素对多糖得率的影响大小为:pH温度时间料液比;最佳酶解提取条件为:浸提时间为120 min、温度为53℃、浸提液pH为4.6、料液比为1:55 g/m L。此条件下石榴皮多糖得率为6.01%。此法可使石榴皮多糖得率比传统水提法提高2倍,是一种提取效率高、温和的多糖提取方法。     

响应面分析法优化油菜花粉多糖提取工艺的研究

研究油菜花粉中水溶性多糖的提取工艺。在单因素试验的基础上,根据Box-Behnken中心组合试验设计原理,选取水料比、提取时间和提取温度3个因素的3个水平进行响应面分析,建立多糖得率的二次回归方程,得到提取工艺的优化组合条件。试验结果表明:水料比、提取时间和提取温度对水溶性多糖得率都有较显著影响,当提取工艺条件为水料比17.4∶1,时间3.4h,温度83.3℃时,多糖得率达到极大值。此条件下水溶性多糖得率预测值为1.4427%,验证值为1.4823%。     

藜麦多糖提取工艺的响应面法优化及其品种差异

研究藜麦种子多糖的最佳提取工艺条件及其品种间的多糖得率差异。采用水浴加热回流法,在单因素试验的基础上,选取提取温度、料液比、浸提时间进行3因素3水平的Box-Behnken中心组合研究,并运用Design Expect 8.0软件对试验数据进行分析,通过响应面分析法对提取条件进行了优化。结果表明,藜麦种子多糖的最佳提取工艺为:提取温度91℃,浸提时间1.5 h,料液比1:34,在此条件下,多糖得率在理论上可达15.81 g/100 g。各因素对多糖提取率的影响程度依次为:料液比提取温度浸提时间;同时发现藜麦种子多糖得率存在明显的品种间差异,其中品种"Quinoa B.Rain Sow"的多糖得率最高,达到15.889 g/100 g。     

油橄榄果渣中多酚提取工艺的优化

采用加热回流提取法,研究了浸提温度、乙醇浓度、料液比和浸提时间对油橄榄果渣多酚提取得率的影响。在单因素试验的基础上,通过正交试验对提取条件进行了优化,得到了油橄榄果渣中多酚的最优提取工艺:浸提温度为60℃、乙醇浓度为75%、料液比为1:13、浸提时间为4 h,油橄榄果渣多酚提取得率为0.2469%。     

茶树花多酚提取工艺的研究

用常规水浴浸提法和超声波辅助浸提法来提取茶树花中的多酚，研究了浸提温度、时间、料液比等因素对多酚得率的影响，比较得出超声波辅助浸提用时短，温度低的优点；通过正交试验设计，研究了各因素对多酚浸提影响的主次顺序，确定了最佳提取参数。实验结果采用统计软件（SPSS）进行分析，影响超声波辅助浸提各因素的主次顺序为料液比、温度、浸提时间,超声波辅助浸提最佳工艺为：温度50℃、提取时间10min、料液比1：30，在此工艺条件下多酚浸提得率75．13ms／g干花。为茶树花资源深度研究开发提供依据。     

油菜花粉多糖提取工艺条件研究

对油菜花粉多糖的提取工艺进行研究。探讨浸提次数、时间、料液比和温度对多糖得率的影响,在单因素试验的基础上,通过正交试验确定最佳提取工艺条件。结果表明:温度对多糖得率的影响最大,其次为提取时间、次数,料液比的影响最小。油菜花粉多糖提取的最优条件为1:4的料液比,90℃水浴条件下,浸提4次,每次浸提4h,其水溶性多糖提取率达1.450%。     

响应面分析法优化菠萝皮渣多糖提取工艺研究

采用Plackett-Burman试验设计及响应面分析法,对影响超声协同热水法提取菠萝皮渣多糖的工艺参数进行优化研究。在单因素试验的基础上,首先利用Plackett-Burman试验设计对影响菠萝皮渣多糖得率的6个因素进行评价,筛选出具有显著效应的3个因素,即水浴浸提温度、料液比和超声时间,随后采用最陡爬坡试验和响应面试验设计优化这3个主要影响因素的最佳参数水平。结果发现,采用料液比1:50(g/m L)、水浴浸提温度98℃、水浴浸提时间2.5 h、超声功率120 W、超声时间40 min、超声水浴温度60℃的提取条件,菠萝皮渣多糖理论得率为1.67%,实际得率为1.62%,表明该优化工艺合理可行,可用于菠萝皮渣中粗多糖的提取。     

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.     

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.     

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.     

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.