Acid In Wine Research Articles

New enzymatic method for estimating fumaric acid in wines

This work aims to develop a new enzymatic method for analysing fumaric acid in wines. Fumaric acid is a very effective lactic acid bacteria inhibitor that is widely used in the food industry as an additive (E297). Using it to inhibit malolactic fermentation has recently been authorized by the International Organisation of Vine and Wine (OIV). However, the official analytical method for fumaric acid involves the classical HPLC method for organic acids, which is overly complicated for use in wineries. This research proposes a very simple and efficient enzymatic method that allows the simultaneous determination of L-malic acid and fumaric acid. The method uses a commercial enzymatic kit for L-malic acid and adds a supplementary step in which the fumarase enzyme is added to transform fumaric acid into L-malic acid. The results obtained show that this method could be used in different media (synthetic solution, white wine, red wine and white grape juice). This article also proposes a modification of the enzymatic method to be applied when the L-malic acid concentration of the sample is very high.

Evaluation of Autochthonous Non-Saccharomyces Yeasts by Sequential Fermentation for Wine Differentiation in Galicia (NW Spain)

Non-Saccharomyces yeasts constitute a useful tool in winemaking because they secrete hydrolytic enzymes and produce metabolites that enhance wine quality; in addition, their ability to reduce alcohol content and/or to increase acidity can help to mitigate the effects of climatic change on wines. The purpose of this study was to evaluate the oenological traits of non-Saccharomyces yeast strains autochthonous from Galicia (NW Spain). To do that, we carried out sequential fermentation using 13 different species from the yeast collection of Estación de Viticultura e Enoloxía de Galicia (Evega) and Saccharomyces cerevisiae EC1118. The fermentation kinetics and yeast implantation were monitored using conventional methods and genetic techniques, respectively. The basic chemical parameters of wine were determined using the OIV official methodology, and the fermentative aroma compounds were determined by GC–FID. The results evidenced the limited fermentative power of these yeasts and the differences in their survival after the addition of S. cerevisiae to complete fermentation. Some strains reduced the alcohol and/or increased the total acidity of the wine. The positive effect on sensory wine properties as well as the production of desirable volatile compounds were confirmed for Metschnikowia spp. (Mf278 and Mp176), Lachancea thermotolerans Lt93, and Pichia kluyveri Pkl88. These strains could be used for wine diversification in Galicia.

Analysis of organic residues from the Châteaumeillant oppidum (Cher, France) using GC–MS

Scientific analysis has provided new evidence in historical and archaeological studies in recent years. Archaeological samples are frequently contaminated because of conservation conditions and/or cleaning before restoration. Roman amphora, made of a material of great interest, is no exception. This study develops the chemical analysis of Dressel I amphorae coming from the Châteaumeillant oppidum in France, dating from the 2nd century-1st century BC. Traces of organic matter located on the internal surface of the amphorae were identified using a gas chromatography-mass spectrometry (GC–MS). This analytical technique notably allows markers of resinous matter (pitch) and wine to be detected. Analytical results showing the presence of syringic acid, along with other wine acids (benzoic, succinic and vanillic acids) in certain amphorae in the archaeological context, demonstrated that the vessels had contained wine. Moreover, two families of resins (Pinaceae and Cupressaceae) were observed. They were used for waterproofing or as an additive to resinated wine. In particular, the observation of sandarac resin (Cupressaceae) is rare in wine amphorae.

Potential Valorization of Organic Waste Streams to Valuable Organic Acids through Microbial Conversion: A South African Case Study

The notion of a “biobased economy” in the context of a developing country such as South Africa (SA) necessitates the development of technologies that utilize sustainable feedstocks, have simple and robust operations, are feasible at small scale and produce a variety of valuable bioproducts, thus fitting the biorefinery concept. This case study focuses on the microbial production of higher-value products from selected organic waste streams abundant in the South African agricultural sector using microbes adapted to utilize different parts of biomass waste streams. A ruminant-based carboxylate platform based on mixed or undefined anaerobic co-cultures of rumen microorganisms can convert the carbohydrate polymers in the lignocellulosic part of organic waste streams to carboxylic acids that can be upgraded to biofuels or green chemicals. Furthermore, yeast and fungi can convert the simpler carbohydrates (such as the sugars and malic acid in grape and apple pomace) to ethanol and high-value carboxylic acids, such as lactic, fumaric, succinic and citric acid. This review will discuss the combinational use of the ruminal carboxylate platform and native or recombinant yeasts to valorize biomass waste streams through the production of higher-value organic acids with various applications.

Correlations between microbes and metabolites of hulless barley wines fermented with varieties of hulless barley and different starters

Hulless barley wine has been widely researched for its high nutritional values and unique flavor. However, the different varieties of hulless barley and a variety of local characteristic starter in the Qinghai-Tibet Plateau, which make the styles of hulless barley wine in different. In this study, the microbial community compositions of representative starters were investigated. Meanwhile, the physicochemical indexes, sensory analysis, volatile flavor compounds and free amino acids of different wines fermented with varieties of hulless barley and different starters were determined, respectively. In addition, the correlations between microbes and metabolomics were explored. The results showed that there were differences between fungal communities and between bacterial in differences starters. The influence of different starters on the quality of hulless barley wine was greater than that of hulless barley varieties. 16 microbial generas Acetobacter, Weissella, Chloroplast, Bacillus, Leuconostoc, Methylobacterium, Rhizopus, Aspergillus, Pichia, Hyphopichia, Wallemia, Xeromyces, Gibberella, Alternaria, Curvularia and Microdochium were discovered to be positive correlated with metabolites by Spearman's correlation analysis. These findings may indicate the key microorganisms of volatile substances and free amino acids in hulless barley wine, help to select hulless barley varieties and control the microorganisms of starter, and improve the quality of hulless barley wine.

Effects of ultrasound on the formation of oxidative pigments in a model red wine solution containing glutathione

Xanthylium cations and its ethyl ester are important pigments derived from (+)-catechin and glyoxylic acid in wine. In this paper, ultrasound treatment was applied in model wine containing glutathione to study its effects on the formation of xanthylium cation pigments triggered by free radicals from the ultrasound cavitation. The changes in color parameters, concentration of pigment compounds and free radicals were investigated during wine storage by the means of ultraviolet visible (UV–vis) spectrophotometer, colorimeter, high performance liquid chromatography with mass spectrometry (HPLC-MS) and electron paramagnetic resonance (EPR), respectively. Results indicate that longer ultrasonic treatment in conjunction with glutathione can significantly enhance the formation of xanthylium cation pigments and accelerate the red wine color evolution, and no extra (+)-catechin was involved, which might be attributed to the stronger 1-hydroxyethyl radicals intensity induced by ultrasound irradiation. In summary, ultrasound treatment can accelerate the oxidative coloration of wine with GSH during ageing, which would contribute to well understand the changing mechanism of wine color properties modified by ultrasound.

SmartSpectrometer-Embedded Optical Spectroscopy for Applications in Agriculture and Industry.

The ongoing digitization of industry and agriculture can benefit significantly from optical spectroscopy. In many cases, optical spectroscopy enables the estimation of properties such as substance concentrations and compositions. Spectral data can be acquired and evaluated in real time, and the results can be integrated directly into process and automation units, saving resources and costs. Multivariate data analysis is needed to integrate optical spectrometers as sensors. Therefore, a spectrometer with integrated artificial intelligence (AI) called SmartSpectrometer and its interface is presented. The advantages of the SmartSpectrometer are exemplified by its integration into a harvesting vehicle, where quality is determined by predicting sugar and acid in grapes in the field.

Evaluation of Anthocyanin Profile and Color in Sweet Cherry Wine: Effect of Sinapic Acid and Grape Tannins during Aging.

Cherries are rich in bioactive phenolic compounds and are often fermented into cherry wines. The degradation of anthocyanins during storage will cause color deterioration. The study aimed to utilize sinapic acid and grape tannins in cherry wine to maintain a high fraction in the colored forms of anthocyanins, in order to maximize the color intensity, the latter being associated with good product quality. The effects on the anthocyanin profile and on color parameters of copigments, utilizing spectral measurement combined with UPLC-MS quantitative analysis, have been evaluated in sweet cherry wines. The copigmentation effect of sinapic acid and grape tannin was accompanied by the bathochromic shift and the hyperchromic effect, which lead to an increase in color intensity (lower L*, higher a* and b*). During the aging process, sinapic and grape tannin increased the content of pyranoanthocyanins in cherry wine, especially the addition of sinapic acid makes the cherry wine generate 10-syringyl-pyranocyanidin-3-rutinoside. These results demonstrate that sinapic acid is suitable for adding before alcohol fermentation, while grape tannins can be added before aging.

Composition and nutritional evaluation of amino acids in Mimai Qu rice wine

An amino acid analyzer was used to detect free amino acids (FAA) in Mimai Qu rice wines (SMW and DMW) and control wine samples (Chinese rice wine [CRW] and Japanese sake [JNS]). It was found that CRW had the highest total amino acid (TAA) content (~2814 mg/L), followed by SMW (~2509 mg/L) and DMW (~1474 mg/L), while JNS had the least (~917 mg/L). Amino acid ratio coefficient method (SRCAA), linear regression method, cluster analysis (CA) and principal component analysis (PCA) were used for evaluating the nutritional value of amino acids in wine samples, giving similar results. SMW had the highest nutritional value, followed by CRW and DMW and JNS.

Polyphenols, L-Ascorbic Acid, and Antioxidant Activity in Wines from Rose Fruits (Rosa rugosa).

The aim of the present study was to determine the influence of the winemaking process on the antioxidant potential and content of phenolic compounds and L-ascorbic acid in wines from the fruits of Rosa rugosa. The results obtained in this study clearly indicate that the fruits of the Rosa rugosa are a desirable raw material for the production of fruit wine. The parameters of the technological process of producing wines from rose fruits had a diversified influence on the tested quality characteristics. Aged wines contained phenolics levels of 473–958 mg/100 mL GAE. The final concentrations of ascorbic acid ranged from 61 to 155 mg/100 mL for the different variants of the wine. Wines revealed high antioxidant activity in assay with DPPH. On the basis of the obtained results, it can be assumed that all the applied variants of the winemaking process are suitable for rose fruit wine. Each variant ensured at least the stability of the antioxidant capacity.

Structural identification of sour compounds in wine and tea by ambient ionization mass spectrometry according to characteristic product ion and neutral loss

Sourness is an important food taste for human. A rapid, accurate method was used to generalize the structure similarity and diversity of sour compounds. Based on the product ion and neutral loss of sour compounds, ambient ionization techniques combined with quadrupole-Orbitrap mass spectrometry (AI-Q-Orbitrap) was employed. According to the behavior of sour compounds in the process of high collision dissociation (HCD) of MS/MS, three fragmentation pathway schemes were proposed: (1) charge-driven fragmentation and CO2 loss, (2) six-membered ring rearrangement and Cα-Cβ cleavage, and (3) elimination rearrangement and H2O, CO2 and CO loss in succession. Besides, structure information about characteristic product ions and characteristic neutral losses was summarized. Finally, multi-class sour compounds including monoacids, diacids, polyacids and phenolic acids in wine and tea were identified and compared. Therefore, sour compounds and their structure information can be determined by AI-MS based on characteristic product ion and neutral loss.

Determination of the amount of volatile acids in oxidized wines and neutralization of these by using chemical reagents and biological materials

The aim of this paper is as follows: (I) determination of physical and chemical characteristics of the wine; (II) determination of the possibility of neutralizing and improving the characteristics of oxidized wines. Two types of wine (red and white) of the individual manufacturer from at south from river Ibar in the territory of Kosovo and Metohia were analyzed. Experimentally determined physico-chemical characteristics are density and quantity of the following: alcohol; extract; reducing sugars; ash; total acids; volatile acids; total; and free sulfur dioxide. Neutralization of oxidized wines (reduction of quantity of volatile acids) was carried out using chemical reagents (sodium hydrogen carbonate, calcium carbonate, calcium oxide, calcium hydroxide) and biological material (corn flour). By using sodium hydrogen carbonate to neutralize oxidized wines, the amount of volatile acids is reduced by 57% in red wine and 54.6% in white. By using corn flour, the content of volatile acids in red wine is reduced by 56% and in white by 54%, which is confirmed by the traditional experience of application of corn pistes during distillation. The methods of classical analytical chemistry were used to perform the experimental part of this paper.

Effect of alcoholic and acetous fermentations on the phenolic acids of Kei-apple (Dovyalis caffra L.) fruit.

The Kei apple is a tree found on the African continent. Limited information exists on the effect of alcoholic and acetous fermentation on the phytochemicals of Kei apple. The fruit has increased concentrations of l-malic, ascorbic, and phenolic acids among other compounds. Juice was co-inoculated with Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) to induce alcoholic fermentation (AF). Acetous fermentation followed AF, using an acetic acid bacteria (AAB) consortium. Saccharomyces cerevisiae + Sp wines and vinegars had the highest pH. Total acidity, soluble solids and l-malic acid decreased during AF and acetous fermentation, and was highest in Sc wines and vinegars. Volatile acidity (VA) concentration was highest in Sp vinegars but was not significantly different from Sc and Sc + Sp vinegars. Gallic acid was highest in Sp wines and vinegars, whereas syringic acid was highest in Sc wines and vinegars. The Sc + Sp wines were highest in caffeic, p-coumaric, and protocatechuic acids. Schizosaccharomyces pombe vinegars were highest in caffeic and p-coumaric acids. Highest concentrations of ferulic and sinapic acids were found in Sp and Sc wines, respectively. Chlorogenic acid was most abundant phenolic acid in both wines and vinegars. Saccharomyces cerevisiae + Sp and Sc fermentation had a positive effect on most phenolic acids; Sc + AAB had an increased effect on syringic and chlorogenic acids, whereas Sp + AAB resulted in an increase in gallic, caffeic, and p-coumaric acids. The AAB selected had minimal performance with respect to VA production in comparison to commercial vinegars. Acetic acid bacteria selection for acetous fermentation should therefore be reconsidered and the decrease of certain phenolic acids during acetous fermentation needs to be investigated. © 2021 Society of Chemical Industry.

Profiling of free amino acids in sparkling wines during over-lees aging and evaluation of sensory properties

Sparkling wines produced with the nontraditional grape varieties Villenave, Niagara, Manzoni and Goethe, and also a classic Chardonnay variety, were investigated in this study. The aim was to determine the influence of the length of time for which the wines were exposed to biological aging in contact with yeast lees (over-lees) on the nitrogen composition and the characteristics of the sensory profile. Significant changes were observed in the concentration of free amino acids in the sparkling wines during over-lees aging. The use of multivariate analysis to investigate the nitrogen composition of sparkling wines proved to be an interesting tool to differentiate sparkling wines according to the time of biological aging. The principal component analysis clearly separated the sparkling wines according to the time of over-lees aging considering the nitrogen composition, and this behavior was observed for all varieties. Sparkling wines with 15 and 18 months of over-lees aging were associated with most of the amino acids analyzed. The sensory profiles obtained for the sparkling wines with 18 months of aging on yeast lees was characterized by descriptors of white and citrus fruits, floral and/or orange blossom, honey, butter, notes of toasted bread and vegetal, and straw-colored.

Miniaturized electrocoagulation approach for removal of polymeric pigments and selective analysis of non- and mono-hydroxylated phenolic acids in wine with HPLC-UV.

Electrocoagulation (EC) approach was developed to allow fast sample cleanup step prior to selective analysis of non- and mono-hydroxylated phenolic acids in red wine samples with high performance liquid chromatography hyphenated with UV detection (HPLC-UV). EC system with the wine in KCl(aq) electrolyte (1.5 mol L−1) was employed removing the polymeric pigments with good recovery of 39 peaks from 64 peaks. The mechanisms mainly involve enrichment induced aggregation and reduction of the pigments at the cathode and the adsorption onto the EC sludge. The EC was further miniaturized employing two intercalated stainless steel spring electrodes at 9.0 V which allowed removal of >99% interference peak area from the pigments within 5 s. The recoveries of the target phenolic acids (p-hydroxybenzoic acid, vanillic acid, syringic acid and ferulic acid) were within the range of 86–102%. The repeated analysis of these standards revealed <2 and ≤10% RSD of the intra-day and inter-day precisions, respectively. The linearities of their calibration curves were observed with R2 > 0.99. Their method detection limits were within the range of 0.02–0.20 mg L−1.

The influence of extraction methods on the quality characteristics of red wines

The main technological task in the production of high-quality red wines is to ensure favourable conditions for the extraction of components from solid elements of a grape bunch. Present work is devoted to the study and comparative assessment of the effect of various extraction methods (carbonic maceration of the must, carbonic maceration of grapes, pre-fermentative maceration of the must) on the quality characteristics of red wines prepared from grape varieties ‘Cabernet-Sauvignon’, ‘Syrah’ and ‘Merlot’. The positive effect of the methods of carbonic maceration of both must and grapes was established in relation to the accumulation of ethyl alcohol (by 0.5-0.9 %), as well as biologically active substances: flavan-3-ols ((+)-D-catechin and (-)-epicatechin) and oxycoric (caftaric and cautaric) acids – by 1.5-1.8 times compared to the classical technology. Therefore, the carbonic maceration method provides a less intensive course of oxidative processes at the stage of must, which causes the preservation of oxycoric acids in wine. Carbonic maceration of must provide a higher content of the reduced extract (up to 15%), effective extraction of anthocyanins (from 9 to 145%) and phenolic compounds (by 7-25%), which manifest itself through the increase in the color intensity index (up to 26%).

Fermentation process optimization and chemical composition analysis on black tea wine

In this study, the fermentation process of black tea wine was optimized, and the changes in catechins, organic acids, and aroma components during fermentation were investigated. The optimal fermentation conditions for tea wine were determined as follows: the addition of 15% sucrose and 0.75% tea leaves, and a fermentation temperature of 25 ºC. Under the optimal conditions, the alcohol content and sensory evaluation score of tea wine were 8.9 %ABV and 88, respectively. The contents of catechins and organic acids in tea wine were 21.29 mg/L and 3.68 mg/mL, which were 1.32-fold and 10.51-fold higher than those of tea infusion, respectively. L-malic acid was the main organic acid in tea wine, which accounted for 56.3% of the total amount of organic acids. A total number of 34 and 33 kinds of aroma components were detected in tea wine and tea infusion, respectively. The main aroma components of tea wine were esters and alcohols, which accounted for 39.7% and 45.9% of the total amount of aroma components, respectively, while the main aroma components of tea infusion were esters and aldehydes, accounting for 34.6% and 33.2%, respectively.

ВЛИЯНИЕ СПОСОБОВ ВЕДЕНИЯ СОРТА КРАСНОСТОП АЗОС И ЕГО НАГРУЗКИ НА УРОЖАЙНОСТЬ И КАЧЕСТВО ВИНОГРАДА И ВИНА ИЗ НЕГО

The qualitative characteristics of technical grapes and wine largely depend on the system of this crop. The objects of research were grapes and wine material of the Krasnostop AZOS variety in grafted and own-rooted cultures with variants of different loads of shoots on a bush. The experience of studying the influence of various agrotechnical methods on the productivity of a grape plant and the quality of wine material was laid down in the Anapo-Taman climatic zone of the Krasnodar Territory of Russia. The largest yield of the Krasnostop AZOS variety during the years of the study was obtained in the variant of own-rooted grape cultivation with its load of 36-40 shoots per bush. In our studies, there is a tendency to increase the sugar content and reduce the titratable acidity of grapes when maintaining vineyards of the Krasnostop AZOS variety in own-rooted culture. The most optimal ratio of sugar content and titratable acidity in the experiment had grapes from the variant of own-rooted culture with a load of shoots of 36-40 pcs/bush. In the studied variants, the largest amount of phenolic substances was found in wine material from own-rooted grapes with a load of 36-40 shoots per bush - 4130 mg/dm3. The maximum total content of substances from a number of biologically active substances was found in wine from grape raw materials obtained from a grafted culture (134.9 - 147.9 mg/dm3). In 2018-2019, from the organoleptic side, wine materials from own-rooted grapes proved to be of the highest quality.

Microanalytical flow system for the simultaneous determination of acetic acid and free sulfur dioxide in wines

Free sulfur dioxide and volatile acidity are parameters related to the quality of wines. Traditional methods for their determination are tedious, time consuming and require analysis in decentralized laboratories, therefore corrective actions cannot be applied on time. This may be more complex in aging wine cellars, where hundreds of individual barrels containing almost finished wines should be monitored. To achieve this aim, a portable microanalytical flow system for the simultaneous detection of free SO2 and acetic acid during the ageing of wines is proposed in this work. The miniaturized system is based on the use of a gas-diffusion membrane and a pH-ISFET, and can be easily installed in barrels. The system was optimized in the range of 5–60 mg L−1 and 0.15–1.40 g L−1 for SO2 and acetic acid, respectively. It was validated with different sets of wine samples by comparing the results with standard methods, demonstrating a good agreement between methods.

Gas Chromatographic Determination of Acetic Acid in Wine Using Ethyl Acetate Extraction

Gas Chromatographic Determination of Acetic Acid in Wine Using Ethyl Acetate Extraction