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目的建立杜马斯燃烧法测定油料作物中粗蛋白质含量的方法,并与凯氏定氮法进行比较。方法以芝麻、大豆、油菜和花生为研究对象,对杜马斯燃烧法的称样量和氧气系数进行优化。分别用杜马斯燃烧法和凯氏定氮法测定4种样品的粗蛋白含量,并对2种测试方法的结果进行比较分析。结果杜马斯燃烧法的测定值略高于凯氏定氮法,但2种方法的测定值间没有显著性差异(P0.05),杜马斯燃烧法比凯氏定氮法的测定精密度和准确度更高。测定结果的相关性分析表明两种方法的测定值呈显著相关(r~2=0.9988)。结论杜马斯燃烧法的精密度和准确度更好,可以替代凯氏定氮法测定油料作物的粗蛋白质含量。 相似文献
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分别利用Lowry、BCA和Bradford三种方法对母乳中总蛋白、乳清蛋白和酪蛋白的含量进行了测定,并以凯氏定氮法为标准,对三种方法的检测结果进行了比较。结果表明Lowry和Bradford法适用于母乳中总蛋白含量的测定,Lowry法适于母乳中乳清蛋白含量的测定,Lowry、BCA和Bradford三种方法均适用于母乳中酪蛋白含量的测定。采用上述方法,只需要4 m L母乳样本,1.5 h内即可完成母乳总蛋白、乳清蛋白和酪蛋白的微量、高通量快速测定。上述方法适用于较大量母婴营养状况的调查研究,可为母乳化婴幼儿配方乳粉的研制以及促进婴幼儿生长发育提供科学依据。 相似文献
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几种测定油料饼粕粗蛋白含量方法的探讨 总被引:3,自引:0,他引:3
采用国家标准规定的凯氏定氮法、改进后的凯氏定氮法以及双缩脲法同时测定油料饼粕中粗蛋白含量,并对三种方法进行比较。结果表明:改进后的凯氏定氮法同国际法相比结果偏高,更皎皎于饼粕中实际粗蛋白含量;采用双缩脲法有测定结果相对平均偏差较大,但操作简便,效率高,更适合于生产厂家进行快速测定大量样品时使用。 相似文献
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凯氏定氮法是测定食品中蛋白质含量的一种普遍使用的常规分析法,目前国内多采用凯氏定氮法,而国际上多采用自动定氮仪进行凯氏定氮法,本文着重对自动定氮仪测定技术的综述评价。 相似文献
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本文介绍用氨气敏电极测定粮食及食品中蛋白质含量的原理和方法。本法与凯氏定氮法比较操作更为简便、快速,结果一致。 相似文献
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考马斯亮蓝G250染色法测定啤酒中蛋白质含量 总被引:11,自引:0,他引:11
以啤酒为原料,利用蛋白质与考马斯亮蓝显色原理,测定啤酒中蛋白质含量,并对测定条件进行优化研究,实验结果表明:波长在595nm处蛋白质有最大吸收峰,反应时间3~5min为最适宜,SDS对马斯亮蓝测定蛋白质含量有干扰。测定所用的标准曲线方程为:v=0.1296x+0.0907。考马斯亮蓝G-250法测量蛋白质含量与凯氏定氮法相比较误差范围3%~8%。 相似文献
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A. L. S. Silva A. S. Nunes J. L. Gesztesi Natura 《International journal of cosmetic science》2005,27(2):139-140
This study intends to present Bradford assay as an alternative to Lowry test to quantify hair damage during combing or brushing. The protocol involves collecting hair fragments that are chipped away from hair during these abrasive treatments and quantitatively measuring the amount of protein using an analytical procedure to detect low amounts of proteins. This protein determination method involves the binding of Coomassie Brilliant Blue G-250 to hair protein (keratin). It is quite rapid and sensitive and less prone to interferences as the standard Lowry procedure. The latter is subject to interference from compounds such as lipids, cationic surfactants and EDTA, which are ingredients commonly used in hair care formulations and may lead to a false positive result. These drawbacks should be eliminated when using the so called Bradford method for hair protein quantitation. Our studies showed reproducible results for human hair protein and the developed color was stable for up to one hour. The data also show that virgin hair releases less protein than bleached hair. The amount detected for the former after combing ranges from 0.875 to 1.03 mg g–1 of hair and 4.85 to 5.35 mg g–1 of hair for the latter. 相似文献
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An important requirement for the correct procedure of allergen analysis in hen’s egg is to obtain complete and unaltered protein extracts. Besides the aim of a quantitative extraction of the allergens from the matrix, it is equally important not to alter their allergenic potential during the extraction process. This paper describes and compares six extraction solutions for the analysis of whole-egg proteins and allergens. These requirements were examined via protein determination according to Bradford [Bradford, M. M. (1976). Rapid and sensitive method for quantitation of microgram quantities of protein utilizing principle of protein–dye binding. Analytical Biochemistry, 72, 248–254] and Kjeldahl [Meyer, A. H. (2006). Lebensmittelrecht, Verlag C.H. Beck München, Stand: 1. February 2006, § 64, Lebensmittel- und Futtermittelgesetzbuch, Amtliche Sammlung von Untersuchungsmethoden, Nr. L 06.00-7] as well as the EAST-inhibition method. It could be demonstrated that the extraction with a urea solution (8 M) led to significant interferences during the protein determination, and substantially reduced the allergenic potential of egg proteins. With all other extraction solutions adequate protein contents could be extracted. The highest protein content was achieved by the extraction with phosphate buffered saline followed by a Tween 20 solution, physiological saline, water, and acetate buffer. The results show that none of these extracts – except for the urea solution (8 M) – was altered in its’ allergenic potential. 相似文献
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Vikrant Narwal Neelima Sharma Rajan Sharma Yudhishthir S Rajput Bimlesh Mann 《International Journal of Dairy Technology》2018,71(2):539-543
Glycomacropeptide (GMP) is a nutraceutical additive, which is released during cheese preparation. In this study, the protein content in a laboratory GMP preparation and two commercial GMP samples, which was estimated by the Bradford, biuret, Lowry and bicinchoninic acid (BCA) assays, were compared using the Kjeldahl method. There were apparent differences in the values of estimated proteins using the different methods. An absence of dose response in the Bradford method and a low dose response using the Lowry method indicated the unsuitability of both these methods. Absorbance in the biuret and BCA methods linearly increased with increasing GMP content. The BCA method was the most sensitive of these methods. 相似文献
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应用Bradford法测定成品茶中水溶性蛋白质的含量,并研究了添加PVP试剂对测定方法以及对茶叶其它品质成分的影响。 相似文献
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为解决菜籽蛋白原料及制品中真蛋白含量难以测定的问题,建立了一种基于分级和定量2步完成的高选择性菜籽蛋白含量测定方法。通过酸化丙酮溶液和沸水萃取实施分级处理,可将样品中的非蛋白氮分离;结合应用可溶性蛋白的染色法测定和不溶性蛋白的凯氏定氮法测定,可获得样品的真蛋白含量。该方法变异系数不大于2.83%,回收率95%~96%,并可排除本源性非蛋白氮(包括芥子碱和硫甙)及外源性非蛋白氮(包括硝酸盐、铵盐、三聚氰胺和尿素)的干扰。该方法具备良好的抗干扰能力且不受蛋白质溶解性的影响,可推广到更多的植物蛋白制品及原料的真蛋白含量测定中,并可为相关行业的掺杂辨识或品质评价提供可靠手段。 相似文献