Vinegar Samples Research Articles

Electrochemical Determination of Antioxidant Capacity of Traditional Homemade Fruit Vinegars Produced with Double Spontaneous Fermentation.

In the current study, the antioxidant activity of traditional homemade fruit vinegars (HMV) was estimated by measuring the rate of homogeneous redox reaction with 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS•+) using cyclic voltammetry. The antioxidant capacity of six HMV produced using traditional methods and the physicochemical characterization were measured in different vinegar production steps throughout a double spontaneous fermentation process, i.e., without any addition of yeasts or acetic acid bacteria. Their antioxidant capacity was compared with seven fruit commercial vinegars (ComV). Furthermore, the antioxidant capacity was independently measured with the TEAC (Trolox equivalent antioxidant capacity) assay, aiming at correlating with the electrochemical experimental data. Obtained results from both methods, the electrochemical and TEAC assays, interestingly indicated that all HMV have at least 10 times higher antioxidant activity than ComV. Furthermore, the large range of values for antioxidant capacity in samples of commercial vinegars from apples attested the importance of the raw material quality and technological procedures. The positive correlation between total phenolic content and antioxidant capacity measured by the two type of assays indicated that rose hip homemade vinegar (HMV5) has the highest antioxidant capacity. In contrast, the lowest levels of phenolic compounds and antioxidant capacity were found in apple and persimmon homemade vinegars (HMV1 and HMV6, respectively) which indicated that the type of fruit is crucial towards the production of high-quality vinegars. In this way, the use of traditional processes for the production of fruit vinegars proved to be very promising in terms of producing differentiated vinegars and, concomitantly, reaching high levels of health-promoting antioxidant capacities.

The Impact of Apple Variety and the Production Methods on the Antibacterial Activity of Vinegar Samples.

Apple vinegar is a natural product widely used in food and traditional medicine as it contains many bioactive compounds. The apple variety and production methods are two factors that play a major role in determining the quality of vinegar. Therefore, this study aims to determine the quality of apple vinegar samples from different varieties (Red Delicious, Gala, Golden Delicious, and Starking Delicious) prepared by three methods using small apple pieces, apple juice, and crushed apple, through determining the physicochemical properties and antibacterial activity of these samples. The antibacterial activity was studied against five pathogenic bacteria: Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli (ATB: 57), Escherichia coli (ATB: 97), and Pseudomonas aeruginosa, using two methods, disk diffusion and microdilution, for determining the minimum inhibitory concentrations and the minimum bactericidal concentrations. The results of this study showed that the lowest pH value was 3.6 for Stark Delicious, obtained by liquid fermentation, and the highest acetic acid values were 4.7 and 4% for the vinegar of Red Delicious and Golden Delicious, prepared by solid fermentation, respectively. The results of the antibacterial activity showed considerable activity of apple vinegar on the tested strains. Generally, the Staphylococcus aureus strain appears less sensitive and Pseudomonas aeruginosa seems to be very sensitive against all samples, while the other strains have distinct sensitivities depending on the variety studied and the method used. A higher antibacterial activity was found in vinegar obtained by the apple pieces method and the Red Delicious variety, with a low MIC and MBC recorded, at 1.95 and 3.90 µL/mL, respectively. This study has shown that the choice of both apple variety and production method is therefore an essential step in determining and aiming for the desired quality of apple vinegar.

Total phenolic content, antiradical, antimicrobial and antibiofilm properties of grape and apple vinegar

Antimicrobial resistance – the capability of microorganisms to resist antimicrobial agents – has been stated as a major concern for public health. The increase in spread of multi- and pan-resistant bacteria which are not treatable with present antimicrobials has brought the need for the use of alternative products. Vinegar is a natural product- produced from alcoholic fermentation- that has shown strong antimicrobial activity. The aim of this study was to determine the total phenolic content and antiradical activity of the commercial grape and apple vinegar as well as to evaluate their antibiofilm and antimicrobial activities against Staphylococcus aureus and Pseudomonas aeruginosa. Grape vinegar showed higher total acidity and total phenolic content, and lower antiradical activity (DPPH activity) compared to apple vinegar. The populations of S. aureus and P. aeruginosa were significantly reduced by neat grape and apple vinegar samples. The antibacterial activity of grape vinegar was superior to apple vinegar. While AV and GV samples at 50% concentration did not form a visible zone of inhibition against S. aureus, they showed an inhibitory effect against P. aeruginosa (16.24 mm for GV and 16.5 for AV). The vinegar applied at the lowest concentration (25%) did not show any antibacterial effect on either bacterium. Solutions containing 50% to 6.25% vinegar samples prevented almost 100% biofilm formation in both bacteria. However, solutions containing lower amounts of vinegar showed stronger inhibition of biofilm formation by P. aeruginosa. A positive correlation was found between the biofilm reducing ability of vinegar samples and their antibacterial activity in this study. Taken together, commercial grape and apple vinegar significantly reduced the viability of S. aureus and P. aeruginosa, thereby decreasing biofilm formation.

Traditional homemade Tunisian vinegars: Phytochemical profile, biological, physicochemical and microbiological properties

Grape (GV), fig (FV), prickly pear (PPV) and date (DV) vinegars are the most popular Tunisian homemade vinegars. Throughout the present study, we investigated the diversity of these fruit vinegars in terms of their physicochemical, microbiological and biological properties, as well as their phytochemical profiles. Despite a great variability between their characteristics, all vinegar samples showed significant total phenolic and flavonoid contents which ranged from 286.36 to 1636.75 mg GAE/L and from 240.58 to 755.84 mg QE/L, respectively. Through the evaluation of their antioxidant activity via DPPH, iron reducing antioxidant power (FRAP) and metal chelating assays, all vinegar samples showed important antioxidant potential which could be associated with their richness in phytochemical compounds. Indeed, 19 phytochemicals were identified using LC-MS, with the most abundant being quinic, protocatchuic, p-coumaric, and transferulic acids. Antimicrobial activity of vinegars was tested against Gram-positive and Gram-negative bacterial strains as well as against fungal strains. Results revealed that most of vinegar samples were found to be more inhibitive against bacterial strains than against fungal ones. Overall, these results indicated the high potential of Tunisia homemade fruit vinegars as antioxidant and antimicrobial agents that could be used as functional food ingredients.

Antifungal and Antibacterial Activities of Apple Vinegar of Different Cultivars.

This study was designed to assess the antimicrobial potencies of apple vinegar against pathogenic microbes. The acidity and total phenolic content were carried out by titration with NaOH 0.1 N and the Folin–Ciocalteu method, respectively, while the spread plate method, agar well diffusion, and MIC assays were used to determine the antimicrobial activities of different vinegar samples. Acidity and phenolic content were dependent on the variety, where the highest values were observed in S2 with 4.02 ± 0.04% and 1.98 ± 0.05 mg GAE/mL for acidity and total phenolic content, respectively. The spread plate method revealed that samples S1 and S2 obtained from the Red delicious variety and Golden delicious variety, respectively, inhibit the growth of all tested strains, while S3 obtained from different varieties and S4 obtained from the Gala royal variety inhibit only two microbes (Escherichia coli and Vibrio cholerae). Sample S1 presented moderate antimicrobial effect against all examined strains with a diameter of inhibition ranging from 11 ± 0.7 to 19 ± 0.5 mm and with MIC values ranging between 1/2 and 1/100. The findings of the current study confirm the usefulness of apple vinegar as a natural sanitizer that inhibits the growth of pathogenic microbes.

Potential of Ultraviolet-Visible Spectroscopy for the Differentiation of Spanish Vinegars According to the Geographical Origin and the Prediction of Their Functional Properties.

High-quality wine vinegars with unique organoleptic characteristics are produced in southern Spain under three Protected Designations of Origin (PDO), namely “Jerez”, “Condado de Huelva” and “Montilla-Moriles”. To guarantee their authenticity and avoid frauds, robust and low-cost analytical methodologies are needed for the quality control and traceability of vinegars. In this study, we propose the use of ultraviolet-visible spectroscopy in combination with multivariate statistical tools to discriminate Spanish wine vinegars according to their geographical origin, as well as to predict their physicochemical and functional properties. Linear discriminant analysis provided a clear clustering of vinegar samples according to the PDO with excellent classification performance (98.6%). Furthermore, partial least squares regression analysis demonstrated that spectral data can serve as accurate predictors of the total phenolic content and antioxidant activity of vinegars. Accordingly, UV-Vis spectroscopy stands out as a suitable analytical tool for simple and rapid authentication and traceability of vinegars.

Analysis of Antioxidant Capacity and Antimicrobial Properties of Selected Polish Grape Vinegars Obtained by Spontaneous Fermentation.

Nowadays, products of natural origin with health-promoting properties are increasingly more common. Research shows that fruit vinegars can be a source of compounds with antioxidant activity. Research on the total antioxidant capacity, total phenolic content, and antimicrobial properties against Staphylococcus aureus, Escherichia coli, and Candida albicans of grape vinegars were conducted. Moreover, gas chromatography was used to measure acetic acid content in the vinegars. The research material consisted of vinegars produced from five different grape varieties. For each variety, two variants were prepared: with and without the addition of sugar in the fermentation process. The highest antimicrobial activity against all micro-organisms was observed in vinegar produced from Solaris grapes with added sugar. The highest polyphenol content was observed in vinegar produced from the Prior grape variety with added sugar and the highest total antioxidant capacity is the Johanniter grape variety with added sugar. The vinegars examined in this study differed, depending on grape variety, in terms of antimicrobial properties, antioxidant capacity, total phenolic content, as well as acetic acid content. Sugar addition caused significant differences in the antioxidant capacity of vinegar samples.

Ultrasound Processing of Vinegar: Modelling the Impact on Bioactives and Other Quality Factors

In recent years, non-thermal technology has been used for the enrichment of ultrasound bioactive components. For this purpose, it was applied to tomato vinegar and modeled with response surface methodology (RSM) and artificial neural network (ANN). At the end of the RSM, cupric reducing antioxidant capacity (68.64%), 1,1-diphenyl-2-picrylhydrazyl (62.47%), total flavonoid content (2.44 mg CE/mL), total phenolic content (12.22 mg GAE/mL), total ascorbic acid content (2.53 mg/100 mL) and total lycopene (5.44 μg/mL) were determined. The ANN model has higher prediction accuracy than RSM. The microstructure, microbiological properties, sensory analysis, ACE (angiotensin-converting–enzyme) inhibitor and antidiabetic effects of the ultrasound-treated tomato vinegar (UTV) (8.9 min and 74.5 amplitude), traditional tomato vinegar (TTV) and pasteurized tomato vinegar (PTV) samples were then evaluated. UTV was generally appreciated by the panelists. It was determined that the microbiological properties were affected by the ultrasound treatment. UTV was found to have more effective ACE inhibitor and antidiabetic properties than other vinegar samples. As a result, the bioactive components of tomato vinegar were enriched with ultrasound treatment and positive effects on health were determined.

Cyclodextrin-based dispersive liquid–liquid microextraction for the determination of fungicides in water, juice, and vinegar samples via HPLC

Cyclodextrin-based dispersive liquid–liquid microextraction (CD-DLLME) was developed for the determination of triazole and strobilurin fungicides in water, juice, and vinegar samples using high-performance liquid chromatography-diode-array detection (HPLC-DAD). Undecanol, which is a green solvent, was selected as the extraction solvent. A cyclodextrin aqueous solution was chosen as the dispersion solvent and demulsifier to avoid the use of a toxic dispersion solvent and eliminate the centrifugation step. Dispersion and phase separation were completed within 1 and 60 s, respectively. The linear range of this method was 1 to 100 µg L−1. The limits of detection were 0.3 μg L−1 along with the preconcentration factor of 133 and enrichment factor of 124. The recovery was 83.2% to 103.2%. This pretreatment method was fast, simple, and environmentally friendly and was successfully applied to the analysis of triazole and strobilurin fungicide residues in water, juice, and vinegar samples.

Effect of Oak Chips Application on Phenolic Compounds of Wine Vinegars at Different Maturation Times

This study was conducted to investigate the effects of oak chips-supplementations on phenolic compound profiles of grape vinegar samples. Total acidity, volatile acids, non-volatile acids, pH, dry extract, ash, color, alcohol, total phenolic compound, individual phenolic compounds and aroma compounds of un supplemented control (UC) samples and oak chips-supplemented (OCS) samples were analyzed at the 0th, 1st and 3rd months of ageing. Total phenolic compound of UC vinegar samples was measured as 1256.50 mg GAE/L at the end of the 3rd month. Total phenolic compound of OCS vinegar samples was measured as 1521.03 mg GAE/L at the end of the 1st month and as 1470.67 mg GAE/L at the end of the 3rd month. Gallic acid, catechin and vanillic acid contents of UC vinegar samples were respectively measured as 8.43 mg/L, 22.26 mg/L and 1.78 mg/L at the end of the 3rd month. Gallic acid, catechin and vanillic acid contents of OCS vinegar samples were respectively measured as 19.12 mg/L, 17.98 mg/L and 2.58 mg/L at the end of the 3rd month. The 3-hydroxy-2-butanone, hexadecanoic acid methyl ester, 9,12-octadecadienoic acid methyl ester and 9-octadecanoic acid methyl ester quantities increased at the end of the 3rd month with oak chips-supplementation to ageing process. It was observed that oak chips-supplementation increased total phenolic compound and some individual phenolics of grape vinegar samples.

A Methodology Based on FT-IR Data Combined with Random Forest Model to Generate Spectralprints for the Characterization of High-Quality Vinegars.

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint (“spectralprint”) of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.

Determination of the Synthetic Antioxidants Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT) by Matrix Acidity-Induced Switchable Hydrophilicity Solvent-Based Homogeneous Liquid-Liquid Microextraction (MAI-SHS-HLLME) and High-Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV)

A rapid and easy sample pretreatment procedure, matrix acidity-induced switchable hydrophilicity solvent-based homogeneous liquid-liquid microextraction, has been developed for the isolation of the synthetic antioxidants butylated hydroxyanisole and butylated hydroxytoluene from vinegar samples. Di-(2-ethylhexyl)phosphoric acid (DEHPA) was selected as the extraction solvent and its hydrophilic form was obtained in alkaline solution followed by the addition of vinegar, which acted as both the sample and the inductor of the switching reaction leading to the formation of DEHPA microdroplets. There was no need to centrifuge at this step, since the DEHPA phase containing the analytes was collected from the resulting mixture through magnetic retrieval due to its high affinity for Fe3O4 nanoparticles. After being magnetically separated, the desorbed analytes were analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Under the optimized conditions, the limits of detection for the analytes were between 3.2 and 5.5 µg L−1 and the linear dynamic range was from 10 to 500 μg L−1. Good precision was obtained with relative standard deviations less than 7.8%. Recovery assays for spiked apple, grape, and white vinegar provided recoveries from 86 to 105%.

Alteration of Antioxidant Activity and Total Phenolic Content during the Eight-Week Fermentation of Apple Cider Vinegar

Apple is one of the delicious fruit consumed by people. Apple cider vinegar was made through the traditional method and the changes occurred during the 8 week fermentation period were determined in this research. Total titratable acidity, pH, total soluble solids (°brix), total phenolic contents, Oxygen Radical Absorbance Capacity (ORAC) and Trolox Equivalent Antioxidant Capacity (TEAC) assays, phenolic contents were determined. Total phenolic substance, ORAC and TEAC values increased significantly weekly and reached the highest level in the 3rd week. Total phenolic substance, ORAC and TEAC values of 3rd week apple vinegar were determined as 1110.63 mg GAE L-1, 10.92 mM and 21.11 µmol TE mL-1, respectively. Apple vinegar samples had gallic acid, catechin, epicatechin, chlorogenic acid, and p-coumaric acid. The major phenolic substances in apple vinegar were gallic acid and chlorogenic acid. While gallic acid value of 3rd and 4th week apple vinegar were detected 11.91 and 23.69 mg L-1, respectively; chlorogenic acid value of 4th and 5th week apple vinegar were found 46.36 and 49.71 mg L-1. Antioxidant activity and phenolic substances values were not significant reduction during the acetic acid fermentation. In this study, the formation process of the functional and sensory properties of apple cider vinegar due to the change in the weekly antioxidant and bioactive component content of apple cider vinegar was emphasized.

Study on Production Vinegar from Apple

The goal of the present study was to ascertain the effect of the addition of certain natural materials such as sugar or Jaggery Syrup, Black Gram, or extracts there of as fortified materials on the consistency of apple vinegar and the types of microorganisms in it. The findings revealed that the addition of whole legume or their extracts during processing enhanced the properties of the resulting vinegar . The findings showed that the better pH was for apple vinegar produced with the inclusion of sugar and protein extract, which had a pH of 3.1. This was accompanied by vinegar resulting from the addition of jaggery with whole legume, where the pH was 3.8, followed by vinegar resulting from the addition of whole legume plus sugar, where the pH was 3.9. Though apple vinegar obtained by adding protein extract with jaggery had a pH of 4.As it was influenced by the acidity of the resultant vinegar due to the content of legumes and sugary compounds, the maximum acidity was 6.5 in the vinegar to which entire legume jaggy was applied. Then vinegar, to which whole legume sugar was added, and vinegar, to which jaggy with protein extract was added, the acidity reached 3. Finally, vinegar made by combining sugar with protein extract, where the acidity reached 2. The best types of vinegar were selected from among the samples (vinegar developed by the addition of protein extract jaggary) and the contents of its microbiology were analysed. The results showed that the vinegar was free of bacteria and yeasts, while its content of moulds was . The four samples of vinegar also showed good antioxidant activity. It was 86.77%, 85.38%, 79.0% and 19.11% in vinegar containing jaggery with extract protein, sugar with extract protein, jaggery with whole legume and sugar with whole legume respectively. The total soled of vinegar were different, 4.8%, 4.5%, 4.0% and 3.0% in vinegar containing jaggery with whole legume, jaggery with extract protein, sugar with whole legume and sugar with extract protein. The colour analysis of the vinegar sample containing the jaggery with extract protein was 75.91, 4.87, 51.4 for the lighter side, red colour and greener side, respectively.

Fig Vinegar as an Antioxidant and Antimicrobial Agent

Fig vinegar is a special product which has a long history and is handed down from generation to generation. In the current study, characteristics of homemade fig vinegars supplied from different cities of Turkey were compared in terms of their physicochemical, antioxidant and antimicrobial properties. Physicochemical properties of the samples were very diverse. Total phenolic and flavonoid content, and ABTS+ and DPPH radical scavenging activities of the samples were ranged from 313.5 to 594.25 mg GAE/L and 42.52-132.42 mg catechin/L, and 0.44-3.98 µg TE/mL and 1.25-7.51 µg TE/mL, respectively. The antioxidant activity of vinegars is highly correlated with their phenolic and flavonoid contents. Furthermore, vinegar samples exhibited inhibitive effect on all test microorganisms and the minimum inhibition concentration values were ranged between 0.39 and 25% (v/v). These results indicated the distinct properties of homemade fig vinegars and the potential of them as antimicrobial and antioxidant substances.

Application of Microwaves as an Advanced Technique for the Development of Sherry Vinegar Macerated with Pineapple

This work proposes the elaboration of a product based on the maceration of Sherry Vinegar together with pineapple in order to extract certain volatile compounds that can be found in pineapples, giving a final product with new organoleptic properties and increased polyphenolic content. Maceration trials were carried out with the application of microwaves and ultrasound, which reduced the maceration time from the traditional three-day solid-liquid maceration to just a few minutes. In addition, through maceration, the total polyphenol index increased significantly with respect to unmacerated vinegar, and the volatile profile of the vinegars was significantly modified. The tasting scores placed the pineapple macerated vinegar sample obtained by traditional maceration in the first place with respect to pineapple aroma; however, the microwave extraction samples were better rated in terms of overall quality. It can be concluded that the application of extracting energies, such as microwaves, can be a viable alternative for the production of sherry vinegar macerated with pineapple.

Simulation and Non-Invasive Testing of Vinegar Storage Time by Olfaction Visualization System and Volatile Organic Compounds Analysis.

An olfactory visualization system conducts a qualitative or quantitative analysis of volatile organic compounds (VOCs) by utilizing the sensor array made of color sensitive dyes. The reaction chamber is important to the sensor array’s sufficient and even exposure to VOCs. In the current work, a reaction chamber with an arc baffle embedded in the front of the air inlet for drainage effect was designed. The velocity of field and particle distribution of flow field in the reaction chamber was simulated by COMSOL Multiphysics. Through repeated simulation, the chamber achieved optimal result when the baffle curvature was 3.1 and the vertical distance between the baffle front end and the air inlet was 1.6 cm. Under the new reaction chamber, principal component analysis (PCA) and linear discriminant analysis (LDA) were employed to identify vinegar samples with different storage time through analyzing their VOCs. The LDA model achieved optimal performance when 8 principal components (PCs) were used, and the recognition rate was 95% in both training and prediction sets. The new reaction chamber could improve the stability and precision of an olfactory visualization system for VOCs analysis, and achieve the accurate differentiation and rapid discrimination of Zhenjiang vinegar with different storage time.

Characterization and identification of different Chinese fermented vinegars based on their volatile components.

In this study, volatile components of 40 Chinese fermented vinegar samples, made from different raw materials, starters, and processing technologies, were collected from different geographic origins in China (Shanxi, Jiangsu, Sichuan, and Fujian Province) and their volatile components were analyzed by headspace-solid-phase microextraction-gas chromatography-mass spectrometry. Sixty-two aroma compounds have been identified by NIST library combined with retention index, mainly including esters, heterocyclics, acids, aldehydes, and ketones. In addition, multivariate analysis including principal component analysis and partial least squares-discriminant analysis (PLS-DA) were carried out to discriminate vinegars based on their composition of volatile components. For PLS-DA models, analysis of variance (ANOVA) or variable importance in the projection (VIP) value were used to select variables with the highest discriminatory power, and the Kennard-Stone algorithm was used to select the training and testing samples. The PLS-DA models (ANOVA or VIP) all provided a classification accuracy of 100% for the training set, and subsequent application of these models allowed the grouping of unknown samples (testing set) according to their characteristics (raw materials and processing technology). PRACTICAL APPLICATIONS: Traditional Chinese vinegars have a long history but nowadays adulterations of them are becoming a problem in the market. In this study, Chinese fermented vinegars from different varieties were identified based on volatile composition. We found that starter cultures and fermentation process have the greatest influence on the volatile components of vinegars, while the influence of raw material and steaming of raw material are weaker volatile components. Then, partial least squares-discriminant analysis models, we carried out could successfully be applied to predict unknown vinegar samples based on a database of volatile components. This study provided a strategy to detect the identity of different vinegars, which can also be used to monitor the quality and safety of traditional Chinese vinegars.

Biological Control of Phytopathogenic Fungi by Kluyveromyces marxianus and Torulaspora delbrueckii Isolated from Iraqi Date Vinegar

Yeasts are distributed in all environments and have been reported as potential biocontrol agents against various phytopathogenic fungi. To investigate their enzymatic and biological activities, 32 yeasts were isolated from 15 date vinegar samples. Evaluation of the antagonistic activities of isolated yeasts against the plant pathogens Fusarium oxysporium, Sclerotinia sclerotiorum, and Macrophomina phaseolina indicated that there are two yeasts had the highest inhibitory effect against plant pathogens, these yeasts identified as Kluyveromyces marxianus and Torulaspora delbrueckii using traditional and molecular methods. These yeast isolates were tested for fungal cell wall degrading enzymes (in vitro), and results indicated that the yeasts had strong protease and amylase enzyme activity and moderate chitinase and cellulase enzyme activity. The antagonistic activities of each yeast were evaluated using a dual culture technique. The results showed that K. marxianus inhibited the mycelial growth of F. oxysporium, S. sclerotiorum, and M. phaseolina by 70.5, 57.5, and 75.5%, respectively, whereas T. delbrueckii inhibited mycelial growth of F. oxysporum, S. sclerotiorum, and M. phaseolina by 55.3%, 66.2%, and 31.11%, respectively. The biofilm production assay indicated that the tested yeast could form biofilms as a mechanism of antagonistic activity against phytopathogenic fungi.

An Investigation of Moroccan Vinegars: Their Physicochemical Properties and Antioxidant and Antibacterial Activities

Vinegar is a natural product rich in bioactive compounds such as phenols, flavonoids, and organic acids. Several factors affect the quality of vinegars such as apple origin, environmental conditions, production methods, processing, and storage conditions. We investigated the quality of apple vinegars as well as their physicochemical properties and the antioxidant and antibacterial activities of vinegars collected from different areas in Morocco. For physicochemical properties, the outcomes showed the following values: pH (3.18–3.83), electrical conductivity (2.11–2.90), acidity (0.24–5.6), Brix (3.25–6), and density (1.0123–1.0233). The polyphenols content of samples was 68.91 mg AG/100 mL in sample S6 as the minimum value and 147.54 mg AG/100 mL in sample S2 as the maximum value. The best ability to scavenge the DPPH radical was observed in sample S3 (IC50 = 0.45 ± 0.013 µL/mL). Sample S2 showed moderate antibacterial effect against microorganisms tested with MICs ranging from 0.78 µL/mL to 1.125 µL/mL and with a diameter of inhibition ranging from 15.65 mm to 27.65 mm. In addition, a strong correlation was observed between the antibacterial activity of vinegars and physicochemical parameters (pH and total acidity). These outcomes have shown that our vinegar samples are an excellent source of bioactive compounds with potent antioxidant and antibacterial potentials.