高分辨质谱库和特征组分诊断比值法快速筛查鉴别食品中非法添加黄芪

目的：建立了一种基于高分辨质谱库和特征组分诊断比值法筛查鉴别食品中非法添加黄芪的方法。方法：采用高效液相色谱-四极杆-飞行时间质谱仪构建黄芪4种特征组分高分辨质谱库进行初步筛查,结合特征组分诊断比值法,对不同产地和采摘时间的黄芪中药材模拟的配制酒、代用茶和饮料样品进行特征组分分析,以不同基质组间无显著性差异的特征组分峰面积诊断比值作为确证指标。结果：建立了黄芪4种特征组分高分辨质谱库,确定了黄芪中不同基质组间无显著性差异的1组特征组分峰面积诊断比值DR1 (毛蕊异黄酮苷/芒柄花苷),诊断比值非异常值范围分别1.86-2.71;并对实际样品配制酒、代用茶及饮料进行分析,1批次配制酒样品与黄芪4种特征组分高分辨质谱库匹配一致,且特征组分诊断比值DR1为1.98,在规定区间内,推断该配制酒样品中加入了黄芪中药材。结论：该方法准确、快捷、稳定性好,可快速鉴别食品中非法添加黄芪,为打击食品中非法添加黄芪违法行为提供技术支撑。     

高分辨质谱库和特征组分诊断比值法快速鉴别食品中非法添加淫羊藿

建立了一种基于高分辨质谱库和特征组分诊断比值法鉴别食品中非法添加淫羊藿的方法。采用高效液相色谱-四极杆-飞行时间质谱仪构建淫羊藿6种特征组分高分辨质谱库进行初步筛查,将不同产地和采摘时间的淫羊藿中药材模拟配制酒、代用茶和饮料样品,构建3种基质中淫羊藿特征组分液相色谱分析方法,选取受产地、采摘时间、加工工艺等影响较小,不同基质组间无显著性差异的3组特征组分峰面积诊断比值DR1(朝藿定A/朝藿定B)、DR3(朝藿定A/淫羊藿苷)和DR7(朝藿定B/淫羊藿苷),合并后绘制箱图确定各诊断比值非异常值范围分别为0.60~0.96、0.26~0.64和0.35~0.91,以此作为鉴别指标。对实际样品配制酒、代用茶及饮料进行分析,1批次配制酒样品与淫羊藿6种特征组分高分辨质谱库匹配一致,且3组特征组分诊断比值DR1、DR3、DR7分别为0.73、0.28、0.38,均在规定区间内,推断该配制酒样品中加入了淫羊藿中药材。该方法准确、快捷、稳定性好,可快速鉴别食品中非法添加淫羊藿,为打击食品中非法添加淫羊藿违法行为提供技术支撑。     

基于高分辨质谱库和特征组分诊断比值法鉴别配制酒和代用茶中非法添加补骨脂

目的:建立一种基于高分辨质谱库筛查和特征比值法确证配制酒和代用茶中非法添加补骨脂的高效液相色谱检测方法。方法:采用高效液相色谱—四极杆—飞行时间质谱仪建立补骨脂中药材特征组分筛查库,结合液相特征组分诊断比值法,对不同采摘时间和产地的共20批次补骨脂模拟的补骨脂配制酒、代用茶样品进行特征组分分析,从13种特征成分中选出2组受产地、采摘时间、加工工艺等影响较小,不同基质组间无显著性差异的特征组分峰面积诊断比值作为确证指标。结果:建立了补骨脂中药材特征组分筛查库,选定出2组特征组分CoryliA/补骨脂酚和补骨脂素/异补骨脂素,绘制箱图确定CoryliA/补骨脂酚的非异常值范围为0.061~0.115,补骨脂素/异补骨脂非异常值范围为1.14~1.68。通过市售样品对建立的筛查和确证方法进行验证。结论:该方法简单高效,适用于配制酒和代用茶中非法添加补骨脂的检测。     

刺五加与短梗五加中紫丁香苷、刺五加苷E及异嗪皮啶含量比较

为比较刺五加及短梗五加样品中主要活性成分差异,选取吉林、黑龙江及辽宁等三省刺五加及短梗五加样品,利用薄层层析(TLC)法进行鉴别,并利用HPLC法测定了紫丁香苷、刺五加苷E及异嗪皮啶含量。结果表明:利用紫外灯(365 nm)显示的刺五加TLC图谱中异嗪皮啶特征条带均非常明显,短梗五加TLC图谱中异嗪皮啶特征条带不明显但存在痕迹,因此该鉴别方法可增加定量指标以保证鉴别结果的确定性。HPLC测试结果显示刺五加样品中三种功效成分含量总体较高,且紫丁香苷及异嗪皮啶平均含量均高于短梗五加样品。个别短梗五加中紫丁香苷含量达到近0.1%,而《药典》中规定紫丁香苷含量不低于0.05%,因此为防止短梗五加的混入,可在进一步深入研究基础上适当提高刺五加中紫丁香苷含量标准。     

配制酒中非法添加淫羊藿的鉴别及含量测定

目的 采用高效液相色谱仪建立配制酒中非法添加淫羊藿的鉴别及淫羊藿7种特征组分的测定方法。方法 样品经水浴蒸干后,用甲醇溶液溶解残渣,提取液离心,过滤,上机测定,Waters Symmetry Shield C18 (250mm×4.6mm,5μm)色谱柱进行分离,乙腈和20mmol/L乙酸铵水溶液(含0.1%乙酸)为流动相梯度洗脱,外标法定量。结果 7种化合物的线性检测范围最高浓度为100 μg/mL,相关系数R_²＞0.99,定量限为0.05～0.08 μg/g,于1倍定量限、2倍定量限、10倍定量限3个添加水平下进行加标回收试验,7种化合物平均回收率为92.64%-107.21%,相对标准偏差(RSD%)为0.75%-3.00%。结论 该方法操作方便、简单、灵敏度高、重复性好,满足配制酒中非法添加淫羊藿中药材的鉴别需求,为配制酒的科学监管提供有效的技术支撑。     

HPLC法同时检测复方产品中西洋参、红景天和刺五加的皂苷含量

采用高效液相色谱法建立了同时检测复方产品中人参皂苷Rb1、人参皂苷Re、红景天苷、刺五加苷B和刺五加苷E含量的方法。以60%乙醇作为提取溶剂,用色谱柱Kromasil 100-5C18(250×4.6mm,5μm)进行分离,以0.1%磷酸-乙腈混合液为流动相进行梯度洗脱,结果表明,在此条件下5种皂苷得到了良好的分离。人参皂苷Rb1、人参皂苷Re、红景天苷、刺五加苷B和刺五加苷E分别在80~800、80~800、40~400、20~160μg/m L和40~320μg/m L范围内呈现良好的线性关系,平均加标回收率在99.5%~106.8%之间,相对标准偏差为0.5%~2.3%。本方法具有重现性好、回收率高等优点,适用于复方产品中人参皂苷Rb1、人参皂苷Re、红景天苷、刺五加苷B和刺五加苷E的同时检测。     

高效液相色谱法测定罗汉果饮料中甜苷V的含量

建立了高效液相色谱法测定罗汉果饮料中甜苷V的方法。样品经70%甲醇溶液提取溶解,采用C18反相色谱柱分离,用乙腈-0.1%磷酸溶液(22∶78)为流动相进行洗脱,检测波长为203nm,流速为1m L/min,以色谱峰保留时间和紫外可见光谱进行定性,外标法进行定量,并应用该方法对多个样品中甜苷V含量进行检测。结果表明,甜苷V在0.0024~0.384mg/m L范围内线性关系良好(R2=0.9999),检出限为3mg/kg,加标回收率为98%~105%。该方法操作简单,精密度好,能满足罗汉果饮料中甜苷Ⅴ的检测要求。固体饮料甜苷V含量在0~65mg/100g之间,液体饮料在0~15mg/100g之间,甜苷在罗汉果饮料生产中对其含量控制较低,因其甜味性质,含量高会导致口感不佳,消费者难以接受。因此,该方法可作为罗汉果饮料产品的质量控制及真伪鉴别的检测方法。     

降血糖类保健食品中非法添加的8 种药物检测及实例分析

目的：建立检测降血糖类保健食品中非法添加8 种药物的方法并用于实际检测。方法：采用高效液相色谱-串联质谱法,以ZORBAX Eclipse Plus C18（2.1 mm×50 mm,1.8 μm）色谱柱,以0.1%甲酸溶液为流动相A,甲醇为流动相B,梯度洗脱。通过分子离子峰、二级碎片、色谱保留时间等信息,对宣称辅助降血糖类保健食品非法添加8 种化学药物进行鉴别和定量测定。结果：8 种药物实现了同时分离与专属鉴定,检出限为5.5～76 ng/g,精密度为0.22%～1.19%,回收率为74.0%～111.9%;本法适用于硬胶囊样品;利用本法,从15 批样品中检测出9 批含非法添加化学药物。结论：本方法专属性强、灵敏度高,结果准确可靠,可作为宣称辅助降血糖类保健食品中检测非法添加化学药物的方法参考。     

白酒中甜蜜素检测方法的研究

本实验采用高效液相色谱法(HPLC)检测白酒中甜蜜素含量,获得了空白白酒以及不同甜蜜素浓度酒样的高效液相色谱图。根据甜蜜素浓度和峰面积的线性关系建立了标准曲线,并求出回归方程：y ＝ 0.0008x+0.0147(R2 ＝ 0.9991);对比空白酒样和添加甜蜜素的酒样,差异明显,添加甜蜜素的酒样在7～8min 时有明显的吸收峰,其中甜蜜素浓度为100μg/ml 的酒样峰面积最大,随着甜蜜素浓度的减小,峰面积也逐渐减小;将不同甜蜜素浓度的酒样进行回收率和精密度分析,得回收率范围为97.04%～115%,经重复测定,得到RSD 为4.1%,定性检测下限为1.5 μg/ml,定量检测下限为5.0μg/ml。     

高效液相色谱-质谱联用法快速检测中成药和保健食品中非法添加的12种减肥类药物

目的建立高效液相色谱-离子阱质谱联用法测定保健食品中非法添加的12种化学减肥药物(去甲伪麻黄碱、伪麻黄碱、甲基麻黄碱、咖啡因、安非他明、甲基安非他明、氯卡色林、芬氟拉明、酚酞、比沙可啶、氟西汀、布美他尼)的分析方法。方法采用资生堂CAPCELL-PAK C_(18)色谱柱(4.6 mm×150 mm, 5μm),梯度洗脱:流动相A为含0.1%冰乙酸的0.02 mol/L乙酸铵溶液,流动相B为甲醇,流速:0.5 mL/min;扫描方式为正离子扫描;通过与对照品色谱图和质谱图的对比,对样品中非法添加的化学药物进行定性鉴别。结果本法检测上述12种化学物质,各化合物色谱峰之间分离度良好,方法的检出限为0.2～0.5 ng/mL。33批样品中,2批检测出酚酞。结论该方法灵敏、选择性强、快速,可用于中药材和保健食品中非法添加的减肥化学药品的定性检测。     

刺五加在中国保健食品中的应用

文章主要阐述了刺五加在中国保健食品中的使用依据、应用现状，综述其保健功能相关的研究进展，并对其未来的发展方向进行了展望。     

Arsenic content of some edible mushroom species

The arsenic contents of 162 fruit body samples of 37 common edible mushroom taxa were analyzed. The samples were gathered from different habitats of Hungary (mainly from mountains) between 1984 and 1999. The arsenic content of the samples was measured by the inductively coupled plasma spectrometry method. Very low [lower than 0.05 mg/kg dry matter (DM)] concentrations were found in the samples of 13 taxa, while higher (or very high) contents were quantified in other common taxa (the highest arsenic content was recorded in the fruit body of Laccaria amethysthea at 146.9 mg/kg DM). The species of eight genera (Agaricus, Calvatia, Collybia, Laccaria, Langermannia, Lepista, Lycoperdon, Macrolepiota) belong to the so-called accumulating taxa, and this tendency is evident on all habitats. This arsenic accumulation capability is found in two orders of Basidiomycetes (Agaricales and Gasteromycetales), which is to say this phenomenon occurs in the families Agaricaceae, Tricholomataceae and Gasteromycetaceae. The accumulating taxa found all have a saprotrophic type of nutrition; arsenic accumulation is not detectable in xilophagous or in mycorrhizal species. The consumption of the accumulating species found has only a low toxicological risk for three reasons: the consumed fresh fruit bodies contain about a tenfold lower arsenic level than the dried ones, the majority of arsenic occurs not in poisonous inorganic, but in less dangerous (or not poisonous) organic forms, and the frequency of consumption is low.     

Organization and localization of the dnaA and dnaK gene regions on the multichromosomal genome of Burkholderia multivorans ATCC 17616

The Burkholderia multivorans strain ATCC 17616 carries three circular chromosomes with sizes of 3.4, 2.5, and 0.9 Mb. To reveal the distribution and organization of the genes for fundamental cell functions on the genome of this bacterium, the dnaA and dnaK gene regions of ATCC 17616 were cloned and characterized. The gene organization of the dnaA region was rnpA-rmpH-dnaA-dnaN-gyrB with a single consensus DnaA-binding box (TTATCCACA) between the rmpH and dnaA genes. This intergenic region, however, did not work as an autonomously replicating sequence in ATCC 17616. On the other hand, the gene organization of the dnaK region was grpE-orf1 (gene for thioredoxin homologue)-dnaK-dnaJ-pabB (gene for p-aminobenzoate synthetase component homologue). A putative heat-shock promoter that showed good homology to the sigma32-dependent promoter consensus sequence in Escherichia coli was found upstream of the grpE gene, suggesting that these five genes constitute an operon. In M9 succinate minimal medium the dnaJ mutant grew more slowly than the wild-type strain, indicating that this operon is functional. Pulsed-field gel electrophoresis and Southern blot analyses indicated that both the dnaA and dnaK gene regions exist as single copies on the 3.4 Mb chromosome.     

鸡源大肠埃希氏菌mcr-1基因携带及分析

目的 了解在农业农村部禁止使用多黏菌素作为动物促生长使用后四川部分地区鸡源大肠埃希氏菌（E.coli）mcr-1基因的携带情况,为制定进一步防控措施提供依据。方法 采集四川部分地区市场售卖点肉鸡直肠拭子,用含有多黏菌素（终浓度4 μg/mL）的EC肉汤增菌接种含多黏菌素（终浓度4 μg/mL）的麦康凯平板,挑取可疑菌落,采用PCR方法鉴定菌株并检测mcr-1基因;微量肉汤稀释法测定mcr-1基因阳性菌株对临床常见抗菌药物耐药情况。脉冲场凝胶电泳（PFGE）对mcr-1基因阳性菌株进行同源分析。耐药基因质粒结合实验验证mcr-1基因传播途径。结果 从70份肉鸡样本中的13份检出mcr-1基因阳性大肠埃希氏菌,检出率18.57%（13/70）,对实验的13种抗生素,除13株mcr-1阳性菌株对头孢西丁有12株敏感以外,对其他抗生素都表现出不同程度的耐药,其中四环素和甲氧苄啶/磺胺甲恶唑耐药率最高,达到了100%（13/13）;其次是氨苄西林和氯霉素,耐药率为84.62%（11/13）。PFGE显示13株mcr-1阳性大肠埃希氏菌分属13个不同的型别;质粒结合实验显示mcr-1基因能够通过质粒传播。结论 mcr-1基因在鸡大肠内大肠杆菌中检测率比较高,且鸡大肠中mcr-1阳性大肠埃希氏菌的耐药情况比较严重。     

Contamination with storage fungi of human food from Cameroon

In a mycological study, a total of 95 human food samples were investigated to evaluate the incidence of fungal contamination in Cameroon by conventional identification method and partly confirmed by DNA sequencing. The isolated fungal spp. were further studied to determine their toxigenic potentials. The investigation revealed the predominance of Aspergillus and Penicillium with 96% of samples contaminated with at least one species of these fungi, whereas the incidence of co-contamination of samples was 85%. Aspergillus flavus and Aspergillus parasiticus (Flavi section) were the most predominant species contaminating mainly maize and peanuts. In addition, P. crustosum and P. polonicum were the most common contaminants belonging to the genus Penicillium. On the other hand, A. ochraceus (Circumdati section) registered a low incidence rate of 5%, including other members of the Aspergillus group. Other members of the genera Rhizopus and Alternaria spp. were also registered in the study. A majority of fungal strains of A. ochraceus, A. parasiticus, P. crustosum and P. polonicum isolated were toxigenic, producing the mycotoxins tested for, while none was detected in cultures of A. fumigatus. The high incidence rate of fungi contamination coupled with their potentials in producing mycotoxins gives a strong indication that the samples tested may likely be contaminated with various mycotoxins. There is need for further study to assess the incidence of mycotoxins contamination in similar food samples.     

Susceptibility of stored product insects to high concentrations of ozone at different exposure intervals

Ozone is a highly reactive gas with insecticidal activity. Past studies have indicated that ozone technology has potential as a management tool to control insect pests in bulk grain storage facilities. The objective of this study was to determine the efficacy of short periods of exposure to high ozone concentrations to kill all life stages of red flour beetle (Tribolium castaneum (Herbst)) (Coleoptera: Tenebrionidae), and Indianmeal moth (Plodia interpunctella (Hübner)) (Lepidoptera: Pyralidae), adult maize weevil (Sitophilus zeamais (Motsch.)) (Coleoptera: Curculionidae) and adult rice weevil (S. oryzae (L)) (Coleoptera: Curculionidae). Insects were treated with six ozone concentrations between 50 and 1800 ppm. The specific objective was to determine minimal time needed to attain 100% mortality. The most ozone-tolerant stages of T. castaneum were pupae and eggs, which required a treatment of 180 min at 1800 ppm ozone to reach 100% mortality. Eggs of P. interpunctella also required 180 min at 1800 ppm ozone to reach 100% mortality. Ozone treatments of 1800 ppm for 120 min and 1800 ppm for 60 min were required to kill all adult S. zeamais and adult S. oryzae, respectively. The results indicate that high ozone concentrations reduce the treatment times significantly over previously described results. Our results also provide new baseline information about insect tolerance to ozone treatment.     

单一及混合乳酸菌发酵对番木瓜汁品质的影响

目的：探讨植物乳杆菌Lactobacillus plantarum （Lp）、鼠李糖杆菌Lactobacillus rhamnosus （Lr）、嗜酸乳杆菌Lactobacillus acidophilus （La）及两两混合菌（Lp+Lr、Lp+La、Lr+La）对番木瓜汁发酵后植物化学、微生物学、风味特性和功能特性的影响，并开发出一种具有改善功能和促进健康特性的番木瓜益生菌发酵饮料。方法：通过测定发酵过程中pH值、可溶性固形物、可滴定酸、活菌数、葡萄糖、果糖、蔗糖、有机酸和挥发性化合物的变化，考察各菌发酵过程中总酚、总黄酮含量和抗α-葡萄糖苷酶、抗酪氨酸酶的能力。结果：在72 h的发酵过程中，单一菌株培养和混合菌株培养的变化相似，pH值显著降低，酸度显著提高；乳酸和琥珀酸含量均显著提高，柠檬酸和苹果酸含量显著降低。发酵后，木瓜汁中总酚类物质和总黄酮含量均有所增加。Pearson相关分析表明，酚类物质的代谢可能有助于增强α-葡萄糖苷酶和酪氨酸酶的抑制作用。所有发酵组中，由植物乳杆菌单菌发酵的番木瓜汁乳酸、总酚、总黄酮含量最高，对α-葡萄糖苷酶和酪氨酸酶的抑制作用最强。未经发酵的番木瓜原汁中主要检出6种挥发性化合物，丁酸含量最大为89.742%，其次为芳樟醇。发酵后，从6组发酵果汁中共鉴定出25种主要挥发性成分，其中丁酸含量显著降低，减少了番木瓜不愉快气味的产生。所有发酵中，Lp单菌产生的挥发性成分最多（18种），混合菌Lp+Lr的较少（5种）。虽然混合菌Lp+Lr存在的活菌数最多[7.61 lg（CFU/mL）]，但总体看来，单一菌种Lp可能更可取。结论：单菌种植物乳杆菌发酵可以改善番木瓜汁的感官特性，并增强其潜在的功能特性。     

植物乳杆菌发酵桑葚酵素工艺优化及质量评价

目的:解决新鲜桑葚难以保存的问题，将新鲜桑葚制成桑葚酵素。方法:以新鲜桑葚汁为原料，植物乳杆菌为生产菌种，总酚含量为评价指标，通过单因素试验结合响应面试验优化了植物乳杆菌桑葚酵素的发酵工艺，并对桑葚酵素的理化、微生物及感官质量指标进行评价。结果:优化后发酵工艺条件为发酵时间40 h、发酵温度32℃、接种量25%,所制得的植物乳杆菌桑葚酵素的总酚含量达(43.48±0.67)μg/mL,是未经发酵的桑葚汁的1.62倍，可溶性固体物含量为5.36%,pH值为4.08±0.01,微生物指标满足国家标准；桑葚酵素呈紫红、色泽均匀，具有浓郁的桑葚果香和发酵的香味、无异味，酸味柔和、风味好，有光泽、无杂质及沉淀。结论:经植物乳杆菌发酵制得桑葚酵素的过程有生物活性物质产生，有利于提高桑葚酵素质量。