Physicochemical properties and antioxidant activities of commercial vinegar drinks in Korea

Pro-Health Potential of Fruit Vinegars and Oxymels in Various Experimental Models

Fruits are excellent sources of substrate for various fermented products, including fruit vinegars, which are typically produced by submerged fermentation. Some evidence suggests that fruit vinegar consumption can alleviate certain disorders, including hyperlipidemia, inflammation, and hyperglycemia. Fruit vinegars also have bacteriostatic and antihypertensive actions. Recent studies also suggest that apple vinegar may offer benefits in treating insulin resistance, osteoporosis, and certain neurological diseases such as Alzheimer's disease; it may also support weight loss. Recent studies in animal and human models have considerably broadened our understanding of the biological properties of not only fruit vinegars but also oxymels, i.e., mixtures of vinegar and honey or sugar. This paper reviews the current state of knowledge regarding vinegars and oxymels, with a special emphasis on their chemical composition and the mechanisms behind their biological activity and pro-health potential. The multidirectional effects of fruit vinegars and oxymels result from the synergy of different chemical compounds, including organic acids (mainly acetic acid), phenolic compounds, vitamins, minerals, and fermentation products. However, more studies are needed to understand the interactions between all the different components, not only the phenolic compounds and organic acids. In addition, more research is needed on their mechanisms of action. Although no serious side effects have been noted to date, further studies with large sample sizes are needed to understand the possible side effects of long-term fruit vinegar and oxymel use.

Investigation of Zhenjiang Aromatic Vinegar Production Using a Novel Dry Gelatinization Process

The traditional process of producing Zhenjiang aromatic vinegar faces challenges such as high water usage, wastewater generation, raw material losses, and limitations in mechanization and workshop conditions. This study introduces and evaluates a novel dry gelatinization process, focusing on fermentation efficiency and the vinegar flavor profile. The new process shows a 39.1% increase in alcohol conversion efficiency and a 14% higher yield than the traditional process. Vinegar produced through the dry gelatinization process has a stronger umami taste and a higher lactic acid concentration. Both processes detected 33 volatile substances, with the dry gelatinization process showing a notably higher concentration of 2-methylbutanal, which imparts a distinct fruity and chocolate aroma. These findings suggest that the dry gelatinization process outperforms the traditional process in several aspects.

Contribution to the Evaluation of Physicochemical Properties, Total Phenolic Content, Antioxidant Potential, and Antimicrobial Activity of Vinegar Commercialized in Morocco

Vinegar is a natural product widely used in food and traditional medicine thanks to its physicochemical properties and its richness in bioactive molecules. However, its direct use by consumers can have complications and undesirable effects. Therefore, this study contributes to investigating the physicochemical and biological properties of eleven vinegars marketed in Morocco. Determination of pH, acetic acid, conductivity, total soluble solids and alcohol content in vinegar was carried out. The polyphenols (TP), flavonoids (TF), and condensed tannins (CT) content was determined, and their antioxidant activities were evaluated using 2,2-diphenyl-1-picryl Hydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP) and Phosphomolybdenum Reduction Assay (TAC). Then, the antimicrobial activity was studied against four pathogenic bacteria and two fungal strains, using the disk diffusion and the microdilution method. This study showed a wide range of acetic acid values from 0.65 ± 0.29 to 5.15 ± 0.20%. The high value of TP, TF, and CT in our samples V10, V9, and V4 was 655.00 ± 22.2 µgGAE/mL, 244.53 ± 11.32 µgQE/mL and 84.63 ± 1.00 µgTAE/mL, respectively. The tested strains showed variable sensitivities to the different samples with inhibition zones ranging from 6.33 ± 2.08 to 34.33 ± 0.58 mm. The lowest minimum inhibition concentrations were recorded against Staphylococcus aureus ATCC29213 ranging from 1.95 to 7.81 µL/mL. While Aspergillus niger ATCC16404 showed resistance against all of the analyzed samples. In general, vinegar commercialized in Morocco presents a variable range of products with variable properties. Indeed, must take into account this diversity when using it. A future study is needed to identify the phytochemical composition that will further the comprehension of this variability and contribute to its valorization.

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.

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.

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.

Screening and molecular characterization of new thermo- and ethanol-tolerant Acetobacter malorum strains isolated from two biomes Moroccan cactus fruits

Industrially, the sensitivity of acetic acid bacteria (AAB) to the high temperatures and the high ethanol concentrations is the major concerns for manufacturers. This study was conceived and designed to isolate and identify new thermo- and ethanol-tolerant AAB from Opuntia ficus-indica L. fruits. As a result, among 140 isolated bacterial strains, five selected strains (CR1, CR5, CR23, CZ2, and CZ15) exhibited important acetic acid production until 40 °C. The use of 16S rDNA gene analysis was insufficient to identify selected bacteria. Indeed, except CR5 that presented 100% similarity to A. cerevisiae, the other strains presented similar homology rates simultaneously to the 16S rDNA sequences of A. cerevisiae and A. malorum. The reidentification by 16S-23S rDNA gene sequencing showed that CR1, CR23, and CZ15 were A. malorum, which were shown tolerance to the highest concentration of ethanol (12%) and produced elevated amount (40 g/L) of acetic acid at 37 °C. In summary, we showed the thermotolerance and ethanol tolerant character of new A. malorum strains, which can be used as a starter for vinegar production. Furthermore, during the molecular characterization of the isolated strains, we concluded that 16S-23S rDNA internal transcribed spacer sequence is of great importance for discriminating between AAB species as a complement to the identification by 16S rDNA sequencing.

Effects of Organic Acids, Amino Acids and Phenolic Compounds on Antioxidant Characteristic of Zhenjiang Aromatic Vinegar

Zhenjiang aromatic vinegar (ZAV) is one of the famous Chinese vinegars, which contains various physicochemical and bioactive compositions. In the present study, physicochemical properties and total antioxidant activity were detected in ZAV samples. The correlation between of organic acids, amino acids, phenolic compounds, and the antioxidant activity of ZAV were explored. The results showed that contents of total acids, soluble solids, reducing sugar and total antioxidant activity in ZAV were increased with aging time, and those in ZAV-5 were the highest. Organic acids and amino acids exhibited weak antioxidant activity, while phenolic compounds had higher antioxidant ability. In addition, amino acids had synergistic effect on the antioxidant activity of phenolic compounds, whereas organic acids inhibited the antioxidant activity of phenolic compounds. Moreover, it was found that phenolic compounds including catechin, vanillic acid and syringic acid showed higher contribution rates to antioxidant activities of mixed phenolic compounds. In conclusion, these findings would provide references to control the antioxidant characteristic of vinegar through regulating the main compositions, and further improve the quality of vinegar production.

Evaluation of Nutritional Compositions, Bioactive Compounds, and Antioxidant Activities of Shanxi Aged Vinegars During the Aging Process

Shanxi aged vinegar (SAV) is known as famous fermented food in China. During the brewing process, a large number of nutritional substances and bioactive compounds are produced, which have beneficial effects on human body. In this study, the contents of nutritional compositions including proteins, fats, carbohydrates, organic acids, and amino acids were determined in SAV samples. The antioxidant compounds and properties of SAV with different aging time were also evaluated. The results showed that the contents of proteins, crude fats, and carbohydrates in SAV were not changed with the aging time. Moreover, Alanine was the main component of amino acids in SAV, and the total contents of amino acids were increased with the aging time. Acetic acid and lactic acid were the predominant organic acids in SAV. The contents of acetic acid and lactic acid accounted for more than 90% of the total organic acids in SAV, which were increased during the aging process of 5 years. Furthermore, total phenols, flavonoids contents, and browning index in SAV were also increased during the aging time. These antioxidant compounds showed a high correlation with the antioxidant activities of SAV measured by ferric reducing antioxidant power and 2,2'-azino-bis(3-ethylbenzthi azoline-6-sulfonic acid) assays. The contribution of polyphenolic fractions and high molecular weight melanoidins to total antioxidant activities was similar (about 49% and 48%, respectively). Our findings would provide new insights to further explore the development of new vinegar-based functional foods.

PRACTICAL APPLICATION

The analysis of nutritional compositions, bioactive compounds, and antioxidant capacities in vinegars provides a theoretical basis for the function of SAV. It also provides references for further explore the development of new-type functional and healthy vinegars.

Blueberry and honey vinegar: successive batch production, antioxidant potential and antimicrobial ability

Abstract Gourmet vinegars are versatile culinary ingredients that have aroused the interest of consumers not only for their unusual taste, but also for their health benefits. In this work, blueberry and honey wine was first obtained using a bench-scale bioreactor. This wine had high concentrations of phenolic compounds (706.18 mg GAE/mL) and appreciable free radical scavenging ability against DPPH (161.42 µmol trolox equivalent/100 mL) and ABTS•+ (356.41 µmol trolox equivalent/100 mL), as well as ferric-ion reducing antioxidant capacity (1419.86 µmol FeSO4/100 mL). In sequence, vinegar was produced from the wine in wooden barrels using successive acetification cycles. The average acetic acid concentration found in the vinegars was 4.4 g/100 mL, and the average acetic acid yield and volumetric productivity were 52.69% and 0.38 g/(L.h), respectively. Appreciable polyphenolic compounds (681.87 to 847.98 µg GAE/mL) and anthocyanin (12.8 to 15.39 mg/L) contents were found and high antioxidant activity. In addition, the vinegars demonstrated antimicrobial ability against Bacillus subtilis and Salmonella enterica Typhimurium.

The antioxidant and anti-cadmium toxicity properties of garlic extracts

Cadmium (Cd) contamination is a highly dangerous international problem because it can transfer into the food chain and become bioaccumulated, endangering human health. Cd detoxication is very interesting particularly the method providing no undesirable side effects. Cd also causes lipid oxidation that leads to undesired food quality. Garlic (Allium sativum L.) has been used as conventional food and in herbal therapy and folklore medicine as an antibacterial, antitumorogenic, and antioxidant agent for over 5000 years. In the present work, fresh garlic and pickled garlic extracted with distilled water was brought to determine antioxidant activities in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging assay, ferric reducing ability power (FRAP) assay, chelating activities, superoxide, and hydroxyl scavenging assay. The data showed that pickled garlic extracts significantly possessed more DPPH, ABTS, FRAP, superoxide, and hydroxyl scavenging assays as 11.86, 13.74, 4.9, 46.67, and 15.33 g trolox equivalent/g sample, respectively, compared with fresh one as 7.44, 7.62, 0.01, 4.07, and 8.09 g trolox equivalent/g sample, respectively. However, iron chelating activity of fresh garlic extract was higher than that of pickled garlic while there was no significant difference in the copper chelating activity of both extracts. For anti-Cd properties, pickled garlic was more effective than fresh garlic and contained less toxicity than standard diallyl disulfide (DADS). Therefore, therapeutic properties of pickled garlic favored its consumption compared with fresh and standard DADS for its antioxidant and anti-Cd properties.