基于DNA酶催化反应建立适配体比色法检测鸡蛋中氯霉素

目的：通过制备适配体—磁珠复合体,利用氯霉素的特异性结合可解离适配体与DNA酶的结合,并解除对该酶与血红素结合催化显色反应活性抑制的机理,建立用于快速检测鸡蛋中氯霉素的方法。方法：通过适配体与DNA酶碱基互补配对后,再将该结合体通过羧基和氨基的缩合反应,制备适配体—磁珠复合体。再通过加入不同浓度的氯霉素溶液以实现与其适配体的结合,使得DNA酶与氯霉素核酸适配体发生解离,被解离出的DNA酶与血红素结合催化显色反应。结果：该方法检测氯霉素的线性范围为0.001～100.000 mg/kg,其吸光度值与氯霉素浓度呈线性相关,在5,10,25 mg/kg 3种添加水平下该比色法的回收率为98.4%～101.1%,相对标准偏差均小于10%。结论：该方法通过引入DNA酶和磁性纳米粒子有效克服了传统快速检测方法的非特异性吸附引起的假阳性结果,适用于快速检测鸡蛋中氯霉素的残留量。     

基于肉鸡性别的鸡汤挥发性物质主成分分析

利用固相微萃取—气相色谱—质谱(SPME—GC—MS)联用内标法,研究基于肉鸡性别差异的传统鸡汤挥发性物质,并分别进行主成分分析。结果显示:两种鸡汤共检测出挥发性物质78种,其中母鸡肉汤和公鸡肉汤分别为76,67种,含量分别为1 369.84,1 029.61μg/100 m L,主要为醛类、酮类、醇类、烷烃类、酸类和酯类,两者共同含有的挥发性物质为65种。母鸡肉汤和公鸡肉汤中反式-2-己烯醛、(E,E)-2,4-庚二烯醛、十三醛、2-庚酮、正己醇等13种风味物质的含量差异显著(P0.05)。两种鸡汤经主成分分析都得到两种主成分物质,且累计贡献率达100%,但种类和含量差别较大。     

葡萄酒中锶的分离及MC-ICP-MS测量

Isotopes can be applied to food geographical origin traceability as “fingerprint”. The radioactive disintegration of Sr in different samples leads to variation of ⁸⁷Sr /⁸⁶Sr in nature. Sr in wine comes from soils, rocks and water in vine yard, ⁸⁷Sr /⁸⁶Sr can give much information about the geographical origin of wine. This paper describes in details the separation procedure by Sr-resin and determination by MC-ICP-MS.     

贮藏温度对即食小龙虾品质及微生物菌群多样性的影响

先通过测定理化指标确定即食小龙虾货架期,再分别从4,25℃两种贮藏温度下中、末期的样品中提取即食小龙虾总DNA,通过高通量测序技术探究贮藏期间其微生物菌群变化。结果表明:随贮藏时间的延长,物种多样性逐渐降低;4℃贮藏条件下,末期优势菌群为海洋杆菌属(Oceanobacillus,81.522%)和希瓦氏菌属(Shewanella,3.625%);25℃贮藏条件下,末期优势菌群为哈撒韦氏菌属(Hathewaya,78.700%)、芽孢杆菌属(Bacillus,12.380%)和狭义梭菌属(Clostridium sensu stricto,8.707%)。     

非传统同位素体系计量标准研究

A new generation of multi-collector isotope ratio mass spectrometers is now capable of measuring isotope ratios with extremely high precision for non-traditional isotope system. As a result, the application of non-traditional isotope system on geology, environmental science, oceanography, medicine and other fields is developing rapidly. However, as there is still lack of the related isotope primary/ standard reference in metrology, it causes a key problem in terms of how to obtain reliability and comparability of measurement results for non-traditional isotopes applied research. Therefore, Researching, developing and promoting the use of accurate and reliable isotope CRMs are a key element for underpinning a good application of non-traditional isotope system. This article reviews the main problems of the isotope measurement, R & D status and development trend related to the non-traditional isotopes. The emphasis is on raising the understanding for the importance of R & D and use the relative metrology standards, promoting the well development of isotopic metrology standards and insuring the fully playing the role of its measurement traceability.     

添加剂处理对油炸胡萝卜脆片含油率及品质的影响

以降低油炸胡萝卜脆片的含油率,提高产品感官品质和营养品质为目的,在油炸前加入不同添加剂(氯化钠、单甘酯、蔗糖酯、卵磷脂、改性淀粉等)对胡萝卜片进行浸渍处理,对处理后油炸样品的质构、含油率、色度、β-胡萝卜素等方面进行检测分析。结果表明:通过加入添加剂处理,能显著降低样品的含油率,减小β-类胡萝卜素损失。虽然各种添加剂对样品品质方面的提高各有所长,但综合含油率、质构特点、β-胡萝卜素保留量、色泽、感官指标等数据比较,添加蔗糖酯的样品硬度是55.62,脆度是20.32,含油率(3.18g/100g)最低,β-胡萝卜素保留量为2.73mg/100g,蔗糖酯对提高整体品质效果最佳。