水浴振荡辅助酶法提取双孢蘑菇多糖的工艺研究

为了提高双孢蘑菇多糖的提取率,本实验初步通过单因素实验和正交实验研究水浴振荡辅助酶法提取双孢蘑菇多糖的工艺条件,研究结果表明:其最佳工艺条件为:料液比为1∶40、振荡频率为40r/min、酶用量为1.2%、pH为6.5、酶解温度为65℃、酶解时间为120min。实验结果表明,双孢蘑菇多糖的提取率可达2.31%。     

绞股蓝多糖提取工艺比较及优化

目的:通过探讨热水浸提法和微波辅助提取确定提取绞股蓝多糖的最佳工艺.方法:采用热水浸提和微波辅助提取绞股蓝多糖,通过分别考察两种方法的单因素,确定其优化条件范围,通过正交实验L9(34)进一步确定绞股蓝多糖的提取工艺条件.最后通过比较两种方法多糖的提取率,得到绞股蓝多糖的优化提取工艺.结果:热水浸提法的优化工艺条件是15倍量水,90℃,2h提取2次.根据确定的工艺条件,测得绞股蓝多糖的平均提取率为4.03%.微波辅助提取的优化工艺条件是浸提70min,微波功率为70%(560W),25倍量水,处理6min.在此条件下,绞股蓝多糖的平均提取率为3.91%.结论:微波辅助提取绞股蓝多糖与热水浸提比较,虽然提取率不如前者高,但微波辅助提取能缩短提取时间,具有成本低、效率高的优点,应用前景广阔.     

纤维素酶提取枸杞多糖及工艺优化

通过单因素和正交实验对纤维素酶提取枸杞粗多糖的工艺条件进行优化,结果表明:最佳酶解工艺条件为纤维素酶用量0.45%、pH为4.5、酶解温度50℃、酶解时间160min,在此优化条件下,提取枸杞粗多糖的得率为23.68%,与热水法浸提的粗多糖8.65%相比有明显提高。其中采用酶法提取的粗多糖中的枸杞多糖含量也提高到了31.3%,为热水浸提法所得枸杞多糖含量的1.8倍。     

巴戟天药渣中多糖的提取工艺研究

巴戟天废弃药渣含有丰富的多糖,故此研究巴戟天药渣中多糖热水提取的最佳工艺条件,为巴戟天废弃药渣的综合利用提供依据。以多糖得率为指标,通过单因素实验研究4个因素:提取温度、提取时间、料液比、提取次数对巴戟天药渣中多糖提取效率的影响。在单因素实验的基础上,通过正交试验对巴戟天热水提取工艺条件进行优化。结果表明,提取温度及提取次数是影响巴戟天多糖提取效率的关键因素,料液比及提取时间是次要因素。最佳工艺条件为:巴戟天药渣在100℃水浴中用7倍量的蒸馏水提取2次,每次1 h,在此条件下,巴戟天多糖的得率为15.67%。该工艺条件可重复,多糖得率较高。     

广东淮山多糖提取工艺的研究

采用正交实验设计方法对热水浸提和碱提广东淮山多糖的工艺条件进行了优化,实验表明,广东淮山水溶性多糖最佳提取工艺条件为固液比1∶8(w∶v)、45℃水浴、浸提2h;当浸提液浓缩4倍,95%乙醇添加量为浓缩液体积的4倍时,可得到多糖的最高沉降率98.3%。碱提广东淮山多糖最佳提取工艺条件为固液比1∶8,NaOH浓度0.3mol/L,浸提时间1h,醇沉浓度80%。     

王不留行多糖提取工艺研究及其含量测定

采用水提醇沉提取工艺,运用单因素实验和正交实验,以多糖提取率为评价指标,确定王不留行多糖的最佳提取工艺条件。多糖含量测定方法采用酶解-苯酚-硫酸法。结果表明,王不留行多糖最佳工艺条件为提取温度100℃,提取时间2h,水料比10∶1(mL/g),提取次数为3次。在此优化条件下的多糖提取率为29.32%。王不留行经清炒炮制后,多糖提取率降为22.15%。     

均匀设计与正交设计联用优选铁皮石斛多糖提取工艺的研究

目的:优选简便高效的铁皮石斛多糖的提取工艺,考察不同务件下的总多糖得率.方法:采用均匀设计与正交设计联用的方法对铁皮石斛多糖的提取工艺进行优选.结果:优选出来的铁皮石斛最佳提取工艺条件为温度85~C,提取时间3h,液料比20倍时,提取的总多糖得率最高为24.9%.结论:正交设计与均匀设计联用是优选工艺的好方法,本实验所得工艺合理,提取率高,适用于工业生产.     

超声波辅助提取霍山石斛多糖及其抗氧化活性研究

以霍山石斛为原料,利用超声波辅助法提取霍山石斛多糖,采用Box-Behnken设计和响应面分析对提取条件进行优化,同时比较了超声波辅助提取工艺和热水浸提工艺所得霍山石斛多糖的还原力和ABTS自由基清除率。结果表明,超声波辅助提取霍山石斛多糖的最优工艺条件为:液料比30:1,浸提温度81℃,浸提时间120 min,超声功率423 W,超声时间8 min,在此优化条件下多糖平均得率为19.96 mg/g,是传统热水浸提工艺的1.70倍。体外抗氧化结果显示,超声波辅助提取工艺所得霍山石斛多糖还原力和ABTS自由基清除率均优于热水浸提的多糖。该试验结果为后续霍山石斛多糖的提取和抗氧化活性研究提供了实验依据和技术支持。     

星点设计-效应面法优选南瓜多糖提取工艺

目的：采用星点设计-效应面法优选南瓜多糖的提取工艺,并选用适宜的大孔树脂进行纯化,探讨适合工业化生产的南瓜多糖最优的提取纯化工艺。方法：本实验以热水浸提法提取南瓜多糖,采用单因素试验和星点试验设计,研究料液比、提取时间、提取温度、提取次数以及醇沉条件对南瓜多糖浸膏得率的影响,并采用乙醇反复沉淀的方法以及大孔吸附树脂对南瓜多糖进行纯化从而得到进一步纯化的南瓜多糖。结果：南瓜多糖提取最佳工艺为36倍量的水在84℃温度下提取3.2h,提取3次,然后浓缩至1/3体积、以3倍体积95%乙醇醇沉。选用AB-8型大孔吸附树脂进行纯化,纯化的最优条件为20℃条件下上柱,初始液质量浓度取2.84mg/mL,以5BV上柱,5BV的20%乙醇溶液洗脱,最终得到纯化后南瓜多糖的含量可达到60%以上。结论：星点设计-效应面法优选南瓜多糖的提取工艺,方法简便,预测性良好。实验选用AB-8型大孔吸附树脂对南瓜多糖进行纯化。     

复合酶法提取红蘑多糖工艺

以野生红蘑为原料,复合酶法浸提红蘑中真菌多糖。在单因素试验的基础上,采用正交试验设计获得最佳多糖提取工艺,即酶解温度60℃、纤维素酶和木瓜蛋白酶的比例为3:1(m/m)、pH5.0、酶解3h,此条件下提取多糖得率为12.0%。与传统方法相比,该工艺具有提取条件温和,提取时间较短,对多糖损伤小等特点。     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.