茶渣微晶纤维素的制备及表征

以茶渣为原料,采用盐酸水解法制备茶渣微晶纤维素。通过单因素试验研究了酸解时间、酸解温度、盐酸浓度及料液比对微晶纤维素得率、聚合度和结晶度的影响,采用正交试验优化了工艺参数,并运用X-射线衍射和红外光谱对微晶纤维素产品进行表征。试验结果表明:最佳制备工艺条件为酸解温度95℃、盐酸质量分数8%、酸解时间90 min、料液比1∶16(g/mL)。各因素对得率影响的显著性为:酸解温度盐酸浓度酸解时间料液比;在此条件下,茶渣微晶纤维素产品的得率为54.34%,聚合度为128;X-射线衍射和红外光谱分析表明,茶渣微晶纤维素与原纤维素材料结构一致,结晶度达67.77%,晶粒尺寸为3.98 nm,晶型为纤维素Ⅰ型。     

响应面试验优化芦笋茎秆微晶纤维素的制备工艺

以芦笋茎秆为原料,采用稀酸水解法制备微晶纤维素。以微晶纤维素得率为指标,对试验中酸水解条件盐酸质量分数、料液比和水解温度进行优化,并在单因素试验基础上通过响应面试验选出最优的制备工艺条件。结果表明:在水解时间60 min时,制备芦笋茎秆微晶纤维素的最佳工艺条件为盐酸质量分数6%、料液比1︰20(g/m L)、水解温度95℃,此条件下微晶纤维素得率达到43.57%。     

椰子中果皮微晶纤维素的制备工艺

本研究以椰子中果皮为原料,采用硝酸-乙醇法提取纤维素,并将提取的纤维素水解制备微晶纤维素;采用分光光度法测定纤维素含量,滴定法测定微晶纤维素得率。单因素实验结果表明椰子中果皮纤维素提取的适宜工艺条件为:80℃下水浴回流2h、料液比为1∶20(g/m L)、酸醇比为1∶3、该条件下,提取所得纤维素含量为75.24μg/m L。以提取的椰子中果皮纤维素为原料制备微晶纤维素的适宜工艺条件为:水解温度100℃、水解时间70min、盐酸质量分数7%、料液比1∶15(g/m L),在此条件下,微晶纤维素得率为97.50%;将制备出来的微晶纤维素进行了红外表征。本工艺能够较好地提高椰子中果皮的应用价值。     

酸解法制备大豆皮微晶纤维素的研究

以大豆皮为原料,采用酸解法制备大豆皮微晶纤维素。通过单因素实验和L9（43）正交实验,研究了料液比、硫酸浓度、酸解时间、酸解温度对制备大豆皮微晶纤维素得率及聚合度的影响。实验结果表明：酸解温度是影响大豆皮制备微晶纤维素的最重要因素,其次是硫酸浓度,酸解时间跟料液比在此实验范围内对测定结果的影响较小,制备大豆皮微晶纤维素的最佳工艺为温度95℃、硫酸浓度3%、酸解时间60min、料液比为1：10（g/mL）。在此最佳条件下,微晶纤维素的得率达到30.12%,聚合度为312。     

响应面试验优化苹果渣微晶纤维素制备工艺

研究利用苹果渣纤维素制备微晶纤维素的方法过程。在水解时间50min、水解温度100℃条件下,采用响应曲面设计法设计、分析,研究酸水解纤维素制备微晶纤维素时,各因素料液比、盐酸质量分数和次氯酸钠添加量及3因素间两两交互作用对微晶纤维素得率的影响。结果表明,各因素对得率影响的显著性表现为盐酸质量分数＞料液比＞次氯酸钠添加量。分析等高线和响应面,得出各因素两两之间的交互作用对得率都显著。通过求解回归方程得出最佳工艺条件为料液比1:25(g/mL)、盐酸质量分数6%、次氯酸钠添加量2.5mL/100mL,此条件下微晶纤维素制备得率达到69.5%。     

沙蒿微晶纤维素制备工艺及性质研究

采用酸水解法制备沙蒿微晶纤维素(MCC),通过单因素试验考察了料液比、盐酸浓度、酸解温度、酸解时间各因素对沙蒿MCC得率与聚合度的影响,利用响应面法优化沙蒿MCC的制备工艺,并对制备的MCC进行了结构性能分析。得到最佳MCC制备条件为:料液比1:30 (g/mL),盐酸质量分数15%,酸解温度70℃,酸解时间60 min。该条件下,沙蒿MCC的得率为85. 14%,聚合度为182. 7,结晶度为72. 85,膨胀力为12. 5 mL/g,持水力为13. 875 g/g,其性能良好,是理想的膳食纤维。     

丰都红心柚落果制备柚皮素

为充分利用柑橘资源、减少环境污染,该文以丰都红心柚落果为原料,探究酸解法制备柚皮素的最佳工艺条件。考察酸解温度、酸解时间、HCl质量分数和液料比对柚皮素得率及柚皮苷水解率的影响,对酸解反应进行单因素及正交试验,确定酸解法的最适工艺条件。结果表明,酸解制备柚皮素最佳工艺条件为,酸解温度110℃、酸解时间1. 5 h、HCl质量分数为3. 5%、液料比为25∶1(m L∶g),此条件下柚皮素得率为42. 39%,柚皮苷水解率为99. 31%。该研究优化的柚皮素酸解制备工艺操作简便,产物得率、原料利用度高,以期为低成本工业化生产柚皮素提供参考依据。     

毛笋壳制备微晶纤维素的工艺分析

以毛笋壳粗纤维为原料,采用酸法处理制备微晶纤维素。通过单因素和正交实验,确定酸法制备毛笋壳微晶纤维素的最佳工艺条件为:料液比1∶20,酸浓度3%,酸解温度65℃、作用时间40 min,该条件下微晶纤维素得率为63.07%,溶胀性为2.14,聚合度为123,性能良好,具有较好的应用前景。     

菊芋秸秆制备微晶纤维素的工艺优化及结构表征

菊芋秸秆是一种富含纤维素的生物质资源,为使其充分转化利用,本文探索了菊芋秸秆(JAS)制备食品添加剂微晶纤维素的可行性。以JAS为原料,采用稀盐酸水解法制备微晶纤维素(JASMCC),着重考察盐酸质量分数、水解时间、温度和料液比4个因素对JASMCC产品聚合度和得率等指标的影响,并通过响应面法优化工艺参数。结果表明:菊芋秸秆中纤维素含量高达43.61%以上。经响应面法优化的JASMCC的最佳制备工艺参数为:料液比1∶14 g/m L、盐酸质量分数5%、温度60℃、时间85 min。在此工艺下所得JASMCC产品的聚合度为255.14,得率为36.96%,纯度为97.80%,符合国标GB1886.103-2015《食品添加剂微晶纤维素》要求。利用傅里叶变换红外光谱、扫描电镜和X-射线衍射对JASMCC制备过程中的微观形貌和结晶结构进行表征,并与商业微晶纤维素比较,结果发现JASMCC的微观形态呈棒状,纤维素晶型为Ⅰ型,相对结晶指数为63.42%,说明利用菊芋秸秆制备食品添加剂微晶纤维素的工艺可行。     

胡萝卜渣微晶纤维素的制备

以胡萝卜渣为原料,采用酸水解法制备微晶纤维素,考察了酸浓度、酸解时间以及酸解温度对微晶纤维素得率的影响。通过单因素和正交试验结果分析确定优化工艺条件,并对制备的微晶纤维素性能进行分析。结果表明:优化的工艺条件是,酸浓度为6%、酸解时间60min、酸解温度80℃,微晶纤维素的得率为33.8%。     

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.     

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.