麦麸中植酸的脱除工艺

植酸是麦麸中的主要抗营养因子,为提高麦麸中蛋白质和膳食纤维的利用率,文中以植酸脱除率为目标,对麦麸中植酸的脱除工艺进行了分析和优化。结果显示,植酸脱除的最佳工艺是：以0.5 mol/L盐酸溶液为植酸提取溶剂,料液比为1:10 (g/mL),20 ℃下提取2 h,植酸脱除率可达到73.54%。结果表明,升高提取温度不利于植酸提取,提取时间过长或料液比过高都不利于植酸的脱除。经上述工艺处理后,麦麸中植酸和灰分含量有显著降低,蛋白质含量略有降低;淀粉含量和粗纤维含量均有明显提高,分别提高了16.70%和30.10%,其总体营养价值有明显改善,更有利于麸皮中营养组分的加工利用。     

麦麸多糖提取工艺及其抑菌活性的研究

通过单因素和L9(33)正交试验对麦麸多糖的微波法提取工艺进行研究,得出提取的最佳工艺条件为:时间90 s、功率320 W、料液比1∶30,在此工艺条件下,麦麸多糖得率为6.57%。通过体外抑菌试验及最小抑菌浓度的测定研究了麦麸多糖的抑菌效果,结果表明:麦麸多糖浓度为40～60 mg/mL时,其对地衣芽胞杆菌、大肠杆菌、金黄色葡糖球菌及沙门氏菌等常见致病菌已达到较好的抑菌效果;麦麸多糖的最低抑菌浓度为地衣芽孢杆菌8.0 mg/mL,大肠杆菌10.0 mg/mL,金黄色葡萄球菌和沙门氏菌均为6.0 mg/mL。     

响应面法优化盐酸降解小麦麸皮中植酸研究

本文旨在优化降解小麦麸皮中残留植酸的工艺。以麦麸为原料,植酸残余率为响应值,采用盐酸降解麸皮中植酸方法,分别研究了盐酸溶液浓度,料液比,时间和温度的影响,依据单因素的实验结果,进行了Box-benhnken响应面优化实验,得到了最佳的工艺条件:时间为2.5 h,温度为52℃,盐酸浓度为1.2 mol/L,料液比为1∶21 g/m L,此时,植酸残余率仅为0.625%。表明此法可以较好的降解植酸。     

响应面法优化小麦麸皮中植酸的提取工艺

分别探讨了盐酸 水溶液、盐酸 丙酮溶液、盐酸 乙醇溶液三种提取溶剂体系对小麦麸皮植酸的提取效果,确定盐酸溶液为最佳提取溶剂;通过单因素试验和响应面实验探讨了提取液的浓度、提取时间、提取温度对小麦麸皮中植酸提取效果的影响。结果表明,当盐酸浓度在0.7~0.9 mol/L,提取时间0.7~1.3 h,提取温度在26~33℃范围内时,植酸得率可以达到1.20%以上,并且在盐酸浓度0.7 mol/L,提取时间1 h,提取温度30℃,植酸得率为1.27%。     

大蒜抑菌成分提取工艺优化

通过采用超声波辅助提取法,对不同提取条件下大蒜提取液抗番茄晚疫病菌作用进行比较,优选出最佳提取工艺,并测定了其最小抑菌质量浓度、最小杀菌质量浓度。研究结果表明:大蒜提取液以体积分数30%乙醇作为提取溶剂,在40℃超声波辅助提取3 h,提取次数为3次,料液比为1∶5(g/mL),得到大蒜提取液抑菌效果最佳的条件。在此条件下大蒜对番茄晚疫病菌的抑菌直径为37.2 mm。大蒜提取液对番茄晚疫病菌最小抑菌质量浓度为12.5 mg/mL,最小杀菌质量浓度为25 mg/mL。     

菠萝蜜果皮黄酮提取工艺优化及比较

为筛选适合菠萝蜜果皮黄酮的提取方法,以得率为评价指标,应用酶法和有机溶剂浸提法提取其果皮中的黄酮类化合物,在单因素基础上,通过正交实验,优化提取工艺,并对两种提取方法结果进行比较评价。结果表明,酶法提取菠萝蜜果皮黄酮最佳工艺条件为:果胶酶用量300 U/g、乙醇浓度80%(v/v)、温度55℃、p H5.5、底物质量浓度45 g/L,时间2.0 h;有机溶剂浸提最佳工艺条件为:乙醇浓度80%(v/v),温度55℃,料液比1∶20(g/m L),时间2.5 h;酶法提取黄酮类化合物得率和纯度分别为4.98%、12.60%,高于有机溶剂浸提法的3.05%、8.92%,提取物的抗氧化性强于有机溶剂浸提法,说明酶法提取菠萝蜜果皮黄酮优于传统有机溶剂浸提法。     

超声波强化提取米糠中植酸研究北大核心

植酸是一种天然食品添加剂,具有强烈防腐、抗氧化能力。该实验以米糠为原料,利用超声波强化提取植酸,研究超声时间、提取温度、料液比及盐酸浓度对植酸提取率影响;通过正交试验对提取工艺进行优化,并采用高效液相色谱法对植酸样品进行分析。结果表明,提取米糠中植酸最优工艺为:盐酸浓度0.10 mol/L、料液比(g/mL)1∶8、提取温40℃、超声时间8 min;在上述条件下,对米糠中植酸提取率为87.13%。     

五倍子抗蕃茄晚疫病原菌有效成分提取工艺研究

对不同提取条件下五倍子提取液抗蕃茄晚疫病原菌作用进行比较,优选出最佳提取工艺,并测定了其最小抑菌浓度、最小杀菌浓度.结果最佳提取工艺为:水为溶剂,在80℃浸提3h,料液比1∶25,提取2次.五倍子提取液对蕃茄晚疫病原菌最小抑菌浓度为15.7mg/mL,最小杀菌浓度为31.3mg/mL.在此条件下五倍子对番茄晚疫病菌的抑菌直径为33.2mm.     

超声辅助提取花生粕中植酸工艺优化

用响应面法研究超声波辅助提取花生粕中植酸的最佳工艺,考察超声温度、超声时间、超声功率、液料比和盐酸浓度5 个因素对植酸提取率的影响。经响应面优化的超声波辅助提取植酸的优化工艺条件：超声温度40℃、超声时间24min、超声功率72W、液料比11:1(mL/g)、盐酸浓度0.01mol/L,此时提取率为1.48%,与模型预测值1.44% 相差不到3%。实验结果说明超声波方法可较好地应用于花生粕中植酸的提取,同时得到一个能较好预测实验结果的提取模型方程。     

响应面法优化菜籽粕中植酸提取工艺研究

利用低浓度(体积分数)的醋酸溶液,在单因素试验的基础上选择了醋酸浓度、提取温度和提取时间进行响应面分析,以提取液中植酸含量(质量分数)为响应值,建立了植酸提取的二次多项式数学模型,确定了植酸提取的最佳工艺条件为:醋酸浓度4.4%,提取温度41℃,提取时间2h,得到提取液中植酸含量为1.64%。     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.