基手SPSS的主成分回归分析在麦芽生产中的应用

利用SPSS for Windows 13.0软件及其主成分回归分析插件,对麦芽生产过程中影响色度的生产控制点进行主成分回归分析,得到线形回归方程,以求对生产提供帮助.     

基于服装生产的4～6岁儿童体型回归模型研究

对河南地区不同县市的4～6岁儿童进行了以服装生产为目的的人体测量,测量项目22项,通过数据筛查,获得531名4～6岁儿童体型的有效测量数据.运用SAS软件进行数据的主成分分析和回归分析,来研究儿童体型特征,通过主成分分析,选取了11个可基本概括儿童体型的特征状况的测量指标;通过回归分析,建立了儿童主要测量部位与身高、胸围和臀围的回归模型.     

基于主成分分析法对纺织品抗紫外线性能的研究

采用主成分分析法对纺织品的抗紫外线性能进行分析,将织物的6个基本参数简化成2个主成分,再通过多元线性回归分析,结果显示织物面密度、厚度、经密、纬密所代表的第1主成分对织物抗紫外线性能的影响程度更大。     

真空油炸马铃薯脆片预处理工艺优化

为优化马铃薯脆片的预处理工艺,采用单因素和响应面试验,以破碎力、含油量、L*值、感官评分、综合评分和电子鼻检测挥发性成分为指标,对实验数据进行主成分分析。结果表明:不同的预处理方式对马铃薯脆片的破碎力、感官评价和综合评分有显著影响(p0.05)。主成分分析共提取5个主成分,前3个主成分总贡献率大于85%,说明提取3个主成分能够全面反映马铃薯脆片的品质信息,决定第1主成分的指标主要是感官评价和综合评分,决定第2主成分的是破碎力和含油量;决定第3主成分的是L*值和含油量。以主成分分析得到的规范化综合得分为响应值建立的二次多项式回归模型回归效果极显著(p0.01,R~2=0.9604)。确定最佳工艺参数为漂烫温度91℃、漂烫时间4 min、切片厚度4 mm和冷冻时间3 h,在此条件得到规范化综合评分0.9572,与预测值(0.9453)相接近,表明以主成分分析得到的规范化综合评分为响应值建立的回归模型具有良好的预测能力。     

主成分回归分析法在精纺毛织物透气性与结构参数关系模型构建中的应用

为了研究精纺毛织物透气性与基本结构参数的关系,利用主成分分析方法对织物基本结构参数进行降维处理,得到4个互相独立的主成分。以主成分为自变量,透气性为因变量,采用回归分析的方法建立了透气性与提取主成分的关系模型。结果表明:建立的回归方程Q=208.544+0.119Z1-0.036Z2-0.145Z3-0.331Z4,达到非常显著水平,对透气性进行预测是可行的。通过主成分分析可知,主成分Z1、Z4是决定精纺毛织物透气性的主要因素。     

蒸煮过程纸浆卡伯值近红外光谱法在线测定

利用近红外光谱法测量蒸煮过程黑液中木素含量的变化，从而在线测定出纸浆卡伯值。通过一元线性回归、多元线性回归和主成分回归分析显示：3种测量模型均具有较好的学习和预测精度，其中主成分回归模型具有较高的预测鲁棒性。     

基于PCA-1DCNN的近红外光谱粮食作物主要成分检测方法

针对传统的近红外光谱定量技术难以选择合适的光谱预处理方法且模型预测精度低的问题,以3个谷物数据集的近红外光谱数据集为研究对象,构建了基于主成分分析光谱筛选算法的一维卷积神经网络模型。与传统的偏最小二乘回归和支持向量机模型的性能做了对比后,一维卷积神经网络构建的模型性能均为最优。其中在对玉米数据集的水分、油脂、蛋白质、淀粉的定量建模中,模型的决定系数分别为99.09%、98.15%、98.89%、99.60%;在对grain数据集的定量建模中,四种成分模型的决定系数分别为100%、100%、100%、99.99%;在对小麦数据集的定量建模中,小麦蛋白质模型的决定系数为99.80%。为了验证主成分分析光谱筛选算法对粮食作物主要成分定量回归模型的有效性,在3个光谱数据集上去除了主成分分析算法进行消融实验。研究结果表明：基于主成分分析算法与一维卷积神经网络的回归建模方法为粮食作物成分含量的检测提供一种快速无损精确的判定方式,研究结果对于粮食作物成分的含量检测具有促进作用。     

关于制丝厂适煮工艺条件确定方法的研究(摘登)

（二）最佳煮茧温度特性图的确定要取得最合适的煮茧条件，如果不考虑煮茧因子间的相互作用来控制因子，就不能得到良好的缫丝状况。本节试进行了这样一种新的尝试，对煮茧各区段的工艺条件相互联系起来影响缫丝成绩的状态进行多元分析，以确定最佳的温度特性图，正确地掌握煮茧工艺。1．由回归主成分确定的温度图对表20变化煮茧工艺条件和由此而得到的缫丝成绩的相关关系进行回归主成分分析，其结果如表22所示。表22回归主成分与因子注：表头中“1”表示解舒不良茧；“2”为解舒良好茧。下表同。图52温度特性曲线（增大回归主成分情况，解…     

化学计量学——光度法在食品多组份分析中的应用评述

本文对化学计量学光度法在食品多组分分析中的应用进行了评述,并简要介绍和讨论了多元线性回归、因子分析法、主成分回归、偏最小二乘法、卡尔曼滤波、人工神经网络及其在食品分析中的应用。引用文献90篇。     

基于主成分回归的曲靖C3F等级烤烟评吸质量估算模型

为探明曲靖烟区烤烟评吸质量与主要化学成分的关系及建立烤烟评吸质量的估算方法,对150个烤烟样品的13项化学指标与评吸质量进行了相关分析和主成分回归分析.结果表明,入选的13项化学指标与烤烟评吸质量均有一定的相关性,其中还原糖、总氮、烟碱、钾含量、氯含量、挥发酸和挥发碱含量是烤烟评吸质量的主要决定因素;基于主成分回归方法建立了曲靖烟区烤烟评吸质量的估算模型,决定系数(R2)为0.723,回归方程通过显著性检验(P=0.000);曲靖烟区烤烟评吸质量可以通过烤烟化学成分含量进行估算,基于烤烟化学指标数据运用主成分回归的方法在既定区域内估算烤烟样品的评吸质量是可行的.     

几种有机酸对紫玉米花青素热稳定性的影响

研究几种有机酸通过辅色作用对紫玉米花青素热稳定性的影响。通过研究热处理过程中紫玉米花青素的残留率、酰基化花青素比例和辅色后花青素热力学性质变化规律,确定单宁酸、琥珀酸、草酸、苹果酸、柠檬酸通过辅色作用有效提高紫玉米花青素的热稳定性,而抗坏血酸降低紫玉米花青素的热稳定性。其中,紫玉米花青素与苹果酸、单宁酸和草酸辅色后,其花青素稳定性显著高于未处理的紫玉米花青素,其主要原因是苹果酸、单宁酸和草酸提高紫玉米花青素中酰基化花青素的含量,提高紫玉米花青素的活化能。因此,苹果酸、单宁酸和草酸通过辅色作用可以有效提高紫玉米花青素的热稳定性。     

酸水解去除谷氨酸母液中的焦谷氨酸

焦谷氨酸没有鲜味,是谷氨酸产品中的无效成分,其安全性尚无定论.控制谷氨酸浓度为16g/100mL、焦谷氨酸的浓度为3.2g/100mL,试验研究了水解温度、硫酸加入量、水解时间等因素对降低谷氨酸母液中焦谷氨酸含量的影响.在保证谷氨酸回收率的基础上,确定出使焦谷氨酸含量达到1.07％及以下的最优水解组合:水解温度(95±5)℃、浓硫酸加入量30％ (v/v)、水解时间2h.在上述试验中,焦谷氨酸的初始含量均为20％.通过改变初始焦谷氨酸氨酸含量20%～35％,最优水解组合下水解后焦谷氨酸含量为0.96％～1.04％,仍可达到1.07％以下.     

Microbial reductive transformation of pentachloronitrobenzene under methanogenic conditions

The reductive transformation of pentachloronitrobenzene (PCNB), an organochlorine fungicide, was investigated with a mixed, methanogenic culture developed from a contaminated estuarine sediment. Batch assays performed with this enrichment culture resulted in the biotransformation of PCNB to pentachloroaniline (PCA), which was then sequentially dechlorinated as follows: PCA --> 2,3,4,5- and 2,3,5,6-tetrachloroaniline (TeCA) --> 2,4,5- and 2,3,5-trichloroaniline (TrCA) --> 2,4-, 2,5-, and 3,5-dichloroaniline (DCA) --> 3- and 4-chloroaniline (CA) (low levels). Glucose fermentation, methanogenesis, and dechlorination were not inhibited at an initial PCNB concentration up to 40 microM, which is 27 times higher than its aqueous solubility. The addition of 25 mM 2-bromoethanesulfonate (BES) to the PCNB-amended culture resulted in the complete inhibition of methanogenesis, but the biotransformation of PCNB to PCA and its sequential dechlorination pathway were not affected. The addition of sodium azide (200 mg/L) to the PCNB-amended culture resulted in complete inhibition of methanogenesis, but did not inhibit the transformation of PCNB to PCA; however, PCA dechlorination was not observed. PCNB was also abiotically transformed to PCA in autoclaved culture media but at much lower rates as compared to the biotic assays. In contrast, the rate of PCNB to PCA transformation in autoclaved culture controls was similar to the rates observed in the azide-amended culture and the active enrichment culture, indicating that biotically derived reductants facilitated the observed transformation of PCNB to PCA. Dechlorination of PCA was not observed in any of the abiotic controls. These findings have significant environmental implications in terms of the fate and transport of PCNB, PCA, and its dechlorination products in subsurface systems.     

原儿茶酸对副溶血弧菌的抑菌和减毒作用

该研究旨在探讨原儿茶酸对副溶血弧菌的抑菌活性和减毒作用,揭示原儿茶酸抑菌的作用机制。通过测定最小抑菌浓度（Minimal Inhibitory Concentration,MIC）、生长曲线、核酸与蛋白质泄漏量、丙二醛（MDA）含量,利用扫描电镜观察副溶血弧菌形态的变化,来评估原儿茶酸对副溶血弧菌的抑菌活性及其对细胞膜完整性和通透性的影响。同时,通过检测亚抑菌浓度（Sub-inhibitory Concentrations,SICs）下原儿茶酸对副溶血弧菌毒力因子合成的影响,研究原儿茶酸对副溶血弧菌的毒力衰减作用。实验结果表明,原儿茶酸的MIC为2 mg/mL,经MIC浓度原儿茶酸处理后,副溶血弧菌发生严重内陷和破裂,上清液中核酸、蛋白质、MDA含量分别是对照组的2.65倍、1.94倍和10.05倍。此外,原儿茶酸在浓度为1/4 MIC时对胞外多糖、胞外蛋白酶、生物被膜的抑制率分别为40.57%、19.79%和26.04%,在浓度为1/2 MIC时的抑制率分别为52.85%、28.38%和34.69%。原儿茶酸主要作用于细胞膜,通过影响细胞膜的完整性和通透性抑制副溶血弧菌的生长,在亚抑菌浓度下便可有效减弱副溶血弧菌毒力。     

GLUTAMINE AS A PREDICTIVE MEASUREMENT IN THE QUALITY ASSESSMENT OF PROCESSED CARROT PUREE

The aim of this investigation was the development of a simple quality test whereby knowing the amount of glutamine present in a fresh sample of carrots and the processing temperature, the amount of PCA and perhaps the acceptability of the final product might be determined. Two different varieties of carrots from two different geographical locations were packed in TDT tubes, flushed with nitrogen and sealed. A process of F_o= 4.9 was given to each series of tubes at temperatures ranging from 240-300°F with 20°F increments. Following this, analyses were conducted for glutamine, pyrrolidone-carboxylic acid (PCA) and pH to determine the effect of initial concentration of glutamine and process temperature upon the formation of PCA. Taste thresholds for PCA were also determined both in model systems and in processed carrot puree. PCA formation was found to exhibit an inverse linear semilogarithmic plot with process temperature such that amounts could be predicted from initial glutamine contents for a given batch. Sensory studies indicated that the levels of PCA found in samples at the lower temperatures were near the taste thresholds established for this compound. With such results it is possible to predict the best process time and temperature for carrot puree based on the initial concentration of glutamine in order to minimize off-flavors due to PCA formation.     

Authentication of honey sample via test sample and principal component analysis

The use of principal component analysis (PCA) of large data sets for the authentication of honey samples is illustrated. The procedure uses a predetermined training set of the most characteristic honeys selected by PCA from a large collection of various honeys. The PCA solution of the training set and sample in question, results in a plot indicating honey position and membership to rape, heather, or honeydew honey. The procedure is general and can be applied and extended for authentication of other foodstuffs.     

分子对接和光谱法研究原儿茶醛和阿魏酸与牛血清白蛋白的互作机理

采用光谱法和分子对接技术分别研究原儿茶醛（protocatechuic aldehyde,PCA）和阿魏酸（ferulic acid,FA）与牛血清白蛋白（bovine serum albumin,BSA）的相互作用,同时比较PCA和FA分别与BSA的结合能力,从而揭示其相互作用机理,为其在食品领域的广泛应用提供实验依据。结果表明：PCA和FA主要靠氢键和范德华力与BSA形成稳定的复合物,由于ΔG小于0,所以此过程可自发进行;与FA相比,PCA与BSA之间的结合能力更强,PCA和FA与BSA各自均只有1 个位于Trp213残基附近IIA结合域和IIIA结合域之间疏水空腔中的结合位点,其最终导致BSA的内源荧光发生静态猝灭。此外,310 K时PCA与BSA相互作用的Ka值大于FA与BSA结合的Ka,其对应关系为9.005×105 L/mol＞2.553×105 L/mol;分子对接结果显示PCA比FA距离BSA的Trp213残基更近,其对应关系为0.512 nm＜0.518 nm,推测可能是因为PCA极性强于FA,所以PCA更容易与BSA结合。     

基于PCA模型的食品高温杀菌过程故障诊断技术研究

针对食品高温杀菌这类典型的工业生产过程,运用主元分析(principal component analysis, PCA)模型进行了故障检测与诊断的研究。讨论了基于PCA模型的故障检测与诊断理论的几个主要方面和实现技术,建立了火腿肠高温杀茵锅生产过程的PCA模型,进行了3种典型的生产故障的诊断与分析。结果表明,该方法对过程故障能实现有效的检测与诊断。     

NITROGEN FERTILIZATION AND THE FORMATION OF 2-PYRROLIDONE-5-CARBOXYLIC ACID IN STORED AND PROCESSED TABLE BEETS

SUMMARY —The conversion of glutamine to the bitter compound, 2-pyrrolidone-5-carboxylic acid (PCA), in table beets was studied. Glutamine was analyzed by a phosphate-buffer hydrolysis and distillation method. PCA was extracted with ethyl acetate and the ditrimethylsilyl derivative prepared and measured quantitatively by gas-liquid chromatography. The accumulation of glutamine in fresh beets with excessive amounts of nitrogen fertilization caused a substantial increase in PCA content of processed beets. Conversion of glutamine to PCA in beets was proportional to the heating time during processing. Glutamine content did not alter during raw beet storage periods at 35°F; PCA content increased gradually.