基于近红外光谱技术的老陈醋可溶性固形物定量分析

可溶性固形物含量(SSC)是食品行业的重要技术参数之一。利用近红外光谱技术对不同醋龄的老陈醋SSC进行分析。在不同光谱预处理下,分别采用主成分回归(PCR)和偏最小二乘法(PLS)建立SSC的定量分析模型。结果表明,采用5点平滑预处理后,利用PLS建立的老陈醋SSC的定量分析模型最优,其校正集的相关系数R为0.999 9,校正标准偏差(RMSEC)为0.038 3,预测标准偏差(RMSEP)和交叉验证标准偏差(RMSECV)分别为0.082 1,0.096 4。表明采用近红外光谱技术对不同醋龄的老陈醋SSC进行定量分析建模是可行的。     

基于近红外光谱技术的小麦粉灰分含量检测方法研究

采用近红外光谱技术建立小麦粉灰分含量的快速检测方法。使用两种不同的近红外光谱仪器采集小麦粉的近红外光谱数据,以常规分析法的测定值作为建模数据,采用偏最小二乘(PLS)回归分析法建立小麦粉灰分的定量分析模型,比较两种不同的近红外光谱仪器扫描的小麦粉近红外光谱图对模型的影响。结果表明,MicroNIR-1700近红外光谱仪扫描的谱图所建校正集模型的相关系数R~2为90.69,均方根误差(RMSECV)为0.031 2,预测集模型的均方根误差(RMSEP)为0.021 7;VERTEX70傅里叶变换近红外光谱仪扫描的谱图所建校正集模型的相关系数R~2为89.40,均方根误差(RMSECV)为0.035 0,预测集模型的均方根误差(RMSEP)为0.036 6。两种仪器都能用于小麦粉光谱采集,并进行灰分含量快速检测,MicroNIR-1700在小麦粉灰分检测方面有更好的应用。     

基于近红外光谱的猪肉蛋白质及脂肪含量检测

蛋白质及脂肪是猪肉的重要营养成分。随着人们对饮食健康的要求越来越高,对猪肉蛋白质及脂肪含量快速检测也成为必然。通过近红外光谱技术对猪肉进行光谱数据采集,将光谱数据分为校正集样本和预测集样本,然后,在MATLAB中利用多元散射校正(MSC)与均值中心化相结合的方法进行光谱预处理并采用联合区间偏最小二乘方法(SiPLS)获得猪肉蛋白质及脂肪含量与光谱数据特征之间的对应关系,从而定量分析猪肉蛋白质及脂肪含量。实验结果表明,建立的SiPLS检测脂肪及蛋白质含量预测模型的最优组合分别为划分为20个光谱区间并联合4个子区间和9个主成分因子,和划分19个光谱区间并联合4个子区间和10个主成分因子。其预测集的相关系数分别为0.9798、0.9788,交互验证均方根误差分别为0.228,0.241。研究结果表明,利用近红外光谱结合SiPLS算法可以快速准确检测猪肉蛋白质与脂肪含量。     

现场收购冻玉米中各成分含量的近红外光谱（NIR）分析

论述了采用近红外光谱漫反射技术检测冻玉米中主要成分含量的方法。讨论了采用偏最小二乘法(PLS)建立校正模型过程中样品预处理及利用常规吸收峰优选波长的方法。经验证：水分、淀粉、蛋白测量值同浓度参考值具有良好相关性(相关系数大于0．9)，测量重复性变并系数(CV)优于2％。结果表明，近红外光谱法可以满足冻玉米中主要成分的实际到量要求，为玉米深加工企业提供了冬季原料玉米按质收购的参考方法。     

基于近红外光谱技术快速检测贵州红薯粉丝中薯粉含量

采用近红外光谱技术结合偏最小二乘法建立预测红薯淀粉及全粉粉丝中薯粉含量的定量模型,实现薯粉含量的在线快速检测。分别制作180份红薯淀粉粉丝和红薯全粉粉丝样品,以一阶导数、最大最小归一化处理、移动平均平滑、多元散射校正、标准正态化等计量学方法预处理光谱。结果表明,选择波数9403.6～7498.2 cm^–1、6101.9～4246.7 cm^–1+消除常数偏移量所建的红薯淀粉粉丝模型效果最好,波数9403.6～4597.6 cm^–1+减去一条直线所建的红薯全粉粉丝模型效果最好,预处理后2个模型相关系数分别为0.9875和0.9892,交叉验证均方根误差(RMSECV)分别为1.23和1.13,校正后预测相对分析偏差(RPD)分别为6.83和7.42。外部验证预测相关系数为0.9625和0.9714,相对标准偏差(RSD)均小于1,模型具有较高的准确度。近红外光谱技术可以实现贵州红薯粉丝中薯粉含量的快速检测。     

基于近红外光谱技术检测白酒基酒中乙醇含量的研究

为了快速测定白酒基酒中的乙醇含量,采用近红外光谱（NIRS）技术结合偏最小二乘法（PLS）处理白酒基酒近红外图谱,建 立白酒基酒中乙醇的定量分析模型。 结果表明：最佳预处理方法为减去一条直线法,最优波段谱为7 502～5 450 cm-1,主成分数为7。 校正集样品的化学值与预测值的决定系数（R2）为0.923 3,交互验证均方根误差（RMSECV）为0.89;对模型进行检验,得到验证集的 决定系数（R2）为0.954 8,预测均方根误差（RMSEP）为1.21。 结果显示近红外检测方法快速有效,所建模型具有很好的预测效果,模型 的精密度和稳定性良好。     

基于近红外光谱技术的米糠粕主要成分分析

为探索米糠粕营养成分的近红外快速测定方法,采集261个米糠粕样品的近红外光谱,分别经过标准正态变量变换、去趋势校正、多元散射校正等20种方法进行预处理,在1000~1799 nm波长范围内,结合化学方法测定数据采用偏最小二乘法、主成分分析结合人工神经网络法、偏最小二乘结合人工神经网络法建立米糠粕营养成分近红外定量模型。结果发现,在3种建模方法中,偏最小二乘法结合人工神经网络法建立的模型效果最好,预测精度最高,所得的水分、灰分和粗蛋白近红外定量模型的相关系数分别为0.9593、0.9168和0.9626。      

䥺Symbol`@@基于近红外光谱漫透射技术的苹果可溶性固形物含量在线检测

为研究苹果的内部品质,提高检测的速度和稳定性,将近红外光谱漫透射技术应用于在线检测研究,并采取偏最小二乘回归(PLSR)算法结合不同光谱预处理方法建立苹果内部的可溶性固形物含量(SSC)的定量模型。结果表明:采用一阶微分结合多元散射校正(MSC)预处理后的模型最稳定,校正集和预测集的标准差分别为0.17和0.39,校正集的相关系数也达到0.988 3。试验结果说明近红外光谱漫透射技术能够快速、无损地检测出苹果的可溶性固形物含量。     

南果梨糖度近红外光谱无损检测模型的建立

利用近红外透射光谱仪,对产自辽宁省鞍山地区的具有代表性的南果梨样品建立了近红外透射光谱与南果梨糖度的数学模型,并对模型进行了预测.结果表明:南果梨中可溶性固形物含量、还原糖含量的近红外光谱预测值与化学实测值之间的相关系数分剐为0.9364、0.8586,预测均方根偏差(RMSEP)分剐为0.2285、0.07929,其中以可溶性固形物含量作为定标参数建立模型的预测能力较强,证实利用近红外透射光谱建立的定标模型来测定南果梨的糖度是可行的.     

基于近红外光谱技术的海参品质快速检测

目的应用近红外光谱技术建立海参产地区分和胶原蛋白快速检测的方法。方法总计43个海参样品来自大连、福建、连云港、山东4个地区。首先采集样品的近红外光谱图,经过标准正态变量(standard normal variables,SNV)预处理,利用不同定性判别模型对海参产地进行区分。通过分光光度计法测定海参的胶原蛋白含量,利用偏最小二乘法(partial least squares,PLS)、区间偏最小二乘法(interval partial least squares,iPLS)、向后区间偏最小二乘法(backwards interval partial least squares,BiPLS)和联合区间偏最小二乘法(synergy interval partial least squares,Si PLS)建立了海参胶原蛋白含量的预测模型。结果产地区分模型中最小二乘支持向量机(least-squares support vector machine regression,LS-SVM)的识别率最高,校正集识别率为100%,预测集识别率为95.35%;海参胶原蛋白预测模型中BiPLS的预测效果较好,校正集相关系数Rc为0.9002,预测集相关系数Rp为0.8517。结论近红外光谱技术可实现对海参的产地区分和胶原蛋白的快速检测。     

YEAST PROTEIN MEASUREMENT USING NEAR INFRARED REFLECTANCE SPECTROSCOPY

The measurement of total protein in yeast cells is useful for fermentation and yeast research as well as for byproduct improvement studies. The protein content of the cell changes with alterations in several fermentation and medium parameters and during the course of the cell cycle. In general, the protein content of the harvested cells is maximised under conditions ideal for yeast growth. Brewers often sell excess yeast as a byproduct and the quality of the yeast, as well as the associated price per unit weight, are often determined by the protein content. Many methods to measure the protein content in yeast cells exist but can be impractical for various reasons or prone to error. In this research, a method was developed to measure the protein content of yeast cells by near infrared reflectance spectroscopy (NIR) - a technique which is finding many applications in brewing and is simple, rapid and amenable to on-line control systems. With this latest application for NIR, it is now possible to measure yeast glycogen, trehalose and protein contents on the same sample in less than 30 minutes including a sample preparation time of 25 minutes .     

DETERMINATION OF THE PROTEIN CONTENT IN RICE BY THE DIGITAL CHROMATIC METHOD

ABSTRACT

The feasibility of using digital chroma measurements to determine the protein content in rice was investigated using red, green and blue (RGB) chroma values to reflect color change. The protein content of rice samples ranged from 5 g/100 g to 13 g/100 g. There was a significant negative linear correlation (r < −0.98) between the protein content in rice and the chroma values of relevant protein solutions treated with biuret reagent. Of all the tricolor values, the G value was the optimal parameter to reflect the chroma difference of the protein solutions. It had a higher correlation coefficient (r < −0.99) and was more sensitive to subtle differences in protein content than R or B values. With a similar structure and the same reaction conditions, rice samples with known protein content were found to be more accurate calibrating substances. The results determined by the digital chromatic method are not significantly different from that of the Kjeldahl method. With the advantages of high precision, easy operation and high efficiency, the method is suitable for applications in quality evaluation and supervising practice in the field of rice circulation.

PRACTICAL APPLICATIONS

A new method to determine the protein content of rice was studied by combining digital image analysis technology and a traditional chemical approach. The study forms a part of the technology foundation to develop quality evaluation systems for rice.

     

近红外光谱技术在蜂蜜真实性鉴定中的应用

由于蜂蜜品种多,组分复杂,真假鉴定技术较难,用传统的分析技术评价蜂蜜质量具有一定的局限性.用具有快速稳定的近红外光谱技术鉴别蜂蜜真实性.对近红外光谱技术(IR)做了简要介绍,同时,详细阐述了该技术在蜂蜜成分、品种和产地来源、掺假鉴定中的应用.对该技术存在的缺陷及与其他技术联用前景进行了探讨,可为蜂蜜真伪鉴别提供新的方法和思路.     

云芝多糖的体外抗氧化活性研究

从清除超氧阴离子自由基、清除DPPH自由基、抑制羟基自由基的产生和还原力4个方面研究了云芝多糖的体外抗氧化效果,并同Vc进行比较.结果表明,云芝多糖对O2·清除作用明显,与Vc接近;还原力和清除DPPH·的能力比Vc差;对·OH的清除表现为在1g/L～5g/L浓度范围内,云芝多糖未达到EC50值.     

微波消解-凯式定氮法测定牛奶中蛋白质含量

建立微波消解-凯式定氮法测定牛奶中蛋白质含量的方法,采用密闭微波消解样品,优化微波消解条件.方法的相对标准偏差RSD为1.82%,回收率在98.8%～101.7%之间.     

DETERMINATION OF COLLAGEN SOLUBILITY AND CONCENTRATION IN MEAT BY NEAR INFRARED SPECTROSCOPY

This paper examines the feasibility of measuring collagen properties by near infrared spectroscopy (NIRS) in ovine Semimembranosus and Biceps femoris muscles. Because collagen concentration within a muscle was rather narrow, the R for collagen concentration was never more than 0.55. By contrast, R for solubility was better, especially for Semimembranosus, always exceeding 0.80. No one scanning method — fiberoptic probe or the in-built transport module — was superior, either in reflectance or transmittance modes. The equations developed were tested for predictive power by cross-validation procedures within muscles and between muscles. In the latter case, Biceps femoris data were used in a Semimembranosus equation and vice versa. The equations worked in any combination. However, there were indications that the correlations were sensitive to the state of the meat, whole tissue or homogenized, although the wavelength range 910 to 950 nm did not vary with sample state.     

考马斯亮蓝法测定野木瓜多糖中蛋白质的含量

采用考马斯亮蓝染色法对野木瓜多糖中蛋白质含量进行测定,在波长595 nm处测定吸光度,实验表明标准蛋白质在1.67μg/mL～16.67μg/mL之间呈现良好的线性关系,该法简便迅速,灵敏度高、重现性好,是测定野木瓜多糖中蛋白质含量的有效方法,并通过此法测得野木瓜多糖中蛋白质平均含量为12.17%.     

杂色云芝漆酶基因在甲醇毕赤酵母中表达条件研究

重组甲醇毕赤酵母（Pichia methanolica）工程菌PMADl6／pMETA-Lccl能分泌表达杂色云芝重组漆酶。本文通过对其发酵条件的研究，找出摇瓶发酵表达漆酶的最适培养条件：在BMMY培养基中添加0．2mmol／L的Cu^2＋．装液量为25mL／250mL三角瓶，接种量体积之比为45：25，0．5％甲醇诱导，20℃条件下摇瓶培养5d，漆酶最高酶活力达1192U／L。