Acid In Wine Research Articles

Levels of 5-hydroxymethylfurfural, furfural, 2-furoic acid in sapa syrup, Marsala wine and bakery products

ABSTRACTIn the last years, the attention to the potential carcinogenic effects of the 5-hydroxymethylfurfural in the human health is increased. This compound is used as a marker of honey adulteration and as an indication of thermal treatment of food containing sugars. In this study, we evaluated the content of 5-hydroxymethylfurfural, furfural, 2-furoic acid, in sapa syrup, Marsala wines and bakery products containing sapa. Average levels of 5-hydroxymethylfurfural in sapa syrup were 2.3 ± 0.8 g/kg while in bakery products were 167 ± 133 mg/kg. Moreover, levels of 5-hydroxymethylfurfural in Marsala wine were 175 ± 150 mg/L. In addition, bakery products showed levels of furfural and furoic acid equal to 7.0 ± 4.5 and 48 ± 46 mg/kg, respectively, while furfural and furoic acid levels of 3.7 ± 1.7 and 27 ± 18 mg/L in Marsala wines. The present study suggested that 5-hydroxymethylfurfural can be used as a marker to fingerprint the use of sapa in food preparation.Abbreviations: DAD: diode array detector, F: furfural, FA: 2-furoic acid, HPLC: high performance liquid chromatography, HMF: 5-hydroxymethylfurfural; LOD: limit of detection, LOQ: limit of quantification, SMF: 5-sulfoxymethylfurfural, TCA: trichloroacetic acid.

Simultaneous analysis of sugars and organic acids in wine and grape juices by HPLC: Method validation and characterization of products from northeast Brazil

Organic acids and sugars are related to the chemical balance of wines and grape juices, besides exerting a strong influence on the taste balance and sensorial acceptance by consumers. The aim of this study was to validate a method for the simultaneous determination of sugars and organic acids in wines and grape juices by high-performance liquid chromatography (HPLC) with refractive index detection (RID) and diode array detection (DAD) and to characterize commercial products from northeast Brazil. The method provided values for linearity (R > 0.9982), precision (CV% < 1.4), recovery (76–106%) and limits of detection (0.003–0.044 g L−1) and quantification (0.008–0.199 g L−1) which are considered acceptable for application in the characterization of these types of matrices. Principal components analysis (PCA) was used to verify the applicability of the method in the quality control of the products and resulted in the correct separation of the samples according to their type of processing. The results obtained in the characterization of the samples studied showed high levels of glucose and fructose in grape juice and the organic acids content was similar to those found in products originating from other regions around the world.

Grape and wine amino acid composition from Carignan noir grapevines growing under rainfed conditions in the Maule Valley, Chile: Effects of location and rootstock

Nitrogen compounds play a key role on grape and wine quality. Their composition in grapes depends mainly on variety, viticultural management, and terroir, and affects fermentation kinetics and the volatile compound formation. The aim of this work was to study grape and wine amino acid composition of ungrafted or grafted onto cv. País Carignan grapevines growing under rainfed conditions in ten sites of the Maule Valley (Chile). The results showed that proline was the most abundant amino acid in grapes and wines. In general, Carignan noir grapevines grafted over País showed lower grape amino acid content respect to ungrafted vines. Cool night index (CI) was inversely correlated to several amino acids, showing that their plant synthesis or accumulation increased with lower minimum temperatures during the last month before harvest. Truquilemu (Tru) and Ciénaga de Name (Cdn) sites showed the highest concentration for several amino acids and total amino acid content in grapes, which led to a faster alcoholic fermentation.

Selective harvest for the ‘Petit Verdot’ vinification from “Campanha Gaucha” in Rio Grande do Sul (RS), Brazil

The State of Rio Grande do Sul (RS) is the main producer state of fine grapes (Vitis vinifera L.) for the preparation of fine wine. Located in the southern half of the RS, the Campanha Gaucho is a region bounded by temperate grasslands called the “Pampa” Biome. Its climatic characteristics has enabled it to become one of the most promising regions for producing fine grapes for winemaking. In this scenario, after a selection of clusters with different levels of maturity, we sought to identify the winemaking characteristics of 'Petit Verdot', from the elaboration of a varietal wine in the traditional method, as well as their sensory characteristics (smell/taste) as a final analysis. Manual sorting of the grape bunches was defined into three divisions with three repetitions each (12 kg of grapes replication-1, totaling 108 kg), these were: sorting T1: mature grapes; sorting T2: incomplete mature grapes and; sorting T3: without sorting the bunches. Grape juice was analyzed by Fourier transform infrared spectrometry (FTIR); where we evaluated the total soluble solids, pH, total acidity, reducing sugar, malic and tartaric acid. In wine, alcohol, pH, total acidity, volatile acidity, reducing sugars, glycerol, malic and lactic acid were evaluated. Sensory analysis of wine for evaluation of its organoleptic characteristics was also carried out. The data was submitted for analysis of variance and mean comparison Tukey test at 5% significance. There were no significant variations of the compounds analyzed in the grape juice and wine cultivar 'Petit Verdot'. Of the sensory analysis results, only the acidity resulted differently between sorting T2 and sorting T1 treatments that presented higher acidity. In this context, the selection of clusters of different levels of wine for aging was not necessary for improving the quality of the wines produced.

Design of titanium nitride- and wolfram carbide-doped RGO/GC electrodes for determination of gallic acid

In the present paper, the electrochemical behavior and the properties of two modified glassy carbon (GC) electrodes used for quantification of gallic acid in sweet wines were compared. A comparative study was conducted between titanium nitride- or wolfram carbide-doped reduced graphene oxide, labeled as TNrGO and WCrGO, respectively, modified GC electrodes, which are promising composite nanomaterials for electroanalytical applications. For the first time, WCrGO was synthesized and its electroanalytical properties compared with those of TNrGO. Results showed that the proposed materials exhibited enhanced characteristics, e.g., low limits of detection (1.1 μM and 3.1 μM for TNrGO and WCrGO, respectively), wide linear ranges (for TNrGO 4.5–76 μM and for WCrGO 10–100 μM), low adsorption, and low background current, which make them promising candidates for electrochemical sensing applications.

EVALUATION OF LACTIC ACID BACTERIA GROWTH DURING AUTOCHTHONOUS ALBANIAN KALLMET WINE PRODUCTION WITH SPONTANEOUS AND INOCULATED FERMENTATIONS

The grape used in wine making has many wild microorganisms like lactic acid bacteria, yeast, acetic acid bacteria. During the alcoholic fermentation, the evaluation of these microorganisms depends on their activity. There is an interaction between yeast and lactic acid bacteria during this period of wine making. In this study, we have made wine from the autochthonous Albanian grape Kallmet variety using the spontaneous fermentation and inoculated fermentation with the yeast Saccharomyces bayannus. Yeasts carry out the alcohol fermentation, and lactic acid bacteria make malolactic fermentation in wine. With this fermentation, lactic acid bacteria convert malic acid to lactic acid, reducing the acidity of the wine and create a microbiological stability. During the alcoholic fermentation, the evaluation of lactic acid bacteria is not required. The aim of our study is to evaluate the first quantity of lactic acid bacteria to Kallmet grape, their performance during the two fermentations, spontaneous and inoculated fermentations.

Enantioseparation of amino acids by micellar capillary electrophoresis using binary chiral selectors and determination of D-glutamic acid and D-aspartic acid in rice wine

ABSTRACTA new chiral capillary electrophoresis (CE) analytical method for the determination of six pairs of amino acid enantiomer-derivatized precapillary with 9-fluorenylmethoxycarbonyl chloride (FMOC) was developed. CE separation parameters such as the pH of background electrolyte, the boric acid concentration, the addition of D-fructose and isopropanol, and the effect of new binary chiral selectors on the electropherograms were investigated. Precapillary and in-capillary derivatization was compared as well. The results showed that enantiomeric separations were obtained with enantio-resolution (Rs) ranged from 2.61 to 9.99 for the FMOC-derivatized amino acid enantiomers except alanine with Rs 1.06. Precapillary derivatization method provides overall better Rs for nearly all the targets except FMOC-aspartate with efficiency up to 1.309 × 106 plates and limit of detection (LOD) down to 2.5 μM. This method was successfully applied to analyze the concentration of the D/L-glutamic acid and D/L-aspartate in seven rice wine samples.

Silica-alginate-encapsulated bacteria to enhance malolactic fermentation performance in a stressful environment

Background and Aims Beginning and completion of malolactic fermentation (MLF) are complicated because of the harsh environment of wine. Encapsulation of lactic acid bacteria could be an attractive strategy to improve their activity and stability. This work evaluates the fermentative capacity of Oenococcus oeni encapsulated into silica–alginate (Si–Al) and alginate capsules under adverse winemaking conditions (high alcohol concentration, low pH and low temperature). Mechanical and chemical stability of capsules was also monitored. Methods and Results Silica–alginate capsules showed higher malolactic activity and better mechanical and chemical stability than untreated alginate capsules. Their capacity for bacteria retention was similar to that of alginate capsules. Ethanol, pH and fermentation temperature had great influence on fermentative behaviour of free and encapsulated bacteria. Under extreme winemaking conditions, such as high ethanol concentration (13–16%), low pH (3.0–3.3) and low fermentation temperature (13–15°C), the highest consumption of malic acid was achieved using Si–Al capsules. Free and encapsulated bacteria showed similar fermentative profiles in the presence of variable concentration of malic acid and nitrogen in wine. Conclusions Encapsulated O. oeni in Si–Al gels enhanced MLF in wines with a high concentration of ethanol and low pH and at low fermentation temperature. Moreover, inclusion of an inorganic network of silicates significantly improved the mechanical robustness and chemical stability of alginate capsules. Significance of the Study The application of Si–Al-encapsulated bacteria is an interesting strategy to improve MLF in warm climates where wines have higher ethanol concentration and in cool climates with higher acidity and low fermentation temperature.

Physicochemical characteristics and antioxidant activity of persimmon wine by technology of pectinase addition and different pre‐macerations

Effects of pectinase addition and different pre-maceration technologies on physicochemical characteristics and antioxidant activity of persimmon wine brewed from two cultivars, Amahyakume and Jinpingshi, were investigated. Results showed that pectinase addition significantly promoted increases of clarity and malic acid, meanwhile reduced titratable acid and color intensity in persimmon wine. Moreover, it induced remarkable increases of predominant phenolic compounds and antioxidant activity in wine. These improvements were also found under three pre-maceration treatments, among which thermovinification showed the best effects as nine different phenolic profiles increased significantly as determined by HPLC analysis. Furthermore, combination treatment of thermovinification and pectinase addition resulted in the highest phenolic concentration and antioxidant potential, reducing content of acetic acid. In addition, changes caused by different treatments were almost similar in two cultivars, whereas Jinpingshi wine possessed prevalent higher phenolic contents and antioxidant activity than Amahyakume wine. Practical application Persimmon wine possesses high development prospects as a deep processing product of persimmon industry. Constant improvement of fermentation technology in wine-making provides essential fundamental supports for industrialization of persimmon wine. This study investigated the influence of pectinase addition and different pre-maceration technologies on physicochemical characteristics and antioxidant activity of persimmon wine. These results could conduce to the establishment of optimal conditions for producing persimmon wines with desired beneficial compounds.

Determination of amines and phenolic acids in wine with benzoyl chloride derivatization and liquid chromatography–mass spectrometry

Amine and phenolic metabolites are important contributors to the flavor and health effects of many foods, including wine. Determination of these metabolites often involves UV detection following separation by liquid chromatography. While this is sufficient for some applications, chemical derivatization with LC–MS provides greater sensitivity and selectivity relative to LC-UV.We have developed an assay for 56 amine and phenolic metabolites in wine using benzoyl chloride derivatization and LC–MS. Isotopically labeled benzoyl chloride was used to prepare internal standards for each metabolite. Nanomolar limits of detection were achieved for all metabolites. To demonstrate the application of this assay, we compared metabolite profiles from Merlot and Cabernet Sauvignon wines from California and Australia. We found five metabolites which were significantly different when grouped by varietal, while twenty-four were different when grouped by location of production. This shows that the method can identify differences between various wines.

Highly Efficient Malolactic Fermentation of Red Wine Using Encapsulated Bacteria in a Robust Biocomposite of Silica-Alginate.

Bacteria encapsulation to develop malolactic fermentation emerges as a biotechnological strategy that provides significant advantages over the use of free cells. Two encapsulation methods have been proposed embedding Oenococcus oeni, (i) interpenetrated polymer networks of silica and Ca-alginate and (ii) Ca-alginate capsules coated with hydrolyzed 3-aminopropyltriethoxysilane (hAPTES). On the basis of our results, only the first method was suitable for bacteria encapsulation. The optimized silica-alginate capsules exhibited a negligible bacteria release and an increase of 328% and 65% in L-malic acid consumption and mechanical robustness, respectively, compared to untreated alginate capsules. Moreover, studies of capsule stability at different pH and ethanol concentrations in water solutions and in wine indicated a better behavior of silica-alginate capsules than untreated ones. The inclusion of silicates and colloidal silica in alginate capsules containing O. oeni improved markedly their capacity to deplete the levels of L-malic acid in red wines and their mechanical robustness and stability.

Determination of γ -aminobutyric acid in Chinese rice wines and its evolution during fermentation

γ-Aminobutyric acid (GABA) is a functional amino acid that is widely present in Chinese rice wine. In this study, high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV) was established for the determination of γ-aminobutyric acid in 22 Chinese rice wines collected from the Shaoxing region of China. Furthermore, the evolution of GABA was studied in Chinese rice wine during primary and post-fermentation process. Results showed that the HPLC method was reliable with good linearity, accuracy, precision and stability. Additionally, the GABA content varied significantly in the 22 Chinese rice wines, and the content was much higher in wine samples with long aging periods. Regarding the evolution of GABA in Chinese rice wine during the brewing process, the level slowly increased during primary fermentation. A decrease in GABA was observed in the wine at the early stage of the post-fermentation process. However, a marked increase on the GABA content occurred in wine at the late stage of post-fermentation. The findings from this study are that HPLC can be successfully applied to determine GABA in Shaoxing brewed rice wines, and further provide useful information on quality control of such wines. Copyright © 2017 The Institute of Brewing & Distilling

A voltammetric determination of caffeic acid in red wines based on the nitrogen doped carbon modified glassy carbon electrode

We reported an electrochemical determination of caffeic acid (CA) based on the nitrogen doped carbon (NDC). The described sensor material was prepared by the flame synthesis method, which gave an excellent platform for the synthesis of carbon nanomaterials with the hetero atom dopant. The synthesized material was confirmed by various physical characterizations and it was further characterized by different electrochemical experiments. The NDC modified glassy carbon electrode (NDC/GCE) shows the superior electrocatalytic performance towards the determination of CA with the wide linear concentration range from 0.01 to 350 μM. It achieves the lowest detection limit of 0.0024 μM and the limit of quantification of 0.004 μM. The NDC/GCE-CA sensor reveals the good selectivity, stability, sensitivity and reproducibility which endorsed that the NDC is promising electrode for the determination of CA. In addition, NDC modified electrode is applied to the determination of CA in red wines and acquired good results.

Development of a quantitative method for organic acid in wine and beer using high performance liquid chromatography.

This study was conducted to compare the organic acid content in liquors (red wine, white wine, and beer) using three different high-performance liquid chromatography analysis methods. Post-column reaction methods (method 2 and 3) were found to be more promising than UV-detection method (method 1). Using method 2 (two columns), the analyzed red wine was found to contain 2,652.4 mg/L tartaric acid and 1,392.9 mg/L lactic acid but relatively lower amounts of malic acid (271.0 mg/L). Furthermore, tartaric acid (1,160.8-2,749.1 mg/L) and malic acid (470.2-3,107.9 mg/L) were the major components in white wine. Beers were analyzed using method 3 (one column). In the analyzed foreign beers, lactic acid (95.9-226.4 mg/L), malic acid (62.2-110.5 mg/L), acetic acid (93.5-183.8 mg/L), and succinic acid (37.0-56.2 mg/L) were detected. Similar to the foreign beers, the contents of succinic acid in the domestic beers were the lowest. The proposed methods could be useful for quantitative analysis of organic acids in wine and beer.

Effect of Juice Turbidity and Yeast Lees Content on Brandy Base Wine and Unmatured Pot-still Brandy Quality

The aims of this project were to identify a suitable grape juice clarification technique for the attainment of the optimal brandy base wine turbidity, to determine the importance of chemical components (volatile components and long-chain fatty acids) in brandy base wine and unmatured pot-still brandy quality, and to study the effect of yeast lees content on quality. Although common industry practice is to use the grape cultivars Colombar(d) and Chenin blanc for the production of brandy base wine, the optimal conditions for Chenin blanc have been defined in this study. The juice clarification treatments applied included no settling, cold settling, whisk, large- and small-scale centrifugation and bentonite. Yeast strain 228 was compared with VIN13, large-scale (L) distillation was compared with small-scale (s) distillation, and the use of no enzyme was compared with the use of pectolytic enzyme. The data for four vintages were compiled and evaluated. Settling with or without pectolytic enzyme, bentonite, small-scale centrifugation and whisk treatments gave clearer Chenin blanc juice, higher concentrations of certain volatile components and long-chain fatty acids, and higher quality brandy base wine and unmatured pot-still brandy. No settling and large-scale centrifugation yielded the most turbid and lowest quality products. There is a definite relationship between treatments, turbidity, concentrations of esters, higher alcohols and acids, and overall brandy base wine and unmatured pot-still brandy quality. The use of yeast strain VIN13 (as opposed to strain 228), in conjunction with an increased yeast lees content of 1.5x that is normally found in brandy base wine, yielded the best quality unmatured pot-still brandy. Based on the results of this study, it is possible to recommend the best juice clarification method(s) for optimal turbidity as well as optimal levels of yeast lees addition, and to identify chemical compounds that positively relate to quality.

Structural characterization of reaction products of caftaric acid and bisulfite present in a commercial wine using high resolution mass spectrometric and nuclear magnetic resonance techniques.

Reaction products of bisulfite and caftaric acid were found in wines containing sulfites as a preservative. Acidic compounds were separated from wine and analyzed by HPLC combined with DAD and QTOF mass spectrometer. HPLC chromatograms of the expected [M-H]- ion and UV absorption revealed the presence of five possible reaction products (a-e). These compounds were isolated then characterized by NMR and confirmed to be the reaction products as follows; 5-sulfo-(E)-caftaric acid (a), 2-sulfo-(Z)-caftaric acid (b), 2-sulfo-(E)-caftaric acid (c), (E)-caftaric acid-4-O-sulfate (d) and (E)-caftaric acid-3-O-sulfate (e). UV spectra and high resolution product ion spectra of the five compounds also supported their identity. The reaction products were confirmed to be commonly present in commercial wines across four vintages and two varieties. Their concentration was found to be as much as that of 2-S-glutathionyl caftaric acid, suggesting that bisulfite consistently competes as a nucleophile with glutathione for the o-quinone of caftaric acid.

Malic Acid in Wine: Origin, Function and Metabolism during Vinification

The production of quality wines requires a judicious balance between the sugar, acid and flavour components of wine. L-Malic and tartaric acids are the most prominent organic acids in wine and play a crucial role in the winemaking process, including the organoleptic quality and the physical, biochemical and microbial stability of wine. Deacidification of grape must and wine is often required for the production of well-balanced wines. Malolactic fermentation induced by the addition of malolactic starter cultures, regarded as the preferred method for naturally reducing wine acidity, efficiently decreases the acidic taste of wine, improves the microbial stability and modifies to some extent the organoleptic character of wine. However, the recurrent phenomenon of delayed or sluggish malolactic fermentation often causes interruption of cellar operations, while the malolactic fermentation is not always compatible with certain styles of wine. Commercial wine yeast strains of Saccharomyces are generally unable to degrade L-malic acid effectively in grape must during alcoholic fermentation, with relatively minor modifications in total acidity during vinification. Functional expression of the malolactic pathway genes, i.e. the malate transporter (mae1) of Schizosaccharomyces pombe and the malolactic enzyme (mleA) from Oenococcus oeni in wine yeasts, has paved the way for the construction of malate-degrading strains of Saccharomyces for commercial winemaking.

Rapid determination of flavonoids and phenolic acids in grape juices and wines by RP-HPLC/DAD: Method validation and characterization of commercial products of the new Brazilian varieties of grape.

A method for rapid determination of phenolic compounds by reversed-phase high-performance liquid chromatography (RP-HPLC), using a new column of faster resolution was validated and used to characterize commercial products produced with new grape Brazilian varieties of Northeast of Brazil. The in vitro antioxidant activity was also measured. The method showed linearity (R>0.9995), good precision (CV%<2.78), recovery (91.8-105.1%) and limits of detection (0.04-0.85mgL-1) and quantification (0.04-1.41mgL-1) according to other methods previously published with the difference of a run time of only 25min. The results obtained in the characterization of the samples differed for juices and wines from other world regions, mainly because of the high values of (-)-epigallocatechin and trans-caftaric acid. The products analyzed showed high antioxidant activity, especially the wine samples with values higher than those from wines of different regions of the world.

Study on two-step rapid acid reducing of lemon wine

The effect of 7 kinds of ion exchange resin combined with lactic acid bacteria on the leaching of lemon wine were studied.The lemon wine was adsorbed by ion exchange resin and lactic acid bacteria fementation for acid treatment. The final resin was weakly alkaline anion exchange resin D311 with the condition that flow rate was 4 BV/h at room temperature.Leuconostoc mesenteroides was a fermentative strain, and its inoculation amount was 106 CFU/m L. The acidity of the wine was reduced to 2.18 g/L, and the content of flavor substances such as isoamyl alcohol, ethyl acetate and ethyl lactate were increased.After the ion exchange resin and lactic acid bacteria fermentation, reduced the sourness and roughness, and the wine quality became soft and mellow.

Geographical Origin Traceability of Red Wines Based on Chemometric Classification via Organic Acid Profiles

A preliminary study on the chemometric classification of red wines produced from different grape varieties and geographical origins was performed based on their chromatographic profiles of organic acids. Tartaric, malic, citric, lactic, acetic, and succinic acids in wines were detected via high performance liquid chromatography (HPLC). Employing multivariate statistical methods including principal component analysis (PCA) and linear discriminant analysis (LDA), pattern recognition models were built for the classification of the investigated wines regarding the grape varieties and geographical origins. The PCA clearly grouped the wines according to variety, and the LDA further offered 100% classification ability toward geographical identification of the wines and the leave-one-out cross-validated assignments were 100%, 86.7%, and 100% correct for Cabernet Sauvignon, Merlot, and Pinot Noir wines, respectively. The results reveal the potential of using chromatographic profiles of organic acid as the characteristic indices for chemometric classification of red wines.