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1.
Beijing Da Xue Xue Bao Yi Xue Ban ; 51(5): 881-886, 2019 Oct 18.
Artigo em Chinês | MEDLINE | ID: mdl-31624393

RESUMO

OBJECTIVE: To compare the corneal biomechanical properties among keratoconus, subclinical keratoconus and normal corneas by using CorVis ST, and to estimate the effect of these biomechanical indices in discriminating keratoconus and subclinical keratoconus from normal. METHODS: A total of 76 eyes of 67 subjects were enrolled and divided into three groups. Keratoconus group included 24 eyes from 17 patients, subclinical keratoconus group included 12 eyes from 12 patients and normal group included 40 normal eyes from 40 subjects.All the eyes were assessed with CorVis ST and ten biomechanical parameters, intraocular pressure (IOP) and central corneal thickness (CCT) were obtained from this machine. The discrimination of biomechanical characteristic of the three groups based on the all indices was reflected by discriminant analysis and the Fisher discriminant function was established. RESULTS: The values of corneal biomechanics of keratoconus, subclinical keratoconus, normal eyes were increased in sequence, except for three indices: the second applamation time (A2T), time taken to reach highest concavity (HCT) and maximum corneal velocity during the first applanation (Vin). Three sets of data were among a statistically significant difference (P<0.05). There were statistically significant differences (P<0.05) between any two groups by comparing with such two indices: radius value of central concave curvature at highest concavity (HCR) and CCT. The grades of the three groups were obvious, evaluated by the discriminant function. The accuracy of reevaluation was 85% by validation method. The biggest contribution of indices in discriminant function was given by such four indices in sequence: CCT, HCR, maximum deformation amplitude of highest concavity (HCDA) and maximum corneal velocity during the second applanation (Vout). CONCLUSION: The corneal biomechanical properties of keratoconus and subclinical keratoconus were decreased compared with normal eyes. The biomechanical parameters based on CorVis ST showed a good performance for discriminating among keratoconus, subclinical keratoconus and normal corneas.


Assuntos
Ceratocone , Fenômenos Biomecânicos , Córnea , Análise Discriminante , Humanos , Tonometria Ocular
2.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(9): 1164-1167, 2019 Sep 10.
Artigo em Chinês | MEDLINE | ID: mdl-31594166

RESUMO

Objective: To construct Bayes discriminant function for clinical classification of common and severe Japanese encephalitis (JE) cases, and to identify cases accurately with quantitative indicators. Methods: Samples of confirmed common and severe JE cases reported by the epidemic surveillance system of Gansu Provincial Center for Disease Control and Prevention from 2005 to 2017 were collected. Non-conditional logistic regression analysis and Bayes stepwise discriminant analysis were used to screen meaningful clinical indicators, so as to construct and evaluate Bayes discriminant function. Results: There were 256 common JE cases and 257 severe JE cases. There were no significant differences in sex, age and occupation distributions between the two groups (P>0.05) and there was significant difference in case fatality rate (P<0.05). Non-conditional logistic regression analysis and Bayes stepwise discriminant analysis, combined with using related literature, to screen 11 clinical indicators for the construction of Bayes discriminant function. Interactive validation showed that the sensitivity of discriminant function was 71.48% (95%CI: 65.53%-76.93%) and the specificity was 73.93% (95%CI: 68.11%-79.19%). The area under ROC curve was 0.761 (95%CI: 0.720-0.803) and the total accuracy rate was 72.71%. Conclusion: Bayes discriminant function can be used to identify common and severe JE cases more accurately, which is helpful for the reasonable treatment and good prognosis of JE patients.


Assuntos
Análise Discriminante , Encefalite Japonesa/diagnóstico , Epidemias , Teorema de Bayes , Encefalite Japonesa/epidemiologia , Humanos , Curva ROC
3.
Bioresour Technol ; 291: 121920, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31382094

RESUMO

An anoxic/oxic membrane bioreactor (AO-MBR), an anaerobic side-stream reactor (ASSR) coupled MBRs (A-MBRs), an A-MBR with carriers packed in ASSR (AP-MBR) and an AP-MBR with sludge ultrasonicated before ASSR (AUP-MBR) were operated for 261 d to investigate effects of ASSR, packing carriers and ultrasonication on sludge reduction and microbial population. Sludge reduction efficiencies of A-MBR, AP-MBR and AUP-MBR were 36.2%, 46.4% and 51.4%, respectively. Packing carriers and ultrasonication both enhanced hydrolysis by stimulating activities of α-glucosidase and protease, while uncoupling metabolism was enhanced greatly by packing carriers but slightly by ultrasonication. Linear discriminant analysis of effect size (LEfSe) results showed that packing carriers promoted the growth of hydrolytic and fermentative bacteria in bulk sludge, and enriched anaerobes and fermentative bacteria on the surface of carriers. Ultrasonication screened ultrasonication-resistant bacteria, and created an anaerobic environment beneficial to hydrolytic and fermentative bacteria.


Assuntos
Microbiota , Esgotos , Anaerobiose , Reatores Biológicos , Análise Discriminante , Rios , Eliminação de Resíduos Líquidos
4.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(4): 531-540, 2019 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-31441252

RESUMO

Individual differences of P300 potentials lead to that a large amount of training data must be collected to construct pattern recognition models in P300-based brain-computer interface system, which may cause subjects' fatigue and degrade the system performance. TrAdaBoost is a method that transfers the knowledge from source area to target area, which improves learning effect in the target area. Our research purposed a TrAdaBoost-based linear discriminant analysis and a TrAdaBoost-based support vector machine to recognize the P300 potentials across multiple subjects. This method first trains two kinds of classifiers separately by using the data deriving from a small amount of data from same subject and a large amount of data from different subjects. Then it combines all the classifiers with different weights. Compared with traditional training methods that use only a small amount of data from same subject or mixed different subjects' data to directly train, our algorithm improved the accuracies by 19.56% and 22.25% respectively, and improved the information transfer rate of 14.69 bits/min and 15.76 bits/min respectively. The results indicate that the TrAdaBoost-based method has the potential to enhance the generalization ability of brain-computer interface on the individual differences.


Assuntos
Interfaces Cérebro-Computador , Potencial Evocado P300 , Máquina de Vetores de Suporte , Algoritmos , Análise Discriminante , Eletroencefalografia , Humanos
5.
J Agric Food Chem ; 67(37): 10543-10551, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31464438

RESUMO

Adulteration of meat and meat products causes concerns to consumers. It is necessary to develop novel robust and sensitive methods that can authenticate the origin of meat by qualitative and quantitative means to minimize the drawbacks of the existing methods. This study has shown that the protein N-glycosylation profiles of different meats are species specific and thus can be used for meat authentication. Based on the N-glycan pattern, the investigated five meat species (beef, chicken, pork, duck, and mutton) can be distinguished by principal component analysis, and partial least square regression was performed to build a calibration and validation model for the prediction of adulteration ratio. Using this method, beef samples adulterated with a lower-value duck meat could be detected down to the addition ratio as low as 2.2%. The most distinguishing N-glycans from beef and duck were elucidated for the detailed structures.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Glicômica/métodos , Polissacarídeos/química , Animais , Bovinos , Galinhas , Análise Discriminante , Patos , Glicosilação , Carne , Análise de Componente Principal , Carne Vermelha , Suínos
6.
J Agric Food Chem ; 67(36): 10273-10284, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31418566

RESUMO

Shiraz wine volatomes from two Australian geographical indications (GIs), that is, Orange and Riverina, were compared using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Shiraz wines were made in triplicate from grapes harvested at two harvest dates from six vineyards in the two GIs. A total of 133 compounds showed a significant trend between wines from the cooler Orange GI and warmer Riverina. Compounds associated with wines from the cooler climate were grape-derived volatiles, such as monoterpenes, sesquiterpenes, green leaf volatiles, and some norisoprenoids. Fermentation-derived compounds, such as esters and S-containing compounds, showed no specific trend related to grape origin. In addition, wines could be also clearly separated according to the harvest date, irrespective of the climate, with C6 compounds, higher alcohol acetates, and other esters contributing utmost to the differentiation of samples, whereas terpenoids and norisoprenoids did not have an influence. This study demonstrated the plasticity of wine volatome related to grape origin and also the maturity level (harvest date), irrespective of climate.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Vitis/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Austrália , Clima , Análise Discriminante , Frutas/química , Odorantes/análise , Terpenos/química
7.
Int J Nanomedicine ; 14: 6165-6178, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31447558

RESUMO

Purpose: Surface-enhanced Raman scattering (SERS) spectroscopy on serum and other biofluids for cancer diagnosis represents an emerging field, which has shown promising preliminary results in several types of malignancies. The purpose of this study was to demonstrate that SERS spectroscopy on serum can be employed for the differential diagnosis between five of the leading malignancies, ie, breast, colorectal, lung, ovarian and oral cancer. Patients and methods: Serum samples were acquired from healthy volunteers (n=39) and from patients diagnosed with breast (n=42), colorectal (n=109), lung (n=33), oral (n=17), and ovarian cancer (n=13), comprising n=253 samples in total. SERS spectra were acquired using a 532 nm laser line as excitation source, while the SERS substrates were represented by Ag nanoparticles synthesized by reduction with hydroxylamine. The classification accuracy yielded by SERS was assessed by principal component analysis-linear discriminant analysis (PCA-LDA). Results: The sensitivity and specificity in discriminating between cancer patients and controls was 98% and 91%, respectively. Cancer samples were correctly assigned to their corresponding cancer types with an accuracy of 88% for oral cancer, 86% for colorectal cancer, 80% for ovarian cancer, 76% for breast cancer and 59% for lung cancer. Conclusion: SERS on serum represents a promising strategy of diagnosing cancer which can discriminate between cancer patients and controls, as well as between cancer types such as breast, colorectal, lung ovarian and oral cancer.


Assuntos
Neoplasias/diagnóstico , Análise Espectral Raman/métodos , Idoso , Neoplasias da Mama/sangue , Neoplasias da Mama/diagnóstico , Estudos de Casos e Controles , Neoplasias Colorretais/sangue , Neoplasias Colorretais/diagnóstico , Diagnóstico Diferencial , Análise Discriminante , Feminino , Humanos , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/diagnóstico , Masculino , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Pessoa de Meia-Idade , Neoplasias Bucais/sangue , Neoplasias Bucais/diagnóstico , Neoplasias/sangue , Neoplasias Ovarianas/sangue , Neoplasias Ovarianas/diagnóstico , Análise de Componente Principal , Prata/química
8.
Food Chem ; 298: 125046, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260981

RESUMO

We established a novel Dianhong black tea grades discriminant analytic technique based on a fluorescence image along with carbon quantum dots (CDs) as fluorescent probes. Different grades of Dianhong black tea contain different various amounts of tea polyphenols. Tea polyphenols can quench the fluorescent intensity of CDs, resulting in different fluorescent peaks; Dianhong black tea grades can then be discriminated through the use of principal component analysis and Bayesian analysis. Compared with the additional data processing required in other methods, the advantage of our method is that the fluorescence curve can be used directly, and it achieves satisfactory results. We firstly used CDs combined with chemometrics to identify eight grades of Dianhong black tea, and we also provide a new method that improves the identification rate using nanotechnology to avoid performing complex data processing.


Assuntos
Camellia sinensis/química , Corantes Fluorescentes/química , Teorema de Bayes , Camellia sinensis/metabolismo , Análise Discriminante , Polifenóis/análise , Análise de Componente Principal , Pontos Quânticos/química , Espectrometria de Fluorescência
9.
Food Chem ; 298: 125052, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31261003

RESUMO

Scotch Whisky has been analysed as a complex mixture in its raw form using high resolution Nuclear Magnetic Resonance (NMR) and previously developed water and ethanol suppression techniques. This has allowed for the positive identification of 25 compounds in Scotch Whisky by means of comparison to reference standards, spike-in experiments, and advanced 1D and 2D NMR experiments. Quantification of compounds was hindered by signal overlap, though peak alignment strategies were largely successful. Statistical total correlation spectroscopy (STOCSY) yielded information on signals arising from the same compound or compounds of similar origin. Statistical analysis of the spectra was performed using Independent and Principal Components Analysis (ICA, PCA) as well as Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). Several whisky production parameters were successfully modelled, including blend or malt status, use of peated malt, alcohol strength, generic authentication and maturation wood type, whilst age and geographical origin could not be modelled.


Assuntos
Bebidas Alcoólicas/análise , Espectroscopia de Prótons por Ressonância Magnética/métodos , Bebidas Alcoólicas/normas , Análise Discriminante , Análise dos Mínimos Quadrados , Análise de Componente Principal , Espectroscopia de Prótons por Ressonância Magnética/normas , Padrões de Referência
10.
Food Chem ; 299: 125107, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31302428

RESUMO

Traceability and authenticity is crucial to the food safety of scallop. The present study investigated the possibility of using stable isotope analysis to identify the origins and species of scallops (Patinopecten yessoensis, Chlamys farreri, and Argopecten irradians) in the coastal areas of China. The δ13C and δ15N values of a total of 575 samples from seven sites around China were determined and additional 150 samples were tested by fisher linear discrimination analysis (LDA) to estimate the accuracy of origin identification and species prediction. The results show that the stable C and N isotope composition differed significantly depending on the origin, season and species of scallops. Meanwhile, the LDA shows that 92% of the samples were correctly classified for origin prediction, and an accuracy of 98.3% was obtained for species prediction. This study reveals that stable isotope ratio is an effective technique to trace the geographical origin and identify the species of scallops.


Assuntos
Isótopos de Carbono/análise , Análise de Alimentos/métodos , Isótopos de Nitrogênio/análise , Pectinidae/química , Frutos do Mar/análise , Animais , China , Análise Discriminante , Análise de Alimentos/estatística & dados numéricos , Especificidade da Espécie
11.
Chem Commun (Camb) ; 55(61): 9019-9022, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31290863

RESUMO

DNA nanohydrogel assembled AuNPs were proposed as a high-throughput multidimensional sensing strategy for small molecule reductant profiling in rat brain. The equilibrium among AuNPs, DNA nanohydrogel and targets produced a unique fingerprint-like pattern for differentiating the reducing capacity.


Assuntos
Encéfalo/metabolismo , DNA de Cadeia Simples/química , Ouro/química , Hidrogéis/química , Nanopartículas Metálicas/química , Substâncias Redutoras/análise , Animais , Colorimetria/métodos , Análise Discriminante , Glutationa/líquido cefalorraquidiano , Oxirredução , Tamanho da Partícula , Ratos
12.
J Agric Food Chem ; 67(32): 9112-9120, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31314506

RESUMO

A reliable and robust tool for supporting the panel test in virgin olive oil classification is still required. We propose four chemometric approaches based on t test, principal component analysis (PCA) and linear discriminant analysis (LDA), applied for combining sensorial data, and chemical measurements. The former was from the panel test, and the latter was from headspace solid-phase microextraction-gas chromatography-mass spectrometry quantitation of 73 volatile organic compounds (VOCs) of 1223 typical commercial virgin olive oils, with most of them recognized as difficult to classify with accuracy by the panel test. The approaches were developed and validated, and the best results, with 83.5% correct classification, were using the PCA-LDA approach. Among the other methods, developed for proposing simplified procedures based on a smaller number of VOCs, the best method gave 80.1% correct classification only using 10 VOCs. All of the approaches suggested that octane, heptanal, pent-1-en-3-ol, Z-3-hexenal, nonanal, and 4-ethylphenol should be considered as a basis of volatiles for classification of olive oil samples.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Azeite de Oliva/química , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Análise Discriminante , Humanos , Olea/química , Azeite de Oliva/classificação , Análise de Componente Principal , Paladar
13.
Food Chem ; 300: 125173, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31319335

RESUMO

The administration of anabolic agents in farm animals to improve meat production has been prohibited in EU, due to the potential risks to human health. Meat quality was investigated to detect the effects of illegal administration of dexamethasone or prednisolone or 17ß-estradiol on Charolais bulls. Three groups of 6 bulls were treated and 12 bulls were the control. Meat quality parameters were measured on live animals, carcasses and on samples of Longissimus thoracis and multivariate statistical data analysis was applied. In Charolais bulls, these parameters were affected by growth promoter administration and the multivariate canonical discriminant analysis was able to distinguish between treated and untreated animals mainly due to three electronic nose's parameters, 24 h carcass temperature and drip loss. Therefore, meat quality control and the multivariate analysis could be useful as a first screening to address targeted controls on farms suspected of illicit use of growth promoters.


Assuntos
Análise de Alimentos/métodos , Substâncias de Crescimento/farmacologia , Carne , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/crescimento & desenvolvimento , Animais , Bovinos , Dexametasona/farmacologia , Análise Discriminante , Nariz Eletrônico , Estradiol/farmacologia , Fazendas , Análise de Alimentos/instrumentação , Análise de Alimentos/estatística & dados numéricos , Qualidade dos Alimentos , Masculino , Carne/análise , Prednisolona/farmacologia
14.
Chem Biodivers ; 16(8): e1900218, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31282123

RESUMO

Croatian wines made from native (Plavac mali and Teran) and non-native grape varieties (Cabernet Sauvignon and Merlot), all grown in Croatian coastal regions, were investigated. Analyses included measurements of antioxidant activities, total phenolic contents and concentrations of non-colored phenolic compounds, chosen based on their known nutraceutical properties. Plavac mali wines were distinguished by higher antioxidant activity, total phenolic content and catechin concentrations but lower flavonol concentrations. Teran wines had higher hydroxytyrosol, myricetin and resveratrol concentrations. Merlot and Cabernet Sauvignon wines had higher flavonol concentrations (except myricetin). Canonical analysis was successful in discriminating Plavac mali from Teran wines, and both varieties were separated from non-native varieties. The results indicate distinct genetic potentials of studied varieties and enable wine authentication based on the investigated bioactive compounds.


Assuntos
Fenóis/análise , Vitis/química , Vinho/análise , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Croácia , Análise Discriminante , Flavonoides/análise , Resveratrol/análise , Vitis/metabolismo
15.
J Chem Ecol ; 45(7): 579-587, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31256322

RESUMO

Domestic cats (Felis silvestris catus) are solitary and territorial, and mark their territories by spraying urine, which emits a strong odor produced by volatile organic compounds (VOCs). Previous studies have focused on identifications of specific VOCs, such as 3-mercpto-3-methyl-1-butanol, a cat-specific VOCs. However, little is known about how whole volatile profiles of their sprayed urine change over time or how the profiles differ among individuals. This study investigated temporal changes and individual differences of volatile profiles produced by whole VOCs in cat urine, and the ability of cats to discriminate between these scent differences. Volatile profiles of fresh and aged cat urine were analyzed by using two-dimensional gas chromatography-mass spectrometry with a VOC preconcentrator comprehensively. Volatile profiles produced by hundreds of VOCs emitted from cat urine were influenced primarily by the age of the urine, and secondarily by individuality. During habituation-dishabituation tests, subjects discriminated between fresh and 24 h-old samples of same individuals, and between odor of different individuals from 0 h-, 3 h-old, and 24 h-old samples. These results strongly suggest that cats can recognize conspecific individuals via olfaction. Since most VOCs varied among individuals but were not stable over time, their urine may contain unknown VOCs that vary among individuals, are stable over time, and act as individual recognition signals.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Orgânicos Voláteis/urina , Animais , Comportamento Animal , Gatos , Análise Discriminante , Masculino , Análise de Componente Principal , Fatores de Tempo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação
16.
J Agric Food Chem ; 67(29): 8279-8289, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31259549

RESUMO

This study is focused on examining the tocopherol isomers (α-, γ-, and δ-) fingerprinting by online RP-HPLC analysis with post column detection using CUPRAC (cupric reducing antioxidant capacity) methodology for argan oil authenticity. The proposed online assay was validated with good precision, reproducibility, and linearity. Sixteen argan oil samples (100% pure-certified and other commercial argan oils), possible adulterating vegetable oils (i.e., olive, sunflower, corn, and soya oils), and virgin argan oil blended with olive, sunflower, corn, and soya oils at levels of 5%, 10%, 15%, and 20% were analyzed. Spectrophotometric CUPRAC, DPPH, and ABTS assays were applied. Discrimination of fraudulent argan oils from virgin samples was performed by utilizing orthogonal partial least-squares discriminant analysis (OPLS-DA) regression modeling with good sensitivity and specificity. We suggested [γ-toc/α-toc] value as a new first screening adulteration factor (AF) that could be used to assess fraudulent argan oil samples. The distinct decrement in AF value was observed by the increase of adulteration rate. The AF values for virgin argan oils were ranged from 11.8 (lower limit) to 18.6 (upper limit). The presence of ß-sitosterol detected in commercial argan oils (with AF values out of limit values) was evaluated as fraudulent which was in accordance with the proposed assay. Our method enabled the detection of argan oil samples at adulteration levels of >5% in the case of sunflower, olive, and soya oils, >15% in the case of corn oil. This method may be an alternative and specific assay for the authentication and quality detection of commercial argan oils.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Óleos Vegetais/análise , Análise Discriminante , Contaminação de Alimentos/análise , Análise dos Mínimos Quadrados , Reprodutibilidade dos Testes , Tocoferóis/análise
17.
J Food Sci ; 84(8): 2112-2120, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313310

RESUMO

Misrecognition and toxic elements are two of several reasons responsible for food poisoning even death in the summer, a time when a great deal of edible mushrooms is celebrated in Southwestern China featured as complex environment conditions. It is highly important to identify the difference of chemical constituents in edible mushrooms at the regional-scale. In this study, Fourier transform infrared (FT-IR) spectroscopy and inductively coupled plasma mass spectrometry were applied to investigate organic matters and 18 mineral elements in porcini mushrooms of six species collected from 17 sampling sites in nine Yunnan cities. Classification models on the species, regions, and part levels were established using sparse partial least square-discriminant analysis and principal component analysis. At the species level and region level accuracies of greater than 92.1% and 92.8% was achieved, respectively, whereas on the part level caps and stipes were classified with 96.7% accuracy. One of the most popular mushrooms is Boletus edulis characterized by polysaccharide, lipid, and ribonucleic acid as well as several phenolic compounds. Temperature and precipitation show possible influences on accumulations of polysaccharides and ribonucleic acid. Furthermore, the most important elements of caps contributed the difference between two parts are copper (Cu), zinc (Zn), and phosphorus (P), whereas stipes instead by manganese (Mn) and cobalt (Co). These results demonstrated that FT-IR spectroscopy and elements contents provide information sufficient for classifying different porcini mushroom samples, which might be helpful for controlling food security and quality assessment of edible mushrooms.


Assuntos
Agaricales/química , Minerais/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Agaricales/classificação , China , Análise Discriminante , Geografia , Análise dos Mínimos Quadrados , Análise de Componente Principal
18.
J Food Sci ; 84(8): 2234-2241, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313313

RESUMO

In order to rapidly and nondestructively identify tea grades, fluorescence hyperspectral imaging (FHSI) technology was proposed in this paper. A total of 309 Tieguanyin tea samples with three different grades were collected and the fluorescence hyperspectral data was acquired by hyperspectrometer (400 to 1000 nm). The characteristic wavelengths were respectively selected by Bootstrapping Soft Shrinkage (BOSS), Variable Iterative Space Shrinkage Approach (VISSA) and Model Adaptive Space Shrinkage (MASS) algorithms. Then, Support Vector Machine (SVM) was applied to establishing the relationship between the characteristic peaks, the full spectra, three characteristic spectra and the labels of tea grades. The results showed that VISSA-SVM model had the best classification performance, but the model precision can still be improved. Thus, Artificial Bee Colony (ABC) algorithm was introduced to optimize the parameters of SVM model. The accuracy and Kappa coefficient of test set of VISSA-ABC-SVM model were improved to 97.436% and 0.962, respectively. Therefore, the combination of fluorescence hyperspectra with VISSA-ABC-SVM model can accurately identify the grade of Tieguanyin tea. PRACTICAL APPLICATION: The rapid and accurate nondestructive tea grade identification method contributes to the construction of the tea online grade detection system. FHSI technology can solve the shortcomings of the reported methods and improved the identification accuracy of tea grades. It can be applied to the rapid detection of tea quality by tea companies, tea market, tea farmers and other demanders.


Assuntos
Algoritmos , Camellia sinensis/química , Imagem Óptica/métodos , Camellia sinensis/classificação , Análise Discriminante , Fluorescência , Folhas de Planta/química , Folhas de Planta/classificação , Máquina de Vetores de Suporte , Chá/química
19.
J Sci Food Agric ; 99(14): 6455-6461, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31294826

RESUMO

BACKGROUND: The illegal undeclared addition of reconstituted milk powder to ultra-heat treated (UHT) milk to lower production costs is an example of economically motivated adulteration. This activity not only defrauds consumers but also places honest traders at a disadvantage, which could damage the reputation of milk producers and reduce the integrity of the markets. In this research, a non-targeted analytical strategy that combines proton (1 H) nuclear magnetic resonance (NMR) spectroscopy with a chemometrics data mining tool was developed for the authentication of bovine UHT milk. RESULTS: Unsupervised principal component analysis was used to distinguish UHT and tap-water-reconstituted powdered milk. Partial least squares-discriminant analysis (PLS-DA) with R2 (Y) and Q2 equal to 0.859 and 0.748, respectively, was used to differentiate UHT and reconstituted milk samples. Three compounds were selected as biomarkers to distinguish UHT and reconstituted milk and identified according to the standard NMR-spectra database. Finally, a PLS-DA model was established, according to the characteristic spectral bands, to identify UHT milk and reconstituted milk. CONCLUSION: This procedure demonstrated the feasibility of using non-targeted NMR profiling combined with chemometric analysis to combat mislabeling and fraudulent practices in milk production. © 2019 Society of Chemical Industry.


Assuntos
Biomarcadores/análise , Contaminação de Alimentos/análise , Metabolômica/métodos , Leite/química , Espectroscopia de Prótons por Ressonância Magnética/métodos , Animais , Bovinos , Análise Discriminante , Análise de Componente Principal
20.
J Sci Food Agric ; 99(14): 6474-6481, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31294829

RESUMO

BACKGROUND: Kimchi, a Korean food, is now produced and consumed in many other countries. In this study, the macro, trace, and toxic element content in varieties of kimchi from Korea and China was evaluated. A health-risk assessment, involving the calculation of estimated dietary intake values, was undertaken. To discriminate among samples with different origins, linear discriminant analysis (LDA) and principal component analysis (PCA) were applied. RESULTS: The analytical methods used for analyses were successfully validated. In the quantification of elements, no significant differences were detected in the concentrations of the elements that were analyzed. Based on the fresh weight of kimchi, among the macro elements, the concentrations of Na and K were relatively high, with values of 4181.9-9919.8 mg kg-1 and 1661.8-6623.5 mg kg-1 , respectively. Among the trace elements that were analyzed, zinc in Korean samples, and strontium in Chinese samples showed the highest concentrations, at 2.67 and 2.98 mg kg-1 , respectively. Concentration levels of the toxic trace elements were within permissible limits. The amount of daily intake and provisional daily intake of each element calculated based on kimchi intake confirmed its safety for consumption. Linear discriminant analysis and PCA successfully discriminated among the samples of Chinese and Korean origin. CONCLUSION: The provisional daily intake of the toxic elements was within provisional tolerable daily intake values. The normal intake of kimchi could not pose a threat upon consumption. © 2019 Society of Chemical Industry.


Assuntos
Alimentos Fermentados/análise , Oligoelementos/análise , Verduras/química , China , Qualidade de Produtos para o Consumidor , Análise Discriminante , Humanos , Análise de Componente Principal , República da Coreia , Medição de Risco , Oligoelementos/toxicidade
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