薏仁米糠蛋白酶法提取工艺的优化

为了研究酶法提取薏仁米糠蛋白的最佳工艺,在单因素试验的基础上,采用Box-Benhnken试验设计,利用响应面法优化薏仁米糠蛋白的提取条件。分析回归方程确定薏仁米糠蛋白提取率的影响因子,确定最佳提取工艺为料液比1∶29（g∶mL）,酶解温度50 ℃,酶解时间1.5 h,酶解pH 9.8。在此最佳提取工艺条件下,薏仁米糠蛋白平均提取率79.66%,产品纯度为73.42%。     

蚕豆蛋白提取工艺的研究

本文采用碱法工艺对蚕豆蛋白的提取方法进行了研究。通过单因素分析,正交试验,确定了蚕豆蛋白的最佳提取工艺条件,即pH9.0,温度45℃,固液比1∶12。在此条件下抽提1h,提取率可达84.1％。     

榛子蛋白提取及纯化的工艺优化

摘要：以榛子粕为原料,采用碱性蛋白酶酶解辅助碱溶酸沉法提取榛子蛋白,然后加入碱液复溶、碱性蛋白酶酶解、酸沉纯化。在单因素试验的基础上采用响应面法对提取过程中酶解工艺条件进行优化,采用正交试验优化榛子蛋白纯化工艺。结果表明：最优酶解工艺条件为酶解温度46 ℃、pH 8、酶解时间3.7 h,在此条件下榛子蛋白提取率达到53.16%;最佳纯化条件为反应温度50 ℃、液料比5∶ 1、复溶pH 11,在此条件下榛子蛋白纯度为95.23%。     

碱酶两步法提取麻渣中蛋白质的工艺研究

采用碱酶两步法提取麻渣中的蛋白质。首先确定了碱溶法最佳工艺;然后对影响酶解法提取率的四个因素pH值、温度、酶用量、时间分别做了单因素试验,确定了各因素的最佳水平,再通过正交试验确定了酶解法的最佳工艺条件。结果表明:碱溶法最佳工艺为固液比1∶20,pH值10,时间3h,温度50℃;酶解法的最佳工艺条件为pH值11,酶用量150U/mL,酶解温度40℃,时间4h。碱酶两步法提取使麻渣蛋白质提取率达到81.21%。     

山核桃饼粕蛋白提取工艺的优化

采用二次正交旋转组合试验设计对碱提酸沉法提取山核桃饼粕蛋白的工艺进行优化。结果表明,山核桃饼粕蛋白的等电点为pI 5.0;其最佳提取条件为提取液pH值9.0,提取时间124min,提取温度53℃,料液比1∶22(m∶V),该条件下的实际平均提取率为(67.94±0.05)%。     

酶法辅助聚乙二醇-200提取野菊花中绿原酸的工艺及数学模型分析（网络首发、推荐阅读）

研究了酶法辅助聚乙二醇(PEG)-200提取野菊花中绿原酸的工艺条件。以绿原酸提取率为考察指标,纤维素酶用量、液固比、酶解温度和酶解时间为试验因素,通过单因素试验和响应面法对提取工艺条件进行优化。在此基础上建立了不同液固比下的野菊花中绿原酸提取的4种数学模型。结果表明：最佳工艺为纤维素酶用量0.8%,液固比20∶1(mL∶g),酶解温度55 ℃,酶解时间2.5 h,在此条件下野菊花绿原酸提取率可达3.92%;Slogistic1模型可以更好地拟合数学模型过程,是描述野菊花中绿原酸提取过程的最佳数学模型。     

燕麦蛋白的碱法提取工艺及其提纯研究

为提高燕麦蛋白的提取率,采用正交试验对碱提酸沉法提取燕麦蛋白的工艺进行优化,确定其最佳提取工艺条件为料液比1∶13(m∶V),浸提液pH值10.5,浸提温度45℃,搅拌时间1.7h。该条件下燕麦蛋白提取率可达68.46%。经石油醚提纯后燕麦蛋白纯度可达86.35%,有效提高了燕麦蛋白的提取率。     

响应面法优化稻壳中木聚糖的提取工艺

为提高稻壳中木聚糖的提取率,稻壳经3％的硫酸预处理后再用碱法进行木聚糖的提取,采用响应面法优化工艺条件,先对提取温度、NaOH浓度、固液比、提取时间4个因素进行单因素试验.根据单因素试验结果设计中心组合试验,以木聚糖提取率为考察指标,采用响应面分析法确定最优工艺参数.结果表明:提取温度69.8℃、NaOH浓度10.7％、固液比1∶13(m∶V)、提取时间5.1h.该条件下,木聚糖提取率可达76.57％.     

响应面法优化燕麦全粉中蛋白质提取工艺

采用传统碱溶酸沉法对燕麦全粉中的蛋白质进行提取,考察pH、温度、料液比、时间等因素对燕麦蛋白提取率的影响。在单因素试验基础上,利用二次正交旋转组合试验进行因素水平优化,由方差分析和响应面分析选出最佳因素水平为pH 11、温度35℃、料液比1∶20(m∶V)、提取时间1.2h,该条件下燕麦蛋白质提取率达到64.47%,纯度为80.21%(干基)。     

酶解米糠蛋白制备米糠营养液的工艺研究

研究酶解米糠蛋白制备米糠营养液的最佳工艺条件.以脱脂米糠为原料,将米糠磨浆后用α-淀粉酶进行预处理,考察在碱性蛋白酶酶解条件下的蛋白质提取率,通过单因素试验和正交试验确定最佳酶解条件:固液比1:5(W:V)、温度50℃、pH值8.5、蛋白酶用量750 U/g、时间3 h,在此条件下的蛋白质提取率可达45.1%.     

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.