北京地区部分市售食用植物油中玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇的污染状况分析

目的分析北京市售植物油中玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇的污染状况。方法实验采用同位素稀释-超高效液相色谱-串联质谱法,在多反应监测模式下对所采集玉米油、花生油、调和油等食用油样中的玉米赤霉烯酮(ZEN)、脱氧雪腐镰刀菌烯醇(DON)进行了检测,并对其污染现状进行分析。结果 ZEN和DON在3~500 ng/mL浓度范围内线性良好,相关系数为0.999,加标回收率为95.05%~107.10%,ZEN和DON方法的检出限分别为0.03μg/kg和0.9μg/kg;ZEN和DON方法的定量限分别为0.1μg/kg和3μg/kg。对北京市售30个油样检测结果表明,DON为未检出,ZEN检出率为100%,最高含量为333μg/kg,最低含量为1.95μg/kg,平均含量为67.7μg/kg,低于欧盟规定的限量标准400μg/kg。结论通过分析食用油中真菌毒素的含量状况,初步了解了北京市售植物油中玉米赤霉烯酮和脱氧雪腐镰刀碱烯醇的污染状况。     

脱氧雪腐镰刀菌烯醇人工抗原和多克隆抗体的制备

对脱氧雪腐镰刀菌烯醇(DON)的两种半抗原合成方法进行对比研究,合成半抗原,并采用活化酯法将半抗原与牛血清白蛋白偶联制备得到免疫原,通过特定程序免疫日本大耳白兔获得了多克隆抗体.抗血清效价为1∶32 000,proteinA-sepharose 4B 亲和层析纯化的DON抗体与DON、3-AC-DON(3-乙酰氧基脱氧雪腐镰刀菌烯醇)、15-AC-DON(15-乙酰氧基脱氧雪腐镰刀菌烯醇)、T-2毒素、OTA(赭曲霉A)、ZEN (玉米赤霉烯酮)的交叉反应率分别为:100%、500%、2.50%、0.10%、0.01%、0.01%,表明了所制备DON抗体的高特异性.     

液质联用同时检测小麦中三种镰刀菌毒素

研究了小麦面粉中玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、雪腐镰刀菌烯醇三种镰刀菌毒素液相色谱-质谱联用同时检测的方法。小麦样品中的毒素提取液经Mycosep 226多功能净化柱净化后，以反相C18柱为色谱柱，甲醇、0．1％乙酸铵水溶液梯度洗脱为流动相，大气压化学电离离子源电离后质谱检测。该方法玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇和雪腐镰刀菌烯醇标准溶液的提取离子峰面积与标品浓度分别在3～4500ng／mL、8～5000ng／mL范围内呈良好的线性关系，加标实验中三种毒素平均回收率在70．9％～93．7％之间，检出限分别为5、10、12ng／g，RSD均小于10％，具有很好的精密度。     

小麦籽粒中原型及修饰型脱氧雪腐镰刀菌烯醇的产生规律研究

目的研究原型脱氧雪腐镰刀菌烯醇(deoxynivalenol, DON)及其修饰型的产生规律。方法以小麦籽粒为培养材料,辐照灭菌后接种禾谷镰刀菌,并分别在不同温度(10、20、30℃)和水活度(0.95、0.98 a_w)下培养不同时间(7、14、21、28、35d)后,运用超高效液相色谱-串联质谱检测DON,3-乙酰化脱氧雪腐镰刀菌烯醇(3-acetyl-deoxynivalenol,3-ADON),15-乙酰化脱氧雪腐镰刀菌烯醇(15-acetyl-deoxynivalenol,15-ADON)和脱氧雪腐镰刀菌烯醇-3-葡萄糖苷(deoxynivalenol-3-glucoside,D3G)的产量。结果在所有培养条件下,原型DON的产量均随时间延长而增加;并于0.98 a_w, 20℃下的第35 d达到最高值100490.0μg/kg;不同培养条件下,修饰型DON的生成情况各不相同,3-ADON、15-ADON和D3G分别于0.98a_w,20℃下的第14、28和35 d达到各自产量最高值(3-ADON:7583.5μg/kg; 15-ADON:592.0μg/kg; D3G:6806.4μg/kg)。此外, 10℃下,D3G/DON比值随时间延长先增高后降低,而20、30℃下D3G/DON比值随时间延长呈指数下降(r~20.90)。结论小麦籽粒中原型和修饰型DON的最适产生条件均为0.98 a_w, 20℃。本研究可为DON及其修饰型的生物合成、日常监管、污染防控等提供理论基础和科学依据。     

高效液相色谱同步检测小麦中脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的方法研究

文章建立了二合一免疫亲和柱净化、紫外检测器串联荧光检测器的高效液相色谱同步检测小麦中脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的方法。样品用60%乙腈水提取,涡旋、振荡、离心、过滤等步骤,滤液过二合一免疫亲和柱净化,甲醇洗脱后氮气吹干,50%甲醇水复溶上机分析。该方法可在25 min内完成2种真菌毒素的同步检测,脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的线性关系r值均大于0.999。在不同水平的加标试验中,脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的回收率分别是85.8%～95.5%和87.8%～92.3%,相对标准偏差分别是3.2%～7.8%和3.2%～7.5%,检出限分别是50μg/kg和5μg/kg,定量限分别是100μg/kg和10μg/kg。该方法用外标法进行定量检测,灵敏度高、操作简单,准确性和重复性好。     

免疫亲和柱净化—高效液相色谱法同时检测小麦中脱氧雪腐镰刀菌烯醇及其衍生物

建立脱氧雪腐镰刀菌烯醇(DON)及其衍生物3-乙酰基—脱氧雪腐镰刀菌烯醇(3-ADON)和15-乙酰基—脱氧雪腐镰刀菌烯醇(15-A-DON)的免疫亲和柱净化—高效液相色谱同时检测方法。小麦样品经超纯水提取、免疫亲和柱净化、吹干、定容后,用配有紫外检测器的高效液相色谱仪进行DON、3-A-DON和15-A-DON三种毒素的同时检测,并与液相色谱质谱法比对。结果表明:该方法检出限,DON、3-A-DON和15-A-DON均为100μg/kg,样品加标回收率范围86.6%~96.5%,变异系数小于10%,具有较好的准确性和精密度。该方法简单、快速、灵敏度高、选择性好,适用于小麦中DON、3-A-DON和15-A-DON的同时检测。     

QuEChERS-同位素稀释内标法-液相色谱-串联质谱法快速测定饼干中的脱氧雪腐镰刀菌烯醇

目的建立QuEChERS-同位素稀释内标法-液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)快速测定饼干中的脱氧雪腐镰刀菌烯醇。方法样品加入~(13)C_(15)-脱氧雪腐镰刀菌烯醇同位素内标后,用水-乙腈(4/1,V/V)溶液提取、旋涡超声离心后,取上清液2.0mL经N-丙基乙二胺(primary secondaryamine,PSA)吸附剂、C_(18)吸附剂净化,净化液过滤膜,采用LC-MS/MS进行测定。结果在优化的实验条件下,脱氧雪腐镰刀菌烯醇的检出限为0.6μg/kg,定量限为2.0μg/kg。在线性范围0.4～50.0μg/L内,相关系数为0.9995。平均加标回收率为82.1%～92.3%,相对标准偏差4.3%～6.6%(n=6)。结论该方法简单、快速,可用于饼干中的脱氧雪腐镰刀菌烯醇的快速测定。     

脱氧雪腐镰刀菌烯醇时间分辨荧光免疫检测体系适用性评价

目的研究已建立的脱氧雪腐镰刀菌烯醇时间分辨荧先兊疫定量检测体系(包括脱氧雪腐镰刀菌烯醇时间分辨荧先兊疫层析检测卡和荧先定量检测仪)的适用性。方法检测20个阴性样本中脱氧雪腐镰刀菌烯醇含量,确定该检测体系的检出限和定量限;对6组含不同浓度脱氧雪腐镰刀菌烯醇的小麦阳性样本和6组含不同浓度脱氧雪腐镰刀菌烯醇的玉米阳性样本进行检测,确定方法的准确性和台间差;重复6次检测含中等浓度脱氧雪腐镰刀菌烯醇的阳性样本和连续12 h检测国家检测限浓度的阳性样本,确定系统的重复性和稳定性。结果该体系的检出限为154μg/kg,定量限为414μg/kg,幵且检测结果与液质联用方法定值结果无显著性差异,仪器台间差无显著差异;测值的精密度未超过国家标准规定要求。结论本研究验证的时间分辩荧先定量检测体系能准确检测玉米和小麦样本中脱氧雪腐镰刀菌烯醇含量。     

脱氧雪腐镰刀菌烯醇胶体金检测试纸的研制及应用

采用合成脱氧雪腐镰刀菌烯醇(Dexynivalenol,DON)人工抗原,制备抗脱氧雪腐镰刀菌烯醇单克隆抗体(mAb),并以此为基础建立胶体金免疫层析检测试纸,于胶体金读数仪配合使用,用于进行玉米和小麦样品中DON的快速定量检测。通过检测玉米和小麦样品,脱氧雪腐镰刀菌烯醇胶体金试纸方法检测限为87μg/kg,定量限为290μg/kg,线性范围400~5 000μg/kg,相关系数r=0.998。以国家标准(GB/T23503—2009)免疫亲和柱-高效液相色谱法检测样品的结果为认定值,胶体金检测法的准确度在80.7%~143.6%,变异系数范围4.7%~16.4%。采用配对t-检验分析,胶体金检测法与国标液相方法无显著性差异。     

脱氧雪腐镰刀菌烯醇胶体金快速检测系统适用性评价

评价脱氧雪腐镰刀菌烯醇胶体金快速检测系统的适用性。用胶体金快速检测系统检测20个阴性样品中的脱氧雪腐镰刀菌烯醇含量,确定该系统的检出限和定量限;用2台胶体金分析仪分别对6个浓度梯度的阳性样品进行检测,考察方法的准确性和台间差;6次重复测定含中等浓度脱氧雪腐镰刀菌烯醇的阳性样品,考察方法的重复性。结果发现,该系统的检出限和定量限分别为199.61μg/kg和457.14μg/kg;测定结果与国家标准方法 GB 5009.111—2016中的高效液相色谱法测定结果之间无显著性差异,2台仪器的测定结果之间也无显著性差异;中等浓度阳性样品6次重复测定的标准偏差未超过国家标准规定要求。该脱氧雪腐镰刀菌烯醇胶体金快速检测系统准确性、重复性较好,能准确检测小麦和玉米样品中的脱氧雪腐镰刀菌烯醇含量。     

Study of the retention capacity of anthocyanins by wine polymeric material

Red wine is an important source of dietary intake of phenolic compounds with antioxidant activity that are related to the prevention of cardiovascular diseases and cancer. However, information concerning their specific release from this food matrix, although necessary to predict their bioavailability along the digestive tract, is still not clear. In this work, the interactions that can occur between the red wine polymeric material and anthocyanins were studied. For this purpose, the diffusion performance of nine anthocyanins through a dialysis membrane was evaluated in the presence and absence of the wine polymeric material. For each anthocyanin, a retention coefficient was calculated. Although in different extents, all anthocyanins were retained by the wine polymeric material. The higher retention coefficient was observed for coumaroyl and acetyl derivatives when compared with the non acylated anthocyanins. It is suggested that these associations are ruled by hydrophobic interactions. These results allow the prediction of a continuous and gradual dosage of wine anthocyanins, contributing to an extension in beneficial health properties upon ingestion.     

Hydrolysis of soybean isoflavone glycosides by a thermostable β-glucosidase from Paecilomycesthermophila

The β-glucosidase from Paecilomyces thermophila J18 was found to be capable of hydrolysing daidzin and genistin in a previous study. This report further evaluated the thermostability and hydrolysis of soybean isoflavone glycosides. The enzyme was found to be very stable at 50 °C, and retained more than 95% of its initial activity after 8 h at 50 °C. It converted isoflavone glycosides, in soybean flour extract and soybean embryo extract, to their aglycones, resulting in more than 93% of hydrolysis of three isoflavone glycosides (namely, daidzin, genistin and glycitin) after 4 h of incubation. Also, addition of the β-glucosidase greatly increased the contents of isoflavone aglycones in the suspended soybean flour and soymilk. The results indicate that the thermostable β-glucosidase may be used to increase the isoflavone aglycones in soy products. This is the first report on the potential application of fungal β-glucosidases for converting isoflavone glycosides to their aglycones in soy products.     

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.