武汉市一般人群血清中全氟及多氟烷基化合物浓度及其影响因素研究

目的 了解武汉市一般人群血清中全氟及多氟烷基化合物(PFASs)浓度,探索血清中PFASs浓度水平的影响因素。方法 以在武汉市某医院进行一般体检的人群为研究对象(n=67),通过超高效液相色谱-三重四级杆质谱(UPLC-TQ/MS)联用仪测定外周血清中12种PFASs浓度,采用多元线性回归分析方法分析一般人口学特征和血清中PFASs浓度的关联性。结果 武汉市一般人群血清中12种PFASs的平均浓度水平为11.60 ng/mL。全氟辛烷磺酸及其盐类(PFOS)和全氟辛酸及其盐类(PFOA)的贡献率较大,分别为45.03%和31.86%。男性人群血清中PFOS、PFOA、全氟己基磺酸(PFHxS)、全氟壬酸(PFNA)等主要化合物的浓度高于女性,其β值(95%可信区间)分别为0.708(0.313,1.104)、0.518(0.069,0.967)、0.724(0.388,1.059)和0.684(0.399,0.968)。同时,发现血清中PFOS、PFHxS、PFNA浓度和年龄呈正相关,其β值(95%可信区间)分别为0.062(0.042,0.081)、0.035(0.019,0.052)和0.030(0.016,0.045)。结论 性别和年龄对血清中PFASs浓度有影响,在进行人体PFASs暴露评估中应考虑这些因素。     

肉类风味影响因素研究进展

肉是人类食物的重要组成部分,为人类提供了必需的蛋白质、脂肪和维生素。肉类风味是评价肉类品质的重要指标,风味的好坏直接影响肉类品质和消费者的选择。肉类风味形成途径复杂,全面分析检测难度较大,影响肉类风味的因素众多,涉及物理、化学、生物等多个领域。文章概述了肉类风味形成途径和分析方法,并着重对肉类风味的影响因素进行了讨论。     

GC-MS法测定塑胶跑道面层中的6种有害物质

建立了检测塑胶跑道面层中6种有害物质(环己基异氰酸酯(CHI)、2,4-甲苯二异氰酸酯(2,4-TDI)、2,6-甲苯二异氰酸酯(2,6-TDI)、六亚甲基二异氰酸酯(HDI)、萘-1,5-二异氰酸酯(NDI)和4,4'-二苯基甲烷二异氰酸酯(4,4'-MDI))含量的GC-MS检测方法,分别讨论了定量方式和萃取时间对6种有害物质回收率的影响。将样品剪碎至10~20目(0.85~2.00 mm)的颗粒,用10 mL乙酸乙酯萃取,室温下超声20 min,提取液用DB-17MS石英毛细管色谱柱(30 m×0.25 mm×0.25μm)分离,采用GC-MS法并选择离子检测,内标法定量。结果表明,在0.5~100.0 mg/L(4,4'-MDI在1.0~100.0 mg/L)浓度范围内,线性良好,相关系数均大于0.998,方法检出限范围为2.0~10.0 mg/kg,定量限范围为6.0~20.0 mg/kg;加标平均回收率在80.1%~100.8%之间,相对标准偏差(n=6)小于5.2%。该方法快速、准确,适用于塑胶跑道面层中有害物质的测定。     

母液中高浓度有机物对甲酸钠生产的影响及应对措施

甲酸钠为季戊四醇装置的副产品,生产中存在的主要问题是蒸汽的消耗高,甲酸钠产品含量偏低,有机物含量高。究其根本原因是甲酸钠母液中有机物浓度升高所致。本文针对系统有机物浓度高对甲酸钠生产的影响进行了分析探讨,同时提出了降低甲酸钠母液有机物浓度的方法。     

基于气相色谱-离子迁移色谱分析不同贮藏方式对洋葱浆馕风味的影响

采用气相色谱-离子迁移谱（gas chromatography-ion mobility spectrometry，GC-IMS）对洋葱浆馕6 种不同贮藏条件下挥发性物质进行分析，包括低温贮藏、室温贮藏、真空贮藏、脱氧贮藏、保鲜剂贮藏和保鲜剂结合脱氧贮藏。研究表明：在洋葱浆馕中共鉴定出66 种挥发性风味物质，其中包括醇类9 种、酮类4 种、醛类18 种、酯类4 种、呋喃衍生物3 种，酸类1 种和未能识别的化合物27 种。随着贮藏时间的延长，低温贮藏和真空贮藏洋葱浆馕在贮藏期内醛类挥发性有机物基本不变，其他处理组的醛类挥发性有机物在贮藏期内变化呈降低的趋势。结合主成分分析和欧氏距离可以发现低温贮藏和其他贮藏方式的第0天挥发性物质种类和浓度较为接近，主成分分析图中点的位置也相聚在一起，说明低温贮藏馕的挥发性物质变化不明显。该研究建立不同贮藏方式洋葱浆馕挥发性气味指纹图谱，可视化出洋葱浆馕挥发性成分轮廓，为洋葱浆馕贮藏期间风味变化规律提供信息。     

<i>Claroideoglomus etunicatum</i> improved the growth and saline– alkaline tolerance of <i>Potentilla anserina</i> by altering physiological and biochemical properties

To investigate the effects of arbuscular mycorrhizal (AM) fungi on the growth and saline–alkaline tolerance of Potentilla anserina L., the seedlings were inoculated with Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker & A. Schüßler in pot cultivation. After 90 days of culture, saline–alkaline stress was induced with NaCl and NaHCO₃ solution according to the main salt components in saline–alkaline soils. Based on the physiological response of P. anserina to the stress in the preliminary experiment, the solution concentrations of 0 mmol/L, 75 mmol/L, 150 mmol/L, 225 mmol/L and 300 mmol/L were treated with stress for 10 days, respectively. The mycorrhizal colonization rate, mycorrhizal dependence, chlorophyll content, malondialdehyde content, antioxidant enzyme activities, osmoregulation substances content and water status were measured. The results showed that with the increase of NaCl and NaHCO₃ stress concentration, mycorrhizal colonization rate, colonization intensity, arbuscular abundance and vesicle abundance decreased, and reached the lowest value at 300 mmol/L. Strong mycorrhizal dependence was observed after the symbiosis with AM fungus, and the dependence was higher under NaHCO₃ treatment. Under NaCl and NaHCO₃ stress, inoculation with AM fungus could increase chlorophyll content, decrease malondialdehyde content, increase activities of superoxide dismutase, peroxidase and catalase, increase contents of proline, soluble sugar and soluble protein, increase tissue relative water content and decrease water saturation deficit. It was concluded that salt–alkali stress inhibited the colonization of AM fungus, but the mycorrhiza still played a positive role in maintaining the normal growth of plants under salt–alkali stress.     

Feasibility of CANON process for treating nitrogenous wastewater containing heavy metals

The appearance of heavy metals in wastewater brings a major burden to wastewater treatment plants, due to the high toxicity to microorganisms. Several commonly used heavy metals, including Zn(II), Cd(II), Hg(II), and Pb(II) were adopted to clear the individual and joint toxicity to the completely autotrophic nitrogen removal over nitrite (CANON) process in six sequencing batch reactors. The obtained results suggested that the nitrogen removal performances were transiently inhibited, but rapidly recovered. The restoration period under the stress of Hg(II) and Pb(II) was shorter than that under Zn(II), Cd(II), and the joint heavy metals. During the long-term exposure, Cd(II) in 1mg L⁻¹ slightly inhibited the nitrogen removal, while Zn(II), Hg(II), Pb(II), and mixture showed a negligible impact on CANON process. The defense of extracellular polymeric substances (EPS), the good adaptability of functional bacteria, and the inducement of resistant genera by heavy metals all contributed to the robustness and stability of CANON process. Therefore, it is feasible to treat nitrogenous wastewater containing low heavy metals using CANON process. © 2020 Society of Chemical Industry     

Steam radish sprout (Raphanus sativus L.): active substances,antioxidant activities and non-targeted metabolomics analysis

Various active substances, antioxidant activities and primary differential metabolite profiles were investigated to assess the nutritional quality of radish sprouts steamed for 0–300 s. The levels of flavonoids, total phenolic content and isothiocyanate in radish sprouts decreased with increased steaming time, and DPPH radical scavenging activity levels and superoxide dismutase levels also exhibited a downward trend (P < 0.05). By contrast, total phenolic acid, ferric-reducing antioxidant power and reducing power levels exhibited significant increases in the early short-term steaming process (P < 0.05). Steaming for 30 s promoted the accumulation of vitamin B₂, whereas, steaming for 300 s promoted the accumulation of phospholipids and myristic acid to a greater extent than steaming for 30 s. Overall, there was a partial non-decreased nutritional indicator in short-term steaming of radish sprouts, and a longer steaming time positively affected the differential metabolites.