非靶向检测技术鉴别茅台酒真假

目的 探究基于非靶向检测技术鉴别茅台酒真假的方法。方法 样品过0.45 μm滤膜, 在超高效液相色谱-串联高分辨质谱Full MS/dd MS2扫描模式下采集数据, 采用Compound Discoverer 3.0(CD3.0)对样品数据进行主成分分析(principal component analysis, PCA)和差异分析; 利用便携式紫外可见分光光度计, 对样品进行250~650 nm波长范围光谱扫描, 扫描图谱进行相似度分析。结果 PCA分析显示采用液质高分辨非靶向技术能够区分真假茅台, 同时利用便携式紫外可见分光光度计进行光谱图谱相似度分析也可以得出一致的结论。结论 2种非靶向检测方法简单、快速、准确, 便携式紫外光谱图谱相似度方法可用于现场快速检验, 为茅台酒的真假鉴别提供多种技术选择。     

基于化学计量学结合甘油二酯和甘油三酯分析的橄榄油等级的鉴别

采用高效液相色谱(HPLC)-大气压化学电离(APCI)源-质谱/质谱仪(MS/MS)对不同等级橄榄油中的甘油二酯(Diacylglycerol,DAGs)和甘油三酯(Triglycerides,TAGs)进行测定。试样用丙酮稀释后,采用C₁₈色谱柱分离,以丙酮-乙腈(1：1,v/v)作为流动相,等度洗脱,大气压化学源-质谱/质谱仪进行定性和定量分析。对测得的DAGs和TAGs进行化学计量学分析,以主成分分析(principal component analysis,PCA)和偏最小二分析(partial least squares discriminant analysis,PLS-DA)建立不同等级橄榄油的判别模型,并采用层次聚类分析(hierarchical clustering analysis,HCA)对模型中的橄榄油进行聚类分析。结果表明,PCA和PLS-DA两种方法都能鉴别不同等级的橄榄油,并且所有橄榄油均可正确分类。DAGs中的LL、OO以及TAGs中的OLLn、LLL是橄榄油等级鉴别的重要指标。     

红外和紫外可见分光光谱法初步鉴别餐饮废油

目的建立简便、快速的餐饮废油、生物柴油以及合格食用油的鉴别检测方法。方法选择市售普通食用油、餐馆用油、生物柴油和餐饮废油(包括潲水油和煎炸老油)为研究对象,以1745 cm-1波数处的共有吸收峰为基准,比较各油脂红外光谱特征吸收峰相对强度;在230~800 nm范围内,比较各油脂的紫外可见吸收曲线,对油脂品质进行比较鉴别。结果比较红外图谱发现,各油脂在3473、3008、1652 cm-1附近对1745 cm-1的吸收峰相对强度差别较大,可以此作为判别依据;通过观察比较各油脂在紫外可见光谱图中的起始和终止吸收波长,以及在668 nm处是否有较高的吸光度或特征吸收峰,可对油脂品质进行鉴别。结论综合红外和紫外可见两种光谱方法的检测结果,本方法可初步地快速鉴别合格食用油与餐饮废油。     

紫外吸收和荧光光谱检测红茶中的胭脂红色素

提出并建立一种基于紫外-荧光相关谱掺胭脂红色素红茶的判别方法,并对掺入的胭脂红色素浓度进行定量分析。配置29个掺胭脂红茶汤(质量浓度范围0.1～20μg/m L)样品,室温下分别采集紫外可见吸收光谱和荧光光谱。在研究未掺入和掺入色素茶汤一维光谱特性的基础上,以胭脂红浓度为外扰,构建了同谱和异谱紫外可见-荧光相关谱,确认茶汤中胭脂红的紫外可见吸收峰和荧光特征峰位置。利用510 nm处吸收峰强度和433 nm处荧光峰强度对胭脂红进行定量分析,其相关系数均在0.99以上。     

溶液pH对番茄红素稳定性及其降解动力学研究

番茄红素易受溶剂环境的影响造成损失。为揭示溶液环境对番茄红素稳定性的影响规律,本文基于紫外可见吸收光谱的变化研究了二甲基亚砜、四氢呋喃、丙酮等不同溶剂种类、比例及酸碱度对番茄红素紫外可见吸收光谱及其吸收强度的影响,并进行降解动力学研究。结果显示:番茄红素在四氢呋喃和二甲基亚砜溶剂中的特征吸收波长与其在丙酮溶剂相比红移,吸收峰3的波长由505 nm分别红移至511 nm和523 nm;番茄红素在有机溶剂水溶液体系中均呈H型聚集,光谱表现为吸收波长蓝移;番茄红素在有机溶剂中的降解均符合一级反应动力学,其在丙酮水溶剂中的半衰期为25.48 h;番茄红素在弱酸和弱碱性条件下更稳定。结果表明:弱酸性或弱碱性的丙酮和四氢呋喃水溶液可作为番茄红素的良好溶剂,本研究为番茄类食品的储藏、加工及开发应用奠定理论基础。     

银纳米粒子基底制备及表面增强拉曼光谱法检测荧光素钠

目的制备具有增强效应的银纳米粒子作为表面增强拉曼光谱的基底,应用于荧光素钠色素的检测,提供一种快速、方便、超灵敏的检测手段。方法用水热法制备银纳米粒子作为表面增强拉曼光谱的基底,通过紫外可见吸收光谱研究以及对比不同激发波长作用下的银纳米粒子增强效应,优化实验条件,对不同浓度的荧光素钠色素进行检测。结果银纳米粒子基底展现出了超灵敏的检测限度和超高的增强效应,在激发波长514 nm、激光强度1 mw、收集时间5 s的实验条件下,荧光素钠色素分子的检测限度达3.01×10~(-4) mg/kg。结论本方法制备的银纳米材料可作为表面增强拉曼光谱的基底,有效应用于荧光素钠色素的检测中,在进口食品安全监测中具有重要的应用价值。     

同步荧光光谱法快速鉴别食用油

利用同步荧光光谱法鉴别沙棘果油、沙棘籽油、核桃油、菜籽油、芝麻油、亚麻仁油。结果显示：不同食 用油荧光光谱具有明显的差异,在激发波长250～720 nm范围内,沙棘果油、沙棘籽油、核桃油、亚麻仁油、芝麻 油和菜籽油的最大激发波长范围分别为315～450、520～650、315～490、300～500、300～550、300～490 nm。在 激发光与发射光波长差为90 nm、激发波长250～720 nm的条件下,对6 种不同食用油进行同步荧光扫描,利用主成 分分析得分图可以直观、快速地区分鉴别各种食用油。     

油脂同步荧光光谱检测及橄榄油掺假鉴别

采用同步荧光光谱仪,在激发波长250~720 nm,波长间隔Δλ=15 nm时,采集20种食用植物油和掺杂的特级初榨橄榄油的荧光光谱图,分析比较了各种植物油脂的同步荧光光谱图。结果表明,同步荧光光谱法能够将特级初榨橄榄油与其他17种植物油明显地区分开来。在橄榄油掺杂鉴别中,其中14种植物油掺兑量在1%的情况下,同步荧光光谱图与特级初榨橄榄油有着明显的差异。同步荧光光谱法对橄榄油掺假鉴别,无需复杂的样品前处理,本方法简便、快速、灵敏,适合快速筛查。     

高光谱图像法对稻谷贮藏中五种常见真菌生长拟合及区分

利用高光谱成像系统(HIS)获取稻谷贮藏中常见真菌(黑曲霉、米曲霉、杂色曲霉、构巢曲霉、桔青霉)在马铃薯葡萄糖琼脂板上培养期间的高光谱图像,波峰709 nm处的光谱值和全波段光谱值的第一主成分得分两种方法构建真菌Gompertz函数的生长模拟模型。Gompertz函数拟合结果显示,五种真菌基于全波段光谱值PCA分析后的第一主成分得分建立的生长拟合模型R2为0.1781~0.9501,基于波峰709 nm光谱值建立的拟合模型R2为0.9095~0.9679,效果明显优于第一主成分得分的建模效果。另外,主成分分析(PCA)结合偏最小二乘法判别分析(PLS-DA)可以区分五种不同菌种。其中,训练集和测试集中,PLS-DA模型对培养48 h的黑曲霉、米曲霉、构巢曲霉、桔青霉四种真菌及对照组的区分准确率为100%;而对杂色曲霉,训练集区分准确率为100%,测试集的区分率为33.33%。结果表明高光谱图像技术能够用来对真菌种类进行区分。     

基于可见-近红外高光谱技术对鸡种蛋性别鉴定的研究

目的 为实现鸡种蛋胚胎性别的无损检测,提出了基于可见-近红外高光谱检测海兰褐鸡种蛋胚胎性别的方法。方法 通过分析种蛋0~14 d大头部位的400~1000 nm波段下的光谱,建立基于偏最小二乘判别分析（PLS-DA）和支持向量机（SVM）的种蛋性别判别模型,比较不同孵育天数下的模型判别率,优选出最佳的检测天数;通过分析四种不同的预处理算法,选出最佳的鸡种蛋胚胎高光谱预处理方法,最后构建基于全波段和特征波段光谱信息的判别模型,并对结果进行比较。结果 基于PLS-DA和SVM的模型在第9 d的预测集结果达到最高,分别为80%和82.5%。主成分分析（PCA）结果表明,雄雌种蛋光谱信息可以进行区分;变量标准化（SNV）为最佳预处理方法;全波段相对于连续投影算法（SPA）、竞争性自适应重加权算法（CARS）选择特征波长的模型更优,建模集、预测集准确率分别为90%和85%。结论 研究结果表明可见-近红外高光谱技术可以快速、较准确、无损检测海兰褐种蛋胚胎性别,该技术为褐壳种蛋胚胎性别鉴定实现在线检测提供了一定的理论基础。     

二维相关近红外光谱快速鉴别食用植物油种类

由于食用植物油中各种脂肪酸的组成基本相同或相近,仅存在含量分布的差异,因此食用植物油的一维近红外光谱图的峰位、峰形、峰强没有明显区别.利用傅里叶变换近红外光谱( FT - NIR)结合二维相关分析技术,分析鉴别了几种不同种类的食用植物油.对花生油、大豆油、菜籽油、芝麻油、油茶籽油和橄榄油,在温度挠动(50～160℃)状...     

基于傅里叶变换中红外光谱识别正常食用植物油和精炼潲水油模型分析

潲水油回流餐桌等食品安全问题越来越受到社会关注,探寻准确、快速、高效的潲水油鉴别新方法成为食用油安全性检测的新要求。用傅里叶变换中红外光谱技术（Fourier transform mid-infrared spectroscopy,FT-MIR）对精炼潲水油（refining hogwash oils,RHOs）和4 种不同正常食用植物油（菜籽油、大豆油、花生油和玉米油）进行快速检测,结合偏最小二乘判别法（PLS-DA）建立了RHOs和4 种不同正常食用植物油的判别模型。结果表明,在全光谱范围（4 000～450 cm–1）内,经二阶求导（Savitzky-Golay,5 点）后,RHOs和4 种不同正常食用植物油FT-MIR有显著差异。PLS-DA模型对22 个未知样品预测发现,判别模型的整体正确判别率均为100%。此结果表明FT-MIR结合化学计量学方法可以作为RHOs和4 种不同正常食用植物油（菜籽油、大豆油、花生油和玉米油）区分的一种有效技术手段。     

Infrared spectroscopy for quantitative analysis and oil parameters of olive oil and virgin coconut oil: A review

Vegetable oils are major lipid sources with high nutritional and calorific values for human diet. Specifically, virgin coconut oil and extra virgin olive oil are the functional oils widely used in food and pharmaceutical products, either as vehicles or main components. The quality of edible oils is determined by its contents and parameters inherent in vegetable oils. Infrared spectroscopy is an ideal technique for quantitative analysis of vegetable oils as well as for determination of oils parameters as the changes in infrared spectra can be associated with the changes of oils parameters. Infrared spectra in complex samples are difficult to interpret, as a consequence, spectroscopist uses additional tools called with chemometrics to analyse edible oils qualitatively and quantitatively. This article reviews the use of infrared spectroscopy combined with chemometrics (multivariate analysis) for quantitative analysis and determination of oil parameters of virgin coconut oil and extra virgin olive oil. Although infrared spectra for edible oils are similar, they exhibit some differences which enable spectroscopist to differentiate due to the nature property of infrared spectroscopy spectra as fingerprint spectra which can be understood that there are no different edible oils having the same infrared spectroscopy spectra.     

Detection of adulteration of extra-virgin olive oil by chemometric analysis of mid-infrared spectral data

This study focuses on the detection and quantification of extra-virgin olive oil adulteration with different edible oils using mid-infrared (IR) spectroscopy with chemometrics. Mid-IR spectra were manipulated with wavelet compression previous to principal component analysis (PCA). Detection limit of adulteration was determined as 5% for corn–sunflower binary mixture, cottonseed and rapeseed oils. For quantification of adulteration, mid-IR spectral data were manipulated with orthogonal signal correction (OSC) and wavelet compression before partial least square (PLS) analysis. The results revealed that models predict the adulterants, corn–sunflower binary mixture, cottonseed and rapeseed oils, in olive oil with error limits of 1.04, 1.4 and 1.32, respectively. Furthermore, the data were analysed with a general PCA model and PLS discriminant analysis (PLS-DA) to observe the efficiency of the model to detect adulteration regardless of the type of adulterant oil. In this case, detection limit for adulteration is determined as 10%.     

近红外光谱法用于橄榄油的快速无损鉴别

通过近红外光谱仪采集各种食用油与掺杂的初榨橄榄油的数据,运用聚类分析法对各种食用油进行聚类分析,结合主成分分析法对橄榄油的掺杂与否进行定性判别。结果表明,聚类分析和主成分分析法都有很好的定性鉴别能力,主成分分析法的鉴别模型预测未知样本的正确率达到100%。该方法快速、无损、简便,为橄榄油掺杂的定性鉴别提供了一种新的选择。     

Classification of edible oils using synchronous scanning fluorescence spectroscopy

Total luminescence and synchronous scanning fluorescence spectroscopy techniques were tested as regards their ability to characterize and differentiate edible oils, including soybean, sunflower, rapeseed, peanut, olive, grapeseed, linseed and corn oils. Total luminescence spectra of all oils studied as n-hexane solutions exhibit an intense peak, which appears at 290 nm in excitation and 320 nm in emission, attributed to tocopherols. Some of the oils exhibit a second long-wavelength peak, appearing at 405 nm in excitation and 670 nm in emission, belonging to pigments of the chlorophyll group. Additional bands were present in the intermediate range of excitation and emission wavelengths in some oils, arising from unidentified compounds. Similarly, bands attributed to tocopherols, chlorophylls and unidentified fluorescent components were detected in the synchronous-scanning fluorescence spectra. Classification of oils based on their synchronous fluorescence spectra was performed using a non-parametrical k nearest neighbours method and linear discriminant analysis. Both methods provided very good discrimination between the oil classes with low classification error. The results presented demonstrate the capability of the fluorescence techniques for characterizing and differentiating vegetable oils.     

食用油储存期品质变化的太赫兹光谱无损识别

为研究食用油在储存期间的品质变化情况，利用太赫兹衰减全反射技术对不同氧化程度的食用油进行无损识别。首先探究储存条件对食用油品质的影响情况，进一步根据国家定义食用油品质的标准将样品分为新鲜油、可食用油和不宜食用油，采集各类油品的太赫兹时域光谱，经数据预处理后采用欧氏距离匹配法进行聚类分析，并采用线性判别分析法进行样本分类，其中欧氏距离匹配法识别食用油折射率谱，准确率为95.65%；线性判别分析法识别吸收系数谱数据，准确率为91.00%，经比较两模型识别准确率理想，分析效果良好。该研究首先得出储存条件对食用油品质的影响规律，以论证太赫兹衰减全反射技术在分析食用油储存期品质变化方面的可行性，实现了食用油品质的快速无损检测；也可为太赫兹光谱技术深入应用于食用油多种属性的研究提供一定参考依据。     

Fluorescence spectroscopy in monitoring of extra virgin olive oil during storage

The present study demonstrates the use of fluorescence spectroscopy for monitoring changes in virgin olive oil during storage. Total luminescence and synchronous scanning fluorescence spectroscopy techniques were tested with the purpose to check their ability to monitor changes occurring in olive oil during storage in different conditions: in clear and green glass bottles exposed to light, and in darkness. Total luminescence spectra of the initial oil samples in n‐hexane solutions exhibited intense peaks, one with a maximum appearing at 320 nm in emission and 290 nm in excitation, attributed to tocopherols, and another appearing at 670 nm in emission and 405 nm in excitation, belonging to the pigments of the chlorophyll group. The intensity of these emissions decreased during storage depending on the storage conditions. Additional bands appeared in oils exposed to light in the intermediate range of excitation and emission wavelengths, arising from unidentified compounds. Bands attributed to tocopherols, chlorophylls and those tentatively ascribed to phenolic compounds were observed in the synchronous scanning fluorescence spectra, allowing monitoring of the storage effects on these constituents and their quantitative assessment after appropriate calibration. The results presented confirm the capability of the fluorescence techniques to monitor the quality of oil products.     

Some of the most significant changes in the Fourier transform infrared spectra of edible oils under oxidative conditions

The oxidation of a broad collection of commercial edible oils, including extra virgin olive, olive, sesame, sunflower, corn, unknown seed, soybean, safflower, rapeseed, peanut and walnut oils, was monitored by Fourier transform infrared spectroscopy. Samples were kept in a convection oven with air circulating at 70 °C. Duplicate spectra were collected each day of the experiment by applying a film of pure oil between two KBr disks. The frequency and absorbance of each infrared band were automatically registered by a macro program. Ratios between absorbances of different bands of the spectra were calculated. Changes in frequency values of different bands and in ratios between absorbances of some bands allow different stages of the oxidation process to be distinguished as well as determining their oxidative stability in a simple and fast way, showing the usefulness of this technique in monitoring oil oxidation processes. © 2000 Society of Chemical Industry