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  • Determination of Free Tryptophan in Beer Samples by Capillary Isotachophoretic Method
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-17
    Aneta Jastrzębska, Sylwia Kowalska, Edward Szłyk

    Abstract Tryptophan is essential amino acid and precursor for many neurotramsmiters that must be obtained from dietary proteins. However, its free form is easily absorbed and could increase the availability of this amino acid to the brain. Because of free tryptophan interaction with human health simple, eco-friendliness and low-cost method of determination are still needed. In this study, new and simple procedure for free tryptophan determination using capillary isotachophoresis is discussed. The method validation pointed good linearity, satisfactory selectivity, accuracy (recoveries varied from 98.4 to 100.1%), intra- and inter-day precision (coefficent of variation was < 5% for each standard solution and < 6% for real samples) and no matrix effect. The proposed procedure was successfully applied to analyse free tryptophan in beer samples and found contents varied from not detected to 40.74 ± 0.27 mg L−1. The obtained results were compared with chromatographic determination after derivatization with 2-chloro-1,3-dinitro-5-(trifluoromethyl)benzene and pointed better selectivity and accuracy of isotachophoretic procedure with similar precision. Due to the simplicity and flexibility, the proposed procedure is suitable for tryptophan analysis in complex matrices.

    更新日期:2020-01-17
  • Sugarcane Stalk Content Prediction in the Presence of a Solid Impurity Using an Artificial Intelligence Method Focused on Sugar Manufacturing
    Food Anal. Methods (IF 2.413) Pub Date : 2019-06-08
    Wesley Nascimento Guedes, Lucas Janoni dos Santos, Érica Regina Filletti, Fabíola Manhas Verbi Pereira

    For the first time in literature, an analytical method was developed using artificial neural networks (ANNs) combined with color information from digital images to predict the content of sugarcane stalks in the presence of a solid impurity. The data were generated using a laboratory-made simple imaging system and free-access computational routine for the conversion of the images into 10 colors. The ANN model was implemented using 10 neurons in the input layer, 8 neurons in the hidden layer and 1 neuron in the output layer related to the content of sugarcane stalks. The ANN model provided relative errors of 3% and achieved correlation coefficients of 0.98, 0.93, and 0.91 for the training, validation and test sets, respectively. A partial least squares (PLS) model showed the nonlinear nature of the data that implies the application of ANN model. The developed method has the potential to be applied in sugarcane mills as an improvement for the production of high-quality sugar.

    更新日期:2020-01-17
  • FTIR and Chemometrics as Effective Tools in Predicting the Quality of Specialty Coffees
    Food Anal. Methods (IF 2.413) Pub Date : 2019-08-13
    Verônica Belchior, Bruno Gonçalves Botelho, Susana Casal, Leandro S. Oliveira, Adriana S. Franca

    Abstract Cup tasting is the most important tool to access the quality of coffee beans. However, the use of sensory evaluation alone can present some problems, since bias from the previous knowledge of a particular sample and health conditions of the taster can influence the results. Given the well-established potential of spectroscopic methods in coffee quality evaluation, in the present study, we sought to evaluate the potential of FTIR spectroscopy for quantitative evaluation of specialty coffee quality. Samples of specialty coffee were provided by the Federação dos Cafeicultores do Cerrado Mineiro and Fazenda Barinas. They were roasted in IKAWA coffee roaster, analyzed by a group of Q-graders, and submitted to FTIR analysis. Physicochemical analyses (pH, titratable acidity, brix, total solids, and browning compounds) were also employed to show potential differences. Only pH showed significant difference between the beverages. PLS results showed consistent models for predicting the quality previously given by the cuppers, with low values of RMSEC and RMSEP (0.23 both). Also, the models showed high values of Rc (0.99) and Rv (0.97). The whole spectra were considered as important to classify the coffees by their quality, showing the complexity of the beverage.

    更新日期:2020-01-17
  • Comparison of Different Multivariate Classification Methods for the Detection of Adulterations in Grape Nectars by Using Low-Field Nuclear Magnetic Resonance
    Food Anal. Methods (IF 2.413) Pub Date : 2019-06-01
    Carolina Sheng Whei Miaw, Poliana Macedo Santos, Alessandro Rangel Carolino Sales Silva, Aline Gozzi, Nilson César Castanheira Guimarães, Maria Pilar Callao, Itziar Ruisánchez, Marcelo Martins Sena, Scheilla Vitorino Carvalho de Souza

    Grape is the most consumed nectar in Brazil and a relatively expensive beverage. Therefore, it is susceptible to fraud by substitution with other less expensive fruit juices. Adulterations of grape nectars by the addition of apple juice, cashew juice, and mixtures of both were evaluated by using low-field nuclear magnetic resonance (LF-NMR) and supervised multivariate classification methods. Two different approaches were investigated using one-class (only unadulterated samples (UN) were modeled) and multiclass (three classes were modeled: UN, adulterated with cashew (CAS), and adulterated with apple (APP)) strategies. For the one-class approach, soft independent modeling of class analogy (SIMCA), one-class partial least squares (OCPLS), and data-driven SIMCA (DD-SIMCA) models were built. For the multiclass approach, partial least squares discriminant analysis (PLS-DA) and multiclass SIMCA models were built. The results obtained demonstrated good performances by all the one-class methods with efficiency rates higher than 93%. For the multiclass approach, the classification of samples containing only one type of adulterant presented efficiencies higher than 90% and 97% using SIMCA and PLS-DA, respectively. The classification of samples containing blends of two adulterants was satisfactory for the CAS class, but not for the APP class when applying PLS-DA. Nevertheless, multiclass SIMCA did not provide satisfactory predictions for either of these two classes.

    更新日期:2020-01-17
  • Calcium, Fe, Cu, Zn, and Mg Fractionation in In Natura and Aged Beef Samples by Bioanalytical Methods
    Food Anal. Methods (IF 2.413) Pub Date : 2019-06-26
    Rodolfo Carapelli, Aline Fernandes de Oliveira, Rodrigo Giglioti, Rymer Ramiz Tullio, Renata Tieko Nassu, Marcia Cristina Sena Oliveira, Ana Rita Araujo Nogueira

    Abstract Proteins play different and essential roles in the human organism. Containing essential amino acids, proteins, and minerals, beef is considered the main source of protein in human nutrition. It is generally accepted that the protein profile is directly correlated to tenderness and beef pigmentation and is also related to its organoleptic properties. In the present work, it is demonstrated the changes in protein profile, differences of metal concentrations, and how metals bonded to proteins can vary during the ripening phase, evaluated over a 14-day beef aging period. The proposed extraction procedure indicated 85% efficiency, preserving the metal-protein structure. Seventeen protein bands were detected using SDS-PAGE, and a 43-kDa band was found to be the most intense. The arrangement of SDS-PAGE and SEC-ICP-MS results indicated the possible links between minerals and organic functional molecules, such as Ca to troponin, Cu and Zn to albumin, and Fe to myoglobin and hemoglobin.

    更新日期:2020-01-17
  • Direct Analysis of Cocoa Powder, Chocolate Powder, and Powdered Chocolate Drink for Multi-element Determination by Energy Dispersive X-ray Fluorescence Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2019-06-27
    Luciane B. Oliveira, Wagna P. C. dos Santos, Leonardo S. G. Teixeira, Maria Graças A. Korn

    The aim of this study was to evaluate the potential of applying energy dispersive X-ray fluorescence (EDXRF) spectrometry to determine Ca, K, P, Mg, Fe, Zn, Cu, Mn, and Al concentrations for direct analysis of cocoa powder, chocolate powder, and powdered chocolate drink samples. The proposed method was calibrated using samples previously analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). For comparison purposes, the samples were also analyzed by ICP OES after an acid digestion procedure, and no significant differences were observed between the concentrations determined by EDXRF when compared to those by ICP OES. The coefficients of correlation (R) from the calibration curves and the limit of quantification (mg kg−1) were Ca (0.996, 0.030), K (0.985, 68), Mg (0.974, 0.020), P (0.986, 0.50), Mn (0.998, 3.6), Fe (0.981, 2.5), Cu (0.978, 1.3), Zn (0.996, 0.80), and Al (0.983, 7.5). The precisions obtained for the elements were between 1.5 and 7.8% (n = 7), indicating that the preparation of the pellets was efficient to perform analysis by EDXRF. Potassium was the macro-mineral with higher concentrations in the samples. In relation to the micro-minerals, Fe had the greatest concentration. Significant concentrations of Al were also found. It was found that, in general, samples of chocolate powder and powdered chocolate drink may be considered good sources for the ingestion of Mg, Mn, Ca, K, P, Fe, Zn, and Cu.

    更新日期:2020-01-17
  • Development of Method Based on Dispersive Liquid-Liquid Microextraction Air-Assisted for Multi-Element Determination of Cadmium and Manganese in Sugarcane Spirit (Brazilian cachaça ) by FAAS
    Food Anal. Methods (IF 2.413) Pub Date : 2019-07-23
    Adrielle S. Fontes, Julia C. Romero, Leonardo B. Guimarães, Erik G. P. da Silva, Daniel de C. Lima, Fábio Alan C. Amorim

    In this work, a new method was developed for multi-element determination of Cd and Mn in samples of sugarcane spirit (cachaça) by FAAS using the air-assisted dispersive liquid-liquid microextraction (AA-DLLME). After univariate and multivariate optimizations (mixture design), the experimental conditions were as follows: 5.2 mL of sample at pH 8.5, 0.7 mL 10% (w/v) NaCl solution, 120 μL of trichlorethylene (extraction solvent) containing 1-(2-pyridylazo)-2-naphthol (PAN) at 0.05% (w/v) as chelating agent, six cycles of stirring the mixture with a glass syringe, and 3 min of centrifugation. In these conditions, the calibration curve obtained for Cd was Abs = 0.0158CCd + 0.0333, with R2 0.9951 and for Mn was Abs = 0.0011CMn + 0.0142 and R2 0.9911. The limits of detection, enrichment factor, and consumption index were, respectively, 0.51 μg L−1, 79 and 0.07 mL for Cd, and 1.64 μg L−1, 18, and 0.28 mL for Mn. Precision was evaluated at concentrations of 5 and 10 μg L−1, and RSD% (N = 10) was 0.97% and 6.6% for Cd and 2.8% and 4.5% for Mn, respectively. Addition and recovery tests in samples of Brazilian cachaça were performed to evaluate the accuracy, and recoveries were 87% to 120%, with concentrations found between 1.20 and 3.05 μg L−1 for Cd and between 6.98 and 14.4 μg L−1 for Mn. The developed method proved to be sensitive, efficient, simple, fast, and having low reagent consumption, and of applicability not previously reported in the literature.

    更新日期:2020-01-17
  • Sequential Determination of Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in Powdered Refreshments by FS-F AAS After a Simple Sample Treatment
    Food Anal. Methods (IF 2.413) Pub Date : 2019-07-17
    Joelem Carvalho Melo, Wellington Correia Carvalho, Elane S. Boa Morte, Rennan Geovanny O. Araujo, Daniele Cristina M. B. Santos

    In this work, a procedure is proposed for the direct analysis of powdered refreshments by fast sequential flame atomic absorption spectrometry (FS-F AAS), after a simple treatment of the sample. A full 23 factorial design was applied, and the variables chosen were as follows: acid concentration, acid type, and sonication time. Optimization provided the best conditions considering a mass of powdered refreshment of about 0.18 g diluted to a final volume of 15 mL with 0.5 mol L−1 HCl. The matrix effect was investigated, and external calibration was feasible for the determination of Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb, and Zn. The limit of quantification (LoQ) obtained was between 0.6 (Cd) and 25 mg kg−1 (Pb). The analyte addition and recovery test were applied to evaluate the accuracy, and recovery percentage values ranging from 83.9 to 109.7% were obtained, which is considered adequate for quantitative analysis. Precision was expressed as relative standard deviation (% RSD); it was less than or equal to 5.0% (n = 7) for all analytes. The procedure was applied to 21 samples of powdered refreshment commercialized in Salvador (Brazil) and Buenos Aires (Argentina). The concentration range and average of the analytes in the samples (in mg kg−1) commercialized in Brazil (BZ) and Argentina (AG) were as follows: Co (BZ < 6.4–9.94, average 8.85; AG < 6.4–10.3, average 9.92), Fe (BZ < 6.9–376, average 270; AG < 6.9–32.81, average 29.11), Mg (BZ < 8.9–363, average 140; AG 770–3139, average 1464), Mn (BZ < 3.2–4.88, average 4.24; AG < 6.9), and Zn (BZ < 1.4–1.68, average 1.68; AG < 1.4). The concentrations of Cd, Cu, Ni, and Pb were lower than the LoQ of the proposed analytical method. For refreshment samples commercialized in Buenos Aires (Argentina), high concentrations of Mg were found in their chemical composition, but Mg had been used as anti-caking agent along with the other components.

    更新日期:2020-01-17
  • Simultaneous Determination of Chromium and Iron in Powdered Milk Using High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2019-08-30
    Adilson S. Santos, Cheilane T. de Souza, Danilo J. Leao, Felipo O. Correia, Tarcísio S. Almeida, Sergio L. C. Ferreira

    Abstract This work proposes the simultaneous determination of chromium and iron in powdered milk samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) and sample digestion in microwave oven using nitric acid and hydrogen peroxide. The method was established using the primary line (357.869 nm) for chromium and the adjacent secondary line (358.120 nm) for iron while employing aluminum as the chemical modifier. The absorbance signals were measured by peak area using three pixels for both elements. Chromium and iron can be determined in powdered milk samples by the external calibration technique with limits of quantification of 28 ng g−1 for chromium and 19 μg g−1 for iron. The precision was evaluated by using a milk sample with chromium and iron concentrations of 0.76 μg g−1 and 151.3 μg g−1, respectively. The results expressed as relative standard deviation (n = 10) were 2.6% for iron and 3.9% for chromium. The method accuracy was confirmed by the analysis of a milk sample by a comparison of results obtained by the proposed method and those found by employing inductively coupled plasma mass spectrometry (ICP-MS). Five samples were analyzed, and the analyte concentrations found varied from 408 to 805 ng g−1 for chromium. Among the five samples, three had an iron concentration lower than 19 μg g−1 and in the other two samples, the iron concentrations varied from 151 to 199 μg g−1.

    更新日期:2020-01-17
  • Lab-On-A-Chip Extraction of Phenolic Compounds from Extra Virgin Olive Oil
    Food Anal. Methods (IF 2.413) Pub Date : 2019-04-08
    Kenia Chávez Ramos, Luis Fernando Olguín Contreras, María del Pilar Cañizares Macías

    Abstract A novel liquid–liquid extraction method of phenolic compounds from extra virgin olive using microfluidic technique was developed. The microdevice of polydimethylsiloxane (PDMS) was designed in two parts; the first one to carry out the extraction of polyphenols using only an alkaline aqueous solution and the second one to develop the reaction product using Folin–Ciocalteu reagent, which was measured at 730 nm at the microchip exit. Hydrodynamic and chemical parameters, such as flowrates of extraction and reaction, length of microchannels, extraction pH, extraction buffer concentration, and concentration of Folin–Ciocalteu reagent, were evaluated. Although all parameters were important, the results showed that pH, carbonate buffer concentration, and the Folin–Ciocalteu reagent concentration were significant factors and that the increase in the length of the extraction coil enhanced the extraction percentage. The results showed higher extraction efficiency by the microfluidic method, between 46 and 67%, than for the other two batch extraction methods.

    更新日期:2020-01-17
  • A Green Analytical Method for the Multielemental Determination of Halogens and Sulfur in Pet Food
    Food Anal. Methods (IF 2.413) Pub Date : 2019-06-08
    Julia Eisenhardt de Mello, Diogo La Rosa Novo, Gilberto Silva Coelho Junior, Priscila Tessmer Scaglioni, Marcia Foster Mesko

    A suitable and green analytical method using microwave-induced combustion and ion chromatography with conductivity detection (IC-CD) and mass spectrometry detection (IC-MS) was proposed for the halogens and sulfur determination in pet food using a single analysis. Samples (up to 500 mg) were efficiently digested in a closed system under oxygen pressure (20 bar). Ultrapure water and 50 mmol L−1 or 100 mmol L−1 (NH4)2CO3 were evaluated as absorbing solutions. Trueness was evaluated by recovery tests using standard solution and certified reference materials. In both tests, mean recoveries ranging from 91 to 108% for all analytes were obtained using 50 mmol L−1 (NH4)2CO3 as absorbing solution. AOAC International recommended official methods for Cl and F determination in animal feed were also performed. Results for Cl using proposed method were in agreement with those obtained using AOAC official method, while the results for F were not compared between them because the concentration in the samples using AOAC official method was not detected. Precision was evaluated in terms of repeatability and the relative standard deviations (RSDs) using the proposed method were always lower than 8%. The proposed method presents several advantages when compared with AOAC International official methods such as the multielemental determination capability, lower waste generation, lower limits of detection, lower RSDs, and higher sample throughput. Sixteen samples destined to cats or dogs from different manufacturers were analyzed and the results showed a wide variation. These results indicate that an efficient quality control should be performed, and the proposed method is an excellent alternative as a new analytical tool for routine analysis of pet food.

    更新日期:2020-01-17
  • Chemometric Approach Using ComDim and PLS-DA for Discrimination and Classification of Commercial Yerba Mate ( Ilex paraguariensis St. Hil.)
    Food Anal. Methods (IF 2.413) Pub Date : 2019-05-22
    Tatiane Francielli Vieira, Gustavo Yasuo Figueiredo Makimori, Maria Brígida dos Santos Scholz, Acácio Antonio Ferreira Zielinski, Evandro Bona

    Abstract Yerba mate samples from three different states of Brazil were evaluated in order to discriminate them regarding the presence of sugar and geographic origin. High-performance liquid chromatography (HPLC), phytochemical compounds, in vitro antioxidant activity, visible and near-infrared (NIR) spectroscopy, colorimetry, and electronic nose were used in tandem with chemometric methods. The multiblock exploratory analysis (ComDim) was able to discriminate the samples containing sugar; however, it was not possible to discriminate them by geographical origin. Furthermore, ComDim results showed the NIR spectra presented the best discriminating capacity. Partial least square discriminant analysis (PLS-DA) models constructed using NIR spectra classified the samples assertively according to the presence of sugar (100% of sensitivity and specificity for the prediction set), and reasonable models were also obtained for the geographic classification (80% of sensitivity and 93% of specificity for the prediction set). The multiblock approach allowed an overall evaluation of the data collected through different analytical methods. In addition, among the methods applied, NIR spectroscopy was faster and cheaper and allowed for better sample discrimination.

    更新日期:2020-01-17
  • Assessment of Brazilian Monovarietal Olive Oil in Two Different Package Systems by Using Data Fusion and Chemometrics
    Food Anal. Methods (IF 2.413) Pub Date : 2019-05-22
    Thays R. Gonçalves, Larissa N. Rosa, Alex S. Torquato, Luiz F. O. da Silva, Paulo H. Março, Sandra T. Marques Gomes, Makoto Matsushita, Patrícia Valderrama

    Abstract The olive oil consumption has spread worldwide, increasing the necessity of quality assessment, and so forth, the search for new, alternative, and rapid data interpretation has started, boosting the interest and the use of data fusion that seek for an integration of results from different techniques or methodologies for the same data set. To better understand the storage effects on the Brazilian monovarietal extra virgin olive oil, data fusion was applied in the classical and alternative analysis, highlighting the similarities and differences between the techniques, assisting in the result interpretation. This perspective and strategy bring development to food chemistry analysis.

    更新日期:2020-01-17
  • Rapid and Sensitive Detection of Isoproturon Via an Electrochemical Sensor Based on Highly Water-Dispersed Carbon Hybrid Material
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-16
    Ying Zhou, Fuliang Cheng, Yanping Hong, Jianping Huang, Xue Zhang, Xiaoning Liao

    Isoproturon (ISO), an herbicide belonging to the phenyl urea family, is extensively used in modern agriculture to guarantee a bumper harvest. However, it has been evidenced that the ISO has heavy toxicity to the liver system and appears to be a tumor promoter. It is therefore urgent to develop sensitive and selective methods to screen its presence in food resources to meet the ever-increasing pollution restrictions. In this work, an electrochemical sensor based on graphene oxide–modified multi-walled carbon nanotubes hybrid material was firstly developed for the rapid and sensitive detection of ISO via square wave voltammetry (SWV). Under optimized experimental conditions, the sensor exhibits a relatively wide linear range from 0.30 to 15.0 μmol L−1, a low limit of detection (LOD) of 0.10 μmol L−1, as well as good repeatability, high reproducibility, excellent selectivity, and long-term stability. The sensor has also been successfully employed in various real samples such as rice field water, tomato, and lettuce analyses. The obtained recoveries are in the range of 97.33–105.0% with low relative standard deviation (less than 2.5%), which is very close to the results of the high-performance liquid chromatography (HPLC), showing the proposed electrochemical sensor has great potential in practical applications.

    更新日期:2020-01-16
  • Analysis of Organochlorine Pesticides in Tomatoes Using a Modified QuEChERS Method Based on N-Doped Graphitized Carbon Coupled with GC-MS/MS
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-06
    Xuemin Ye, Hua Shao, Ting Zhou, Jiahui Xu, Xiaoji Cao, Weimin Mo

    A modified QuEChERS protocol with a nitrogen-doped graphitized carbon derived from dicyandiamide sludge as a cleanup sorbent has been developed to determine 20 organochlorine pesticides in tomatoes using gas chromatography coupled to a triple-quadrupole mass analyzer. Compared with traditional QuEChERS adsorbents, N-doped graphitized carbon exhibited higher recoveries toward the target pesticides in tomatoes. And the modified protocol exhibited the advantages of environmental-friendly and low-cost. The use of dicyandiamide sludge to produce NGB as an adsorbent for QuEChERS opened up a new field for the comprehensive utilization of dicyandiamide waste. Under the optimum conditions, the modified method provided excellent linearity with correlation coefficient higher than 0.9980 and low limits of detection ranging from 0.001 to 0.1 μg/kg. The mean recoveries of the majority of pesticides in tomatoes ranged from 71.2 to 95.3% with relative standard deviation lower than 20%. Thus, the proposed protocol could be considered a good alternative for traditional QuEChERS method for pesticide analysis in agricultural vegetables.

    更新日期:2020-01-06
  • Colorimetric Immunoassay for the Detection of Staphylococcus aureus by Using Magnetic Carbon Dots and Sliver Nanoclusters as o -Phenylenediamine-Oxidase Mimetics
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-06
    Shuo Yao, Chao Zhao, Yushen Liu, Heran Nie, Gaolei Xi, Xiaolian Cao, Zhuolin Li, Bo Pang, Juan Li, Juan Wang

    Abstract Staphylococcus aureus (S. aureus) is an important foodborne pathogen that causes food poisoning and severe infections. Herein, we design a novel and sensitive colorimetric immunoassay for the detection of S. aureus based on the formation of a magnetic bead-based sandwich complex and signal amplification via an enzyme mimic. Magnetic nanoparticles decorated with carbon dots offer rapid enrichment and separation of target bacteria in complex matrices. Sliver nanoclusters are used as an artificial enzyme that can oxidize o-phenylenediamine to form a yellow product with a maximum absorption peak at 421 nm. This method can visually detect S. aureus ranging from 10 to 106 cfu mL−1. Its limit of detection reaches down to 4.9 cfu mL−1. By analyzing food samples, the recovery is from 85.6 to 103.7%.

    更新日期:2020-01-06
  • Highly Sensitive Detection of Thiabendazole Residues in Food Samples Based on Multiwall Carbon Nanotubes Decorated Two-Dimensional Layered Molybdenum Disulfide
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-02
    Fuliang Cheng, Xiaoning Liao, Zhiwen Huang, Liting Xu, Ying Zhou, Xue Zhang

    Abstract Thiabendazole (TBZ), a widely used agricultural antifungal, has been evidenced to pose serious threat to human health. However, highly sensitive detection of it in food samples is difficult owing to the complexity of food matrix. Herein, an electrochemical sensor, based on multiwall carbon nanotubes (MWCNTs) decorated two-dimensional layered molybdenum disulfide (MoS2), was firstly developed for rapid detection of TBZ using square wave voltammetry method. It is demonstrated that the modification of MoS2 with MWCNTs enhances the catalytic performance to TBZ oxidation. Under optimized conditions, the electrochemical sensor shows admirable linearity range, high selectivity and low detection limit. In pear, water spinach and tap water sample analyses, satisfactory recoveries from 92.83 to 101.92% with coefficients of variation less than 5% were obtained, showing high consistence with the HPLC results. This work puts forward a rapid and reliable method for the highly sensitive screening of the residues of TBZ in food resource.

    更新日期:2020-01-04
  • Chemical Characterization of Wine Vinegars Belonging to the Vinagre de Montilla-Moriles Protected Designation of Origin, Using Near-Infrared Spectroscopy
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-02
    María-Teresa Sánchez, Rocío Márquez, Irina Torres, María-José De la Haba, Dolores Pérez-Marín, María-Isabel López

    Spanish wine vinegars belonging to Vinagre de Montilla-Moriles protected designation of origin (PDO) must satisfy some chemical characteristics. These characteristics are mainly responsible of their high and exceptional quality. This study assessed the potential of near-infrared spectroscopy (NIRS) as a non-destructive technology for characterizing wine vinegars belonging to this PDO. A total of 107 vinegars were used to predict major chemical quality parameters (volumic mass, reducing sugars, total acidity and pH) using a scanning monochromator (spectral range 400–2500 nm) with the spinning module, working in transflectance mode. The models developed showed values for the coefficient of regression for cross-validation between 0.95 and 0.99 for volumic mass, reducing sugars and total acidity. Therefore, the results confirm that NIRS technology combined with linear regression strategies such as the modified partial least squares (MPLS) regression can indeed respond to the needs of the vinegar cellars and help them to measure the commonest chemical quality parameters of wine vinegars belonging to Vinagre de Montilla-Moriles (PDO), especially in the case of vinegars with different sugar contents (dry, semi-sweet, sweet and balsamic). However, the number of vinegars as well as their variability should be increased in order to obtain more robust models.

    更新日期:2020-01-02
  • Modified QuEChERS Method for Multiresidue Determination of Pesticides in Pecan Nuts by Liquid Chromatography Tandem Mass Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2020-01-02
    Paulo E. P. Barci, Larissa da S. Alves, Állisson A. S. Avellar, Lucila R. Cendon, Pimpernelli J. dos Santos, Fabiane M. Stringhini, Osmar D. Prestes, Renato Zanella

    Pecan nut is a crop of growing economic importance with a worldwide production around 124,000 tons during the 2017/2018 harvest. Thus, a simple and fast method for the determination of pesticide residues in this crop based on a QuEChERS sample preparation procedure and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis was developed and validated. Despite the complexity of this matrix, with high fat content, the method was suitable to analyze 47 compounds in pecan nuts employing original QuEChERS salts and clean-up with the sorbents PSA and C18. This combination showed best results for lipid removal and compound recoveries when compared with the sorbents Z-Sep+, EMR-Lipid®, chitosan, diatomaceous earth, silica, and Florisil®. Validation was performed according to SANTE guideline using blank samples spiked at 5, 10, 20, 50, and 100 μg kg−1, and the proposed method presented satisfactory results with recoveries for most of the pesticides in the range of 70–120% with RSD < 20% and practical limits of quantification from 5 to 10 μg kg−1 for all compounds. The method was successfully applied in real samples and demonstrated to be simple, robust, and effective to be applied in routine analysis.

    更新日期:2020-01-02
  • A Monoclonal Antibody-Based Immunoassay for Mepanipyrim Residue Sensitive Analysis in Grape Juice and Wine
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-21
    Josep V. Mercader, Consuelo Agulló, Antonio Abad-Somovilla, Antonio Abad-Fuentes

    Abstract Mepanipyrim is a new-generation anilinopyrimidine pesticide that is employed nowadays to fight fungal diseases in a variety of crops. Rapid and user-friendly analytical methods that can complement the instrumental techniques are demanded. To analyse residues of this toxic compound in foodstuffs, monoclonal antibodies were generated for the first time, and an enzyme-linked immunosorbent assay was developed. In the present study, a series of haptens mimicking the mepanipyrim molecule, and with a linker at alternative sites of the molecular framework, were designed and prepared by total synthesis in order to study the influence of the linker tethering site over the binding properties of the generated antibodies. This strategy afforded high-affinity and specific monoclonal antibodies to mepanipyrim. Interestingly, the highest sensitivity was reached with antibodies that had been raised using haptens with the spacer arm at the most characteristic moiety of the analyte, the 1-propynyl group. Moreover, the influence of the triple bond was investigated both in immunizing bioconjugates and in assay antigens. Finally, a competitive enzyme-linked immunosorbent assay was optimized and characterized, showing an IC50 value of 0.3 μg/L for mepanipyrim. Good accuracy and precision values were found when grape juice and wine samples were analysed.

    更新日期:2019-12-21
  • Automatic Detection and Grading of Multiple Fruits by Machine Learning
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-20
    Anuja Bhargava, Atul Bansal

    Classification of various types of fruits and identification of the grading of fruit is a burdensome challenge due to the mass production of fruit products. In order to distinguish and evaluate the quality of fruits more precisely, this paper presents a system that discriminates among four types of fruits and analyzes the rank of the fruit-based on its quality. Firstly, the algorithm extracts the red, green, and blue values of the images and then the background of images was detached by the split-and-merge algorithm. Next, the multiple features (30 features) namely color, statistical, textural, and geometrical features are extracted. To differentiate between the fruit type, only geometrical features (12 features), other features are used in the quality evaluation of fruit. Furthermore, four different classifiers k-nearest neighbor (k-NN), support vector machine (SVM), sparse representative classifier (SRC), and artificial neural network (ANN) are used to classify the quality. The classifier has been contemplated with four different databases of fruits: one having 4359 color images of apples; out of which 2342, are with various defects, second having 918 color images of avocado out of which 491 are of with various defects, third having 3805 color images of banana out of which 2224 are with various defects, and fourth having 3050 color images of oranges out of which 1590 are with various defects. The system performance has been validated using the k-fold cross-validation technique by considering different values of k. The maximum accuracy achieved for fruit detection is 80.00% (k-NN), 85.51% (SRC), 91.03% (ANN), and 98.48% (SVM) for k = 10.The classification among Rank1, Rank2, and defected maximum accuracy is 77.24% (k-NN), 82.75% (SRC), 88.27% (ANN), and 95.72% (SVM) achieved by the system. SVM has seen to be more effective in quality evaluation and results obtained are encouraging and comparable with the state of art techniques.

    更新日期:2019-12-20
  • Potential Use of Stable Isotope and Multi-element Analyses for Regional Geographical Traceability of Bone Raw Materials for Gelatin Production
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-20
    Di Jiang, Lin Du, Yanchuan Guo, Jifei Ma, Xiaoyun Li, Ling Han, Yisheng Xu, Yuan Qian

    Geographical authentication of bone raw materials to determine whether they come from non-epidemic areas and natural pastoral areas is critical to quality control, food safety, and brand protection of gelatin. The establishment of an effective traceability method independent of paper records has become increasingly urgent. Therefore, the potential of the stable isotope and multi-element analyses for distinguishing the geographical origin of bone samples from various provinces in China was investigated. The C, N, and H isotopic compositions and the contents of 18 elements in bovine bone samples were studied by isotope ratio mass spectrometry (IRMS), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma optical emission spectrometer (ICP-OES), combined with one-way analysis of variance (ANOVA), principal component analysis (PCA), and linear discriminant analysis (LDA). It was shown that the values of δ13C, δ15N, and δ2H as well as the contents of 16 of the 18 elements in bone samples were significantly different among the regions. A total correct classification rate of 95.7% and 100% was obtained by the stable isotope traceability method and multi-element traceability method, while the cross-validation rate was 91.5% and 97.9%, respectively. It was concluded that both stable isotopes and mineral elements can be good indicators for tracing the geographical origin of bone raw materials. Due to the minor difference in the discrimination accuracy of these two methods, it is preferable to establish traceability models using stable isotope method in practical work considering economic feasibility and efficiency.

    更新日期:2019-12-20
  • Optimization Strategy for Extraction of Active Polyphenols from Leaves of Eugenia uniflora Linn
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-19
    Isabelle Cristinne Ferraz Bezerra, Rhayanne Thaís de Moraes Ramos, Magda Rhayanny Assunção Ferreira, Luiz Alberto Lira Soares

    This study aimed to evaluate the performance of polyphenolic extraction from leaves of Eugenia uniflora by using solvent systems and different extractive conditions. The solvent systems containing water, methanol, ethanol, and acetone (binary, ternary, or quaternary mixtures) were used to produce extracts by turbo-extraction in accordance with a simplex centroid. The extraction performances were determined by dry residue, total tannin, and flavonoid contents, which were used to calculate the extractive efficiency, and content of markers gallic acid, ellagic acid, and myricitrin. Fingerprints were also obtained by high-performance liquid chromatography and high-performance thin layer chromatography. The mixture of H2O to MeOH to EtOH to acetone (46:13:18:23) demonstrate a larger extractive efficiency and was used as solvent to evaluate the influences of drug amount and extraction method. A 32-design with response surface methodology allowed to optimize the extraction conditions, showing better extraction at 5% (w/v) of the herbal drug and by turbo-extraction, standardized condition for extracts from Eugenia uniflora leaves.

    更新日期:2019-12-20
  • Assessment of Japanese Awamori Spirits Using UV–VIS Spectroscopy
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-18
    Xinyue Li, Mizuki Tsuta, Fukuyo Tanaka, Masatoshi Tsukahara, Keiko Tsukahara

    Awamori is a traditional distilled alcohol beverage unique to Okinawa, Japan. This study evaluated the potential of ultraviolet–visible (UV–VIS) spectroscopy in the assessment and differentiation of different Awamori samples. Thirty-one Awamori samples that could be classified differently based on attributes such as their distillation methods (atmospheric distillation and vacuum distillation), aging periods (0–18 years), batches (years 2017 and 2014), and distilleries of origin were investigated by UV–VIS spectroscopy and chromatographic analysis. Principal component analysis (PCA) of UV–VIS spectra showed that Awamori of atmospheric distillation and vacuum distillation could be clearly distinguished based on low and high PC1 scores, respectively; both young Awamori (aged less than 3 years) and Awamori from the 2017 batch exhibited low PC1 scores and high PC2 scores. Wavelength ranges with high loading values that correspond to the volatile compounds which have high correlations with PC scores, such as furfural, phenethyl alcohol, vanillin, and benzaldehyde, were observed in the UV–VIS spectral profiles. These volatile compounds with unique aroma characteristics can characterize Awamori attributes. Therefore, UV–VIS spectroscopy with the aid of chemometric analysis was demonstrated as a high potential technique for the rapid and low-cost evaluation and characterization of Awamori samples.

    更新日期:2019-12-19
  • HPTLC-Densitometry Determination of Riboflavin Fortified in Rice Noodle: Confirmed by SERS-Fingerprint
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-17
    Yisheng Chen, Caihong Huang, Bernhard Hellmann, Xueming Xu

    This paper presented a facile and efficient HPTLC method for quantifying riboflavin fortification in rice noodle that was a staple food popular in Asian countries. After high-throughput separation on silica gel plates with methanol/ethyl acetate/triethylamine (3/7/1, v/v/v) as the mobile phase, the obtained results were analyzed by fluorescence densitometry (mercury lamp, 360 nm excitation wavelength in combination with K400 optical filter). Quantification in this way offered high linearity (R2 = 0.9998 within 10–80 ng/band) and precision (RSD < 5.2%), adequate detectability (LOD = 0.1 and LOQ = 0.3 mg/kg), and accuracy (spike-recovery rates within 91.4–105.1%, RSD < 8.1%). While yielding good comparison to conventional HPLC detection, the developed quantification featured superiorly high efficiency. Apart from that, the separation results were further evaluated by SERS. By jointly using sodium borohydride reduced AgNPs as the active substrate and 633 nm incident laser wavelength, the developed HPTLC-SERS detection gave clear and sensitive fingerprint-like proof which enabled unambiguous confirmation by visual inspection. Balancing well between simplicity, detectability, efficiency, and reliability, the proposed method exemplarily shown the promising applicability of HPTLC as a versatile tool in food analysis.

    更新日期:2019-12-18
  • Predicting Mechanical Properties of Golden Delicious Apple Using Ultrasound Technique and Artificial Neural Network
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-16
    Haydar Vasighi-Shojae, Mohammad Gholami-Parashkouhi, Davood Mohammadzamani, Ahmad Soheili

    Non-destructive quality assessment of Golden Delicious apple is the aim of this study. The ultrasound non-destructive testing (NDT) system in the range of 40 kHz–20 MHz ultrasonic wave was applied in combination with artificial neural network (ANN) as a powerful modeling tool. The studied quality factors were the mechanical properties including firmness, elastic modulus, and stiffness of apples. To develop the ANN models, the feed-forward neural network with the backpropagation algorithm was developed. For firmness, the best ANN model with 7-11-1 topology (7 features as inputs, 11 neurons in the hidden layer, and one output) had the highest R2Prediction and the lowest MAEPrediction and SEPrediction which were equal to 0.999, 0.0836 N, and 0.1119 N, respectively. For elastic modulus, the 7-17-1 structure of ANN was the best with corresponding R2Prediction equal to 0.999, MAEPrediction equal to 0.0087 MPa, and SEPrediction equal to 0.0117 MPa. The model with structure of 7-13-1 and R2Prediction of 0.999, MAEprediction of 0.027 N/mm, and SEPrediction of 0.0371 N/mm was also selected for predicting the stiffness of apple. The results proved the ability of this method to non-destructively predict mechanical properties of Golden Delicious apple.

    更新日期:2019-12-17
  • Potential of Recent Ambient Ionization Techniques for Future Food Contaminant Analysis Using (Trans)Portable Mass Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-16
    Marco H. Blokland, Arjen Gerssen, Paul W. Zoontjes, Janusz Pawliszyn, Michel W.F. Nielen

    In food analysis, a trend towards on-site testing of quality and safety parameters is emerging. So far, on-site testing has been mainly explored by miniaturized optical spectroscopy and ligand-binding assay approaches such as lateral flow immunoassays and biosensors. However, for the analysis of multiple parameters at regulatory levels, mass spectrometry (MS) is the method of choice in food testing laboratories. Thanks to recent developments in ambient ionization and upcoming miniaturization of mass analyzers, (trans)portable mass spectrometry may be added to the toolkit for on-site testing and eventually compete with multiplex immunoassays in mixture analysis. In this study, we preliminary evaluated a selection of recent ambient ionization techniques for their potential in simplified testing of selected food contaminants such as pesticides, veterinary drugs, and natural toxins, aiming for a minimum in sample preparation while maintaining acceptable sensitivity and robustness. Matrix-assisted inlet ionization (MAI), handheld desorption atmospheric pressure chemical ionization (DAPCI), transmission-mode direct analysis in real time (TM-DART), and coated blade spray (CBS) were coupled to both benchtop Orbitrap and compact quadrupole single-stage mass analyzers, while CBS was also briefly studied on a benchtop triple-quadrupole MS. From the results, it can be concluded that for solid and liquid sample transmission configurations provide the highest sensitivity while upon addition of a stationary phase, such as in CBS, even low μg/L levels in urine samples can be achieved provided the additional selectivity of tandem mass spectrometry is exploited.

    更新日期:2019-12-17
  • A Graphene Oxide–Based Composite for Solid-Phase Extraction of Carbamate Pesticides from Vegetables
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-13
    Tian Gao, Juntao Wang, Qiuhua Wu, Chun Wang, Zhi Wang

    In this work, a graphene oxide-based composite (DABP-GO) was prepared by aminating graphene oxide (GO) with the diazonium salt of 4,4′-diaminobiphenyl (DABP). The DABP-GO composite was characterized by scanning electron microscopy, infrared spectroscopy, and nitrogen adsorption-desorption. The DABP-GO showed to be an effective solid-phase extraction (SPE) adsorbent for carbamate pesticides. A SPE method with the DABP-GO as the adsorbent combined with high-performance liquid chromatography with ultraviolet detection was established to determine trace carbamate residues in vegetable samples (benincasahispida and pakchoi). Under the optimal conditions, the linear range was from 1.0 to 40.0 ng g−1. The limits of detection and limits of quantitation of the six carbamates (metolcarb, arprocarb, carbaryl, isoprocarb, fenobcarb, and diethofencarb) were 0.3–0.5 ng g−1 and 0.9–1.5 ng g−1 for benincasahispida sample and 0.5–1.0 ng g−1 and 1.5–3.0 ng g−1 for pakchoi sample, respectively. The relative standard deviations (RSDs) for the intra-day precision at the analyte concentration of 40 ng g−1 are from 2.3 to 8.2% (n = 5) and the inter-day RSDs (n = 5) are from 4.5 to 9.2%.

    更新日期:2019-12-13
  • Identification of Fresh-Chilled and Frozen-Thawed Chicken Meat and Estimation of their Shelf Life Using an E-Nose Machine Coupled Fuzzy KNN
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-13
    Esmaeil Mirzaee-Ghaleh, Amin Taheri-Garavand, Fardin Ayari, Jesús Lozano

    In this study, the capability of an electronic nose machine to identify chilled and frozen-thawed chicken meat was investigated. According to the importance of fresh chicken meat consumption in people’s daily diet, recognition of fresh chicken meat from frozen-thawed one is an essential issue. In the mentioned system, eight sensors (MOS type) were applied. The outputs of sensors were preprocessed, then features were extracted, and fuzzy K-nearest neighbors (F-KNN) algorithm was applied for classification. Chicken meats were classified in two classes (fresh and frozen-thawed). Also, each group of fresh and frozen-thawed chicken meat was classified in five classes according to their shelf life (elapsed day after slaughtering/thawing). The obtained results showed that the average amount of accuracy for fresh-chilled chicken meat classification and frozen-thawed one were 95.2 and 94.67%, respectively. Finally, the accuracy of fresh chicken meat with 95.83% demonstrated the high accuracy of it compare with frozen-thawed one. According to the results, high performance of F-KNN algorithm demonstrated that e-nose system can be applied as a rapid, accurate, and nondestructive method for online and automated identification of fresh and frozen-thawed chicken meat.

    更新日期:2019-12-13
  • Evaluation of DNA Extraction Methods for Culture-Independent Real-Time PCR-Based Detection of Listeria monocytogenes in Cheese
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-12
    Minarovičová Jana, Véghová Adriana, Kaclíková Eva

    Listeria monocytogenes, the causative agent of listeriosis, is a foodborne pathogen with significant public health and economic impacts. The control of pathogen presence in food requires rapid and sensitive methods. Real-time PCR is considered to be a fast and accurate tool for the detection of foodborne pathogens. A crucial step for the success of a culture-independent PCR-based detection is the template DNA extraction. Two open-formula extraction procedures and five kits were used to extract DNA prior to detection of L. monocytogenes in cheese. The extraction procedures were evaluated in quantitative PCR analyses of the total extracted bacterial DNA from cheese samples artificially contaminated with L. monocytogenes. The results of the study suggested that all seven extraction procedures can be used to obtain intact and amplifiable bacterial DNA, although with different L. monocytogenes detection limits in four types of cheese. PowerFood Microbial DNA Isolation Kit and DNeasy Mericon Food Kit performed the best with detection limits of 2.1 × 102 to 4.7 × 102 CFU/g in all analysed cheese samples. No differences in PCR detection limits of low numbers were found when different L. monocytogenes serotypes (1/2a, 1/2b, 1/2c and 4b) were used, despite the relatively lower DNA extraction efficiency observed in L. monocytogenes serotype 1/2c strain. Six out of seven evaluated methods demonstrated quantitative response with linear calibration lines and quantification limits of 4.6 × 102 to 9.3 × 103 CFU/g. The results demonstrated that culture-independent sample preparation and total DNA extraction, followed by target-specific DNA amplification have a potential to direct determination of low L. monocytogenes numbers in cheese within hours.

    更新日期:2019-12-13
  • Method Development and Validation for Determination of Indoxacarb Using LC-ESI-MS/MS and Its Dissipation Kinetics in Pigeonpea
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-11
    Harischandra R Naik, M. S Pallavi, Rahul Chawan, M Bheemanna, Anand Naik, M Paramasivam

    A simple, sensitive and reproducible analytical method for quantitative determination of indoxacarb residues in pigeonpea green pod, pigeonpea dry grain and soil was developed and validated using LC-MS/MS. The developed methodology was linear having correlation coefficients (R2) value of 0.999. The LOD and LOQ were 0.0015 and 0.005 μg g−1, respectively. QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique involved for extraction of indoxacarb residues with 1% ethyl acetate in acetonitrile provided acceptable recoveries in the range of 83.80–99.01% at 0.005, 0.025 and 0.050 μg g−1 spiking level with precision RSD of less than 1.20 %. Initial deposit on green pods following two application (15 days interval between application) of indoxacarb 14.5% SC at 60 and 120 g a.i.ha−1 was 0.583 and 1.342 μg g−1 and dissipated to 0.005 and 0.006 μg g−1 on 7 and 10 days after application, respectively. Half-life and safe waiting period (SWP) were ranged from 1.13 to 1.23 days and 3.23 to 5.03 days for the dose 60 and 120 g a.i.ha−1 in pigeonpea green pods, respectively. Hazard index (HI) value was more than 1 in green pods drawn on 5th and 7th day after application in recommended (60 g a.i.ha−1) and double the recommended dose (120 g a.i.ha−1), respectively.

    更新日期:2019-12-11
  • Development and Evaluation of a Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid Detection of Pistachio ( Pistacia vera ) in Food Samples
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-11
    Ruifeng Mao, Kaiwen Xie, Menghuan Zhao, Mengqiu Li, Lu Lu, Yu Liu, Qian Wu, Yingying Chen, Tong Zhang, Enjie Diao

    Pistachio consumption has increased significantly, mostly due to their potential health effects and their good organoleptic properties. However, pistachio is also an important food allergen and therefore, it is necessary to develop an appropriate method to detect this nut in foodstuffs. In this work, a loop-mediated isothermal amplification (LAMP) assay targeting Pis V 1 allergen coding gene was developed. The developed LAMP assay performed high specificity for pistachio and had no cross-reactions with cashew, mango, walnut, almonds, macadamia nut, hazelnut, peanut, and soybean. The assay can detect at least 10 pg of purified pistachio genomic DNA and 10 mg kg−1 of pistachio nuts in binary mixtures. The autoclave treatment influenced the amplificability of pistachio; however, this impact was not found after boiling treatment. Practical applicability of the developed LAMP assay has been analyzed by testing different commercial foods and this method may be useful for rapid detection of pistachio in foodstuffs.

    更新日期:2019-12-11
  • Effects of Solid-Liquid Ratio, Time, and Temperature on Water Extraction of Anthocyanin from Campbell Early Grape
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-10
    Dayeon Ryu, Hyun-Mee Park, Eunmi Koh

    This study was conducted to optimize anthocyanin extraction conditions from Campbell Early grape using acidified water. A response surface methodology with Box-Behnken design consisting of 17 experiments was employed to investigate the effects of three variables. The grape was extracted at three different solid-liquid ratios (1/30–1/50 g/mL), extraction times (10–60 min), and extraction temperature (30–80 °C). Under optimum conditions (1/50 g/mL, 10 min, and 80 °C), experimental values were 197.52 mg/100 g for total anthocyanins, 1363.12 mg/100 g for total phenols, and 315.79 mg/100 g for 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity in the dry weight basis. The difference between experimental and predicted values was less than 5.1%, indicating that the model fits well. Eight anthocyanins were identified in the extract of Campbell Early grape using an ultra-performance liquid chromatograph (UPLC) with a tandem mass spectrometry. Three major anthocyanins were cyanidin-3-(coumaroyl)-5-diglucoside (44.1% of the total), delphinidin-3-(coumaroyl)-5-diglucoside (20.7% of the total), and peonidin-3-(coumaroyl)-5-diglucoside (12.4% of the total).

    更新日期:2019-12-11
  • Rapid Detection of Food-Borne Escherichia coli O157:H7 with Visual Inspection by Crossing Priming Amplification (CPA)
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-09
    Zhenbo Xu, Yuting Luo, Thanapop Soteyome, Chii-Wann Lin, Xingyong Xu, Yuzhu Mao, Jianyu Su, Junyan Liu

    Escherichia coli O157:H7 is an important food-borne pathogen and has ability to contaminate food, such as water, meat products, and milk. Moreover, E. coli O157:H7 is the main toxin-producing serotype which can produce Shiga toxin type 1 and type 2 and cause intestinal disease. The strong pathogenicity and lethality of Escherichia coli O157:H7 pose a serious threat to human. This study aims to develop a rapid and visual detection assay of E. coli for rfbE, stx1, and stx2 genes by crossing priming amplification (CPA). The limit of detection of CPA assay for rfbE, stx1, and stx2 genes was 3.20 fg/μl, 320 fg/μl, and 320 fg/μl in genomic DNA, while that of in artificially contaminated food samples was 103 cfu/ml, 105 cfu/ml, and 105 cfu/ml, respectively, which was distinctly higher than that of PCR methods. And the specificity of CPA assay was tested by 22 different bacterial strains and except for E. coli O157:H7 ATCC43895 and other E. coli O157:H7 isolated from eggs, milk, and beef, all strains showed negative results. The visible detection assay was conducted by the addition of calcein in the reaction solutions. The CPA assay showed a successful detection of E. coli O157:H7 (Shiga toxin–producing and non-Shiga toxin–producing) within 60 min under 63 °C with high sensitivity and specificity. These results indicated that the CPA assays with calcein can provide an advanced method to achieve the rapid and visual detection of food-borne E. coli O157:H7.

    更新日期:2019-12-11
  • Colorimetric Sensing of Putrescine and Cadaverine Using Ninhydrin as a Food Spoilage Detection Reagent
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-07
    S. Sudalaimani, A. Esokkiya, Shekhar Hansda, C. Suresh, P. Tamilarasan, K. Giribabu

    A simple colorimetric method is demonstrated for the quantitative detection of aliphatic biogenic amines, putrescine and cadaverine using ninhydrin. The protocol is based on the formation of a complex equivalent to that of Ruhemann’s purple with a molar ratio of 1:2.5 between putrescine and ninhydrin which exhibited an absorption peak at 564 nm. The observation was theoretically verified using density functional theory (DFT). It is observed that the colorimetric detection protocol was rapid at 80 °C. Putrescine and cadaverine exhibited a similar colour on reaction with ninhydrin at pH 8.0, since the structure of both the biogenic amines is quite similar except for an addition of a methylene group, a distinguishable colour change was not observed. The analytical response was studied at 564 nm and 570 nm for putrescine and cadaverine respectively. Putrescine exhibited a linear range of 25–150 ppm, while cadaverine showed a non-linear range of 35–150 ppm. The detection limit for putrescine and cadaverine was observed to be 10 ppm and 40 ppm respectively. The specificity of the method was tested employing nine amino acids in comparison with that of aliphatic biogenic amines.

    更新日期:2019-12-11
  • Sensing the Addition of Vegetable Oils to Olive Oil: The Ability of UV–VIS and MIR Spectroscopy Coupled with Chemometric Analysis
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-05
    Michael Didham, Vi Khanh Truong, James Chapman, Daniel Cozzolino

    The aim of this study was to assess the ability of both UV–VIS and ATR-MIR spectroscopy to identify and quantify the addition of vegetable oils (canola and sunflower) to olive oil (artificial adulteration). The spectra of pure oils and mixtures was collected using an UV–VIS (200–800 nm) (1 cm path length) and an ATR–MIR instruments. This study showed that both UV–VIS and ATR-MIR spectroscopy can detect levels of adulteration above 10% due to their lower error values in prediction. However, both methods have difficulties to detect low levels of adulteration (less than 1%). Interpretation of the UV–VIS and MIR spectra indicated that differentiation between adulterated samples might be explained by the different fatty acids, products of the oxidation of lipids and change in the pigment profiles derived from the different oil samples. It was concluded that both UV–VIS and MIR spectroscopy might detect and quantify the level of addition of vegetable oils into olive oil.

    更新日期:2019-12-11
  • Construction of Co@C Hybrid Nanostructure: Electrochemical Biosensor for Detection of Penicillin Sodium in Milk
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-05
    Yi Xiu, Ruiping Luo, Baoqing Han, Lu Liu, Hongsu Wang

    In this study, a cobalt-based mesoporous carbon material (Co@C) was prepared by self-assembly method and impregnation method, and carboxyl functionalization was carried out to obtain COOH-Co@C. Then, the penicillinase (Pen X) was immobilized on the carrier material by covalent binding. The methylene blue was electropolymerized onto the glassy carbon electrode, and then the immobilized enzyme material was modified onto the modified electrode to prepare a biosensor. After optimization of experimental conditions, the differential pulse method was used to detect penicillin sodium (Pen G) as an antibiotic model. Notably, measurement was performed without any pH redox probe, and a low limit of detection was obtained. The results showed that when the concentration of Pen G was 0.1–10 ng mL−1, the corresponding current and concentration of the sensor showed a good linear relationship. The linear equation is y = 0.3881x + 17.20 (r2 = 0.9974); when the concentration range is 10–100 ng mL−1, the linear equation is y = 0.1170x + 19.73 (r2 = 0.9959). The limit of detection is 0.64 ng mL−1. The sensor is not only simple to prepare but also has high sensitivity and accurate detection. Finally, using the spike method, the actual sample detection was successfully realized.

    更新日期:2019-12-11
  • Total Antioxidant Capacity with Peak Specificity via Reaction Flow Chromatography and the Ferric Reducing Antioxidant Power Assay
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-05
    Andrew Jones, Agustín Acquaviva, Thirada Suktham, Gary R. Dennis, R. Andrew Shalliker, Arianne Soliven

    An established ferric reducing antioxidant power (FRAP) assay was optimised by preparation of the derivatisation reagent in 300 mM formate instead of 300 mM acetate conditions, resulting in increased sensitivity signal to noise responses by up to five to ten times. The quantitative protocol for selective detection of antioxidants via a HPLC post column derivatisation (PCD) technique using the 300 mM formate FRAP reagent conditions was then transformed into a high-speed qualitative screening protocol by utilizing an emerging technology ‘reaction flow (RF) chromatography’. Reaction flow chromatography’s ability to screen for total antioxidant capacity with additional peak specificity/profile information of active peaks could be achieved in under 2 min.

    更新日期:2019-12-11
  • Development of a Rapid Method for Determination of Main Higher Alcohols in Fermented Alcoholic Beverages Based on Dispersive Liquid-Liquid Microextraction and Gas Chromatography-Mass Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2019-12-04
    Zhilei Zhou, Wei Ni, Zhongwei Ji, Shuangping Liu, Xiao Han, Xiuting Li, Jian Mao

    Higher alcohols are important flavor compounds in alcoholic beverages. A new method was developed to determinate the main higher alcohols based on dispersive liquid-liquid microextraction (DLLME) coupled with GC/MS. Huangjiu was selected as an example to develop the method. The optimal DLLME parameters were acquired: the sample was diluted one time with water, no pH adjustment was required, 600 μL dichloromethane as extraction solvent, 1.5 mL acetonitrile as dispersant, 3.5 mL of sample volume, 1 min of extraction time and no salt addition. The performance of the method was satisfactory. The results obtained from DLLME were consistent with those from head space solid phase microextration (HS-SPME) and static headspace (SHS). In addition, DLLME is simpler and more time-saving compared with HS-SPME and SHS. These results indicated that the present method is satisfactory and suitable for determination of higher alcohols in Huangjiu, especially for routine inspection and batch analysis.

    更新日期:2019-12-11
  • Non-Targeted Identification of Brine Covered Canned Tuna Species Using Front-Face Fluorescence Spectroscopy Combined with Chemometric Tools
    Food Anal. Methods (IF 2.413) Pub Date : 2019-09-09
    Ferdaous Boughattas, Bruno Le Fur, Romdhane Karoui

    The most common frauds of tuna cans supply chain concern the substitution or mixing of valuable tuna species with cheaper ones, which is strictly forbidden. The objective of the present study was to determine the potential use of front-face fluorescence spectroscopy (FFFS) as a rapid tool to authenticate species in canned tuna: skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares), Albacore tuna (Thunnus alalunga), and bigeye tuna (Thunnus obesus). Different spectra (tryptophan residues, aromatic amino acids, and nucleic acids (AAA + NA), riboflavin, nicotinamide adenine dinucleotide (NADH), and vitamin A) were recorded on 256 canned tunas, produced at the pilot scale, that were used for the establishment of models. The robustness of the established models was tested on 40 commercial canned tunas. According to the label tunas, the percentage of correct classification reached 75% allowing us to conclude that FFFS may represent a promising tool to be used by both canning industry and governmental control agencies to ascertain correct labeling of canned tuna.

    更新日期:2019-12-11
  • Meat Species Identification: Amplification Refractory Mutation System-Polymerase Chain Reaction–Based Assay
    Food Anal. Methods (IF 2.413) Pub Date : 2019-09-06
    Muhammad Waqas, Zahid Hussain, Awais Ihsan

    True verification of meat species is critical for religious, economical, legal, and/or public health concerns. Current methods available for verification of meat species are very time-consuming and/or costly. So considering the necessity, a novel polymerase chain reaction assay (PCR)–based ARMS (amplification refractory mutation system) type identification assay for detection of 6 most common mammalian species—Equus asinus (donkey), Equus caballus (horse), Bos Taurus (cow), Bubalus bubalis (buffalo), Capra hircus (goat), and Canis lupus familiaris (dog)—was described in present study by designing species-specific forward primers against variable regions and a single universal reverse primer against a very conserved region of nuclear beta actin (ACTB) gene by investigation of areas of homology and variation. As compared with conventional designing of primers, ARMS type primer designing is a better alternative as it allows more room for choice and offers differentiation of closely related species by exploiting just a single nucleotide base difference. PCR bands of 128, 229, 273, 362, 710, and 796 bp were generated on electrophoretic gel for buffalo, donkey, cow, horse, dog, and goat meat species respectively. Besides singleplexing, duplex (multiplex) PCR for donkey and horse, donkey and goat, and donkey and buffalo were also performed which successfully generated corresponding bands. The method is a simple and straightforward setup; results can be interpreted easily in a short time and do not need validation by sequencing. Results of the present study clearly demonstrate that the method can be used as an identification tool for differentiation between cow, buffalo, goat, donkey, horse, and dog species.

    更新日期:2019-12-11
  • A Novel Nanoscaled Chemo Dye–Based Sensor for the Identification of Volatile Organic Compounds During the Mildewing Process of Stored Wheat
    Food Anal. Methods (IF 2.413) Pub Date : 2019-10-17
    Hao Lin, Wencui Kang, Felix Y. H. Kutsanedzie, Quansheng Chen

    This work presents a novel colorimetric sensor based on nanoscaled chemo dyes which can detect inert volatile organic compounds (VOCs) during the mildewing process of stored wheat. 1-Octen-3-ol and 3-octanone were selected as the marked compounds by gas chromatography mass spectrometry (GC-MS) analysis. In this work, poly(styrene-co-acrylic acid) microbeads were prepared by soap-free emulsion copolymerisation. Boron-dipyrromethene dyes with PSA were fabricated as a novel sensor to obtain digital data before and after exposure to VOCs, and the correlation coefficients (R2) between the digital data and the concentration of VOCs were 0.8078 and 0.8324, respectively. And root mean square errors (RMSEs) were 3.05 g L−1 and 1.65 g L−1, respectively. The data based on the identification of mouldy wheat samples were processed by principal component analysis (PCA) and linear discriminant analysis (LDA). The optimal performance obtained for the LDA model was 83.33% in the prediction set and 90% in the calibration set.

    更新日期:2019-12-11
  • Simplified Quantification of Representative Bioactives in Food Through TLC Image Analysis
    Food Anal. Methods (IF 2.413) Pub Date : 2019-10-15
    Lujing Xu, Tong Shu, Songbai Liu

    In this work, simplified quantification of representative bioactives through thin-layer chromatography (TLC) image was established employing state-of-the-art quantitative image analysis technology. A general protocol including developing system, visualization condition, and image analysis procedure was developed for representative bioactives such as polyphenols, flavonoids, anthocyanins, phytosterols, and carotenoids. Applicability of this method including linearity, repeatability, and accuracy was validated by comparison with the conventional UV-Vis spectrophotometry methods. Application in actual food samples including carrot and green tea demonstrated this method was accurate and selective. The high-throughput potential of this method was also demonstrated. This method is free from special instrument, is efficient, and would be a fantastic substitute for the conventional UV-Vis spectrophotometry methods. This work has unveiled the power of quantitative image analysis in bioactive analysis and would encourage further application in food industry.

    更新日期:2019-12-11
  • Effect of Light Exposure on Functional Compounds of Monovarietal Extra Virgin Olive Oils and Oil Mixes During Early Storage as Evaluated by Fluorescence Spectra
    Food Anal. Methods (IF 2.413) Pub Date : 2019-08-24
    G. Díaz, J. Pega, D. Primrose, A. M. Sancho, M. Nanni

    The oxidation of antioxidants in bottled extra virgin olive oil (EVOO), especially vitamin E and chlorophyll, can affect the quality of the product. However, the effect of light exposure on these functional compounds and their relation with oil quality, during the early storage of EVOO, is not clear. In this study, we evaluated the photochemical stability of vitamin E and chlorophyll in two monovarietal EVOO, Picual (PEVOO) and Farga (FEVOO), and in mixed olive oils (MOO) containing 70:30 v/v of EVOO and sunflower oil (SO), respectively. PEVOO, FEVOO, MOO and SO were subjected to light exposure for 7 days, and the amounts of vitamin E and chlorophyll were assessed by fluorescence spectra. Peroxide value (PV) and acidity index (AI) were also determined. Results showed that MOO contained significantly lower contents of vitamin E and chlorophyll than PEVOO or FEVOO before light exposure (p < 0.001). However, these compounds showed a significant decrease in PEVOO and FEVOO throughout light exposure (p < 0.001). Interestingly, although the effect of oil variety and light exposure on PV and AI determinations was significant (p < 0.001), all the oils showed values which were in accordance with the International Olive Council (IOC) standards. Principal component analysis (PCA) highlighted antioxidant changes in EVOO, MOO and SO upon this short period of light exposure. As a whole, our results indicate that, unlike PV and AI determinations, fluorescence spectra analysis may be an interesting tool for quality control in EVOO mixed with other oils or subjected to inadequate storage conditions.

    更新日期:2019-12-11
  • A Dilute-and-Shoot ICP-MS Method for Analysis of Selenium in Liquid Infant Formula
    Food Anal. Methods (IF 2.413) Pub Date : 2019-08-20
    Ippei Suzuki, Yasuhito Kumai, Shunsuke Zama, Takashi Abe, Tsuyoshi Chiba, Jun Takebayashi

    Proper determination of the amount of selenium (Se) in infant formula is important to maintain the health of non-breastfed babies. A simple dilute-and-shoot method using inductively coupled plasma mass spectrometry (ICP-MS) to determine Se in liquid infant formula was developed and validated in single- and cross-laboratory validations. Samples were diluted in an aqueous solution containing a surfactant and acetic acid and then directly introduced to ICP-MS without microwave digestion. For ICP-MS detection modes, the no-gas mode was preferable to the helium mode. In the single-laboratory validation, the developed method indicated excellent linearity (R2 = 0.998), satisfactory limit of quantification (instrumental 0.03 ng/mL, method 0.075 μg/100 mL), and acceptable accuracy (relative standard deviation = 1.8–6.6%, recovery = 87–101%) in a recovery test at three spike levels. Furthermore, the result of a certified standard reference material (SRM 1849a) suggested good trueness (115%). In the cross-laboratory validation between two laboratories, the reproducibility of the dilute-and-shoot method was comparable with the authentic microwave digestion method based on the AOAC official method. The ratios of observed Se by the dilute-and-shoot method to that of the microwave digestion method ranged from 81 to 113%. These data suggest that the method presented here is a reliable method to determine Se content in liquid infant formula.

    更新日期:2019-12-11
  • A “Two-in-One” Tandem Immunoaffinity Column for the Sensitive and Selective Purification and Determination of Trace/Ultra-Trace Olaquindox and Its Major Metabolite in Fish Tissues by LC–MS/MS
    Food Anal. Methods (IF 2.413) Pub Date : 2019-08-14
    Jie Xie, Weijie Zeng, Xiaoyun Gong, Rui Zhai, Zejian Huang, Meiying Liu, Guoqing Shi, You Jiang, Xinhua Dai, Xiang Fang

    A “two-in-one” bilayer immunoaffinity column (IAC) coupled in tandem was prepared for the highly selective purification of olaquindox (OLA) and its major metabolite, 3-methyl-quinoxaline-2-carboxylic acid (MQCA), and their determinations were carried out with the developed high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. The prepared highly selective two-in-one IAC was used for fish tissue sample clean-up after acidolysis. Then, the purified samples were analyzed by LC–MS/MS in ESI+ and multiple reaction monitoring mode. The calibration curves showed excellent linearity, with a correlation coefficient (R2) greater than 0.999. Under the optimal conditions, the average recoveries at the spiked levels of 1.0, 5.0, and 10.0 μg/kg were 81.2–94.6% with intra- and inter-day relative standard deviations (RSD; intra-day, n = 5; inter-day, n = 3) that were less than 8.1% and 11.7%, respectively. The limits of detection (LODs) were 0.01 and 0.3 μg kg−1, and the limits of quantifications (LOQs) were 0.04 and 0.5 μg kg−1 for OLA and MQCA, respectively. The validated method was successfully applied to the qualitative and quantitative detection of real samples collected from several local markets.

    更新日期:2019-12-11
  • Quantitative Determination of Arsenic Species from Fruit Juices Using Acidic Extraction with HPLC-ICPMS
    Food Anal. Methods (IF 2.413) Pub Date : 2019-09-10
    Kevin M. Kubachka, Sean D. Conklin, Cynthia C. Smith, Consuelo Castro

    Throughout the US Food and Drug Administration’s routine monitoring of various juice samples for elemental contaminants, a limited number of samples exhibited unexpected behavior related to the arsenic content. Juice samples were subjected to total arsenic determination and those containing arsenic > 10 μg kg−1 were subjected to arsenic speciation analysis using FDA Elemental Analysis Manual (EAM) 4.10 method (AOAC First Action Method 2016.04) to determine the concentration of iAs and other common organic arsenicals. For a subset of samples, the sum of the arsenic species was significantly less than the total arsenic value (i.e., mass balance < 65%), which is uncommon for a liquid-based matrix. Juice types that have exhibited this behavior include pomegranate, prune, and cherry juices. Causes for this issue were explored which ultimately led to an alternate sample preparation technique, extraction with 0.28 M HNO3 along with heat, which resulted in drastically improved mass balances approaching 100%. The method proved robust, with both accurate and precise measurements for multiple juice samples analyzed by a total of four laboratories. Two laboratories performed a level 3 multilaboratory validation. This work discusses various issues that were encountered, attempts to determine the source of the problem, the eventual solution in the form of a modified extraction procedure, and the multilaboratory validation results.

    更新日期:2019-12-11
  • Coupling of GC-MS/MS to Principal Component Analysis for Assessment of Matrix Effect: Efficient Determination of Ultra-Low Levels of Pesticide Residues in Some Functional Foods
    Food Anal. Methods (IF 2.413) Pub Date : 2019-10-15
    Amr H. Shendy, Basma M. Eltanany, Medhat A. Al-Ghobashy, Sohair A. Gadalla, Wael Mamdouh, Hayam M. Lotfy

    Functional foods provide nutritional and health benefits, yet they could be contaminated with residues like pesticides and polychlorobiphenyls. These residues affect the safety, quality, and consequently the commercial value of functional foods. Therefore, the validity and efficiency of residue determination methods constitute a major analytical concern. Reduction of matrix effect (ME) has always been the golden key for guaranteed sensitivity, selectivity, and high throughput analysis. This study aims for accurate determination and streamlined quantification of 200 pesticide residues in 16 matrices. Hence, QuEChERS protocol coupled to GC-MS/MS was then employed and separations were obtained in 25 min. Dilution of the final extracts of fresh and herbal samples was carried out to achieve an acceptable balance between sensitivity and peak characteristics. Dilution factors of 1x and 5x were selected for fresh and herbal samples, respectively. Principal component analysis (PCA) was then independently applied on the digitally exported total ion chromatograms (TICs) of the studied matrices and the calculated ME%. PCA score/loading plots of TICs demonstrated the key matrix constituents that influenced the obtained trends. Similarly, three main clusters were obtained after PCA of ME% indicating a dependent relationship between matrix type and the obtained effects. Out of the obtained three clusters, an appropriate representative matrix-matched calibration (R-MMC) was selected for ME compensation. Based on the EU validation guidelines, the proposed protocol was validated at 2 and 10 μg Kg−1 with acceptable method performance. Four proficiency testing (PT) and commercial samples were successfully analyzed. The proposed protocol would help laboratories to increase sample processing capacity and to ensure the safety of functional food products. This work should serve in setting standards that warranty the quality/safety of functional foods by national regulatory authorities.

    更新日期:2019-12-11
  • Optimization by experimental design of headspace sorptive extraction and solid-phase microextraction for the determination of terpenes in spices
    Food Anal. Methods (IF 2.413) Pub Date : 2019-09-04
    Zélie Triaux, Hugues Petitjean, Eric Marchioni, Damien Steyer, Christophe Marcic

    Headspace sorptive extraction (HSSE) was compared with solid-phase microextraction (SPME), a reference method for the extraction of volatiles. HSSE and SPME were optimized by experimental design for the extraction of terpenes and terpenoids from spices. The different extraction parameters studied were the extraction time, the extraction temperature, the sample mass, and the equilibrium time (only for SPME). Extracts were obtained by HSSE and SPME from six spices: cinnamon, cumin, thyme, fennel seeds, nutmeg, and clove. Those extracts were analyzed by gas chromatography coupled to a mass spectrometer (GC-MS) qualitatively and quantitatively. The quantitative analysis was conducted using 28 standards. For each standard, calibration curves, limits of detection (LOD) and quantification (LOQ) were determined. The study shows that HSSE is selective, sensitive, and highly repeatable method for the extraction of volatile terpenes and terpenoids from spices and allows to produce extracts concentrated in the μg/g range of terpenes.

    更新日期:2019-12-11
  • Multiclass Method for the Determination of Pesticide Residues in Oat Using Modified QuEChERS with Alternative Sorbent and Liquid Chromatography with Tandem Mass Spectrometry
    Food Anal. Methods (IF 2.413) Pub Date : 2019-09-10
    Estéfani M. C. de Matos, Lucila C. Ribeiro, Osmar D. Prestes, José A. G. da Silva, Bruna S. de Farias, Luiz A. de A. Pinto, Renato Zanella

    Many pesticides are used for pest control during oat production and storage, making necessary to employ multiclass methods for pesticide residue determination. In this work, an efficient QuEChERS method was established for multiresidue determination of 60 pesticides in oats by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Different sorbents, such as chitosan, Forisil®, C18, PSA, Supel QuE Z-Sep+, and EMR-Lipid were evaluated for cleanup by dispersive solid-phase extraction (d-SPE). The original QuEChERS method had the best performance and the biosorbent chitosan presented similar results to the other conventional sorbents evaluated and being an efficient and low-cost biodegradable material was chosen for the cleanup step. The method presented adequate accuracy and precision using blank samples spiked between 5 and 100 μg kg−1, with recovery from 70 to 120% and RSD < 20% for all 60 pesticides and limits of quantification of 5 μg kg−1 for almost all studied pesticides, with exception of triflumizole for which was 10 μg kg−1. The method was successfully applied in real samples proven to be a good option for routine analysis. Oat samples presented residues of azoxystrobin, metalaxyl, and thiamethoxam.

    更新日期:2019-12-11
  • Cyclodextrin-Promoted Fluorescence Detection of Aromatic Toxicants and Toxicant Metabolites in Commercial Milk Products.
    Food Anal. Methods (IF 2.413) Pub Date : 2018-10-06
    Dana J DiScenza,Julie Lynch,Molly Verderame,Melissa A Smith,Mindy Levine

    The detection of polycyclic aromatic hydrocarbons (PAHs) and their metabolites in food and in agricultural sources is an important research objective due to the PAHs' known persistence, carcinogenicity, and toxicity. PAHs have been found in the milk of lactating cows, and in the leaves and stems of plants grown in PAH-contaminated areas, thereby making their way into both cow milk and plant milk alternatives. Reported herein is the rapid, sensitive, and selective detection of 10 PAHs and PAH metabolites in a variety of cow milks and plant milk alternatives using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, combined with subsequent array-based statistical analyses of the fluorescence emission signals. This system operates with high sensitivity (low micromolar detection limits), selectivity (100% differentiation even between structurally similar analytes), and general applicability (for both unmodified lipophilic PAHs and highly polar oxidized PAH metabolites, as well as for different cow and plant milk samples). These promising results show significant potential to be translated into solid-state devices for the rapid, sensitive, and selective detection of PAHs and their metabolites in complex, commercial food products.

    更新日期:2019-11-01
  • Rapid Food Product Analysis by Surface Acoustic Wave Nebulization Coupled Mass Spectrometry.
    Food Anal. Methods (IF 2.413) Pub Date : 2018-10-03
    Thomas Schneider,Benjamin L Oyler,Sung Hwan Yoon,Tao Liang,Gloria S Yen,David P A Kilgour,Erik Nilsson,David R Goodlett

    Rapid food product analysis is of great interest for quality control and assurance during the production process. Conventional quality control protocols require time and labor intensive sample preparation for analysis by state-of-the-art analytical methods. To reduce overall cost and facilitate rapid qualitative assessments, food products need to be tested with minimal sample preparation. We present a novel and simple method for assessing food product compositions by mass spectrometry using a novel surface acoustic wave nebulization method. This method provides significant advantages over conventional methods requiring no pumps, capillaries, or additional chemicals to enhance ionization for mass spectrometric analysis. In addition, the surface acoustic wave nebulization - mass spectrometry method is ideal for rapid analysis and to investigate certain compounds by using the mass spectra as a type of species-specific fingerprint analysis. We present for the first time surface acoustic wave nebulization generated mass spectra of a variety of fermented food products from a small selection of vinegars, wines, and beers.

    更新日期:2019-11-01
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