仓储小麦隐蔽性害虫的检测模型及算法

粮食在存储过程中极易发生虫蚀现象,因此需要一种快速高效的检测手段来检测粮食是否染虫。结合机器学习和生物光子学的相关理论,分别测量正常和含虫小麦的自发光子数,然后提取8个统计特征和13个直方图特征,分别采用线性判别分析LDA和二次辨别分析QDA算法对正常小麦和含虫小麦进行识别,同时针对小样本情况下协方差矩阵奇异性问题,引入正则化判别分析RDA方法,对QDA算法进行优化,提高分类正确率。实验结果证实了所提方法的有效性。     

基于软X射线与低场核磁检测小麦隐蔽性害虫玉米象

针对小麦内部隐蔽性害虫玉米象(Sitophilus zeamais)难以检出的问题,本文将高清软X射线与低场核磁两种检测技术相结合,通过高清软X射线拍摄的图片,观察玉米象在小麦内部的整个生长周期,提取图片纹理特征,用线性判别分析(linear discriminant analysis,LDA)与二次判别分析(quadratic discriminant analysis,QDA)算法进行分类判别,并对被不同虫态玉米象感染的小麦进行低场核磁检测。研究结果表明:在12%水分含量小麦中,玉米象的生长周期大约为36 d,LDA与QDA模型对未感染小麦与不同感染阶段小麦进行单独分类判别时,准确率都达到了95%以上,对卵期以及幼虫具有较高的分类准确率。根据小麦被玉米象感染后特征峰值比例P2b与P22的变化,可以用来作为小麦是否受玉米象感染定性判断的依据。     

基于生物光子学的小麦籽粒品质检测分析与建模

为了科学有效地开展保粮减损工作,基于生物光子分析技术,对经过水浸泡和去胚后的小麦籽粒的自发光子进行测量,进而使用模式识别中的K-means和支持向量机(SVM)算法,进行小麦籽粒品质检测分析.该方法是一种新的精准、无损检测手段,可用于小麦品质的早期辅助决策,指导粮库科学有效地开展保粮减损工作.     

基于人工免疫算法的储粮害虫特征选择研究

储粮害虫特征选择是粮虫图像识别中一个关键的预处理环节.提出基于v折交叉验证训练模型识别率和所选特征个数的特征子集评价准则,将人工免疫算法应用到粮虫的特征选择.该算法从粮虫的17雏形态学特征中自动选择出面积、周长等7个特征的最优特征子空间,采用参数优化之后的SVM分类器对90个粮虫样本进行分类,识别率达到95.5%以上,并与PCA法、GA法和原始特征法进行了对比,结果表明人工免疫算法降低了特征空间的维数,提高了分类器的识别率,证实了基于人工免疫算法的粮虫特征选择是可行的.     

贵州主粮霉菌污染调查及其限量指标的探讨

本文对251份正常粮食进行霉菌带菌量分析,并测定部分粮食中 AF_(B1)含量。提出大米、面粉、小麦每克样品带菌量正常范围上限值≤10~4个,玉米、豆类≤10~3个,     

基于高光谱成像技术小麦籽粒霉变鉴别方法研究

小麦霉变籽粒是小麦不完善粒一种,鉴别小麦霉变粒是粮食霉变程度的重要参考。为了更精确地鉴别小麦霉变籽粒,本文利用高光谱成像技术采集不同品种小麦霉变籽粒及非霉变籽粒的光谱信息,建立小麦霉变籽粒的鉴别预测模型,实现小麦霉变籽粒快速、无损、有效、稳定的鉴别。首先收集了100粒霉变和100粒正常非霉变籽粒400-1000 nm范围的高光谱图谱,通过不同的光谱预处理方法进行处理,选出最优光谱信息预处理方法。接着,采用连续投影算法(SPA)和竞争性自适应重加权采样(CARS)提取特征波长,分别比较通过全波长范围和特征波长下建立的偏最小二乘判别分析(PLS-DA)和支持向量机(SVM)模型并进行比较。结果表明,淮麦22和宁麦13的最优预测模型分别为全波长-OSC-SVM和SPA-OSC-SVM模型,对应的R分别为0.9963和0.9998,RMSEP分别为0.0309和0.0064,R分别为0.9975和0.9995,RMSECV分别为0.0247和0.0111。     

基于PCA-ELM和光谱技术预测香蕉成熟度

本文利用高光谱成像技术(Hyperspectral imaging)对常温下贮存的450个未剥皮香蕉样本光谱数据进行采集,首先检测样本果肉可溶性固形物含量(TSS)、坚实度(FIM),采用SPSS单因素方差分析,然后运用线性优化岭回归分析-偏最小二乘法(RR-i PLS)建立了香蕉成熟度理化指标的光谱和图像特征分类模型,结果表明通过实验平台获取光谱数据预测香蕉可溶性固形物含量以及坚实度的相关系数R2值分别为0.92和0.94。再通过连续投影法(successive projections algorithm,SPA)法以及主成分分析法(principal component analysis,PCA)分别选取特征波长,建立基于特征波长的极限学习机(extreme learning machine,ELM)对光谱数据进行建模交叉验证。通过比较RR-i PLS,SPA-ELM与PCA-ELM三种分类预测模型,表明基于特征波长的PCA-ELM分类模型具有较好的预测性能。交叉验证准确率达到99%。为能快速无损识别香蕉果实品质提供一种有效的预测研究,基本满足对香蕉成熟度分类检测且显示出有效建模分析,且能达到有效的经济效益。     

肉类电子鼻识别模型的建立

采用电子鼻对牦牛肉、牛肉和鸭肉样品进行检测,同时对经热处理的牦牛肉和牛肉样品进行分析.通过对所获得的数据进行主成分分析(principal component analysis,PCA)和判别因子分析(discriminant factor analysis,DFA),建立用于识别不同肉类的DFA模型,并对模型进行验证,DFA模型对于未知样品的识别率达到100%,能够有效的区分和识别牦牛肉、牛肉和鸭肉样品.电子鼻分析的结果显示,热处理对牦牛肉的挥发性物质影响较大,而对牛肉的影响较小.     

基于手持式电子鼻的白酒识别

现有电子鼻存在体积偏大、价格昂贵等问题,阻碍了其普及应用。为解决这一问题,该文提出了一种用于白酒检测的手持式电子鼻设计方案,传感器阵列由6种贴片式气体传感器和1个温湿度传感器组成,并置于一个微型仿生气室中。基于所设计的手持式电子鼻对6种白酒的识别问题进行了研究。首先,从电子鼻传感器响应中提取特征,并采用主成分分析法(principal component analysis, PCA)、核主成分分析法(kernel principal component analysis,KPCA)和核熵成分分析法(kernel entropy component analysis,KECA)进行特征降维;然后,通过支持向量机(support vector machine,SVM)、K近邻(k-nearest neighbor,KNN)和反向传播人工神经网络(back-propagation artificial neural network,BP-ANN)对白酒进行识别。结果表明,所设计的手持式电子鼻可以对不同种类的白酒进行在线检测与准确识别。     

发芽小麦对面粉品质特性及卫生安全研究

针对小麦在收获季节连遇降雨造成籽粒穗发芽现状,研究分析发芽小麦对原料籽粒品质特征容重、硬度指数、生芽率、降落数值等的影响,以及对制成面粉后其特征品质如灰分、粗蛋白、湿面筋、降落数值、白度等所产生的影响。本研究选择发芽小麦按照不同比例混入正常小麦中进行实验研究,探究发芽小麦对改良小麦特性品质、加工品质和食用品质的影响和变化规律,并进行了馒头、面条的蒸煮试验分析及食品质量安全检测分析。结果表明:混入不同比例发芽小麦均对小麦品质、加工品质、食用品质以及面团的流变学特性有一定的影响,其中降落数值对发芽小麦的反映比较灵敏;真菌毒素检测表明随着发芽小麦含量的增加,黄曲霉毒素增多,发芽小麦含量与黄曲霉毒素成正相关。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the