牛奶中抗生素残留快速检测方法分析

利用TTC法和SNAP快速检测法对牛奶中β-内酰胺类、四环素类、大环内酯类、氨基糖苷类、氯霉素、磺胺类、氟喹诺酮类等7个类别9种代表性抗生素检测结果进行比较分析,根据检测结果认为两种检测方法均存在一定缺陷,在原料乳质量控制检测工作中单独使用都存在一定风险,但在对原料收购地区奶牛饲养用药普查基础上,可以考虑使用SNAP法来控制原料乳中β-内酰胺类抗生素残留.     

荧光定量技术快速检测生乳中磺胺类药物残留

目的 利用荧光定量技术分析检测生乳中磺胺类药物残留,评价该方法的可行性.方法 取生乳空白样品进行加标回收实验(磺胺恶唑13.50、27.00μg/L;磺胺喹恶啉5.00、10.00μg/L;磺胺嘧啶0.82、1.64μg/L),取200μL样品与金标抗体结合,50℃孵育3 min,取120μL样品加到检测卡,反应10 ...     

用阻抗分析法快速检测牛奶中抗生素残留的研究

研究立足于牛奶中抗生素的快速检测,用嗜热乳酸链球菌作为指示菌,通过“阻抗分析仪”的自动检测、分析,根据DT时间的产生,判断牛奶中抗生素的残留情况。试验表明,方法操作简单、快捷,结果易判断,全部检测过程可在2 h之内完成。该方法的检测灵敏度与GB方法相类似,可检测牛奶中的青霉素为0.04U/mL。     

近红外光谱法快速检测牛奶中氯霉素残留

本研究利用近红外透射技术和偏最小二乘法(PLS)快速测定牛奶中氯霉素残留含量, 氯霉素残留的预测值与真实值的相关系数达0.9893,预示集的平均回收率为99.77%。结果表明该方法可快速测定牛奶中氯霉素残留含量。     

基于荧光法的牛奶中单诺沙星的快速检测

采用荧光法结合化学计量学来建立牛奶中单诺沙星(DANO)残留的快速检测方法 先利用加标法制备含有不同浓度的DANO(0～56μg/L)的全脂奶作为校正集,除蛋白后经扫描得到荧光光谱,利用化学计量学技术对其进行主成分分析(PCA)并建立偏最小二乘法(PLS)和判别分析(PLSDA)模型.采用加入不同浓度DANO的4种品牌的超高温杀菌和巴氏杀菌牛奶作为预测集,验证了两种模型的准确性.实验结果表明,定性模型可以准确地将阴性与阳性样品区分,定量模型预测出的样品回收率在88％ ～ 114.4％,预测误差在可接受范围内.     

基于荧光法的牛奶中单诺沙星的快速检测

采用荧光法结合化学计量学来建立牛奶中单诺沙星(DANO)残留的快速检测方法。先利用加标法制备含有不同浓度的DANO(0～56μg/L)的全脂奶作为校正集,除蛋白后经扫描得到荧光光谱,利用化学计量学技术对其进行主成分分析(PCA)并建立偏最小二乘法(PLS)和判别分析(PLSDA)模型。采用加入不同浓度DANO的4种品牌的超高温杀菌和巴氏杀菌牛奶作为预测集,验证了两种模型的准确性。实验结果表明,定性模型可以准确地将阴性与阳性样品区分,定量模型预测出的样品回收率在88%～114.4%,预测误差在可接受范围内。      

时间分辨荧光免疫层析快速检测牛奶中地塞米松

目的 建立基于时间分辨荧光微球对牛奶中的地塞米松残留进行快速检测的方法,并对该方法性能进行评估。方法 使用地塞米松抗体标记时间分辨荧光微球,分别采用湿法和干法制备检测试纸条,比较两种方法的灵敏度,同时确定微球的最佳抗体标记量,并对试纸条的重复性、检测灵敏度进行评估。结果 以20μg抗体/mg微球的标记量,湿法制备的试纸条检测灵敏度更佳。该方法重复性检测中变异系数(coefficientof variation, CV)为8.2%,地塞米松溶液的检出限为0.07 ng/mL,检测牛奶中地塞米松的半抑制浓度(half maximal inhibitory concentration, IC50)为0.24 ng/mL。结论 该方法具有测试简单、灵敏度高等特点,制备的试纸条可满足牛奶中地塞米松残留的检测要求。     

牛奶中抗生素残留及其检测技术的研究进展

论述了牛奶中抗生素残留的原因和危害性,列举了目前国内外较流行的牛奶中抗生素的检测技术,并阐述了其检测原理。      

牛奶中抗生素残留及其检测技术的研究进展

论述了牛奶中抗生素残留的原因和危害性,列举了目前国内外较流行的牛奶中抗生素的检测技术,并阐述了其检测原理.     

低场核磁技术结合化学计量学法快速检测掺假牛奶

应用低场核磁共振技术结合主成分分析法(PCA)、偏最小二乘判别法(PLS-DA)、线性判别法(LDA)对掺水、食盐、尿素和蔗糖的牛奶及纯牛奶进行测定。结果表明:在主成分得分图中,不同掺假牛奶随掺假物质的掺假比例呈一定规律性分布,并得到了很好的区分。利用PLS-DA和LDA方法建立不同掺假牛奶的判别模型,对掺水、掺尿素牛奶的判别准确率均为100%,掺食盐牛奶的判别准确率分别为83.33%和100%,掺蔗糖牛奶的判别准确率分别为73.33%和76.67%。可见PCA法、PLS-DA法、LDA法可用于快速处理分析低场核磁共振数据,并且LDA法鉴别准确率最高。     

前表面荧光法在牛奶美拉德反应检测中的应用

在热处理中,牛奶中的乳蛋白容易与乳糖发生美拉德反应,使牛奶的色泽、风味、营养等发生变化。与传统化学检测法相比,前表面荧光法具有快速灵敏、前处理简便等优点。为了评估前表面荧光法在检测牛奶美拉德反应程度上的准确性和适用性,本文对比了不同热处理下牛奶的美拉德反应的荧光图谱和美拉德产物的含量,分析了指标间的相关性。并以前表面荧光法和羟甲基糠醛含量建立模型对商业乳品进行预测,结果良好,为荧光检测的工业应用提供理论依据。结果显示,前表面荧光法可应用于牛奶前中期美拉德产物的无损检测。     

Application of fluorescence spectroscopy for monitoring changes in nonfat dry milk during storage

The objective of this study was to determine if fluorescence spectroscopy could be used to characterize the biochemical characteristics of nonfat dry milk (NDM) caused by manufacturing and storage conditions. Nine low-heat NDM samples were collected from 3 manufacturers and stored at 4 temperatures (4, 22, 35, and 50°C) for 8 wk. The spectra of Maillard products, tryptophan, and riboflavin were recorded and analyzed with principal components analysis. Colorimetric indices L*, a*, and b* were also determined. The before-storage NDM samples collected from each manufacturer had different fluorescent characteristics. Inconsistency was observed for the NDM samples collected from 1 manufacturer, whereas the samples from the other 2 manufacturers displayed consistent fluorescence characteristics. Biochemical reactions, such as Maillard reaction, modification of the tryptophan environment, and degradation of riboflavin occurred during the manufacturing process. For each of the data collections, discrimination of the NDM samples stored at 50°C from the samples stored at 4, 22, and 35°C was observed in the similarity maps. The factor loadings of the first 2 principal components for the fluorescence spectra of the samples before storage were similar to the principal components analysis results of the samples during storage. It appears that similar factors are responsible for the variation in the samples before storage and their changes during storage. Additionally, storage of the samples at 50°C accelerated these reactions. The results demonstrate that front-face fluorescence spectroscopy, coupled with multivariate statistical methods, can be utilized as an analytical technique to monitor variation in NDM samples from different manufacturers and changes during storage.     

Front-face fluorescence spectroscopy and chemometrics in analysis of yogurt: rapid analysis of riboflavin

The present study demonstrates the use of front-face fluorescence spectroscopy and chemometrics for monitoring light-induced changes in plain yogurt during storage. Fluorescence analysis is suggested as a new rapid method for measuring riboflavin content in yogurt. Fluorescence landscapes with excitation wavelengths from 270 to 550 nm and emission wavelengths in the range 310 to 590 nm were obtained from front-face fluorescence measurements directly on yogurt samples during two storage experiments over a period of 5 wk at 4 degrees C. Yogurts were stored in two different packaging materials (polylactate and polystyrene) and under fluorescent light (3500 lux) or in darkness. Principal Component Analysis of unfolded fluorescence emission spectra revealed systematic changes in fluorescence signal throughout the storage period, strongly related to the storage conditions, i.e. storage time and differences in packaging materials. Correlation between fluorescence spectra and riboflavin content determined by the standard AOAC fluorometric method was evaluated using a Partial Least Square Regression model. The regression model showed a good ability to predict riboflavin in plain yogurt with a high correlation (R = 0.99) and a prediction error of 0.092 microgram riboflavin/g. Thus, it is concluded that nondestructive fluorescence spectroscopy can be used to monitor riboflavin content in yogurt, and that the suggested rapid method has the potential to substitute the standard method for analysis of riboflavin in yogurt.     

Application of fluorescence spectroscopy and chemometrics in the evaluation of processed cheese during storage

Front face fluorescence spectroscopy is applied for an evaluation of the stability of processed cheese during storage. Fluorescence landscapes with excitation from 240 to 360 nm and emission in the range of 275 to 475 nm were obtained from cheese samples stored in darkness and light in up to 259 d, at 5, 20 and 37 degrees C, respectively. Parallel factor (PARAFAC) analysis of the fluorescence landscapes exhibits four fluorophores present in the cheese, all related to the storage conditions. The chemometric analysis resolves the fluorescence signal into excitation and emission profiles of the pure fluorescent compounds, which are suggested to be tryptophan, vitamin A and a compound derived from oxidation. Thus, it is concluded that fluorescence spectroscopy in combination with chemometrics has a potential as a fast method for monitoring the stability of processed cheese.     

基于核酸适配体识别-时间分辨荧光共振能量转移检测牛奶中培氟沙星兽药残留

培氟沙星(pefloxacin,PEF)广泛用于畜禽疾病的预防和治疗,常造成兽药残留,影响人体健康.因此,有必要对其构建有效快速的检测方法.实验采用溶剂热法合成具有时间分辨特性的荧光纳米材料NaYF4:Ce/Tb,并基于分子对接辅助设计PEF适配体的互补链.纳米金与发光纳米材料分别修饰在适配体、互补链上,通过碱基互补配...     

Fluorescence spectroscopy coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems

Rapid measurements of milk properties and discrimination of milk origin are necessary techniques for quality control of milk products. The present study was undertaken to evaluate the potential of using front face fluorescence spectroscopy (FFFS) and synchronous fluorescence spectroscopy (SFS) for monitoring the quality of forty-five ewe’s milk samples originating from different feeding systems. Physico-chemical analyses and fluorescence spectra were conducted on samples during lactation periods (the first 11 weeks). The principal component analysis (PCA) separately applied to the physico-chemical and fluorescence spectral data showed only small discrimination between milk samples based on lactation periods and diet compositions. Similar results were obtained by separately applying factorial discriminant analysis (FDA) on each technique. In a second step, concatenation technique were applied to FFF spectra acquired after excitation set at 250, 290, 380 nm and emission set at 410 nm. Results obtained showed a good discrimination among milk samples with regard to feeding systems given to the ewes throughout the lactation periods. In addition, a better discrimination was observed with FFFS than with SFS.     

Technical note: Nontargeted detection of adulterated plant proteins in raw milk by UPLC-quadrupole time-of-flight mass spectrometric proteomics combined with chemometrics

We built and validated a chemometric model to detect possible milk adulteration with plant proteins. Specifically, we extracted proteins in raw milk, treated with tryptic digestion, and obtained peptide fingerprints by UPLC-quadrupole time-of-flight-mass spectrometry with proteomics to differentiate authentic milks from their counterparts adulterated with nonmilk proteins. This approach is able to detect soybean and pea powder-adulterated milks at as low as 1% (wt/wt). Additionally, we obtained the characteristic peptide sequences for milk authentication by principal component analysis. The prediction accuracies for milk authentication by partial least-squares-discriminant analysis were greater than 95%. These results indicated that peptide fingerprints with the chemometric analysis could be successfully applied for milk quality control.