大孔树脂纯化灵芝子实体和孢子粉中总三萜

研究比较大孔树脂对灵芝子实体和孢子粉两个不同部位中总三萜的吸附特性,优选其对灵芝总三萜的分离纯化工艺条件。采用紫外分光光度法测定灵芝子实体和孢子粉两个不同部位中总三萜的含量,选择8种大孔树脂,以总三萜吸附率和解吸率为指标,筛选最佳树脂型号,并考察最佳树脂纯化灵芝子实体和孢子粉中总三萜的工艺参数。结果表明：8种大孔树脂中,HPD-500型大孔树脂对灵芝子实体总三萜的吸附解吸效果最好,最佳纯化工艺条件为上样液浓度1.0 g干样/mL,最大上样量2 BV,用8.5 BV的75%乙醇进行洗脱,该工艺下灵芝子实体总三萜纯度达60.59%;而AB-8型大孔树脂对灵芝孢子粉总三萜的吸附解吸效果最好,且最佳纯化工艺条件为上样液浓度0.4 g干样/mL,最大上样量3 BV,用8.5 BV的95%乙醇进行洗脱,该工艺下灵芝孢子粉总三萜纯度达65.48%。综上,HPD-500型和AB-8型大孔树脂分别富集纯化灵芝子实体和灵芝孢子粉中总三萜的工艺效果显著,简单可行,为灵芝三萜的深入探究和工业化纯化灵芝子实体和孢子粉总三萜提供理论依据。     

大孔吸附树脂纯化八角枫根中水杨苷工艺

研究大孔树脂纯化八角枫根中水杨苷的最佳工艺条件。以水杨苷的吸附率和解吸附率为评价指标,筛选树脂种类,并优化吸附和洗脱条件。8种大孔吸附树脂中,HPD-826型大孔树脂对水杨苷具有较好的吸附分离性能,最佳的纯化工艺条件为上样液质量浓度45.12μg/mL、最大上样量6.5BV、径高比1:8、洗脱流速3BV/h,先用4BV的水洗柱除去水溶性杂质,再用5BV体积分数30%乙醇溶液洗脱。经HPD-826型大孔树脂处理后的水杨苷回收率可达78%左右,HPD-826大孔树脂对水杨苷纯化的综合性能较好,工艺稳定、可行,适合于工业化生产。     

大孔吸附树脂分离纯化蛹虫草固体培养基中虫草素工艺

比较D101、AB-8、HPD-100、HPD-400、HPD-500、HPD-722、DM130七种大孔吸附树脂对蛹虫草固体培养基中虫草素的吸附与解吸性能,筛选出HPD-100树脂为最佳树脂,并确定HPD-100树脂吸附分离最佳工艺条件：上样液质量浓度0.6mg/mL、上样流速3BV/h、上样体积6BV;解吸剂为体积分数25%乙醇溶液、解吸流速2BV/h、解吸体积4BV。根据此工艺条件,蛹虫草固体培养基粗提物经HPD-100树脂纯化后,虫草素产品纯度可达14.1%,较粗提物产品提高了8倍多。     

大孔树脂法纯化陕产重楼总皂苷工艺研究

研究陕产重楼中总皂苷利用大孔吸附树脂纯化的最优工艺。应用7种大孔吸附树脂吸附重楼中的总皂苷进行静态实验,筛选得到最佳树脂;通过动态实验确定最佳树脂对重楼总皂苷的纯化的最优工艺参数。结果表明,HPD-400A树脂纯化重楼总皂苷的效果最优,最优工艺条件为上样液质量浓度5mg/mL,上样量8BV,流速3BV/h,解吸流速2BV/h,解吸剂体积分数75%的乙醇,洗脱剂用量4BV,按此工艺条件制备的重楼总皂苷的含量为62.68%;Freundlich等温吸附模型可更好的描述树脂对重楼总皂苷的吸附,采用HPD-400A树脂分离纯化陕产重楼中的总皂苷效果较好。     

大孔吸附树脂纯化富集川芎总生物碱的工艺

以盐酸川芎嗪为对照品,采用酸性染料比色法测定川芎总生物碱含量。以吸附率和解吸率为指标,比较7种不同型号大孔吸附树脂的静态吸附与解吸附能力,考察动态吸附与洗脱参数,筛选最佳大孔吸附树脂纯化富集川芎总生物碱的工艺条件。结果表明AB-8型大孔树脂对川芎总生物碱的吸附与解吸性能最好,静态吸附率为75.10%,解吸率为81.45%,静态吸附和解吸时间分别为12h和8h。其动态富集工艺条件为:最佳上样液pH为8.0,上样质量浓度为4.4799mg/mL,上样量为8BV,用13BV去离子水除杂后,再用14BV体积分数85%的乙醇进行洗脱。经AB-8大孔树脂纯化富集后,川芎总生物碱纯度提高了2.38倍,回收率为75.15%(RSD=1.22%,n=3)。     

大孔树脂纯化苦菜多酚及其组成分析

研究大孔树脂纯化苦菜多酚的吸附特性、工艺条件,分析了苦菜多酚粗品、纯品的组成。分别进行静态吸附和解吸、静态吸附等温曲线(Langmuir和Freundich等温吸附方程)、动态吸附试验,从6种大孔树脂中筛选用于苦菜多酚分离的最佳树脂,并系统研究最佳大孔树脂分离纯化的吸附性能和最优洗脱参数。结果表明:NKA-9型大孔树脂为分离苦菜多酚类组分的最佳树脂,其分离的最佳工艺条件为样液总酚浓度0.5mg/mL,上样流速3BV/h,pH 5的50%乙醇以1BV/h流速进行洗脱,该纯化条件下所得苦菜多酚含量为72.38%,较纯化前提高了4.92倍。应用高效液相色谱法分析其组成,结果显示苦菜多酚主要成分为卢丁、绿原酸、咖啡酸、芹菜素、原儿茶素,经NKA-9型大孔树脂纯化后的芹菜素达8.53mg/g,较粗品提高了20.16倍。     

辣椒叶多酚纯化工艺研究

目的:建立并优化辣椒叶多酚的纯化工艺.方法:利用静态吸附与解吸附实验筛选出最适宜纯化辣椒叶多酚的大孔树脂,并利用单因素方法考察最优柱色谱条件.结果:HPD-100型大孔树脂具有较高的吸附率和解吸率,并确定其最优色谱条件为:树脂柱径高比1∶4,样品多酚浓度在0.6～1.2mg/mL之间,吸附速率2BV/h,以5BV/h的流速水洗3BV,再用3BV 70％乙醇洗脱,合并洗脱液真空干燥即得.结论:该工艺对辣椒叶提取物中多酚的纯化简单高效,纯化后产物中多酚含量自4％提高到68％.     

大孔树脂对二角菱壳多酚的吸附及解吸性能研究

研究了大孔树脂分离纯化二角菱壳乙酸乙酯萃取液中多酚的方法。对7种大孔树脂进行了静态吸附和解吸的研究,筛选出了效果最佳的大孔树脂D101。对D101大孔树脂进行动态吸附和解吸条件的优化,最佳条件为:上样固形物质量浓度5mg/mL,上样流速1mL/min,洗脱溶剂乙醇体积分数70%,洗脱流速4mL/min,洗脱体积5 BV。总多酚含量由提取物冻干样品的478mg GAE/g上升到纯化后的825mg GAE/g,提高了1.73倍,回收率为59.43%。放大试验中,其回收率和纯化率并不随大孔树脂数量的增加而改变,说明该优化条件适合于大规模生产应用。     

大孔吸附树脂纯化菜芙蓉黄酮工艺研究

研究大孔吸附树脂分离纯化菜芙蓉黄酮的最佳工艺条件。以总黄酮吸附量和解吸量为指标,进行静态吸附和解吸试验对14种型号大孔树脂进行筛选,再通过动态吸附和解吸试验对纯化工艺参数进行优化。Z801大孔树脂对菜芙蓉总黄酮的吸附与解吸性能最佳。HZ801纯化菜芙蓉黄酮的最佳工艺条件为:上样浓度为1 mg/m L,上样流速2 m L/min,上样量为140 m L;依次用2 BV水洗脱,用70%乙醇以2 m L/min的速率洗脱2.2 BV。在优化工艺条件下,菜芙蓉黄酮的平均吸附率是95.03%,纯化倍数4.04。HZ801型大孔树脂富集黄酮的效果最佳,是一种较理想的分离纯化介质。     

大孔树脂纯化寒富苹果渣多酚工艺优化

通过研究10种大孔树脂对寒富苹果渣多酚的静态吸附及解吸性能,筛选出一种最佳的大孔树脂,并利用这种树脂对寒富苹果多酚的纯化工艺进行优化。结果表明:HPD-826型树脂有较好的吸附和解吸性能,经实验确定其纯化苹果多酚的最佳动态吸附条件:苹果多酚提取液pH为5,浓度在0.5～0.8mg/mL之间,上样速度1mL/min;最佳洗脱条件:洗脱液为60%的乙醇溶液,解吸温度20℃,洗脱流速0.5mL/min。在此条件下,纯化样品的多酚纯度为52.26%。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.