草酸铵超声辅助提取豆腐柴果胶

以豆腐柴为原料,采用草酸铵及超声辅助对豆腐柴果胶的提取工艺进行研究。在单因素试验的基础上,通过正交试验确定提取豆腐柴果胶的最优工艺条件,并对该工艺条件下的果胶进行了质量检测。结果表明：采用超声提取可以显著提高提取率。在试验范围内,提取温度、提取时间、草酸铵质量浓度和液料比对果胶提取效果均有一定的影响,其最佳工艺条件为提取温度70℃、提取时间70min、草酸铵质量浓度8g/L和液料比50:1(mL/g),其中草酸铵质量浓度和提取温度达到显著水平;在该工艺条件下果胶提取率达63.79%。本实验方法获得的果胶提取率高,各项指标均达到了行业标准(QB 2484-2000《食品添加剂：果胶》)要求。     

菠萝皮渣果胶超声波提取工艺条件研究

目的:探讨采用草酸铵作为提取溶剂和超声波振荡处理法提取菠萝皮渣果胶的工艺条件。方法:以果胶提取率作为测定指标,通过正交实验,确定了菠萝皮渣果胶最佳提取工艺条件。结果:最佳组合为草酸铵浓度0.4﹪、料液比1∶40、pH5.0、温度70℃、超声波频率47kHz、提取时间90min,菠萝皮渣中的果胶提取率达到90%。     

超声辅助草酸铵法提取南瓜果胶及其理化性质研究

以籽用南瓜废弃果肉为原料,将超声法的"空化"作用与草酸铵法的"螯合"作用相结合,优化提取果胶工艺。通过单因素试验确定了各影响因子(草酸铵浓度、料液比、提取时间和提取温度)的数据范围,并揭示了正交试验最优条件下果胶的理化特性。结果表明,各因素对提取率有不同程度的作用,提取温度80℃,草酸铵浓度0.8%,料液比1∶30,提取时间60 min,果胶平均得率为6.09%。该方法提取的果胶具有GB 25533-2010中的果胶凝胶特征,与QB 2484-2000标准和《食品化学法典》的要求一致,酯化度为75.23,属高甲氧基果胶。     

大豆皮果胶多糖的提取工艺研究

对从豆皮中提取果胶多糖的工艺条件进行了研究。在提取过程中,通过单因素法分析了四个主要因素:提取液浓度、提取温度、提取时间及料液比对提取率的影响。在单因素的基础上,通过正交实验,得到的最佳工艺条件为草酸铵浓度:0.6%,料液比1∶35,提取温度:100℃,提取时间:2h。     

响应面法优化磨盘柿果胶的提取工艺

为了充分开发磨盘柿资源,以磨盘柿加工柿子酒后的废弃物-柿子渣为原料,对果胶的提取工艺进行了研究。采用草酸铵提取法对柿子渣的果胶进行提取,单因素实验考察了提取时间、提取温度、提取液pH、料液比、草酸铵浓度对提取率的影响,并利用响应面分析法对果胶的提取工艺进行了优化。结果表明,最佳的提取条件为:草酸铵浓度为0.60%,提取温度95℃,反应时间4 h,pH1.9,在此条件下果胶的提取率为11.2%±0.3%。通过此方法,能够有效地提取出果渣中的果胶,为磨盘柿子的综合开发提供了思路。     

草酸铵法提取冬瓜皮果胶及其理化性质研究

以冬瓜皮为原料,采用草酸铵法提取冬瓜皮果胶。通过单因素试验和正交试验确定提取冬瓜皮果胶的最优工艺条件,并对提取的果胶成品进行理化指标测定。结果表明:在试验范围内,草酸铵质量浓度、提取温度、提取时间和料液比对冬瓜皮果胶的提取得率均有一定的影响,其最佳工艺条件为草酸铵质量浓度1.5%、温度为80℃、提取时间2.0 h、料液比为1∶30(g/m L);在该工艺条件下果胶提取率达8.91%。该方法提取的果胶各项指标均达到了国家标准GB 25533-2010《食品添加剂果胶》和行业标准QB 2484-2000《食品添加剂果胶》要求。     

红湘莲莲皮粉果胶多糖的提取工艺研究

用草酸铵溶液作为提取溶剂提取了红湘莲莲皮粉中的果胶多糖。通过单因素实验法考察了草酸铵浓度、提取温度、提取时间以及料液比等四个因素对果胶多糖得率的影响。在单因素实验的基础上,通过正交实验,得到的最佳工艺条件为:草酸铵浓度0.7%,提取温度100℃,提取时间2 h,料液比1:30(m/V)。在该条件下,果胶多糖的得率为12.50%。所得果胶多糖经FTIR分析和酯化度测定为低酯化度果胶。     

超声辅助提取香蕉皮多酚工艺优化及其抗氧化性的分析

采用超声辅助技术从香蕉皮中提取多酚类物质,利用响应曲面法建立多酚提取率与液料比、乙醇体积分 数、超声温度、超声时间之间的数学模型,确定香蕉皮多酚的适宜提取工艺参数;通过体外实验评价香蕉皮多酚的抗 氧化能力。结果表明：多酚提取率模型拟合度良好,超声辅助提取香蕉皮多酚的适宜工艺参数为液料比9∶1（mL/g）、 乙醇体积分数54%、超声温度53 ℃、超声时间43 min,在此条件下多酚提取率为2.931%,提取的香蕉皮多酚具 有较强的清除DPPH自由基、超氧阴离子自由基和羟自由基的能力,半抑制质量浓度分别为0.422 8、0.255 2 mg/mL 和0.243 9 mg/mL。     

菠萝蜜丝果胶提取工艺优化

采用酸提取方法对菠萝蜜丝果胶的提取工艺条件进行研究,考察乙醇浓度、沉淀时间、提取温度、提取液pH、液料比、提取时间等因素对果胶提取率的影响。确定了酸提取菠萝蜜丝果胶的最佳工艺条件:乙醇浓度为70%、沉淀时间为50 min、提取液pH为2.5、提取温度为95℃、提取时间90 min、液料比为20∶1(mL/g)。在最佳提取工艺条件下,菠萝蜜丝中果胶的提取率为2.12%。     

桑枝皮中果胶的提取工艺优化

以桑枝皮为原料,采用草酸铵-草酸水解、乙醇法沉淀提取果胶,研究料液比、pH值、提取温度和提取时间对果胶提取率的影响,并分析湖桑32、育711、农桑14和农桑8桑树品种在不同时期和不同部位的桑枝皮中果胶的提取率。结果表明,提取桑枝皮中果胶的最佳工艺条件为料液比1:14(g/mL)、pH2.0、提取温度90℃、提取时间120min,脱色条件为温度60℃、时间30min、活性炭与浸提液比例1:100(g/mL),在此条件下果胶提取率可达12%左右。不同桑树品种、不同采摘时期、不同部位的桑枝皮中的果胶提取率都有所差异,其中湖桑32号、夏伐桑枝皮、春秋季中部位桑枝皮及夏伐一年生桑枝皮中果胶提取率较高。湿桑枝皮中果胶提取率比烘干后的桑枝皮中的提取率高。     

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.