棉籽分离蛋白制备工艺研究

以脱脂棉籽粕为原料,采用碱溶酸沉法制备棉籽分离蛋白。以蛋白质提取率、产品蛋白质含量为指标,考察提取温度、提取时间、p H、液固比对棉籽分离蛋白提取效果的影响。另外,采用SDS-PAGE对所制备棉籽分离蛋白中蛋白质亚基相对分子质量分布进行了分析。结果表明,通过正交实验优化得到棉籽分离蛋白最佳制备工艺条件为:提取温度60℃,提取时间60 min,p H 10,液固比14∶1。在最佳工艺条件下,蛋白质提取率为73.21%,产品蛋白质含量为90.76%(N×6.25,干基),且游离棉酚含量由原料的0.12%下降到0.033%。棉籽分离蛋白中蛋白质亚基相对分子质量主要为59.3 k Da与53.7 k Da,占47.66%。     

萝卜籽蛋白提取及其功能性质研究

以萝卜籽为原料,用正己烷脱脂得萝卜籽粕,采用碱溶酸沉法对萝卜籽粕中的蛋白质进行提取,并测定其等电点。通过考察料液比、碱溶p H、浸提时间和浸提温度对萝卜籽蛋白提取率的影响,确定最佳的萝卜籽蛋白提取条件,并对所提取的萝卜籽蛋白和大豆分离蛋白进行功能性质的对比。结果表明:萝卜籽蛋白溶解度为84.9%,有很高的营养价值;在料液比1∶20、碱溶p H 9.0、浸提时间120 min、浸提温度50℃的条件下,萝卜籽蛋白提取率为52.3%;萝卜籽蛋白等电点有两个,分别为p H 0.5和p H 4.5;萝卜籽蛋白吸油能力为328.67%,乳化性及乳化稳定性与大豆分离蛋白相近,起泡性及泡沫稳定性较大豆分离蛋白好。     

糖化酶纯化棉籽分离蛋白的工艺研究

以脱酚棉籽为原料,对比碱溶酸沉法和酶水解-超声波辅助碱溶酸沉法对棉籽蛋白提取率的影响发现,酶解和超声辅助可以显著增加碱溶酸沉的蛋白提取率。在酶水解-超声波辅助碱溶酸沉提取蛋白的基础上,利用糖化酶纯化所提取的蛋白粗品,并在单因素试验的基础上采用正交试验优化棉籽蛋白纯化工艺,得到高纯棉籽蛋白制备的最佳工艺条件为:酶解温度60℃,酶解pH 4.5,酶解时间120 min,糖化酶用量0.4%,液料比9︰1(mL/g)。验证试验表明,利用该工艺两次纯化棉籽蛋白所得的纯化产品蛋白质含量可达93.10%。采用SDS-PAGE对纯化后的棉籽分离蛋白亚基相对分子质量分布进行分析,结果表明,纯化产品中蛋白质亚基相对分子质量主要为55.1 k Da与47.5 k Da。该研究可为棉籽蛋白在食品工业中的应用提供理论参考。     

红花籽粕蛋白质提取工艺优化

以红花籽粕为原料,采用超声波辅助碱溶酸沉法提取红花籽粕中的蛋白质,研究蛋白质提取的最佳工艺条件。结果表明,在料液比1:35、超声波功率225 W、pH9.5、时间80 min、温度50℃的条件下,红花籽粕蛋白质提取率为88.12%。     

沙棘分离蛋白提取工艺研究

采用“碱溶酸沉”原理对沙棘蛋白质进行提取,讨论固液比、浸提碱液pH值、浸提时间和温度等条件对提取率的影响,确定了最佳提取条件为固液比1：12,pH12,时间40min,温度35℃。在此条件下可使沙棘籽粕分离蛋白提取率达到79．3％,沙棘分离蛋白蛋白含量89．67％。     

苦瓜籽蛋白碱溶酸沉体系的选择研究

采用碱溶酸沉方法从苦瓜籽中提取苦瓜籽蛋白,考察了NH3·H2O、NaOH 2种碱溶试剂及3种酸沉试剂H2SO4、柠檬酸和H3PO4对苦瓜籽蛋白的提取效果,确定较佳的提取苦瓜籽蛋白碱溶酸沉体系。试验结果表明:苦瓜籽蛋白酸沉最佳pH值为4,提取苦瓜籽蛋白较佳的碱溶酸沉体系为NaOH-柠檬酸体系;通过与专利报道的NH3·H2O-H2SO4体系对比,得出NH3·H2OH2SO4体系苦瓜籽蛋白活性成分质量较NaOH-柠檬酸体系的低23%。     

牡丹籽粕蛋白提取工艺优化及其等电点分析

以牡丹籽粕为原料,对碱提酸沉法提取其蛋白的工艺条件进行优化,并对沉降蛋白质的等电点进行分析。研究结果表明,提取牡丹籽粕蛋白的最佳工艺参数为pH 11、提取时间100min、提取温度55℃、料液比1∶20(m∶V),蛋白提取率可达86.77%;牡丹籽粕蛋白质的等电点为pH 4.0,其沉淀率最高可达94.55%。     

文冠果油渣中蛋白质的提取工艺研究

分析了文冠果蛋白的氨基酸组成,并以文冠果压榨油渣为原料,采用单因素实验和正交实验优化了碱溶酸沉法提取文冠果蛋白的工艺条件。结果表明：文冠果蛋白含有18种氨基酸,其中谷氨酸(14.25%)、精氨酸(6.00%)和天门冬氨酸(5.08%)的含量较高;采用碱溶酸沉法提取文冠果蛋白的最佳工艺条件为料液比1∶30、提取pH 9、提取时间150 min、提取温度60℃,在此条件下提取2次,蛋白质得率为22.58%;酸沉分离蛋白质的最佳pH为4.6,此条件下蛋白质沉降率为94.67%;通过碱溶酸沉法可使文冠果蛋白的纯度从38.46%提高到84.03%。     

响应面法优化牡丹籽粕蛋白提取工艺及其功能性质

以脱脂牡丹籽粕主要原料,在碱溶酸沉法的基础上,采用超声波辅助酶解法提取其中蛋白质。研究超声温度、超声时间、料液比、糖化酶剂量对蛋白质得率的影响,利用响应面法优化牡丹籽粕蛋白质提取工艺条件,并将提取的牡丹籽粕蛋白功能性质与大豆分离蛋白进行对比。结果表明:提取牡丹籽粕蛋白的最佳工艺条件为料液比1∶10 (g/mL)、超声温度50℃、超声时间120 min、糖化酶添加量2%;影响因素大小按顺序排列为超声温度>超声时间>糖化酶剂量>料液比;最优工艺条件下的牡丹籽蛋白质得率为26.65%,其蛋白质含量为91.02%;牡丹籽粕蛋白的持水性、泡沫稳定性和乳化稳定性比大豆分离蛋白强,但其吸油性、乳化性和起泡性弱于大豆蛋白。     

油茶籽粕中茶皂素和蛋白质同时提取工艺研究

介绍了以油茶籽粕为原料,分别采用传统的水浸法和碱溶酸沉法同时提取皂素和蛋白质的工艺研究结果。结果表明,所采用的工艺简单可行;水浸法提取茶皂素的最佳工艺条件为液料比11:1,pH11,提取时间8h,提取温度80℃,提取率最高可达36.38%;碱溶酸沉法提取提取油茶籽粕蛋白的最佳工艺条件为料液比1:25,pH10,浸提时间130min,浸提温度60℃,提取率最高可达48.59%。     

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.     

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.     

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.     

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.     

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.     

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.     

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.