Grape Wine Samples Research Articles

Wine component tracing method based on near infrared spectrum fusion machine learning

An intelligent wine detection and traceability method based on infrared spec-troscopy and machine learning is proposed, in order to meet the needs of online rapid nondestructive testing of wine. On the basis of extracting infrared spectrum of wine, the principal component analysis (PCA) – support vector machine (SVM) model was modified by chemometrics. A total of 300 grape wine samples were collected from six production areas. The composition of the samples was analyzed by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). According to the experimental results, indole, sulfacetamide and caffeine were selected as characteristics of different origins. Near infrared spectral wavelengths of wine samples were compressed between 900 and 2,500 nm. The ranges of 1,000 nm ~ 1,400 nm and 1,500 nm ~ 1800 nm were selected for PCA principal component analysis and key spectral wavelengths were extracted. The unsupervised learning model of SVM is used to classify and identify key spectral wavelengths. The experimental results show that the algorithm has higher classification accuracy than traditional PCA-LDA, PCA and other algorithms. The classification accuracy of the algorithm is improved from 98.3 to 99.75%. The improved PCA-SVM algorithm can achieve fast and loss-less source tracing of wine.

A sensitive biomimetic enzyme-linked immunoassay method based on Au@Pt@Au composite nanozyme label and molecularly imprinted biomimetic antibody for histamine detection

ABSTRACTIn this paper, a sensitive biomimetic enzyme-linked immunoassay (BELISA) method based on an Au@Pt@Au composite nanozyme label was developed for histamine (HA) detection. A molecular imprinted polymer prepared directly on the 96-well plate served as a biomimetic antibody. A BELISA method was developed for HA standard solutions at concentrations ranging from 0.01 to 100.00 mg/L. Under optimal conditions, the novel BELISA method had a low limit of detection (0.069 mg/L) and high sensitivity (7.20 mg/L). The HA spiked in yellow rice wine and liqueur samples were detected by this BELISA method with the recoveries ranging from 84.28% to 108.82%. There was no significant difference of the results between the BELISA method and HPLC for the detection of HA in the red and white grape wine samples.

Fabrication of porous ionic liquid polymer as solid-phase microextraction coating for analysis of organic acids by gas chromatography – mass spectrometry

A kind of porous ionic liquid polymer was designed as coating material for solid-phase microextraction (SPME) fibers to extract polar organic acids. The synthesized ionic liquids (1-vinyl-3-(4-vinyl-benzyl)imidazolium chloride) were polymerized in the presence of azobisisobutyronitrile (AIBN), and subsequently coated on stainless steel wires with physical adhesion. To guarantee the adhesion between coating and the surface of stainless steel wires, micro-wave induced plasma was applied to modify the stainless steel wires. The derivatives of extracted organic acids were analyzed by gas chromatography combined with mass spectrometry (GC-MS) with N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) as the derivatization reagent. Under the optimal condition, a calibration study was carried out to evaluate the performance of the SPME fibers. The calibration curves were linear (R2>0.99) in the range from 0.01μg/ml to 1μg/ml for six organic acids. Detection limits were detected down to 0.07ng/ml. To further validate the extraction efficiency of the fibers, experiments were conducted in comparison with commercial fibers. Lower LOD and LOQ values were obtained by the in-house fabricated fibers especially for polyatomic acids. Good repeatability (RSD≤16%) and fiber-to-fiber reproducibility (RSD≤20%) were obtained. The acceptable recovery of the spiked grape wine samples ranged from 78.19% to 98.11%. Additionally, long lifetime and good durability of the fibers have been demonstrated. The performance of the established SPME-GC-MS method for analysis of organic acids was shown to be greatly improved in comparison to the direct HPLC/CE method or other SPME materials as reported in the literature. In summary, a feasible and effective approach has been demonstrated to fabricate the in-house fabricated fibers based on porous ionic liquid polymers, which were proved to be advantageous and sensitive for extraction of polar organic acids. Simultaneously, application of the SPME derivatization GC-MS method for analysis of organic acids has been successfully verified as feasible and reliable.

Determination of Six Pyrazole Fungicides in Grape Wine by Solid-Phase Extraction and Gas Chromatography-Tandem Mass Spectrometry.

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the first simultaneous identification and quantification of six pyrazole fungicides (furametpyr, rabenzazole, fluxapyroxad, penflufen, bixafen, and isopyrazam) in grape wine samples. The grape wine samples were first diluted with water, then purified by solid-phase extraction, and finally examined by GC-MS/MS in multiple reaction monitoring (MRM) mode. Matrix-matched calibration curves were used to correct the matrix effects. The limits of quantification (LOQs), calculated as 10 times the standard deviation, were 0.2-0.8 μg kg(-1) for the six pyrazole fungicides. The average recoveries were in the range of 74.3-94.5%, with relative standard deviations (RSDs) below 5.8%, measured at three concentration levels. The proposed method is suitable for the simultaneous determination of six pyrazole fungicides in grape wine samples.

Several Mineral Elements Discriminate the Origin of Wines from Three Districts in China

The concentrations of eight mineral elements were determined by inductively coupled plasma-atomic emission spectrometry in 48 grape wine samples to distinguish the wine origins from three districts in China. The results of principal component analysis indicated that the samples from Yinchuan city could be separated from Penglai and Changli cities. The samples could be clustered into three groups according to region of origin by cluster analysis with only two miss-cluster. The stepwise method of discrimination analysis with three mineral elements was able to 100% classify the original groups of all samples. Sr and Mn are characteristic elements for wines originating from Yinchuan city and Changli city, respectively, as determined from the results of Duncan multiple comparisons on the concentrations of Mn and Sr.

Flavor characteristics of rice-grape wine with starch-hydrolyzing enzymes

A brewing process for rice-grape wine, in which rice powder and grapes are concurrently fermented, was developed. Rice powder was mixed with α-glucosidase, glucose isomerase, and yeast, and then incubated for 2 days at 25°C. Then a mixture of ‘Muscat Baily A’ and ‘Campbe Early’ grape must was added to the fermented mixture of rice and maintained at 4°C to allow for complete ethanol fermentation. The rice-grape wine contained 11.6% ethanol, compared to 9.6% ethanol for grape wine. The aroma profile revealed that 2-methyl-1-propanol, 2-methyl propyl acetate, and phenethyl acetate were in greater abundance in the rice-grape wine, whereas ethyl hexanoate, diethyl succinate, and ethyl decanoate were more abundant in the grape wine. The esters formed from fatty acids and ethanol increased during 2 years of storage for both wines. An electronic nose analysis revealed no significant difference in the aromas of the rice-grape and grape wine samples.

Direct determination of ethyl carbamate in Chinese rice wine and grape wine by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry

An ultra performance liquid chromatography-electrospray ionization tandem mass spectrometric (UPLC-ESI-MS/MS) method was established for the direct determination of ethyl carbamate in Chinese rice wine and grape wine. The Chinese rice wine and grape wine samples were diluted with distilled water, filtered through 0. 22 microm microporous membrane. The LC separation was performed on a Waters Acquity UPLC system with a BEH C18 column, acetonitrile and 0. 1% (v/v) acetic acid aqueous solution as the mobile phase. The ethyl carbamate was determined in the mode of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The butyl carbamate (BC) was used as the internal standard for the quantitative determination. The calibration curve showed good linearity in the range of 2 - 500 microg/L with the correlation coefficient greater than 0.995. The limit of detection (LOD) was 1.7 microg/L and the limit of quantification (LOQ) was 5.0 microg/L. The recoveries of the ethyl carbamate in Chinese rice wine and grape wine was in the range of 90% - 102%. The relative standard deviations (RSDs) of intra-day and inter-day determinations were 0. 8% - 4.5% and 1.4% - 5.6% (n = 6). The results indicated that the proposed method is easy, fast, sensitive, and suitable for the determination of ethyl carbamate in Chinese rice wine and grape wine.

Analysing organophosphorus pesticides in wines using graphitized carbon black extraction cartridges

A quick and simple method was developed to determine the residues of 15 organophosphorus pesticides of different polarity in grape wine, based on liquid-solid extraction with graphitized carbon black cartridges and capillary gas chromatography. Aliquots of diluted wine (10ml wine + 40ml deionized water) and 250mg graphitized carbon black cartridges were used to extract the analytes. The pesticides were eluted with 2 x 0. 5ml acetone and 3 x 2. 5ml ethyl acetate/acetone (80 : 20). The eluates were then dried with anhydrous sodium sulphate and concentrated to 1ml under a nitrogen current. After adding triphenylphosphate internal standard (i.s.), this extract was analysed by capillary gas chromatography using a nitrogen-phosphorus detector (GC-NPD). Pesticide recovery percentages at levels of 0.01 and 0.02 mug/ml were between 74% and 111%, with a 2–13% relative standard deviation interval. The chromatograms of extracts had few co-extracted species peaks, with no analytical interference. Dilution of the grape wine samples removed most of the pigments, thus producing clear extracts. The results indicate that liquid-solid extraction from wine samples using graphitized carbon is fast (25min per sample), efficient and reproducible for analysing organophosphorus pesticides of different polarity.