双水相萃取分离葡萄籽中原花青素

采用双水相萃取葡萄籽中原花青素,首先研究双水相萃取体系组成、辅助萃取方法、萃取策略对原花青素萃取效果的影响,并采用正交试验对原花青素萃取条件进行优化。结果表明,双水相萃取体系组成为无水乙醇/硫酸铵,辅助萃取方法为微波辅助法,萃取策略为乙醇+水+葡萄籽微波处理后加入硫酸铵,条件为无水乙醇/硫酸铵萃取体系为质量分数30%无水乙醇/质量分数20%硫酸铵,加入葡萄籽质量分数为3%,pH为4.0,微波功率100 W,微波时间5 min,在该条件下,葡萄籽中原花青素的萃取率为94.1%,得率为25.8mg/g;     

离子液体双水相体系分离辣木叶凝乳酶

采用[C_4mim]Br/K_2HPO_4双水相抽提技术从辣木叶蛋白中分离凝乳酶,研究双水相参数[C_4mim]Br浓度、K_2HPO_4浓度、粗酶浓度、体系pH对凝乳酶活力和分离效果的影响,并与传统的硫酸铵三步盐析法相比较。结果表明:1.3 g/mL的[C_4mim]Br,2.2 g/mL的K_2HPO_4,粗酶添加量为20 mg/mL,pH7.5可达最佳凝乳酶萃取效果,此条件下辣木叶凝乳酶的酶活性回收率达到85.5%,纯化因子达1.49。与三步盐析法相比,较强的疏水相互作用提高了酶的分离效果,且分离步骤少可有效降低酶活力损失。根据电泳结果,分相后的辣木叶凝乳酶分子量为(55~60)ku存在于上层的富离子液体相,部分杂蛋白的分子量为(25~40)ku保持在富盐底部。     

盐诱导乙醇水体系萃取分离葡萄皮中原花青素

采用盐诱导乙醇水体系萃取分离葡萄皮中原花青素,利用单因素试验和正交试验研究了盐的种类和加入量、乙醇体积分数、样品加入量、温度对原花青素萃取效果的影响。并且以1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、还原Fe3+能力、羟自由基清除能力分析葡萄皮中原花青素的抗氧化活性。结果表明,乙醇体积分数为50%,料液比为1∶15(g∶mL)制备原花青素粗提液;然后向15 mL粗提液中加入3.6 g Na2HPO4,在30 ℃条件下充分混匀分相后,葡萄皮中原花青素萃取率和分配系数分别为85.51%和2.48。抗氧化实验结果表明,葡萄皮中原花青素有一定抗氧化活性,萃取后原花青素比粗提液中原花青素的抗氧化能力强。     

均匀设计优化超临界CO2提取含原花青素的葡萄籽油

以原花青素的提取率和葡萄籽的出油率为考察指标,利用均匀设计法对超临界CO2萃取时间、萃取压力、萃取温度进行了优化,得到最佳工艺条件为:萃取压力15 MPa,萃取时间3 h,萃取温度50 ℃;在最佳条件下葡萄籽出油率为(10.92±0.25)%,原花青素提取率为(23.4±7.2)mg/100 g.在加入无水乙醇夹带剂的前提下,利用超临界CO2萃取葡萄籽油,可以使油中含有原花青素,提高葡萄籽油的品质.     

芦丁在异丙醇/无机盐双水相体系中分配行为的研究

采用异丙醇与无机盐构建双水相体系,以芦丁在两相间的相比R、分配系数K、萃取率E为指标,考察了无机盐种类、无机盐质量分数、异丙醇质量分数以及芦丁浓度对其分配行为的影响。实验结果表明:不同种类无机盐所构建双水相体系萃取率高低顺序为:K_2HPO_4Na_2SO_4(NH_4)_2SO_4Na_2CO_3K_2CO_3;以K_2HPO_4和异丙醇构建的双水相体系中,萃取率随盐浓度以及异丙醇浓度的增加呈先升高后降低的趋势,萃取率随芦丁浓度的增加而升高,但高浓度对萃取率的提高贡献有限。以质量分数28%的异丙醇和质量分数28%的K_2HPO_4构建的双水体系配系数为13,萃取率达93.4%。     

猪肉内源性脂肪酶三种提取方法的比较研究

比较PEG2000/(NH4)2SO4双水相体系萃取法、反胶团提取法、双水相萃取和壳聚糖沉淀相结合的三种方法对猪肉内源性脂肪酶萃取效果的影响。通过正交实验进一步优化每一种方法的提取条件。结果表明:在PEG2000浓度25%、(NH4)2SO4浓度12%、pH6.5、壳聚糖浓度为2.5mg/mL的条件下,进行双水相萃取和壳聚糖沉淀相结合法萃取脂肪酶的萃取效果最佳,其萃取率为97.83%,分配系数为5.209,纯化倍数为7.74倍。     

鲣鱼肝脏乙酰胆碱酯酶的双水相萃取

乙酰胆碱酯酶(AchE)是生物神经传导中的一种关键性酶,其活性受到有机磷和氨基甲酸酯类农药的特异性抑制,已成为监控农药残留的靶标物质。选取三亚常见海鱼——鲣鱼,利用双水相萃取技术,对其肝脏中的乙酰胆碱酯酶进行萃取并对萃取工艺进行优化,结果表明:以PEG400/K_2HPO_4为双水相,室温下PEG400的质量分数为28%,K_2HPO_4质量分数为25%,pH 10.0时,分配系数为4.263 1。     

壳聚糖对茶皂素水溶液絮凝工艺的研究

以壳聚糖为絮凝剂,研究了茶皂素水溶液的絮凝工艺,考察了壳聚糖加入量、助剂加入量和絮凝时间对絮凝效果的影响。通过正交试验得出最佳絮凝条件为：壳聚糖加入量5mL、助剂加入量5mL、絮凝时间4h。在最佳条件下验证试验,杂质去除率为34．33％,茶皂素损失率为5．64％。     

鲣鱼鱼脑乙酰胆碱酯酶的双水相萃取

乙酰胆碱酯酶(AchE)是生物神经传导中的一种关键性酶,其活性受到有机磷和氨基甲酸酯类农药的特异性抑制,已成为监控农药残留的靶标物质。选取三亚常见海鱼——鲣鱼,利用双水相萃取技术,对其鱼脑中的乙酰胆碱酯酶进行萃取并对萃取工艺进行优化,结果表明:以PEG400/K_2HPO_4为双水相,室温下PEG400的质量分数为25%,K_2HPO_4质量分数为22%,pH值10.0时,分配系数为2.8750。     

PEG/四水合酒石酸钾钠双水相法萃取发酵液中的谷胱甘肽

采用PEG/盐的双水相系统,从离心除菌后的发酵液中萃取谷胱甘肽,考察PEG分子质量、盐、PEG浓度、四水合酒石酸钾钠浓度、pH、环境温度、发酵液加入量对谷胱甘肽萃取率的影响.采用响应面分析法优化试验条件,结果表明,选用PEG/四水合酒石酸钾钠双水相系统的最佳提取条件:PEG(15%)/四水合酒石酸钾钠(13%)双水相溶液10mL、pH 6.7、温度63℃、发酵液加入量1 mL.此时谷胱甘肽分配系数K为3.5,萃取率84.13%,该方法可行.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the