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根据较低硬度的水(软水)具有较好的溶解性、乳化性这一特点,试验用不同总硬度的水,采用传统淋醋方法,分别浸泡发酵成熟的醋醅,然后进行淋醋,测定不同醋液中总酸的含量,确定淋醋用水的总硬度是否对醋液总酸的含量有影响.采用相同的方法,通过多次小试,发现存在随着淋醋用水总硬度的降低,淋醋后的醋液总酸含量明显升高的趋势,即淋醋出品率的提高.应用该理论可使酿造食醋生产企业的经济效益有较大程度的提高. 相似文献
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胶体金免疫层析法定量检测猪肉中克伦特罗 总被引:4,自引:0,他引:4
建立了基于T/C比值的胶体金免疫层析法快速定量检测猪肉中克伦特罗残留的新方法。胶体金免疫层析试纸条的定量检测线性范围为0.1~1.5 ng/g,检测猪肉中克伦特罗残留的最低检测灵敏度为0.19 ng/g。比较了5种猪肉组织样本中克伦特罗的简便提取方法,其中采用0.02 mol/L,含2.8%NaCl的HCl溶液抽提猪肉样品2次的提取方案,克伦特罗的平均回收率达到76.7%,变异系数为7.4%。实际样本加标回收实验显示,加标量为0.5、1.0、2.0及3.0 ng/g时,胶体金试纸条检测回收率分别为(60.4±12.8)%,(70.24±4.2)%,(75.9±4.9)%,(71.1±5.0)%。与传统ELISA方法比对,结果显示2种方法具有较好的相关性(R2=0.9136)。以上实验结果证实,基于T/C比值法的胶体金免疫层析试纸条可用于猪肉组织样品中克伦特罗的快速及定量检测。 相似文献
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文章介绍了常用几种硬度的检测方法,给出了不同检测方法在轧辊检测中的不同结果,分析了轧辊的基体硬度和残余应力产生的硬度差异及对轧辊使用的影响。 相似文献
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牛奶中β-内酰胺类和三聚氰胺检测方法的建立 总被引:1,自引:0,他引:1
建立一种快速、简便,同时针对牛奶中β-内酰胺类抗生素和三聚氰胺残留的检测方法。应用竞争抑制免疫层析原理,研制β-内酰胺类和三聚氰胺胶体金试纸条。该试纸条检测限分别为青霉素G2μg/L、氨苄青霉素3μg/L、阿莫西林3μg/L、苯唑青霉素6μg/L、邻氯青霉素6μg/L、双氯青霉素6μg/L、萘夫西林20μg/L、头孢喹肟20μg/L、头孢哌酮40μg/L、头孢曲松50μg/L、头孢噻呋90μg/L、头孢洛宁10μg/L、三聚氰胺50μg/L,假阳性率低于5%、假阴性率为0,检测时间不超过15min。该方法操作简便、灵敏度高、特异性强,适用于乳品流通环节中β-内酰胺类抗生素和三聚氰胺残留的快速检测。 相似文献
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目的研制一种适用于相关检测仪器校准及分析方法评价的国家有证标准物质。方法经过标准物质原材料的选择、特性量值的测量方法、标准物质的制备方法、均匀性检验、12个月稳定性考察以及定值测量,并对样品的均匀性、测量的分散性及其他因素引入的不确定度分量分析和确定后,计算得到水中总有机碳标准物质测量过程不确定度的合成结果。结果水中总有机碳溶液标准物质的均匀性良好,稳定性优异,标准值定值结果为1000mg/L,相对扩展不确定度为2%。该标准物质已获批国家二级标准物质,编号为:GBW(E)082426。结论该标准物质性能良好,可满足食品、药品、日化、环境保护及化工产品研究和检测的需要,可用于相关仪器(总有机碳分析仪)的校准、分析方法评价,为统一相关量值发挥应有的作用。 相似文献
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Human hair can extract significant levels of calcium and magnesium, water hardness metals, from tap water immediately following chemical treatments and during hygiene practices. We have previously shown that this uptake is primarily a function of the condition of the hair. Depending on the extent of chemical damage, the hair can extract notable amounts of water hardness metals even from soft water. As water hardness metals concentrate primarily in the cuticle layers of the hair fibre, it is hypothesized that their presence will affect the structural properties that are chiefly driven by the cuticle. We examined hair mechanics and styling by technical measures of single-fibre torsional and tensile properties, combability and style retention as a function of the calcium and magnesium content of virgin and bleached hair. Our work has indicated that water hardness can affect hair properties. Fibre stiffening was induced by the presence of water hardness metals inside the fibres of both virgin and bleached hair. A reduction in combing forces was also observed, and this effect is believed to be a result of the stiffening. The style retention of virgin hair was improved by water hardness metals, whereas that of bleached hair was slightly reduced. 相似文献
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Lameness of dairy cows is a major welfare and economic problem. Degree of hardness of claws may influence chances for injury or for claw lesions, and exposure of claws to moisture may make them soft. To assess the relationship among hardness of the claw horn, quantity and rate of absorption of water, and incidence of claw lesions, 4 experiments were carried out. In the first 3 experiments, we soaked pieces of the claw horn in water for 12 to 24 h. Soaked claws gained weight and became significantly softer, indicating that water was absorbed. One-third of the total water absorbed in 24 h occurred during the first hour. Base of the abaxial and dorsal walls of the claw was harder than the sole, but became softer more rapidly when soaked in water. In the 4th experiment, significant negative correlations were detected between claw hardness of cows and severity of claw lesions, suggesting that cows with softer claws have the most severe claw lesions. Claw horn tissue absorbs water rapidly and claw hardness decreases with moisture content, suggesting that brief exposures to moist surfaces result in claws that absorb water and consequently become softer. The relationship between hardness and claw lesions indicates that cows with softer claws are at greater risk for lameness. 相似文献
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肉品中菌落总数和大肠菌群快速检测试纸片的研究 总被引:3,自引:0,他引:3
对肉品中菌落总数和大肠菌群快速检测试纸片进行了研究.选择中速定性滤纸为材料,分别浸入经不同特殊处理(不同浓度的TTC、琼脂、NaCl)的培养基中,40℃下烘干制得试纸片;将所制得的菌悬液涂布于成份不同的试纸片上,于32℃,培养20h(试纸片法),或涂布于平板计数琼脂上,于32℃,培养48h(国标法),然后计数,将二者得到的数据进行比较.结果表明:试纸片法与国标法具有很高的相似性.在100ml培养基中,TTC的浓度为0.02‰时试纸片的显色情况最好,生成的红色菌落数目最多.菌落生长受琼脂浓度的影响,当琼脂的浓度高于或低于0.15%时,细菌生长速度逐渐减慢.NaCl的浓度在0.4%时菌落生长呈现最好势态. 相似文献
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研究选择牛肉糜为原料,考察谷氨酰胺转胺酶用量(≤1.0%)、反应温度(40~60℃)与时间(≤180 min)对牛肉凝胶保水性和硬度的影响。结果表明:肉糜蒸煮损失(CL)随TG添加量的增加和反应时间的延长显著增大(P<0.05),而随反应温度的提高则表现出先升后降的变化;0.2%~0.4%的TG添加量明显降低了凝胶WHC值,而高于45℃的反应温度则显著提高了WHC(P<0.05),但反应时间、以及高于0.6%的TG添加量对凝胶WHC均无显著性影响(P>0.05);较少的TG添加量(≥0.2%)和一定的反应时间(≥36min)均可显著提高凝胶的硬度(P<0.05),而高于0.4%的添加量或长于72 min的反应时间则对凝胶硬度的增加均不明显(P>0.05),而反应温度对凝胶硬度的影响也表现出先升后降的变化规律;此外,50℃的反应温度会形成最高的CL值和凝胶硬度值。 相似文献
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根据国家标准方法测定水中总铬,分析实验过程中不确定度的可能来源,建立不确定度的数学模型,对重要的不确定度分量进行分析评定。结果表明,测定水中总铬的不确定度来源主要是标准曲线拟合过程中产生的不确定度,其次是样品重复测定过程中产生的不确定度。因此,采用定期维护仪器使性能保持在最佳状态、仪器预热、增加标准系列溶液和样品的测量次数等方式可以增加测量结果的可靠性。 相似文献
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以还原法为理论基础,研制生乳细菌总数检测仪进行生乳细菌总数快速检测,以克服经典还原法目测比色主观性强的缺点,而且检测结果可以定量表示。该仪器连续检测加入试剂后的生乳样品颜色(RGB),通过数理统计分析,采用斜率法以R值斜率表示样品颜色的变化速度。研究以标准平板计数法(SPC法)为标准,建立了R值斜率与菌落总数之间的标准方程,经验证生乳细菌总数检测仪检测结果与SPC法检测结果差异不显著。与流式细胞仪比较,在与SPC法的相关性、运行成本及便携性等方面具有一定优势。 相似文献