Fermentation Of Musts Research Articles

The Role of Keeving in Modulating Fermentation and the Flavour Profiles of Apple Brandy

Keeving is the removal of nutrients from apple musts due to their binding to pectin, resulting in a slower fermentation and spontaneous arrest. The aim of this study was to determine the effect of keeving on the chemical composition of fermented apple must and on the volatile profile and sensory analysis of apple brandies. We compared the application of keeving during spontaneous fermentation with fermentation carried out by Saccharomyces cerevisiae (SafSpirit HG-1). We evaluated the impact of adding different doses of calcium chloride on various parameters of fermented musts and distillates. Calcium chloride had a greater effect on the ethanol concentration, total extract, and fermentation efficiency than on the type of fermentation used. However, a different phenomenon was observed with respect to the volatiles. The concentration of most of the higher alcohols, acetaldehyde, dodecanal, and geranylaceton, decreased after spontaneous fermentation and increased during the fermentation carried out with Saccharomyces cerevisiae SafSpirit HG-1. In general, the application of keeving contributed to a decrease in the concentration of ethyl and methyl esters, but caused an increase in the concentration of all acetate esters and terpenoids. When the amount of nutrients in the environment is limited and starvation occurs, microorganisms use the available nutrients for basic metabolic processes that allow them to survive and limit the formation of side metabolites such as volatiles. However, most of the samples fermented after the faecal depletion achieved high scores for the floral, fruity, and “overall note” parameters in the sensory analysis. This means that this method, carried out with a properly selected yeast strain, could be feasible for the distilling industry.

Non-Conventional Cuts in Batch Distillation to Brazilian Spirits (cachaça) Production: A Computational Simulation Approach

In this work, an algorithm was developed to determine different possibilities of distillation cuts to support productivity and improve the final quality of cachaça, a Brazilian spirit beverage. The distillation process was simulated using the Aspen Plus® software, considering a wide range of fermented musts compositions available in the literature obtained by fermentation with different yeast strains. Twenty-four simulations were carried out considering eight compounds as follows: water and ethanol (major compounds); acetic acid, acetaldehyde, ethyl acetate, 1-propanol, isobutanol, and isoamyl alcohol (minor compounds). The calculations considered a long-time process, i.e., until almost all the ethanol in the fermented must was distilled. The algorithm enabled the identification of countless distilling cuts, resulting in products with different alcoholic grades and process yields. One fermented must became viable to produce cachaça after the suggested non-traditional method of cuts proposed in this work. Furthermore, the non-traditional distilling cut provided a productivity gain of more than 50%. Finally, the ratio of acetaldehyde and ethanol concentration was the key parameter to determine whether the fermented musts could provide products meeting cachaça’s legislation.

Enzymatic Biocatalysis of Biomass from Aquatic Plant Phragmite Karka for Second-Generation Bioethanol Production

In the context of energy transition and the reduction of greenhouse gas emissions, the production of second-generation bioethanol is also recognized as a promising way to reduce our dependence on fossil fuels. Then, the present studies aim to evaluate the enzymatic biocatalysis of biomass from aquatic plant Phragmite karka in the second-generation bioethanol production. Results obtained revealed a rapid decrease of °Brix during the fermentation of musts and underlined the efficacy of enzyme hydrolysis. The rate of sugar consumption by yeasts is between 32.43 and 70.27%. The yield of ethanol production of yeasts indicated that Angel Brand Thermal-tolerant alcohol active dry yeast was the best yeast strain for this fermentation. These findings underline the potential of Phragmite karka plant materials in the perspective of intensive production of second-generation bioethanol.

Influence of keeping the calyces during fermentation on physicochemical and sensory properties of Hibiscus sabdariffa wines.

Hibiscus (Hibiscus sabdariffa) wines are usually made through the fermentation of its calyces extracts. However, the exhausted calyces could still contain a considerable amount of extractable bioactive compounds. This work analyzed the effect of keeping the hibiscus calyces during fermentation on the physicochemical and sensory characteristics and acceptance of its wines. Hibiscus wines Filtered-Ch and Filtered-C were generated by fermentation of filtered musts of China and Colima varieties, respectively, while Unfiltered-Ch and Unfiltered-C were obtained by fermentation of musts from calyces that were kept for 120days. Unfiltered-C and Unfiltered-Ch wines had higher contents of total monomeric anthocyanins (32.5mg/L in Unfiltered-C and 48.5mg/L in Unfiltered-Ch), condensed tannins (around 200 mgCE/L), total phenolic compounds (800 mgGAE/L), and antioxidant activity (8.4-8.8 mMTE/L), as well as a higher concentration of tartaric, citric and malic acids (0.26, 0.32 and 2.25g/L, respectively) than Filtered-C and Filtered-Ch wines (P < 0.05). Moreover, Unfiltered-C and Unfiltered-Ch wines had darker red colors, evidenced by lower lightness, chroma and hue values, than those observed in Filtered-C and Filtered-Ch wines (P < 0.01). Furthermore, Unfiltered-Ch and Unfiltered-C wines were more appreciated, having a more intense taste and smell according to the descriptions obtained from consumers by applying the Check-All-That-Apply technique. Sensory attributes observed in hibiscus wines were statistically correlated with the physicochemical characteristics. Keeping hibiscus calyces during fermentation allows for the production of wines with acceptable sensory characteristics and a higher concentration of bioactive compounds than producing wines from filtered musts.

Influence of curettage on Esca-diseased &lt;i&gt;Vitis vinifera&lt;/i&gt; L. cv. Sauvignon blanc plants on the quality of musts and wines

Aim: A study on Sauvignon blanc (SB) cultivar in France showed that curettage had an effect on the resilience of GTD grapevines. No experiments, however, have been conducted on its effects on wine quality, particularly on white Sauvignon blanc cultivar wines.Methods and results: Grapevines from Sauvignon blanc cultivar that had expressed Esca-foliar symptoms were used for the study, with some of them having been curetted in 2014. Subsequently, bunches from Control (asymptomatic), Curetted and Esca-symptomatic vines were harvested in 2017 and 2018 in order to produce white wine. Technical and chemical results on both must and wine showed that wines from curetted plants were similar to those from asymptomatic vines. There were differences, however, for Esca-diseased vines, where the alcoholic fermentation of musts was faster than for the other modalities. Olfactometry results showed that, for the one-year-old 2017 vintage wines, no differences were detected, although they were for the 2018 vintage.Conclusion: The results of the chemical analyses and wine tasting showed that the wines from curetted and asymptomatic grapevines were similar, and that their quality was the same.Significance of the study: The quality of wines from curetted vines compared to asymptomatic ones was confirmed and validated through chemical and sensory analyses of the must and the one-year-old wines.

Fungal Diversity Analysis of Grape Musts from Central Valley-Chile and Characterization of Potential New Starter Cultures.

Autochthonous microorganisms are an important source of the distinctive metabolites that influence the chemical profile of wine. However, little is known about the diversity of fungal communities associated with grape musts, even though they are the source of local yeast strains with potential capacities to become starters during fermentation. By using internal transcribed spacer (ITS) amplicon sequencing, we identified the taxonomic structure of the yeast community in unfermented and fermented musts of a typical Vitis vinifera L. var. Sauvignon blanc from the Central Valley of Chile throughout two consecutive seasons of production. Unsurprisingly, Saccharomyces represented the most abundant fungal genus in unfermented and fermented musts, mainly due to the contribution of S. uvarum (42.7%) and S. cerevisiae (80%). Unfermented musts were highly variable between seasons and showed higher values of fungal diversity than fermented musts. Since microbial physiological characterization is primarily achieved in culture, we isolated nine species belonging to six genera of fungi from the unfermented must samples. All isolates were characterized for their potential capacities to be used as new starters in wine. Remarkably, only Metschnikowia pulcherrima could co-exist with a commercial Saccharomyces cerevisiae strain under fermentative conditions, representing a feasible candidate strain for wine production.

Solvent Extraction of Citric Acid with Different Organic Phases

The present work aimed at the study of citric acid solvent extraction in order to establish the composition of the organic phase and to obtain thermodynamic and kinetic data for the chosen system. Discontinuous extraction experiments in a single stage were performed from a synthetic solution of citric acid, with the typical concentration (10% w/v) observed in industrial fermented musts. Exploratory experiments were carried out using different organic phases in order to select the most suitable solvent phase to further continuous extraction tests in a mechanically agitated column. The selected organic phase composition was: Alamine® 336, ExxalTM 13 tridecyl alcohol, and the aliphatic diluent EscaidTM 110. Next, the effects of the contact time and of the concentrations of extractant and modifier on the citric acid extraction were studied. Among the investigated conditions, the best one was 10 minutes of contact time, 30% w/v of Alamine® 336, and 10% w/v of ExxalTM 13 tridecyl alcohol. For this condition, the equilibrium isotherm (28°C ± 2°C) was determined, and the equilibrium constant was calculated (36.8 (mol·L-1)-1.5). It was considered that trioctylamine and citric acid complexation reaction occurs mainly with non-dissociated citric acid form, because the aqueous feed solutions’ pH is lower than the citric acid pKa1. It was found that 1.5 molecules of the extractant, on average, are required to react with one citric acid molecule, which can indicate that reactions with different extractant/citric acid ratios occur simultaneously. Next, the rate constants for the direct and inverse reactions, 2.10 (mol·L-1)-1.5·s-1 and 5.69 × 10-2 s-1, respectively, were calculated. Coefficients of determination (R2) values higher than 0.93 were found in these calculations, suggesting that the results obtained using a computer modeling would be very close to those results obtained experimentally. Therefore, the present work provides data required to future modelling, design, and simulation of citric acid solvent extraction processes.

Improvement on the productivity of continuous tequila fermentation by Saccharomyces cerevisiae of Agave tequilana juice with supplementation of yeast extract and aeration.

Agave (Agave tequilana Weber var. azul) fermentations are traditionally carried out employing batch systems in the process of tequila manufacturing; nevertheless, continuous cultures could be an attractive technological alternative to increase productivity and efficiency of sugar to ethanol conversion. However, agave juice (used as a culture medium) has nutritional deficiencies that limit the implementation of yeast continuous fermentations, resulting in high residual sugars and low fermentative rates. In this work, fermentations of agave juice using Saccharomyces cerevisiae were put into operation to prove the necessity of supplementing yeast extract, in order to alleviate nutritional deficiencies of agave juice. Furthermore, continuous fermentations were performed at two different aeration flow rates, and feeding sterilized and non-sterilized media. The obtained fermented musts were subsequently distilled to obtain tequila and the preference level was compared against two commercial tequilas, according to a sensorial analysis. The supplementation of agave juice with air and yeast extract augmented the fermentative capacity of S. cerevisiae S1 and the ethanol productivities, compared to those continuous fermentations non supplemented. In fact, aeration improved ethanol production from 37 to 40 g L−1, reducing sugars consumption from 73 to 88 g L−1 and ethanol productivity from 3.0 to 3.2 g (Lh)−1, for non-aerated and aerated (at 0.02 vvm) cultures, respectively. Supplementation of yeast extract allowed an increase in specific growth rate and dilution rates (0.12 h−1, compared to 0.08 h−1 of non-supplemented cultures), ethanol production (47 g L−1), reducing sugars consumption (93 g L−1) and ethanol productivity [5.6 g (Lh)−1] were reached. Additionally, the effect of feeding sterilized or non-sterilized medium to the continuous cultures was compared, finding no significant differences between both types of cultures. The overall effect of adding yeast extract and air to the continuous fermentations resulted in 88 % increase in ethanol productivity. For all cultures, pH was not controlled, reaching low pH values (from 2.6 to 3). This feature suggested a reduced probability of contamination for prolonged continuous cultures and explained why no significant differences were found between continuous cultures fed with sterilized or non-sterilized media. Concentrations of volatile compounds quantified in the distillates (tequila) were in the allowed ranges established by the Mexican regulation of tequila (NOM-006-SCFI-2012, Norma Oficial Mexicana: Bebidas alcohólicas-Tequila-specificaciones, 2012). The preference level of the distillates was similar to that of two well-known commercial tequilas. The results suggested the possibility of implementing this innovative technology on an industrial scale, attaining high productivities and using non-sterilized agave juice.

Isolation, identification and oenological characterization of non-Saccharomyces yeasts in a Mediterranean island.

We isolated, identified and characterized yeast strains from grapes, and their fermented musts, sampled in the small island of Linosa, where there are no wineries and therefore the possibility of territory contamination by industrial strains is minimal. By traditional culture-dependent methods, we isolated 3805 colonies, distinguished by molecular methods in 17 different species. Five hundred and forty-four isolates were analysed for the main oenological characteristics such as fermentative vigour with and without sulphites, sugar consumption and production of alcohol, volatile acidity, hydrogen sulphide, glycerol and β-glucosidase. This analysis identified Kluyveromyces marxianus (seldomly used in winemaking) as the most interesting candidate yeast for the production of innovative wines. In recent years, interest is growing for wine production by non-Saccharomyces yeasts, both in research and in the industry. This study describes the yeast population of the grapes in a small-secluded island in the Mediterranean Sea, useful site for the search of new strains. Evaluation of fundamental oenological characters identifies potential best yeasts to assay in experimental vinifications. We also describe, for the first time, 14 new colony morphologies on WL Nutrient Agar, culture medium used to monitor the yeast population dynamics.

Volatile composition of partially fermented wines elaborated from sun dried Pedro Ximénez grapes

In this work, we used a cell immobilisation system consisting of Penicillium chrysogenum fungi (GRAS) bound to the osmotolerant yeast strains Saccharomyces cerevisiae X4 and X5 for the partial fermentation of raisin musts. The resulting wines were compared with others obtained by partial fermentation of musts with free yeasts and with a traditionally produced sweet wine (i.e. without fermentation of the must). The analysis of volatile compounds grouped by aroma series showed the partially fermented musts had a more complex aroma than the traditional wine. Specially prominent among aroma series was that of ripe fruit, followed by the milky and chemical series. The volatiles with the greatest impact on wine aroma as assessed in terms of odour activity were ethyl hexanoate, ethyl octanoate, butyrolactone, isoamyl alcohols, acetaldehyde, ethyl acetate, 2,3-butanediol, acetoin and 2,3-butanedione. A cluster analysis according to the Ward method was performed to assess the similarity between the traditional sweet wine and those obtained by partial fermentation with free and immobilised yeasts revealed small differences between the wines obtained with free and immobilised yeasts, and marked differences between partially fermented and traditionally obtained sweet wine. The wines provided by immobilised yeasts were the most appreciated in the sensory analysis (especially those obtained with X4 yeasts).

Sensory and chemical characterisation of the aroma of Prieto Picudo rosé wines: The differential role of autochthonous yeast strains on aroma profiles

This study evaluates the specific impact of isolated yeast strains on the aromatic profile of fermented musts from Prieto Picudo, an autochthonous Castilla y León (Spain) red grape variety with an increasing demand in the local marketplace. For this purpose, the aroma profiles of wines elaborated from Prieto Picudo grapes have been studied by sensory analysis, gas chromatography–olfactometry (GC–O) and gas chromatography–mass spectrometry (GC–MS), with the aim of determining the potential of each strain to generate distinctive varietal and fermentation-derived aromatic compounds. The results have shown that the yeast strain exerts a critical influence on the levels of some fermentative (linear and branched ethyl esters, fatty acids, ethyl phenylacetate) and varietal compounds (4-mercapto-4-methyl-2-pentanone, 3-mercaptohexylacetate, β-damascenone), thus inducing a deep influence on the final aroma of the wine. Combination of both sensory and chemical data arises as a major tool to monitor the different patterns of aroma release and formation from selected yeast strains during the winemaking process.

Indigenous Saccharomyces cerevisiae strains and their influence on the quality of Cataratto, Inzolia and Grillo white wines

The present paper deals with three new strains of Saccharomyces cerevisiae, isolated in old wineries of Sicily, which were microbiologically and molecularly characterized and tested for their ability to produce white wines. Examined in terms of their growth pattern, fermentation vigour, sulphite tolerance, fermentative power, spore formation, and production of acetic acid, hydrogen sulphide and phenolic off-flavours, the strains were utilized as starters in experimental fermentations of musts obtained from the cultivars Inzolia, Grillo and Catarratto. Further, the three musts were also fermented using two commercial S. cerevisiae strains. The quality of the wines produced was confirmed by their principal oenochemical parameters, by sensory analysis and qualitative and quantitative determination of the volatile aroma constituents. All the data were statistically elaborated. Interestingly, the new selected yeasts were able to increase the pear notes (Z)-ethyl-4-decenoate, (E)-ethyl-3-decenoate, and (Z)-ethyl-3-decenoate which are fundamental for the aroma of these Sicilian wines. From our results, the new yeast strains were found to produce white wines of a quality which was not inferior to those obtainable with the best commercial strains selected in other geographical areas, but also with a distinctive aromatic profile.

Discrimination of sweet wines partially fermented by two osmo-ethanol-tolerant yeasts by gas chromatographic analysis and electronic nose

Some special sweet wines are obtained by partial fermentation of musts from off-vine dried grapes containing large amounts of sugars. This process is very slow and subject to serious stop problems that can be avoided by using osmo-ethanol-tolerant yeasts. Musts containing 371g/l of sugars were partially fermented with selected Saccharomyces cerevisiae strains, X4 and X5, to 12% (v/v) and the wines obtained with X5 exhibited a higher volatile acidity but lower concentrations of higher alcohols, carbonyl compounds and polyols than those obtained with X4. A principal component analysis (PCA) of the data provided by an electronic nose (E-nose) afforded discrimination between fermented and unfermented musts, but not between wines obtained with X4 or X5. The PCA applied to the major volatile compounds and polyols shows similar results, but a clear discrimination between wines is obtained by removing the polyols glycerol and 2,3-butanediol from the PCA.

Formation of vinylphenolic pyranoanthocyanins by Saccharomyces cerevisiae and Pichia guillermondii in red wines produced following different fermentation strategies

The strains of two species of yeast, Saccharomyces cerevisiae and Pichia guillermondii, both with high hydroxycinnamate decarboxylase (HCDC) activity (56% and 90% respectively), were used in the fermentation of musts enriched with grape anthocyanins, to favour the formation of highly stable vinylphenolic pyranoanthocyanin pigments. The different strains were used to ferment the must separately, simultaneously, or sequentially, the latter involving an initial period using the yeast with the greatest HCDC activity ( P. guillermondii). The must was made from concentrated grape juice diluted to 220 g/l of sugar, and enriched with grape anthocyanins to 100 mg/l and with p-coumaric acid to 120 mg/l. The pH was fixed to 3.5. All 50 ml micro-fermentations were done in triplicate. The development of anthocyanin-3- O-glucoside precursors, the decarboxylation of p-coumaric acid, and the formation of 4-vinylphenol and vinylphenolic pyranoanthocyanin derivatives were studied during the fermentation. The fermentation strategy used and the yeast HCDC activity significantly influenced the formation of vinylphenolic pyranoanthocyanins. The latter molecules were separated, identified, and quantified using high performance liquid chromatograph with diode array detection and electrospray-mass spectrometry (HPLC-DAD-ESI/MS). The volatile compounds profile was screened during fermentation using gas cromatogrphy-flame ionisation detection (GC-FID), in order to detect and quantify the main molecules. The best results were reached with the sequential fermentation (3.74 mg/l of malvidin-3- O-glucoside-4-vinylphenol). This work shows that during mixed or sequential fermentations carried out with non- Saccharomyces or highly fermentative Saccharomyces strains, with high HCDC activity, the content of stable pigments can be increased without sensorial modifications.

Minimization of ethylphenol precursors in red wines via the formation of pyranoanthocyanins by selected yeasts

Different strains of Saccharomyces with different hydroxycinnamate decarboxylase (HCDC) activities, estimated by a bioconversion assay, were used for the fermentation of musts enriched with p-coumaric acid and grape anthocyanins, with the aim of favouring the formation of vinylphenolic pyranoanthocyanins, colour stabilization and (especially) the minimization of 4-ethylphenol. The development of anthocyanin-3-O-glucosides (precursors of vinylphenolic adducts), the decarboxylation of p-coumaric acid, and the formation of 4-vinylphenol, 4-ethylphenol and vinylphenolic pyranoanthocyanins were monitored by HPLC-DAD-ESI/MS. After fermentation, the wines were inoculated with large numbers (10 4 CFU/ml) of Dekkera bruxellensis to establish their potential for ethylphenol production. The HCDC activity of the strains significantly increased the formation of vinylphenolic pyranoanthocyanins and reduced the final concentration of 4-ethylphenol and 4-ethylguaiacol generated by the vinylreductase activity (VPhR) of D. bruxellensis. Early decarboxylation of hydroxycinnamates to vinylphenols, by means of Saccharomyces strains with strong HCDC activity, and their subsequent binding with anthocyanins to form stable pyranoanthocyanins, is a possible way to reduce the likelihood of ethylphenol production by Brettanomyces during in-barrel aging.

Dynamics of changes in total anthocyanins during the fermentative maceration of grapes

&amp;nbsp;This paper deals with the results of studies on changes in the content of total anthocyanins depending on their fermentative maceration from grapes of traditional Moravian cultivars (Blauer Portugieser, Saint Laurent and Blaufrankisch). Colouring matters were macerated in the course of alcoholic fermentation either in a closed rotary tank or in an open tank with a periodically plunging pulp cap. The losses resulting from adsorption of anthocyanins on yeast biomass were quantified. Concentration losses of anthocyanins were also observed in the course of fermentation of musts made of teinturier grape cultivars Alibernet and Neronet, when the skins of berries were separated. The process of fermentative maceration of anthocyanins from grape skins consisted of three dynamically different stages. In the stage with the exponential increase in the content of anthocyanins no significant differences were observed between the closed rotary tank technique and the open tank technique with periodic plunging of pulp cap. It was demonstrated that the losses of anthocyanins took place during the whole process of fermentation. The correlation between the anthocyanin losses and the production of yeast biomass was statistically highly significant. &amp;nbsp;

Effect of different fermentation conditions on the kinetic parameters and production of volatile compounds during the elaboration of a prickly pear distilled beverage

An experimental design considering thermal treatment of must, yeast strain, prickly pear variety and degree of ripeness was chosen to evaluate the fermentation behavior and generation of volatile compounds, during the elaboration of a distilled beverage from prickly pear. Four Mexican prickly pear varieties were characterized physically and two of them were selected for fermentation studies. The thermal treatment of the must showed the highest statistical influence on fermentation behavior and production of volatile compounds, followed by prickly pear variety, then yeast strain and finally the degree of ripeness was the least statistically significant factor. The growth rate increased when the thermal treatment was applied whereas the ethanol production rate and alcoholic efficiency were unaffected. The results also suggested that thermal treatment was effective for inhibition of microbial contamination. As regards volatile compounds production, acetic acid and methanol decreased while other volatiles increased when the thermal treatment was applied. Despite the influence of thermal treatment, prickly pear variety strongly influences the volatile profile of fermented musts.

Volatile compounds after spontaneous fermentation of musts from Vitis vinifera cv. Albariño grapes cultivated in different origins from Rías Baixas AOC, Spain

AbstractWhite wines experimentally produced from the white grape variety Albariño from three different areas from Rias Baixas AOC, north‐western Spain, have been analysed in this study. The contents of terpenes, C13‐norisoprenoids, alcohols, acetates and ethyl esters were determined by GC–MS. The Albariño wines from O Rosal are characterized by a high content of higher alcohols, while wines from Val do Salnés show the highest concentrations of free terpenes, acetates and ethyl esters; and wines of Condado do Tea show the highest concentrations of C13‐norisoprenids, principally due to the α‐ionone. Two principal components accounting for 90.7% of the total variance were calculated by means of a principal components analysis (PCA), and the graphical representation of these two components allows grouping the wines according their respective origins. Volatile compounds with fruity and floral odours showed the highest odour activity values, contributing in a great measure to the aroma of Albariño wines. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Influence of Saccharomyces cerevisiae yeast strain on the major volatile compounds of wine

As must fermentation is often conducted with selected yeasts, it is important to determine the influence of the inoculated yeast strain on the wine organoleptic properties. We analysed the production of major volatile compounds (acetaldehyde, ethyl acetate and some fusel alcohols) during fermentations of musts from different grape cultivars and conducted with selected Saccharomyces cerevisiae yeast strains. The production of these volatile compounds was variable, and depended mostly on the must composition and the fermentation conditions. Occasionally, the amount of certain volatiles compounds in the wine depended on the yeast strain. We observed inverse correlations between acetaldehyde and isobutanol production, and, between ethyl acetate and total fusel alcohol production. Also, a direct correlation was found between the organoleptic wine quality and the amount of ethyl acetate. The most appreciated wines were made with yeast strains that did not produce high amounts of any of the analysed compounds, while the lowest quality wines were made with yeast strains that produced high amounts of acetaldehyde and fusel alcohols.

Oxidase-Peroxidase Method of Ethanol Assay in Fermented Musts and Wine Products

A new alcohol oxidase-peroxidase method of ethanol assay in fermented musts and wine products is described and compared to conventional methods routinely used in winemaking. The sensitivity, accuracy, and reliability of this method were determined. The results of ethanol determination in fermented musts and wines correlated well with the data obtained by refractometry (correlation coefficient R = 0.9595, p < 0.0001) and densitometry (correlation coefficient R = 0.9384, p < 0.0001). The proposed method is less time- and labor-consuming and allows simultaneous analysis of a series of wine samples.