THG创造“体育明星”

关于兴奋剂 为维护奥林匹克运动的纯洁，防止和抵制兴奋剂对世界体育的侵袭，从1968年第12届奥运会开始，对运动员进行兴奋剂检测并形成制度，在各项竞技运动中实施，至今已有100多件重大兴奋剂丑闻被曝光。     

国内外食源性兴奋剂误服事件分析与法规标准现状

食源性兴奋剂的预防控制是各类体育赛事管理机构和供应服务基地保障的重要内容。本文介绍了食源性兴奋剂的食物来源与分类,并对2008年—2018年国内外食源性兴奋剂误服的阳性案例进行统计,分析其误服产品种类、主要检出成分与类型、误服原因,并归纳其主要特征,最后对国内外近年食源性兴奋剂法规标准进展进行梳理,为加强我国食源性兴奋剂检测研究与预防管理提供思路。     

干血点一种新型反兴奋剂检测技术

干血点（DBS）技术作为新型反兴奋剂采样技术在2022年北京冬奥会、冬残奥会兴奋剂检测中进行了首次应用。结合已有的研究文献资料,对干血点（DBS）与传统采样技术相比的（1）便于采集,对运动员损伤小;（2）样本的运输与储存方便,经济实惠;（3）采集样本中的物质具有更高的稳定性这几个优势进行阐述;同时,也对干血点（DBS）采样技术和相关检测技术的联用,对兴奋剂禁用清单中蛋白同化制剂,肽类激素,刺激剂这几个方面进行了综述,表明干血点（DBS）技术在各类禁用物质检测中具有良好的适用性,是传统采样基质的一个很好补充。并基于干血点（DBS）技术在2022年北京冬奥会、冬残奥会中的成熟应用,对我国运动员在训练中进行兴奋剂监控的应用推广进行了前景展望。     

运动员特供食品中兴奋剂检测研究进展

β_2-受体激动剂类(β_2-Agonists)、合成类固醇类(anabolic steroids)、糖皮质激素类(glucocorticoid)和玉米赤霉醇类(zeran01)都有促进蛋白合成、提高肌肉含量等作用。尽管这些物质在很多国家的畜牧业养殖中都被禁止或限制使用,但不少养殖户依旧非法滥用以提高经济效益。运动员在摄入有药物残留的食品后,会导致兴奋剂检测呈阳性,这无论对运动员个人还是国家,都会造成重大损失。为杜绝食源性兴奋剂,运动员特供食品常常需要进行上述4类项目的检测。本文主要对这4类物质的定义、作用、危害以及国内外检测方法等进行简要阐述。     

动物性食品中β-兴奋剂残留概述

β-兴奋剂能促进动物蛋白质的合成,提高饲料转化率,但其在动物性食品中的残留物给人的身体健康带来威胁,因此,多数β-兴奋剂在畜牧业中已被禁止使用,各国政府通过一系列法律法规限制该类药物的滥用以加大对β-兴奋剂的监管力度。通过介绍β-兴奋剂在动物性食品中的残留现状及常见的β-兴奋剂使用情况,比较主要国际组织和国家,包括国际食品法典委员会、欧盟、美国、日本和中国对β-兴奋剂最大残留限量、检测标准的异同,同时总结近年来β-兴奋剂残留的检测方法。     

食品源兴奋剂在体育运动中的风险

兴奋剂,其实就是国际体育组织明确规定予以禁止的药物以及方法的总称。在体育运动中,兴奋剂的使用,能够通过捷径来使运动员提高自己的成绩,却会对运动员的身体造成一定的危害。因此,在体育运动中,兴奋剂一直是被禁止使用的。但是,在现实情况中,兴奋剂却普遍存在,很多种食品中都有可能会含有一定的兴奋剂。所以,在平时,运动员的饮食也需要严格把控。本文就针对这方面的内容进行了分析。     

β-兴奋剂在动物性食品中残留的免疫分析方法研究进展

β-兴奋剂能够降低动物体内脂肪含量,促进蛋白质合成,提高瘦肉率和饲料转化率,常被用作饲料添加剂。但是由于β-兴奋剂会在动物组织内残留,通过动物源食品进入人体内,会引起心悸、头疼、毒害肝肾等严重危害,包括我国在内的大多数国家已禁止畜牧业中应用此类药物。文章就免疫分析法总结介绍其基本原理、研究进展、优缺点、发展趋势,涵盖放射免疫分析、酶免疫分析、化学发光免疫分析、荧光免疫分析、胶体金标记免疫分析、免疫传感器、免疫芯片、流动注射免疫分析、免疫PCR等技术。     

瑞士开发食品检测新方法

据国际《应用化学》杂志介绍，瑞士联邦技术大学最近开发出一种快速检测食品质量的新方法。这种对食品表面和成分组织快速分析的方法不仅适合于食品质量的控制，也可用于检测兴奋剂、爆炸物以及物质转化的研究。     

瑞士开发食品检测新方法

据国际《应用化学》杂志介绍，瑞士联邦技术大学最近开发出一种快速检测食品质量的新方法，这种对食品表面和成分组织快速分析的方法不仅适合于食品质量的控制，也可用于检测兴奋剂、爆炸物，以及物质转化的研究。     

选用合适的方法 对食品中重金属进行准确检测

正人类不合理的社会活动导致重金属在环境中的含量远远超出了合理的水平,而微生物无法对重金属进行分解,重金属就会在植物和动物体内逐渐积累,最后被人类食用,当人类体内的重金属积累到一定程度后就会发生中毒。因此,对食品中的重金属进行检测非常重要。一、食品中重金属污染的危害目前,导致食品重金属污染的主要物质是铅、汞、砷和镉。如果食品被铅污染,将会给人体的神经系统、造血系统和     

不同仪器测试马克隆值的对比分析

对Y145、Y175、MC、920型气流仪测试马克隆值的结果进行了对比分析,结果表明,国产仪器与920型气流仪测试结果没有显著差异;Y175与MC型、Y175与920型气流仪测试结果的线性相关关系显著。     

Changes in functional properties of common carp (Cyprinus carpio) myofibrillar protein as affected by ultrasound-assisted freezing

Ultrasound-assisted freezing (UF) has proven to be a method that can effectively increase the freezing rate of frozen food and improve its quality. The functional properties of myofibrillar proteins (MP) are important factors that affect the further processing quality of meat products. At present, the effect of UF on the functional properties of frozen MP is not yet clear. Therefore, in the present study, changes in the functional properties (emulsifying and gel properties) of MP in common carps (Cyprinus carpio) frozen with UF at different power levels were investigated. The results revealed that, compared with immersion freezing (IF), UF at 175 W (UF-175) effectively inhibited the decrease in protein solubility, absolute Zeta potential, emulsion activity index, storage modulus (G'), and loss modulus (G'') caused by freezing. UF-175 sample had lower protein turbidity, and smaller protein particle size than any other frozen samples (P < 0.05), which suggested that UF-175 inhibited protein aggregation induced by freezing. In addition, shorter T₂₁ and T₂₂ relaxation times were obtained in UF-175 sample than other frozen samples, indicating that UF-175 reduced the mobility of immobilized and free water. Accordingly, UF-175 sample had higher gel strength and water holding capacity than other frozen samples (P < 0.05). A denser and more uniform gel network structure was also found in UF-175 sample than other frozen samples. In general, improved functional properties of common carp MP can be achieved by optimal UF.     

不同仪器测试马克隆值的对比分析

对145、175、MC、920气流仪测试马克隆值的结果进行对比分析,得出结论：国产仪器与920气流仪测试结果没有显著差异;175与MC气流仪测试结果线性相关关系显著;175与920气流仪测试结果线性相关关系显著。     

175g/m~2进口铜版纸定量测量不确定度的评估

根据国家标准GB/T451.2-2002,对175g/m2进口铜版纸进行定量测量,并根据标准JJF1059-1999对其进行了不确定度的评估。不确定度主要来源是:重复性测量、仪器自身示值准确度、数值修约。这批175g/m2进口铜版纸定量测量扩展不确定度为0.8266g/m2。     

Polymorphic AP-1 binding site in bovine CSN1S1 shows quantitative differences in protein binding associated with milk protein expression

Polymorphisms in 5′-flanking regions of milk protein encoding genes can influence the binding activity of the affected response elements and thus have an impact on the expression of the gene products. However, precise quantitative data concerning the binding properties of such variable response elements have so far not been described. In this study we present the results of a quantitative fluorescent electromobility shift assay comparing the allelic variants of a polymorphic activator protein-1 binding site in the promoter region of the bovine α_s1-casein encoding gene (CSN1S1), which is affected by an A→G exchange at −175 bp (CSN1S1^−175bp). A supershift assay using a commercial c-jun antibody was carried out to verify the specificity of protein binding. The gel shift analysis revealed specific and significantly reduced protein binding of oligonucleotides containing the G variant of the CSN1S1^−175bp binding site. Further investigations comprised genotyping of the variable CSN1S1^−175bp activator protein-1 element by an NmuCl restriction fragment length polymorphism in 62 cows of the breed Simmental and 80 cows of the breed German Holstein. Single milk proteins from at least 4 milk samples per cow were quantified by alkaline urea polyacrylamide gel electrophoresis. Homozygotes for CSN1S1^−175bp*G were not observed, and the allele frequencies were 0.19 in Simmental and 0.05 in German Holstein. Carriers of CSN1S1^−175bp*G showed higher content (%) as well as quantity (g/d) of α_s1-casein than CSN1S1^−175bp*A homozygotes, independent of breed. We assume that the positive association of the CSN1S1^−175bp*G variant with CSN1S1 expression is likely to be caused by a reduced affinity of the affected response element to a c-jun-containing CSN1S1 dimer with repressor properties.     

Wheat Gluten and Glutenin Thermal Conductivity and Diffusivity at Extruder Temperatures

Thermal properties (thermal conductivity and diffusivity) of gluten and glutenin were measured in the temperature range 60-175°typically used in extrusion processing. Thermal conductivity and diffusivity of gluten decreased with increasing temperature and increased with increasing moisture content. Thermal conductivity and diffusivity of glutenin increased with temperature and moisture content. Thermal conductivity of gluten was 0.06-0.35 W/m-C and glutenin was 0.29-0.49 W/m-C for the temperature range 60-175°and moisture content range of 0-30%.     

中国部分沿海海域牡蛎体内多环芳烃和多氯联苯的空间分布及组分特征

对中国部分沿海海域牡蛎体内16种多环芳烃(PAHs)和16种和多氯联苯(PCBs)空间分布和组分特征进行分析,于2010年夏、秋季在辽宁、山东、浙江、福建及广东共设置175个采样点,分布采用气相色谱-质谱联和气相色谱方法进行检测分析。结果显示：所取175个采样点牡蛎体内16种PAHs总含量的平均值为3.79μg/kg,其中浙江省被测样品的PAHs总含量最低,辽宁相对略高;检测样品16种PCBs总含量在1.41～13.95μg/kg之间;PCBs含量总的空间变化趋势是由北向南先增加后减少;样品的PAHs优势组分为三环结构,五环和六环PAHs含量很低;PCBs被检出的仅有三氯代和五氯代两种。被测牡蛎样品总体PAHs和PCBs残留量符合中国和一些发达国家贝类卫生标准,不影响消费者食用安全。     

Foam‐Mat Freeze‐Drying of Bifidobacterium longum RO175: Viability and Refrigerated Storage Stability

Foaming as a pretreatment was used prior to freeze‐drying of Bifidobacterium longum RO175 to investigate the potential acceleration of the drying rate and increase in microorganism viability after the process. A study on storage of foamed and nonfoamed freeze‐dried products at 4 °C completed this study. B. longum RO175 in foamed medium could be freeze‐dried in 1/7 to 1/4 of the time required for nonfoamed suspensions. In addition, foamed suspensions presented higher viability immediately after freeze‐drying (13.6% compared to 12.81 % or 11.46%, depending on the cryoprotective media). Refrigerated storage led to a reduction in B. longum RO175 viability for all tested protective agents (foamed and nonfoamed). No correlation between glass transition temperature and stability of probiotic powders was observed during storage. In addition, lower viability after 56 d of storage was observed for foamed materials, probably due to foam porous structure and higher hygroscopicity, and oxygen presence and moisture pickup during storage.     

Analysis of essential carboxylic amino acid residues for catalytic activity of fungal chitosanases by site-directed mutagenesis

A comparison of amino acid sequences of fungal chitosanases, belonging to family 75 of glycosyl hydrolases, revealed three carboxylic amino acid residues completely conserved among all of the chitosanases. To study the role of these residues in catalysis, they were replaced with other residues by site-directed mutagenesis in the chitosanase gene of Fusarium solani. The mutated genes were expressed in the yeast Saccharomyces cerevisiae and the resulting recombinant chitosanases were used in kinetic analysis. Chitosanases with Asp-175-->Asn and Glu-188-->Gln mutations were essentially inactive, whereas those with Asp-175-->Glu and Glu-188-->Asp mutations retained 25-50% specific activity as compared with the wild-type enzyme. The mutation of Asp-212-->Asn did not decrease specific activity to a large extent. Circular dichroism analysis confirmed that the mutant chitosanases had similar secondary structures to that of the wild-type enzyme. These results indicate that Asp-175 and Glu-188 are essential residues for the catalytic activity of chitosanase. Time-dependent (1)H-NMR analysis for the hydrolysis of D-glucosamine hexamer revealed that a fungal chitosanase is an inverting enzyme producing only the alpha anomeric form of reaction products.     

Technological properties of microwave parboiled rice

Two rice varieties, a short grain (Giza 175) and a long grain (Giza 181), were parboiled by soaking in water at 80–85 °C for 1.5 h and then dried in the microwave oven for 3, 5, 6 and 8 min. The effect of such parboiling treatment on milling output and technological properties (cooking and eating quality) of milled rice were studied. There was a negative significant correlation between head rice and the drying time and a positive correlation between the drying time and the broken grains. The effect of such treatment on the chemical composition of milled parboiled rice, i.e. amylose, protein, fat and ash contents, showed that the amylose content of Giza 175 variety significantly decreased while not affect in Giza 181 variety. No significant differences were obtained in protein, fat and ash contents by increasing drying time. Microwave drying was more pronounced on Giza 175 variety rather than Giza 181 one. However, the optimum cooking time of the parboiled samples of the two varieties was not affected as a result of increasing the microwave drying time.