氢化物原子荧光法分析不同地区刺参总硒和无机硒含量及分布规律

为测定我国黄渤海海域刺参群体硒含量并探索其分布规律,采用氢化物原子荧光光谱法进行含量分析。结果显示,呼吸树为总硒和无机硒含量最高的组织,平均值分别为（14.171±3.412） mg/kg和（6.194±3.829） mg/kg,不同组织内的总硒、无机硒含量变化呈现一致的规律,硒含量由高到低为：呼吸树＞消化道＞肌肉＞内壁＞外壁,同时刺参体壁和肌肉（食用部分）中有机硒比例在75.6%～89.4%之间（除东营地区刺参群体肌肉组织的有机硒比例最低为53.6%）;5 个地区刺参群体同一组织内的总硒及无机硒含量有显著性差异,东营地区呼吸树、消化道和肌肉中无机硒含量较高。     

不同来源氨基脲在刺参体内的富集和消除规律研究

目的分析刺参中低浓度氨基脲的残留分布特征,明确不同来源引起的低浓度氨基脲的变化趋势。方法采用超高效液相色谱-串联质谱法对不同来源氨基脲在刺参(Apostichopusjaponicus)体内的富集和消除规律进行研究。结果非呋喃西林源氨基脲, 1 d后氨基脲在刺参体壁的含量为0.57μg/kg,之后含量逐渐上升,到3d时含量度达到最大值1.00μg/kg。富集实验共持续3d,按天计算平均富集速率,分别为0.57、0.24、0.19μg/(kg·d),第140 d时体壁未检出,平均消除速率为0.0073μg/(kg·d);呋喃西林源氨基脲, 1 d后体壁的含量为0.52μg/kg,之后含量逐渐上升,到3 d时,含量达到最大1.00μg/kg。富集实验共持续3 d,按天计算平均富集速率,分别为0.52、0.26、0.22μg/(kg·d),第160 d时体壁未检出,平均消除速率为0.0064μg/(kg·d)。跟踪监测至180 d时,非呋喃西林源氨基脲和呋喃西林源氨基脲在刺参体壁内均未检出,半衰期分别为1045.7 h和1224.2 h,呋喃西林源大于非呋喃西林源。内脏的富集和消除速率相对较快,但内脏中氨基脲残留量大于体壁,所以降至未检出所需时间更长。结论在投喂过呋喃西林或暴露于一定浓度氨基脲的刺参,需经较长时间净化后才能降至未检出。     

阿特拉津在太平洋牡蛎体内的蓄积、分布与消除

采用半静态水质接触染毒法,将太平洋牡蛎分别暴露在阿特拉津质量浓度为10 μg/L和100 μg/L的海水中,研究阿特拉津在太平洋牡蛎体内的蓄积特征、组织分布和消除规律。结果表明,不同暴露质量浓度下,各组织中阿特拉津含量在3～7 d达到平衡,半衰期为0.20～0.32 d,生物富集系数为1.68～3.46 mL/g,鳃和内脏团是太平洋牡蛎的主要蓄积靶组织,而闭壳肌中阿特拉津含量最低。太平洋牡蛎对阿特拉津的消除能力随暴露质量浓度的增大而增强,各组织中阿特拉津的含量随净化时间呈指数下降,净化1 d后的消除率为90.1%～97.1%,其主要代谢途径推测为鳃的作用。     

刺参物性参数实验研究

刺参的物性参数是确定其加工工艺和研制加工设备的重要基础参数,但相关数据严重缺乏。通过实验方法测试得到了刺参的导热系数、比热容、密度和孔隙率4个物性参数的计算公式,分析其随含水率变化的规律。结果表明,在所研究的含水率范围内,刺参的导热系数为(0.043～0.245)W/m·K,比热容为(1.35～4.35)kJ/kg·K,密度为(917.6～967.5)kg/m~3,孔隙率为42.3%～37.2%,且刺参的导热系数、比热容、密度均随含水率的增加而增加,而孔隙率则随含水率的增加而降低。     

乙酰甲喹在刺参幼参中的代谢及其对成品刺参食用安全性评价

对乙酰甲喹在刺参幼参中的代谢及代谢物对成品刺参食用安全性影响进行研究评价。将刺参幼参分别暴露于2、4、6 mg/L的乙酰甲喹药浴液,浸泡24 h,消除96 h,采集不同时间点样品,用高效液相色谱法检测其中乙酰甲喹及代谢物3-甲基喹噁啉-2-羧酸（3-methyl-quinoxaline-2-carboxylic acid,MQCA）含量。结果表明：刺参幼参对水体中的乙酰甲喹吸收迅速,分别在2.5、1.5、1.5 h达到峰值,分别为0.89、1.73、2.56 mg/kg;各药浴组刺参幼参对乙酰甲喹富集系数分别为0.45、0.43和0.43;其药时曲线下面积值与药浴质量浓度呈正相关（R2=1）;乙酰甲喹在刺参幼参中消除迅速,消除0.5 h后,约85%的药物从体内排出或代谢,72 h后无检出。代谢物MQCA最早于药浴15 min产生（6 mg/L组）,且含量不断增长,24 h达到最大值29.2 μg/kg;MQCA在刺参幼参中消除缓慢,将在刺参体内长时间存在。采用食品安全指数法对成品刺参中MQCA进行食用安全性评价,食品安全指数值为1.23×10－4,即MQCA对成参食用安全性没有影响。     

防刺参不同部位营养成分的分析及综合评价

对仿刺参体壁、肠、呼吸树营养成分作了分析和测定,结果表明,参肠、呼吸树中蛋白质、粗脂肪、多糖、皂苷含量均高于体壁,氨基酸的EAA/TAA、EAA/NEAA指标更接近FAO/WHO的理想模式,脂肪酸EPA的含量高于体壁。经综合评价分析,海参肠、呼吸树具有较高的营养价值。     

采用原子力显微镜研究刺参体壁酶促溶性胶原蛋白的溶液聚集状态

为研究刺参热加工过程中体壁胶原蛋白的物性变化规律,利用原子力显微镜(atomic force microscopy,AFM)考察样品浓度、溶剂和热处理条件对刺参体壁酶促溶性胶原蛋白(pepsin-soluble collagen,PSC)溶液聚集状态的影响。结果表明:在乙酸缓冲液(pH2.7)、PBS缓冲液(pH7.2)和超纯水中,海参体壁酶促溶性胶原蛋白均随着浓度的增大而逐渐开始自组装,并最终形成无规则的团状结构或者片状网络结构。但是,溶剂不同,其开始自组装所需要的胶原蛋白浓度也不同。随着加热温度的升高或加热时间的延长,刺参体壁酶促溶性胶原蛋白分子逐渐聚集成网络结构,但加热温度超过100℃或时间超过2 h后,其交联程度逐渐降低,网络结构逐渐消失。     

菲律宾蛤仔对扑草净的生物富集与消除规律

采用半静态水质接触染毒法,研究菲律宾蛤仔对养殖海水中扑草净的生物富集和消除规律。生物富集实验结果表明：在水温（20±1） ℃条件下,在扑草净质量浓度分别为1.0、10.0、200.0 μg/L的养殖海水中,菲律宾蛤仔中扑草净残留量随所暴露海水中扑草净质量浓度的升高而逐渐增加,二者之间呈正相关。3 个实验组分别在第24、24、6小时达到最大富集值,最大富集系数分别为40.3、9.54、5.35。随着时间的延长,菲律宾蛤仔的扑草净残留量均表现为先迅速上升,升至最高值后迅速降低,低至一定质量浓度后再次上升至一个高点然后下降,之后维持在某一质量浓度水平呈小幅波动的变化趋势。消除实验结果表明：在消除实验初期,3 个实验组菲律宾蛤仔中扑草净的残留量均迅速下降,24 h时降至原质量浓度的10%左右,此后下降缓慢,1.0、10.0、200.0 μg/L暴露实验组菲律宾蛤仔的扑草净残留量降至10.0 μg/kg以下的时间分别为2、24、768 h,其中1.0 μg/L组在消除实验持续96 h时检测结果低于检出限,其余2 组在为期45 d的消除实验结束时仍可检出扑草净残留量。研究表明,菲律宾蛤仔对扑草净具有快速富集能力,但完全消除需要较长时间。     

仿刺参不同部位ACE抑制活性分析及活性肽制备工艺优化

本文对仿刺参具有高降血压活性部位进行筛选并优化其活性肽制备工艺。采用酶解法对仿刺参不同部位(体壁、肠、卵)进行水解,以血管紧张素转换酶(Angiotensin converting enzyme,ACE)抑制率为指标筛选最适蛋白酶,通过对各酶解物ACE抑制率的半数抑制浓度(IC₅₀)测定比较筛选出最优抑制活性部位。经单因素实验与响应面试验优化确定活性肽最佳酶解制备条件,对蛋白酶解物进行分子量测定确定其分布范围,经超滤膜分离后对不同组分的ACE抑制活性分析。结果显示,选用碱性蛋白酶为最适水解酶,体壁、肠、卵各蛋白酶解物的ACE抑制率的IC50分别为1.11、4.02、0.65 mg/mL,仿刺参卵具有更好的ACE抑制效果,为最优抑制活性部位。其最佳的酶解制备工艺参数为：酶解时间5 h,加酶量3.5 U/mg,酶解温度65.26℃,底物浓度3.51%,酶解pH9.02,在该条件下仿刺参卵酶解产物的ACE抑制率为80.65%±0.52%,与预测值接近。蛋白酶解产物的分子量集中分布在3000 Da以下,占总含量的98.37%,其中1000～3000 Da占比9.50%,小...     

重金属Cd与Cu在克氏原螯虾体内富集与释放规律

研究克氏原螯虾分别在Cd2+质量浓度为0、0.05、0.10 mg/L和Cu2+质量浓度为0、0.5、1.0 mg/L的单一水环境中暴露时,肝胰腺、鳃和肌肉对Cd和Cu的生物富集和释放特性。通过非线性拟合得到克氏原螯虾对Cd和Cu的生物富集动力学参数：富集速率常数k1、排出速率常数k2、生物富集系数（bioconcentration factors,BCF）和生物半衰期（T1/2）,并得出理论富集平衡状态时生物体内Cd和Cu富集量（ρAmax）。结果表明：克氏原螯虾的肝胰腺和鳃对水体中Cd2+和Cu2+都有很强的富集特性,且富集量与富集时间、水体中Cd2+和Cu2+的质量浓度成正相关;肌肉组织中富集规律则不明显。同种重金属在不同组织中的富集量不同,即重金属富集具有组织选择性：在分别含Cd2+和Cu2+的水体中暴露实验9 d后,3 种组织对Cd的富集量顺序为鳃＞肝胰腺＞肌肉;对Cu的富集量顺序为肝胰腺＞鳃＞肌肉。克氏原螯虾对Cu和Cd的富集代谢都较缓慢,暴露9 d仍未达到稳定。克氏原螯虾体内Cd和Cu的BCF范围分别约为2～207、3～226;T1/2分别约为3～29、7～36 d;在理论平衡状态下,鳃、肝胰腺和肌肉中Cu和Cd的ρAmax随着环境中Cu2+和Cd2+质量浓度的增大而增大,且呈正相关。     

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.     

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.     

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.     

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.     

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.     

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.