Vinegar Samples Research Articles

An effervescence tablet-assisted microextraction based on the solidification of deep eutectic solvents for the determination of strobilurin fungicides in water, juice, wine, and vinegar samples by HPLC

In this study, a simple, efficient, and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent (ETA-ME-SDES) was developed to determine picoxystrobin, pyraclostrobin, and trifloxystrobin in water, juice, wine, and vinegar samples by HPLC. An eco-friendly, hydrophobic, deep eutectic solvent (DES, acting as the extraction solvent) was synthesized by thymol and octanoic acid in the molar ratio of 1:5. The extraction solvent dispersed in sample solutions with the assistance of pH adjustment and effervescence reaction, and was collected after solidification in an ice bath. Several essential conditions, including the type and the volume of DESs, the amount of ammonia hydroxide, and the components of effervescence tablets were optimized. The limits of detection ranged from 0.15 to 0.38 μg L−1. Extraction recovery ranged from 77.4 to 106.9%. The proposed method was successful in determining the amount of strobilurin fungicides in water, juice, wine, and vinegar samples.

Copper Complexing Capacity and Trace Metal Content in Common and Balsamic Vinegars: Impact of Organic Matter

Complex formation is among the mechanisms affecting metal bioaccessibility. Hence, the quantification of organic metal complexation in food items is of interest. Organic ligands in solutions of environmental and/or food origin function as buffering agents against small changes in dissolved metal concentrations, being able to maintain free metal ion concentrations below the toxicity threshold. Organic matter in vinegars consists of bioactive compounds, such as polyphenols, Maillard reaction endproducts, etc., capable of complexing metal ions. Furthermore, transition metal ions are considered as micronutrients essential for living organisms exerting a crucial role in metabolic processes. In this study, differential pulse anodic stripping voltammetry (DPASV), a sensitive electrochemical technique considered to be a powerful tool for the study of metal speciation, was applied for the first time in vinegar samples. The concentrations of Cu complexing ligands (LT) in 43 vinegars retailed in Greece varied between 0.05 and 52 μM, with the highest median concentration determined in balsamic vinegars (14 μM), compared to that of common vinegars (0.86 μM). In 21% of the vinegar samples examined, LT values were exceeded by the corresponding total Cu concentrations, indicating the presence of free Cu ion and/or bound within labile inorganic/organic complexes. Red grape balsamic vinegars exhibited the highest density of Cu ligands per mass unit of organic matter compared to other foodstuffs such as herbal infusions, coffee brews, and beers. Among the 16 metals determined in vinegars, Pb is of particular importance from a toxicological point of view, whereas further investigation is required regarding potential Rb biomagnification.

EV YAPIMI İNCİR VE DUT SİRKESİNİN TOPLAM FENOLİK İÇERİĞİ VE ANTİBAKTERİYEL AKTİVİTESİ

In this study, antimicrobial activity of traditionally produced fig and mulberry vinegar was examined. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of vinegar samples against eight microorganisms including Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus and Pediococcus acidilactici were determined. Both types of vinegar exhibited inhibitive effect on all test microorganisms. The MIC values of fig and mulberry vinegar were determined as ranging between 0.39-12.5% and 3.12-12.5% (v/v), respectively. The most sensitive bacteria to fig vinegar was B. subtilis while S. typhimurium was the most sensitive one to mulberry vinegar. After neutralization of vinegar, bactericidal effect was observed only in fig vinegar sample, which had higher total phenolic content than mulberry vinegar. These results indicated the potential of home-made vinegars as antimicrobial substance that could be used as functional food ingredients and as food supplements.

The physicochemical properties and antioxidant capacities of commercial and homemade Greek vinegars.

Due to its high content of antioxidant compounds, vinegar can be considered an excellent source of health promoting compounds. The aim of this study was to compare the physicochemical composition and antioxidant capacity of eighteen vinegars made from red and white wine, apple, rose petals, and balsamic acid. Eight randomly selected commercial vinegars from the Greek market and ten homemade vinegars were used. Their quality characteristics, color profile, polyphenol content and antioxidant capacity were determined. The results showed that there is a high diversity of values among the examined vinegar samples indicating that the raw material and the applied production methods can affect their composition. Red wine vinegars and red balsamic vinegars exhibited the highest levels of total phenols, followed by fruit vinegars, white wine vinegars and white balsamic vinegars. The antioxidant capacity was strongly affected by the total phenolic content, followed by the total flavonoid content and less so by the color density. Our findings could provide important information to consumers about the randomly selected vinegars from the Greek market and could be used for the development and optimization of homemade and commercial vinegars.

Cognitive chaos on spectrofluorometric data to quantitatively unmask adulterations of a PDO vinegar

Different types of intelligent chaotic algorithms have been used for the determination and quantification of adulterants in Sherry vinegar. The product analyzed is one of the most exclusive and high-priced vinegars in the world, with protected designation of origin “Manzanilla-Sanlúcar de Barrameda”, from the Spanish province of Cádiz. It is produced and stored following classic procedures that allow the consumer to enjoy the typical outstanding organoleptic characteristics of this vinegar. Derived from its prestige and price, a spectroscopic tool based on fluorescence has been designed to locate several adulterations including cheap and low-quality vinegars such as those obtained from molasses, rice, cider, and white wine (adulteration range from 1 to 15% in weight). For this purpose, 192 fluorescence spectra from different vinegar samples obtained after irradiating with a laser diode have been analyzed mathematically. The goals established have been to determine the specific type of adulteration as well as their amounts in the prepared mixtures. Among the most outstanding results, it is worth mentioning that the intelligent models can quantify any of the adulterations with relative errors ranging from 1.4 to 7.2%.

Characterization and Differentiation of Spanish Vinegars from Jerez and Condado de Huelva Protected Designations of Origin.

Thirty one Jerez vinegar samples and 33 Huelva vinegar samples were analyzed for polyphenolic and volatile compound content in order to characterize them and attempt to differentiate them. Sixteen polyphenolic compounds were quantified by means of ultraperformance liquid chromatography method with diode array detection (UPLC–DAD), and 37 volatile compounds were studied by means of stir bar sorptive extraction–gas chromatography–mass spectrometry (SBSE–GC–MS). Spectrophotometric CIELab parameters were also measured for all the samples. The results obtained from the statistical multivariate treatment of the data evidenced a clear difference between vinegars from the two geographical indications with regard to their polyphenolic content, with Jerez vinegars exhibiting a greater phenolic content. Differentiation by the volatile compound content was, however, not so evident. Nevertheless, a considerable differentiation between the two groups of vinegars based on their volatile fraction was achieved. This may bring to light the grape varieties and geographical factors that have a clear influence on such differences.

A new ion-pair ultrasound assisted-cloud point extraction approach for determination of trace V(V) and V(IV) in edible vegetal oils and vinegar by spectrophotometry

A new ion-pair ultrasound-assisted-cloud point extraction (UA-CPE) procedure for the preconcentration and determination of V(V) and V(IV) in edible vegetal oils and vinegar by spectrophotometry at 530 nm was developed. The method is based on selective and sensitive anionic chelation of V(V) and V(IV) with EDTA, and then a stable ion-pair formation of the formed chelate complexes with cationic phenazine dye, Safranin T, at pH 4.0 and/or pH 5.0 respectively, which can be easily extracted into the micellar phase of Triton X-114 with the help of ultrasound energy. The variables affecting ion-pair formation and extraction efficiency were evaluated and optimized. Under the optimized conditions, there was a linear relationship in range of 1–40 μg/L for V(IV) at pH 5.0 with higher calibration sensitivity while it obtained a rectilinear behavior in the range of 2–180 μg/L for V(V) at pH 4.0. The limits of detection and quantification for V(IV) were 0.26 and 0.85 μg/L with a sensitivity enhancement of 83.6 from preconcentration of 35-mL sample, respectively where these values are 0.53 and 1.77 μg/L, respectively, for V(V). The recovery rate and precision for five replicate measurements of 5, 25 and 100 μg/L V(V) and V(IV) were in range of 98–101%, 3.1–4.2% and 3.2–4.5%, respectively. The accuracy was statistically verified by analysis of a certified oil sample with both the developed method and independent comparison method, and the method was successfully applied to the analysis of total V contents of edible vegetal oils and vinegar samples after preconcentration.

Developing an Excitation-Emission Matrix Fluorescence Spectroscopy Method Coupled with Multi-way Classification Algorithms for the Identification of the Adulteration of Shanxi Aged Vinegars

In this paper, an excitation-emission matrix (EEM) fluorescence spectroscopy method coupled with two kinds of multi-way classification algorithms was developed for the identification of the adulteration of Shanxi aged vinegars. The first classification model was built from selective information provided by parallel factor analysis (PARAFAC) based on partial least squares-discriminant analysis (PLS-DA) algorithm and the other one was modeled based on strictly multi-way classification algorithm multi-way partial least squares-discriminant analysis (N-PLS-DA). Both classification models showed good clustering tendency for authentic and adulterated Shanxi aged vinegars. Compared with the PARAFAC-PLS-DA method, more accurate and reliable classification results were provided by the N-PLS-DA method because it is a strictly multi-way classification method and can make the utmost use of the EEM fluorescence information of the vinegar samples. The N-PLS-DA model constructed from the EEM spectra enabled the recognition of adulterated samples with accurate rate of 100% both in training and prediction sets and obtained maximum sensitivity and specificity. This study showed that EEM fluorescence spectroscopy combined with multi-way classification algorithm N-PLS-DA could be used as a good method for the identification of the adulteration of Shanxi aged vinegar samples.

Extraction of total phenolic content and antioxidant activity of Capsicum chinense and Capsicum spp in different solvents and extraction time

The purpose of this work was to evaluate the extraction and quantification of total phenolic compounds and the antioxidant activity of two peppers processed by four different methods (in natura, dried, preserved in vinegar and preserved in oil). The extraction efficiency of total phenolics using seven solvents (distilled water, ethanol, 50% ethanol, methanol, 50% methanol, ketone p.a and 50% ketone) were checked. Total phenolic analyzes were performed using the Folin-Ciocalteu and gallic acid method to obtain the standard curve with 650 nm absorbance reading. The antioxidant activity was determined using a spectrophotometric method using the reagent 2,2-diphenyl-1-picryl hydrazyl (DPPH). No significant differences were observed in the two extraction times 6 and 24 h. For samples preserved in vinegar, no significant differences were observed between the solvents used for the extraction. The Capsicum chinense pepper showed the highest amount of phenolic compounds in all treatments when compared to the chili pepper, except when conserved in oil. For the dry pepper, the lowest total phenolic extraction value was obtained with 99.5% ethanol (p.a.) and acetone p.a ACS 99.5% (p.a.), which differed from the peppers preserved in oil. The analysis of the antioxidant activity of Capsicum chinense and Capsicum spp did not present a significant difference (p>0.05) when compared to the dried or vinegar preserved samples. However, the sample of Capsicum chinense pepper in natura presented higher antioxidant activity than the samples conserved in oil. It can be considered from the experimental results that the peppers in this study, especially in fresh and dried form are good sources of natural antioxidants.

A feature selection strategy of E-nose data based on PCA coupled with Wilks Λ-statistic for discrimination of vinegar samples

In order to enhance the correct discrimination rate of six kinds of vinegar samples using electronic nose (E-nose), a feature selection strategy based on principal component analysis (PCA) coupled with Wilks Λ-statistic is put forward. PCA is used to generate principal component (PC) variables so as to eliminate the correlation between original feature variables; then some PC variables that are beneficial to identify the vinegar samples are selected by Wilks Λ-statistic. Considering that each PC variable is a linear combination of all original feature variables, so the sum of absolute values of combination coefficients of one original feature variable to the selected PC variables can be calculate, and some different original feature variable sets are formed by the sums from large to small, and the best variable set can be determined by further exploring their discrimination results. By the strategy, 51 original feature variables were selected as representational features of the E-nose data. In order to verify the effectiveness of the feature selection strategy, Fisher discriminant analysis (FDA) and radial basis function neural network (RBFNN) were employed to discriminate the six kinds of vinegar samples, and correct discrimination rates of training sets were 94% and 97%, respectively, and the correct discrimination rates of corresponding test sets were 90% and 92% at least, respectively. Moreover, Bhattacharyya distance (B-distance) was employed to explain the separability of these vinegar samples and the reliability of the FDA and RBFNN results.

Cellulose-coated CoFe2O4 nanoparticles as an adsorbent for extraction and preconcentration of bioactive compounds in vinegars

In this work, an extraction and preconcentration flow system using mini-column packed with cellulose-coated CoFe2O4 was developed for the determination of bioactive compounds in vinegar samples by high-performance liquid chromatography with diode array detector (HPLC-DAD). The CoFe2O4 nanoparticles were synthetized by a sonochemical method and coated with cellulose biopolymer. Both synthetized nanoparticles and nanocomposites were characterized employing the techniques of X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) and Derivative Thermogravimetry (DTG). The flow system was optimized employing two-level full factorial design and Doehlert matrix, in which the established optimum conditions were: adsorbent mass of 254 mg, eluent concentration of 92% (v/v methanol/water) and sampling flow rate of 2.0 mL min−1. In these conditions, the flow system allows the determination of 12 bioactive compounds with limits of detection and quantification that varied in the range of 0.0009–0.091 mg L−1 and of 0.0028–0.276 mg L−1, respectively. Enrichment factors (EF) were in the range of 2.31–63.72. The proposed flow system was applied for the analysis of 24 vinegar samples of brands locally available in Salvador City, Bahia, Brazil.

Multiple headspace solid-phase micro-extraction for the total content determination of tetramethylpyrazine in various vinegar samples by GC-FID

The total tetramethylpyrazine (TMP) content in vinegar samples could be detected by multiple HS-SPME coupled with GC-FID (MHS-SPME-GC-FID) as a routine method.

Manganese oxide nanoparticles electrodeposited on graphenized pencil lead electrode as a sensitive miniaturized pH sensor

pH monitoring in micro volume samples is required for environmental and clinical analysis. Low cost, miniaturized and stable metal oxide based pH sensors could be a suitable alternative to glass electrodes. In this study, a sensitive potentiometric solid state pH sensor based on manganese oxide nanoparticles electrodeposited on graphenized pencil lead electrode (MnO2/GPLE) was reported. The prepared MnO2/GPLE was carefully characterized by SEM, XRD and electrochemical techniques. To miniaturize the prepared pH sensor, a stainless steel 304 needle was used as a reference electrode. Selectivity, response time, stability and reproducibility of the miniaturized pH sensor were studied and compared with conventional glass pH electrode. According to experimental results, a near-Nernstian slope of − 57.051 mV/pH and linearity over the pH range of 1.5–12.5 were obtained for the developed MnO2/GPLE pH sensor. The prepared sensor represented high ion selectivity to mono-valence and multi-valence ions with $$- \log K_{{{\text{A}},{\text{B}}}}^{{{\text{Pot}}}}$$ values around 6.49. A fast response time of 20 s in acidic medium and 60 s in alkaline medium, long-term stability and reproducibility in 2 months, the simplicity of fabrication, low cost and accuracy makes this sensor as a suitable choice for rapid pH recording in micro volume samples. The MnO2/GPLE pH sensor was successfully used for the pH monitoring of human tear, human blood, saliva, apple juice, lemon juice, milk, and vinegar samples with satisfactory results.

Multipurpose sensing applications of biocompatible radish-derived carbon dots as Cu2+ and acetic acid vapor sensors.

A recent trend in the preparation of carbon dots, optically unique nanomaterials, revolves around the use of readily-available, low-cost natural resources as precursors and their multipurpose applications. In this work, a hydrothermal method for preparing biocompatible carbon dots from radish was developed. The carbon dots were then tested for sensing of Cu2+ and acetic acid vapor. The carbon dots exhibited blue emission under UV illumination with, a quantum yield of 15%. The fluorescence emission was selectively quenched when Cu2+ ions were added, giving a detection limit of 0.16 μM. A paper-based fluorescent sensor was fabricated and shown to sense Cu2+ with a limit of detection of 6.8 μM. The carbon dots were able to determine the Cu2+ concentration in real water samples, with excellent recovery and reliability. The carbon dots were also used as the sensing material in an optical electronic nose, and tested for real-time detection of acetic acid vapor. Using principal component analysis, different ratios of acetic acid to methanol in solution were successfully identified with a detection limit of 15.5%. The acetic acid concentration in a real vinegar sample was also accurately determined. Our results demonstrated that label-free carbon dots derived from readily available radish can be simply used as versatile probes, giving them potential uses in multipurpose sensing applications.

A portable eight-channel titrator based on high-throughput capacitively coupled contactless conductivity measurements

Analytical chemists require multichannel and automatic tools for batch measurements. Herein, an eight-channel electronic titrator (8-CET) system was constructed to facilitate high-throughput titrations. In this system, multichannel piston pumps were used for delivery, and an 8-channel capacitively coupled contactless conductivity detector (8-C4D) was used to monitor the conductivity of the titration solutions in arrays of disposable reaction cells. The delivery and the monitoring were both fully software-controlled allowing a simultaneous formation of eight titration curves. Its capacity for classical acid-base and precipitation titration was characterized with satisfactory results. It was also used to measure the content of CH3COOH in batched vinegar samples. The RSD between each reaction cell was 1.9%. There are two outstanding features of this new system: 1) Up to eight samples can be measured simultaneously; and 2) simple operation is realized by avoiding electrode switching and cleaning after each measurement. Therefore, it is reasonable to believe that this 8-CET system is a prospective alternative for developing more automatic and efficient titration platforms.

Some Quality Properties of Rice Vinegar and Various Commercial Vinegar Samples

Bu çalışmada geleneksel yöntemle
 üretilen ve Türkiye’de ilk defa bilimsel olarak araştırılan pirinç sirkesi,
 yerel marketten temin edilen ticari üzüm ve elma sirkeleri ve geleneksel
 yöntemle üretilen ev yapımı üzüm sirkesi kullanılmıştır. Sirkelerde yoğunluk,
 alkol, kuru madde, toplam asit, uçar asit, pH, kül, renk, toplam fenolik madde
 analizleri yapılmıştır. Analizi yapılan sirke örneklerinden sadece tarafımızdan
 üretimi yapılan pirinç sirkesi toplam asit miktarı bakımından TS 1880 EN 13188
 standardında belirtilen alt limit olan 40 g/L’nin üzerinde kalarak standarda
 uygunluk göstermiştir. Ticari sirkelerinin toplam toplam fenolik madde içeriği 0-692.93
 mg gallik asit eşdeğeri (GAE)/L aralığında saptanmıştır. Pirinç sirkesinde ise
 514.61 mg GAE/L olarak belirlenmiştir.

The development of an alternative fermentation model system for vinegar production

This study was conducted to develop and optimise an alternative fermentation model system using mushrooms (Pleurotus pulmonarius and Volvariella volvacea) and yeast (Saccharomyces cerevisiae) as the starter cultures, while standard glucose solution was used as the substrate for fermentation. The optimisation was performed on two factors, fermentation time and culture ratio, using D-optimal mixture design. Both fermentation time and culture ratio showed significant (p < 0.05) effects on reducing sugar content and increasing the ethanol content for alcoholic fermentation. The optimum fermentation conditions were 72 h of fermentation and using a S. cerevisiae:P. pulmonarius mycelia:V. volvacea mycelia culture ratio of 1:1:1, achieving a desirability of 0.901. A verification test was performed, and there was no significant difference (p > 0.05) in the ethanol content between the experimental value (13.45 ± 0.99%) and the predicted value (13.52%). Vinegar production was carried out using the optimised alcoholic sample through the inoculation of mother of vinegar and Kombucha. The concentrations of acetic acid from both samples of vinegar were between 2.05% and 2.41% with zero residual ethanol. In conclusion, an alternative fermentation model system for vinegar production using mushrooms and yeast, followed by mother of vinegar and Kombucha inoculation, has been successfully developed with the desired physiochemical properties.

Effervescent-assisted dispersive liquid–liquid microextraction based on the solidification of floating organic droplets for the determination of fungicides in vinegar and juice

ABSTRACTA method of effervescent-assisted dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet is reported. This approach was used to measure the fungicides myclobutanil, tebuconazole and epoxiconazole in vinegar and juice. Acidic vinegar and juice reacted with the carbonate to produce effervescence in situ, which then promoted contact of the sample with the extraction solvent. The 1-dodecanol extraction solvent helped solidify the floating organic droplets and could be fully dispersed by effervescence. The extraction solvent, salt, carbonate, and extraction time were optimised. The optimal conditions were 200 μL of 1-dodecanol, 100 mg of sodium chloride, 50 mg of sodium bicarbonate, and 30 s of extraction time. The proposed method has good linearity between 10 and 1000 ng mL−1. Recoveries were between 70.4% and 103.1% in different vinegar and juice samples. This method was successfully used to measure fungicides in vinegar and juice. This system is simple, fast and environmentally friendly.

Combination of sugar and stable isotopes analyses to detect the use of nongrape sugars in balsamic vinegar must.

"Aceto Balsamico di Modena" (ABM) is a protected geographical indication salad dressing obtained from cooked and/or concentrated grape must, with the addition of wine vinegar and a maximum of 2% caramel (EU Reg 583/2009). In this study, we investigated whether the combination of 13 C/12 C of ethanol using isotope ratio mass spectrometry with 2 H-site-specific natural isotope fractionation-nuclear magnetic resonance and minor sugars using ion chromatography with pulse amperometric and charged aerosol detection is able to improve detection of sugar addition to ABM must. A large selection of authentic Italian grape musts and different samples of balsamic vinegar with an increasing percentage of added beet, cane, and sugar syrups were considered. The possible degradation of sugars in the ABM matrix during shelf life was also investigated. While stable isotope ratios analysis remains the favoured method for determining cane and beet sugar addition, dosage of minor sugar (in particular maltose) proved to be very useful for detecting the addition of sugar syrup. Thanks to this innovative approach, 3 out of 27 commercial ABMs were identified as adulterated. A combination of stable isotope ratio and ion chromatography with pulse amperometric and charged aerosol detection analysis can be therefore proposed as a suitable tool for detecting the authenticity of ABM must.

Shelf‐life extension and quality improvement of a Portuguese traditional ready‐to‐eat meat product with vinegar

SummaryCabeça de xara is a traditional ready‐to‐eat meat product (RTEMP) from the Portuguese region of Alentejo. It is a moulded galantine made of low value pork pieces. The aim of this work was to test the addition of vinegar in reducing the spoilage microbiota, as well as controlling Listeria monocytogenes, in order to increase the shelf‐life of cabeça de xara. Physicochemical (fatty acids and biogenic amines profiles), microbiological (mesophiles, psychrotrophic bacteria, enterobacteria, yeasts and L. monocytogenes) and sensory analyses were performed throughout the storage period. RTEMP vinegar samples always showed lower microbiological counts than control samples. Moreover, RTEMP vinegar samples showed significantly lower contents in vasoactive amines throughout the storage period, which might be explained by their significantly lower enterobacteria counts. Concerning sensory analysis, RTEMP vinegar samples generally scored higher in overall appreciation. Our results showed that shelf‐life of cabeça de xara may be extended from 1 to 3 months.