Acid In Wine Research Articles

Evaluation of Red Wine Acidification Using an E-Nose System with Venturi Tool Sampling.

The quality of wine is checked both during the production process and upon consumption. Therefore, manual wine-tasting work is still valuable. Due to the nature of wine, many volatile components are released, and it is therefore difficult to determine which elements need to be controlled. Acetic acid is one of the substances found in wine and is a crucial substance for wine quality. Gas sensor systems may be a potential alternative for manual wine tasting. In this work, we have developed a TGS2620 gas sensor module to analyze acetic acid levels in red wine. The gas sensor module was refined according to the Venturi effect along with signal slope analysis, providing promising results. The example included in this paper demonstrates that there is a direct relationship between the slope of the MOS gas sensor response and the acetic acid concentration. This relationship is useful to evaluate the ethanol oxidation in acetic acid in red wine during its production process.

Disposable three-dimensional graphene oxide electrode with sandwich-like architecture for the determination of ascorbic acid in fruit juices

This work reports the development of a three-dimensional graphene oxide structure on the screen-printed electrode surface for the detection of ascorbic acid. This electrode was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, RAMAN spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The present work also investigated the electrochemical behavior of ascorbic acid and its electrooxidation mechanism on the three-dimensional graphene oxide surface. The detection of ascorbic acid was conducted by linear scanning voltammetry in the concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1, and the limits of detection and quantification obtained for the proposed electrode were 3.4 × 10−6 and 1.1 × 10−5 mol L−1 (n = 3), respectively. The device also exhibited excellent selectivity, repeatability, reproducibility and stability. The methodology developed was applied for the determination of ascorbic acid in grape and orange juice samples with an accuracy rate ranging from 99% to 105%. These results show that the proposed electrode can be safely and reliably applied for the monitoring of ascorbic acid in fruit juices.

Wine Making: Influence of pH on Physicochemical Parameters of Wine Must Produce from Hot Water Extract of Broom-cluster Fig (Ficus capensis) Leaf using Saccharomyces cerevisiae

The chemical and biological stability of wine are very dependent on pH value, hence winemakers believe that pH plays a critical role in fermentation and final wine quality. This paper optimized and assessed the influence of pH on different physicochemical parameters of wine must prepared from hot water extract of the leaf of Broom-cluster Fig (Ficus capensis) leaf with Saccharomyces cerevisiae, ameliorating to 22 oBrix using table sugar and adding potassium metabisulfite. Then the pH of the must was adjusted as required and subjected to pasteurization. The must was inoculated with yeast inoculum at 0.8g/ml. Soluble solid, alcohol, titratable acidity and pH profile of the wine was monitored daily. After optimization and fermentation physicochemical parameters of the wine were analyzed. It was shown that pH of the must increase and decreased as the fermentation days progressed from day 1-12 for pH 3 -3.5 and 4-4.5 respectively. Total soluble solid decreased in all the must samples. The alcohol content increased gradually during fermentation. pH 3 and 4 had the highest titratable acidity when compared to pH 3.5 and 4.5. The pH of 4.5 wine had the lowest TSS and highest alcohol content. This study shows that wine can be produced from hot water extract of Ficus capensis leaf and the must fermented at lower pH gave highest percentage of alcohol. There is need to optimize and assess the pH of vegetable must before fermentation.

The arginine transporter Can1 acts as a transceptor for regulation of proline utilization in the yeast Saccharomyces cerevisiae.

Proline is the most abundant amino acid in wine and beer, because the yeast Saccharomyces cerevisiae hardly assimilates proline during fermentation processes. Our previous studies showed that arginine induces endocytosis of the proline transporter Put4, resulting in inhibition of proline utilization. We here report a possible role of arginine sensing in the inhibition of proline utilization. We first found that two basic amino acids, ornithine, and lysine, inhibit proline utilization by inducing Put4 endocytosis in a manner similar to arginine, but citrulline does not. Our genetic screening revealed that the arginine transporter Can1 is involved in the inhibition of proline utilization by arginine. Intriguingly, the arginine uptake activity of Can1 was not required for the arginine-dependent inhibition of proline utilization, suggesting that Can1 has a function beyond its commonly known function of transporting arginine. More importantly, our biochemical analyses revealed that Can1 activates signaling cascades of protein kinase A in response to extracellular arginine. Hence, we proposed that Can1 regulates proline utilization by functioning as a transceptor possessing the activity of both a transporter and receptor of arginine.

Quality assessment of grapes and wines of the Alminskiy terroir (Crimean Western-Coastal Piedmont viticultural and winemaking region)

Climatic conditions significantly impact the technology of grape cultivation, starting with selecting of varieties, choosing a place to establish a vineyard, and finishing with determining the harvesting time. The study of the effect of abiotic environmental factors on the quality characteristics of grapes and their products of processing is a hot topic. Assessment of the Crimean western-coastal piedmont viticulture and winemaking region was carried out in accordance with the climatic factors. Their impact on the carbohydrate-acid complex of grape varieties ‘Aligote’, ‘Rkatsiteli’, ‘Cabernet-Sauvignon’ and ‘Merlot’, as well as wines from these varieties, was studied. The sum of active temperatures in the region varied in the range of 3100°C - 3650°C. The hydrothermal coefficient was 0.35-0.76, which characterized the region as arid. Grapes cultivated in this region reach technical ripeness, mass concentration of sugars ranges from 186 to 260 g/L. An inverse correlation between the mass concentration of titratable acids in grapes and precipitation amount during the growing season (r= -0.63) was established. The wines prepared were characterized by distinctive varietal characteristics.

Multidimensional analysis of the interaction of volatile compounds and amino acids in the formation of sensory properties of natural wine

The content of free amino acids and aroma compounds present in wine and dependent on the grape variety, conditions of its growing and technology of production form its consumer properties. In this paper, the structure of interactions of amino acids and volatile organic compounds in 150 samples of natural dry red and white wines produced in the Krasnodar region, Russia, (2010–2013) was studied. The aim of this work was to comparatively evaluate the contribution of volatile compounds and amino acids to the sensory properties of wines by using regression, canonical, covariance, factor analyses, as well as principal component analysis. The list of volatile compounds, i.e., acetaldehyde, ethyl acetate, methanol, the total content of higher alcohols, acetic acid, and furfural, and such amino acids as arginine, proline, threonine was selected based on their influence on sensory properties of wines. The concentrations of volatile compounds and amino acids in wines were determined by gas chromatography and capillary electrophoresis, respectively. Sensory evaluation was conducted by experts with professional experience in wine tasting. Application of statistical methods allowed to establish intra- and inter-group correlations among amino acids and volatile compounds as well as between the groups of these compounds, which determined sensory properties of wines. More than 80% of the variability of the sensory assessment of wines is determined by the degree of relationship between the selected amino acids and volatile compounds; the contribution of amino acids to this indicator is 4.5-fold higher. The results obtained can be used to predict the sensory assessment of red and white wines based on the levels of volatile compounds and amino acids.

Validation of a routine HPLC method for added fumaric acid determination in wines

Nowadays, grape berries mature earlier due to climate change. Higher sugar contents are observed, whereas lower ones in organic acids, leading to increased pH values. Those biochemical changes have direct consequences on the balance and quality of wines made from such grapes. Chemical acidification, commonly used to compensate for the lack of acidity in musts or wines, includes tartaric, malic, lactic, and citric acids. Fumaric acid (FA), naturally present in the grape berries at low concentrations and already authorized in the member states of the OIV to inhibit malolactic fermentation in wines, seems to be a promising alternative to those acids to lower the pH. However, the evolution of FA levels added at bottling and its impact on wine quality during its conservation have not yet been studied. Therefore, the aim of the present study was to develop and validate a simple method using liquid chromatography coupled with a diode array detector, which can be used routinely for the determination of the added fumaric acid in wines. The proposed and validated method uses a ProntoSIL C-18 analytical column and an isocratic elution with water acidified at 0.1% formic acid. The run time, including column cleaning with acetonitrile and re-equilibration, was 40 minutes.

Effects of different koji on aroma components of Rice Wine

Aroma composition is critical to the quality of rice wine. In order to clarify the effect of different koji on the aroma components of rice wine. The Yuanyang rice was selected as raw material, and three kinds of rice wine koji were added during rice wine fermentation. The aroma components of three wine samples fermented at 31 °C for nine days were qualitatively and quantitatively analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that a total of 81 aroma components were detected in the three groups of wine samples, including 30 esters, 18 alcohols, 4 acids and 29 other organic substances. The ester with the most content was ethyl palmitic acid, and the alcohol with the most content was ethanol. Therefore, the amount and type of esters, the ratio and interaction among esters, alcohols and acids in wine play an important role in the sensory quality of rice wine, and the joint action of various aroma components affects the quality of rice wine.

Analysis of the formation mechanism of volatile and non-volatile flavor substances in corn wine fermentation based on high-throughput sequencing and metabolomics

The purpose of this study was to reveal the relationship between core microorganisms and flavor substances in the fermentation process of corn wine. Microbial diversity, volatile and non-volatile flavor substances were detected by high-throughput sequencing (HTS), headspace solid phase micro-extraction gas chromatography-mass spectrometry (HS-SPME/GC–MS) and gas chromatography time of flight mass spectrometry (GC-TOF-MS). High performance liquid chromatography (HPLC) was used to detect organic acids in corn wine fermentation, and its physiochemical properties were tracked. The results showed that physiochemical factors changed obviously with fermentation time. Bacillus, Prevotella_9, Acinetobacter and Gluconobacter were the predominant bacterial. Rhizopus and Saccharomyces were the dominant fungi. Acetic acid and succinic acid were important organic acids in corn wine. According to variable importance of projection (VIP) > 1 and P < 0.05, 24 volatile flavor substances with significant difference were screened out from 52 volatile flavor substances. Similarly, 25 non-volatile flavor substances with significant differences were screened out from the 97 reliable metabolites identified by 223 chromatographic peaks. Eight key metabolic pathways were enriched from 25 non-volatile flavor substances according to path influence values > 0.1 and P < 0.05. Based on Two-way Orthogonal Partial Least Squares (O2PLS) model and Pearson correlation coefficient, Saccharomyces, Rhizopus, uncultured_bacterium, Aneurinibacillus, Wickerhamomyces and Gluconobacter may be the potential volatile flavor-contributing microorganism genus in corn wine. The Pearson correlation coefficient showed that Saccharomyces was significantly positively correlated with malic acid, oxalic acid, valine and isoleucine, and Rhizopus was positively correlated with glucose-1-phosphate and alanine. These findings enhanced our understanding of the formation mechanism of flavor substances in corn wine and provided the theoretical basis for stabilizing flavor quality of corn wine.

Development of a diphenyl sulfide structure derivatization reagent for amino acid enantiomers analysis: Application of dynamic monitoring in human urine after drinking wine

We developed a novel chiral mass spectrometry derivatization reagent (S)-(3-(4-carboxythiazolidin-3-yl)-3-oxopropyl) diphenylsulfonium (CTOD) with a positively charged sulfur-containing structure for high-sensitivity detection of the chiral resolution of amino acid enantiomers. CTOD reacted with DL-amino acids at 60oC for 60 min to generate the corresponding diastereomers, fifteen chiral amino acid-derived products were separated. Resolution (Rs) values were of the range 1.54-4.36, except Asn 1.07, achieving good separation. A highly sensitive and selective UHPLC-MS/MS method for the simultaneous determination and chiral separation of five chiral amino acids (Pro, Ala, Glu, Asp, and Phe) based on CTOD derivatization was established and applied to the detection of chiral amino acids in different wines. The diastereomeric resolution of the five amino acids was 1.71–5.42, and an excellent linear relationship was obtained in the range of 0.25–500 pmol (R2 ≥0.9993). The detection limit was 0.05–0.25 pmol. The intra- and inter-day precisions were 0.51–5.76% and 0.78–5.18%, respectively, and the average recovery was 90.03–99.99%. In addition, the metabolic concentration of chiral amino acids was monitored after drinking red wine and white wine, and the fitting curve of metabolic concentration was drawn.

The influence of the vine rootstock on the agrobiological and technological characteristics of the Kaylashki Rubin variety

The rootstock had a significant impact on the quantity and quality of grapes of the varieties grafted on it. That had been determined by the different growth strength of the rootstocks, their different absorption capacity and compatibility with the cultivated vine. During the period 2017-2020, a study was carried out on the agrobiological and technological properties of grapes and wine of the Kaylashki Rubin variety, grafted on vine rootstocks SО4, 110 Rihter, 44-53 Malegue and Fercal. Differences in the investigated indicators were found as a result of the influence of the used rootstocks. A mechanical analysis was made to determine the composition and structure of the clusters and berries. For the period, the highest average yield per vine was reported for Fercal rootstock, while the best theoretical yield had the variant on 44-53 Malegue rootstock. The chemical composition of grapes and experimental wines had been determined. On the average for the period the highest sugar accumulation and respectively the lowest titratable acids in grapes were reported in the variant of 44-53 Malegue rootstock. The opposite relationship was observed for 110 Richter. Differences in the chemical composition of the wines depending on the used rootstocks were found. The wines from 44-53 Malegue variant had the highest average alcohol content and sugar-free extract, but the lowest rates of titratable acids. The average amounts of the total phenolic compounds and anthocyanins in the wines from the variants of the different rootstocks were close. Their values were the lowest in the samples 2017 vintage. The rootstock type also affected the organoleptic properties of the Kaylashki Rubin wines; however, there was no common trend for the studied period. In 2018 and 2020, the samples from the 110 Rihter variant showed the best tasting qualities.

Development and Validation of a New GC-FID Method for the Determination of Short and Medium Chain Free Fatty Acids in Wine.

A new analytical method for the determination of six volatile short and medium-chain fatty acids (acetic, propionic, isobutyric, isovaleric, hexanoic, and octanoic acids) through liquid-liquid extraction with diethyl ether, followed by GC-FID analysis, was developed and validated. The extraction conditions were optimized by evaluating the effect of the number of extractions (1 to 3) and the effect of the addition of salts (NaH2PO4, (NH4)2SO4, NaCl, (NH4)2SO4/NaH2PO4) to increase the concentration of the analytes in the ethyl ether phase. Results showed that a single extraction allows obtaining the highest sensitivity (due to the impossibility of evaporating the solvent to avoid losses of the analytes). The use of salting out agents, in particular, NaH2PO4, showed an important increase in the extraction extent, on average, 1.5 times higher as compared to the extraction performed without salt. The proposed method is rapid, requiring a total of 30 min for preparation and analysis, and it makes use of small amounts of sample (500 µL) and solvent (400 µL). The method was then applied to quantify the analytes in 5 white wines and 5 red wines, allowing to highlight some clear differences between red and white wines, with the red ones having a significantly higher amount of acetic acid (715.7 ± 142.3 mg/L in red wines and 351.5 ± 21.2 mg/L in white wines) and the white wines having a significantly higher amount of hexanoic and octanoic acid (6.1 ± 3.0 mg/L and 2.6 ± 0.8 mg/L, respectively, are the mean concentrations in white wines, and 4.7 ± 0.8 and 2.4 ± 0.4 mg/L, respectively, are the mean concentrations in red wines).

Reductive amination of aldehyde 2,4-dinitrophenylhydrazones using cyanoborohydride for determination of selected carbonyl compounds in Port wines, table wines, and wine spirits

Carbonyl compounds are mainly analysed by HPLC with ultraviolet detection after reaction with DNPH, yielding carbonyl-hydrazones. The presence of geometrical isomers whose relative abundance is dependent on the reaction condition introduces analytical errors and increases the complexity of the chromatograms. In this work, a simple, fast, and robust method for determining pyruvic acid, acetaldehyde, and α-ketobutyric acid in Port wines, dry table wines, and wine spirits by reductive amination of aldehyde 2,4-dinitrophenylhydrazones using cyanoborohydride followed by HPLC-DAD was developed, optimised and validated. The developed method was simple and showed good performance in several parameters such as linearity (0.025–200 mg/L), detection limits (0.0043–0.0097 mg/L), quantification (0.014–0.032 mg/L), precision (1.1–4.2 %) and accuracy (99.02 %). The method was applied to five different wine matrices, White, Tawny, and Ruby Port wines, white and red table wines, and wine spirits. The quantification of these carbonyl compounds simultaneously was achieved in Port wines for the first time.

Phage-host interactions as a driver of population dynamics during wine fermentation: Betting on underdogs

Winemaking is a complex process in which numerous microorganisms, mainly yeasts and lactic acid bacteria (LAB), play important roles. After alcoholic fermentation (AF), most wines undergo malolactic fermentation (MLF) to improve their organoleptic properties and microbiological stability. Oenococcus oeni is mainly responsible for this crucial process where L-malic acid (MA) in wine converts to softer L-lactic acid. The bacterium is better adapted to the limiting conditions imposed by the wine matrix and performs MLF under regular winemaking conditions, especially in wines with a pH below 3.5. Traditionally, this process has been conducted by the natural microbiota present within the winery. However, the start, duration and qualitative impact of spontaneous MLF are unpredictable, which prompts winemakers to use pure starter cultures of selected bacteria to promote a more reliable, simple, fast and efficient fermentation. Yet, their use does not always ensure a problem-free fermentation. Spontaneous initiation of the process may prove very difficult or does not occur at all. Such difficulties arise from a combination of factors found in some wines upon the completion of AF (high ethanol concentration, low temperature and pH, low nutrient concentrations, presence of free and bound SO2). Alongside these well documented facts, research has also provided evidence that negative interactions between O. oeni and other biological entities such as yeasts may also impact MLF. Another insufficiently described, but highly significant factor inhibiting bacterial growth is connected to the presence of bacteriophages of O. oeni which are frequently associated to musts and wines. The purpose of this review is to summarize the current knowledge about the phage life cycles and possible impacts on the trajectory of the microbiota during winemaking.

ОСОБЕННОСТИ СОСТАВА ОРГАНИЧЕСКИХ КИСЛОТ СУСЕЛ И ВИН ИЗ КРАСНЫХ СОРТОВ ВИНОГРАДА МЕЖВИДОВОГО ПРОИСХОЖДЕНИЯ

The aim of the work was to study the composi-tion of organic acids of musts and wines made from red grapevine varieties of interspecific origin growing in the conditions of Rostov re-gion. The objects of the study were must and wines prepared under conditions of micro winemaking from red grapevine varieties of interspecific origin bred by ARRIV&amp;W, a branch of FSBSI FRASC ‒ Denisovsky, Cab-ernet Severniy, Augusta, Cabernet Sauvignon (control), according to the classical technology adopted for red dry wines. As a result of the study the following results were obtained. In must of all studied varieties the predominance of tartaric acid over malic acid was observed in several times, while in the interspecific grape-vine varieties the concentration of tartaric acid was 5‒6 times higher than malic acid, while in the control only 2.5 times higher. The greatest amount of tartaric acid was observed in the must from Cabernet Severniy grapes ‒ 5.6 g/dm3. Malic acid accumulation was signifi-cantly lower in all variants (0.48‒1.1 g/dm3) compared with the control Cabernet Sauvignon (2 g/dm3). There was a slight accumulation of succinic acid in the must from Denisovsky and Cabernet Severniy grapes. In all variants, with the exception of Augusta wine, the concentra-tion of tartaric and malic acids decreased. The total proportion of tartaric and malic acids in the experimental wines was 38‒74.7 % of all acids in wine. The highest concentration of succinic acid was observed in wines from Den-isovsky and Cabernet Sauvignon varieties.

Comparison of Ion Chromatography Conductivity Detection (IC-CD) and Ion Chromatography Inductively Coupled Plasma Mass Spectrometry (IC-ICP-MS) for the Determination of Phosphonic Acid in Grapevine Plant Parts, Wine, and Soil.

Potassium dihydrogen phosphonate had been allowed as a plant strengthener in organic viticulture in the European Union only until 2013, supporting the control of grapevine downy mildew. Therefore, low or nondetectable levels are a prerequisite for marketing of organic wines and, consequently, validated analytical methods are of major interest. Herein, two methods based on ion chromatography conductivity detection (IC-CD) or ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) for the determination of phosphonic acid (H3PO3) from 14 different plant matrices of Vitis vinifera L., wine, and soil were developed, validated, and compared. Extraction recoveries ranged from 95.1 to 99.3%. Limits of quantification (LOQ) ranged in liquid and solid samples from 3.8 to 16.8 μg/kg and 0.08 to 2.41 mg/kg for ICP-MS detection and from 39.9 to 593.7 μg/kg and 3.51 to 58.7 mg/kg for CD, respectively. Data on a current anonymized selection of 100 conventionally and 30 organically produced wines are briefly presented to demonstrate the suitability of the method.

Determination of sugars and amino acids in Japanese wine using core–shell liquid chromatography tandem electrochemical detection

Determination of sugars and amino acids in Japanese wine using core–shell liquid chromatography tandem electrochemical detection

Monoterpenoids and norisoprenoids in Italian red wines

This work aimed to investigate the occurrence of different monoterpenoids and norisoprenoids in 10 monovarietal Italian red wines (Aglianico, Cannonau, Corvina, Montepulciano, Nebbiolo, Nerello, Primitivo, Raboso, Sangiovese and Teroldego) from 12 regions across Italy. The wines were produced in their terroirs following the oenological practices and legislation of the respective appellation. Data showed that different wine varietals were characterised by peculiar profiles of monoterpenoids and norisoprenoids.Montepulciano and Cannonau wines showed highest levels of nerol, terpinolene, α-terpineol, limonene and of the norisoprenoids β-damascenone, α-ionone, TPB, TDN and vitispirane.Aglianico, Corvina, Nebbiolo and Primitivo were characterised by relatively high levels of linear monoterpene alcohols such as linalool and geraniol. Sangiovese samples from Tuscany could be differentiated from those of Romagna, with the former characterised by a higher content of α-terpinene and the latter of γ-terpinene. The monoterpene 1,4-cineole was present in Montepulciano, Raboso and Sangiovese at potentially relevant olfactory levels, its occurrence associated with higher content of terpinen-1-ol acting as a potential precursor under wine acid conditions.

Solubility, acidifying power and sensory properties of fumaric acid in water, hydro-alcoholic solutions, musts and wines compared to tartaric, malic, lactic and citric acids

The lower content of organic acids in grape berries due to global warming, and therefore high pHs, is forcing winegrowers to acidify must or wine to preserve their microbiological stability and their physico-chemical equilibrium. Acidification is essential to avoid damageable consequences on the colour and the sensory quality of the wines. Of the possible modes of acidification, chemical acidification is still the most common one used by OIV country members. It consists of adding lactic, malic, tartaric or citric acids to the musts and wines. Fumaric acid, with its high acidifying power and availability on the market, could be an interesting alternative at lower cost than other acids. Very few studies describing the effects of the addition of this acid on the chemical and organoleptic quality of musts and wines have been published. The present study therefore investigated the impacts of fumaric acid - namely its solubility, acidifying power, and impacts on colour and phenolic compounds - on musts and wines in comparison to other acids. Sensory analyses were also carried out to evaluate the perception threshold of each acid in the wines and compare how the acids are perceived. Except for its low solubility, fumaric acid seems to be a good candidate for an economic alternative to wine acidification. It had the highest acidifying power and slightly affected wine chemistry and organoleptic qualities. Further studies are needed to determine the appropriate step during which this acid should be added during winemaking.

Organic acids characterization: wines of Pinot noir and juices of ‘Bordeaux grape varieties’

The main goal of this work is to evaluate the organic acids (acetic, citric, lactic, malic, tartaric and succinic) profile of fifteen Pinot noir wines from different vineyards by HPLC-DAD. In addition, this method was applied to characterize grape juices of ‘Bordeaux grape varieties’ grown in Napa Valley, California, USA and Bolgheri, Tuscany, Italy. The method was validated on grape juices and wines. Organic acids concentrations in wines varied about 2-fold for tartaric, lactic, and acetic acids; 3-fold for malic and citric acids; and 4-fold for succinic acid. In grape juices, the concentrations varied approximately 3-fold for tartaric and citric acids and 8-fold for malic acid. Principal component analysis presented correlations with higher tartaric and malic acids in wines from Russian River Valley AVA and Sonoma Coast AVA regions, which are relatively close to each other. Cabernet sauvignon juices from different regions in the USA and Italy had similar correlations with citric, malic and tartaric acids concentrations. Organic acids profiles obtained in this work are consistent with the literature, thereby demonstrating the reliability of this single methodology for the characterization of a wide variety of grape juices and wines by sampling from different growing regions.