Wine Fermentation Research Articles

Vine Pruning Residues and Wine Fermentation By-Products: A Non-Exploited Source of Sustainable Agriculture, Albania Case

Albania, situated in southeastern Europe, enjoys a Mediterranean climate that is well-suited for grape cultivation. The vineyard area totals 7.202 million hectares. Since the 1990s, the country has experienced a resurgence in its rich winemaking traditions, which have gained considerable attention over the last decade. Alongside its significant wine production, large amounts of vine pruning waste and fermentation by-products are generated, estimated at over 50,000 t of prunings and 35,900 t of grape pomace annually. This waste is often burned, and the ash is used as fertilizer, releasing considerable CO2 emissions, and contributing to greenhouse gas levels. However, recycling these prunings into fertilizer by chipping and grinding them in the vineyard presents a sustainable choice, providing key minerals, nitrogen, phosphorus, and various micronutrients, thereby reducing the dependence on synthetic fertilizers in farming. Characterized by small plantations, the vine pruning issue needs site-specific, economically feasible solutions for the farmer. Additionally, there is unexplored potential for applying wine fermentation pressing residues as fertilizer for agricultural land or vineyards. The Albanian wine sector has significant untapped opportunities, such as employing vine pruning ash as a mineral fertilizer to help achieve sustainability goals.

Chemical and microbiological assessment of early wine fermentation phase can predict yeast cell viability during post-fermentation process.

The management of post-fermentation phase is essential for the protection of wine oxidation. The prolonged contact of yeast lees and wine can help to limit this problem, although off-flavours can originate. It is known that some cellular components (mannoproteins, lipids, glutathione, etc.) released into the wine influence oxygen protection; however, still active cells could contribute to maintaining protection against oxidation. To date, in the literature there is a lack of data that evaluates cell viability, especially in the post-fermentation phase, particularly using methods different by plate count that identifies only a small part of the viable population. The aim of the work was to investigate the yeast viability of 12 wine Saccharomyces cerevisiae strains during 45days after the fermentation in natural grape juice. The major fermentation parameters were measured at early phase (40h) and at the end of the process, and were correlated with total and viable cells in the post-fermentation phase. Contrary to what has been observed in the literature, this work demonstrates that cell viability in the post-fermentation phase is very high and dependent on the yeast strain. A predictive model that can estimate viability in the post-fermentation phase, based on parameters measured at the early fermentation phase, was successfully set up. This approach can be adopted by wineries or winemakers as it uses fermentation data (sugar and nitrogen residues, ethanol and glycerol production, total cell count) obtained through simple chemical and microbiological analyses.

Ultrasonic-enzymolysis effects on proso millet wine fermentation

Ultrasonic-enzymolysis effects on proso millet wine fermentation

The forgotten wine: Understanding palm wine fermentation and composition.

Palm wine is an alcoholic beverage that has existed for centuries and has important economic and socio-culture values in many tropical and sub-tropical countries. Lesser known than other types of wines, palm wine is made by spontaneous fermentation of palm sap by naturally occurring microbial communities. The palm sap ecosystem has unique microbial composition and diversity, which determines the composition of the eventual wine and is likely affected by geographical distinctiveness. While these features are well understood in grape and rice wine, these features have not been understood in palm wine. Here, we gather information of microbial communities and metabolite profiles from published studies, covering a wide range of methodologies and regions to better understand the causal links between the principal microbial species and major metabolites of palm wine. We assessed palm wine quality across production regions and local practices to provide general characteristics of palm wine and identify specific regional information. These will provide better understandings to the function of microbial communities and metabolite diversity, the contribution of regional variations and to ensure product quality in this unique, yet overlooked, fermented beverage.

Chromosome level genome assembly and annotation of Hanseniaspora mollemarum CBS 18055 strain.

Hanseniaspora species gained attention due to the ability of these species to ferment simple sugars and to actively contribute to the development of bouquet aromas in wine and cider fermentations. We present a chromosome-level assembly of an isolate of Hanseniaspora mollemarum that would enhance its potential applications.

Isolation and Evaluation of Rhizopus arrhizus Strains from Traditional Rice Wine Starters (Jiuqu): Enzyme Activities, Antioxidant Capacity, and Flavour Compounds.

Seventy-eight autochthonous strains of Rhizopus arrhizus were isolated from rice wine starter samples across twenty-nine regions in China to evaluate their potential in traditional rice wine fermentation. Strains were assessed for enzyme activity, antioxidant properties, amino acid production, and volatile flavour compounds. Significant variation in enzyme activities was observed, with acidic protease activity ranging from 280 to 1023 U/g, amylase from 557 to 1681 U/g, and esterase from 370 to 2949 U/g. Strains W17 and W42 exhibited the highest enzyme activities and antioxidant capacities, with a total phenolic content of 828 mg/L, total flavonoids of 215 μg/L, and an ABTS scavenging rate of 96.3%. They also produced high levels of glutamic acid (up to 3083 mg/L), enhancing the flavour profile. Histamine levels were low, ranging from 8 to 205 μg/L, ensuring product safety. Analysis of volatile compounds identified 80 substances, including 16 key aroma-active compounds, contributing to a complex flavour profile. These results provide a basis for selecting R. arrhizus strains to optimise rice wine fermentation, addressing market demand for diverse and functional products.

Comparative Proteomics of Two Flor Yeasts in Sparkling Wine Fermentation: First Approach.

The traditional method is considered the highest-quality sparkling wine making technique. Its main characteristic is that the entire sparkling transformation takes place in the bottle, producing complex, refined wines with fine, persistent bubbles. Currently, the second fermentation in the bottle is initiated by a few commercially available strains of Saccharomyces cerevisiae. This lack of yeast diversity leads to a predominant uniformity in the sensory profiles of the final products and a lack of distinctive wines. The aim of the present study is to compare the proteomic profiles of the first flor yeast strain (G1) on the market for the production of high-quality sparkling wines with a new flor strain (N62) selected for its specific characteristics for potential use in sparkling wine production, such as flocculation, tolerance to high ethanol concentrations, and β-Glucosidase-positivity, which is valuable for improving wine aroma complexity. The results showed that these strains behaved differently in the middle fermentation tested: the strain that reached 3 atmospheres faster was strain N62, which achieved higher growth, viability, glycerol content, and volatile acidity. In G1, a higher ethanol content was reached, and lower growth and viability were observed. Key protein data support the relationship between these differences, and the proteomic analysis could show that strain N62 had a higher abundance of proteins related to protein synthesis, such as PAB1, TEF2, and RPL25; DAK1, GPP1, and GPP2 are involved in glycerol synthesis and PDC6 and ALD4 in acetate synthesis. In the case of G1, the abundance of ADHI is associated with ethanol production and cell wall proteins with YGP1, EXG1, SCW11, PST1, CIS3, and PIR3, while the onset of autophagy is associated with PRC1, PRB1, ATG42/YBR139W, PRE8, PRE9, and PUP2.

Changes in Microbial Community Diversity and the Formation Mechanism of Flavor Metabolites in Industrial-Scale Spontaneous Fermentation of Cabernet Sauvignon Wines.

The key flavor compound formation pathways resulting from indigenous microorganisms during the spontaneous fermentation of wine have not been thoroughly described. In this study, high-throughput metagenomic sequencing and untargeted metabolomics were utilized to investigate the evolution of microbial and metabolite profiles during spontaneous fermentation in industrial-scale wine production and to elucidate the formation mechanisms of key flavor compounds. Metabolome analysis showed that the total amount of esters, fatty acids, organic acids, aldehydes, terpenes, flavonoids, and non-flavonoids increased gradually during fermentation. Enrichment analysis indicated that metabolic pathways related to the synthesis, decomposition, transformation, and utilization of sugars, amino acids, and fatty acids were involved in the formation of key flavor compounds in wine. Metagenomic analysis revealed that Saccharomyces, Hanseniaspora, Zygosaccharomyces, Wickerhamiella, Lactobacillus, and Fructobacillus were the dominant taxa during spontaneous fermentation. They were significantly positively correlated with organic acids, fatty acids, esters, phenols, aldehydes, terpenes, and phenols. In conclusion, this research provides new insights into the metabolic pathways of key flavor compounds formed by indigenous microorganisms during wine fermentation.

Acidity, sugar, and alcohol contents during the fermentation of Osmanthus-flavored sweet rice wine and microbial community dynamics.

Sweet rice wine is a popular traditional Chinese rice wine widely loved by Chinese people for its high nutritional value. Osmanthus flower petals contain various nutrients and have good medicinal value. However, the dynamics of the sugar level, acidity, alcohol content, and microbial community during the fermentation of Osmanthus-flavored sweet rice wine have not been evaluated, which can lead to the unstable quality of Osmanthus flower sweet rice wine (OFSRW). In this study, the dynamic changes in sugar level, acidity, alcohol content, microbial community composition, and microbial metabolic pathways during traditional fermentation of OFSRW at four-time points-0 h (AG0), 24 h (AG24), 36 h (AG36), and 43 h (AG43)-were analyzed via direct titration, total acid assays, alcoholometry, and high-throughput macrogenomic techniques. First, we found that bacteria were the dominant microorganisms in the early stage of OFSRW fermentation (AG0), fungi were the dominant microorganisms in the middle and late stages of fermentation (AG24 and AG36), and Rhizopus was the main fungal genus throughout fermentation. Acidity and total sugars increased with fermentation time, and alcohol was not detected until the end of fermentation. Diversity analysis revealed that the dominant species at the beginning of natural fermentation was A. johnsonii, and R. delemar became the dominant species as natural fermentation progressed. Metabolic pathway analysis revealed that energy production and conversion, carbohydrate transport, amino acid transport, and metabolic pathways were the most active metabolic pathways in the fermenter. These results provide a reference basis for changes in the microbial community during the fermentation of cinnamon-flavored sweet rice wine.

Microbial diversity during wine fermentation in Beijing region and its influence on wine flavor

Microbial diversity during wine fermentation in Beijing region and its influence on wine flavor

Fermentation of buckwheat rice wine based on a new mixed Jiuqu and its quality evaluation

Fermentation of buckwheat rice wine based on a new mixed Jiuqu and its quality evaluation

Co-evolutionary dynamics of microbial communities and flavor profiles during natural fermentation of Cabernet Sauvignon and Merlot: A comparative study within a single vineyard.

Indigenous microorganisms play a crucial role in determining the quality of naturally fermented wines. However, the impact of grape cultivar specificity on microbial composition is often overshadowed by the geographical location of the vineyard, leading to underestimation of its role in natural wine fermentation. Therefore, this study focuses on different grape cultivars within a single vineyard. The physicochemical results revealed that during fermentation of Merlot and Cabernet Sauvignon wines, ethanol content significantly increased, while residual sugar, pH, malic acid, citric acid, and yeast assimilable nitrogen notably decreased. High-throughput sequencing (HTS) results showed that fungal diversity and richness in Merlot were significantly higher than in Cabernet Sauvignon, whereas bacterial diversity exhibited the opposite trend. The predominant fungal genera in Merlot were Hanseniaspora, followed by Lachancea, whereas the opposite was observed in Cabernet Sauvignon. Erysiphe and Pantoea were exclusively present in Merlot, whereas Erwinia was detected only in Cabernet Sauvignon. A total of 106 flavor compounds were quantified using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), identifying 22 core volatile compounds in Merlot and 19 in Cabernet Sauvignon. Moreover, at the end of fermentation, the total ester content in Cabernet Sauvignon was significantly higher than in Merlot, imparting a more pronounced fruity and floral aroma, which was further confirmed using sensory analysis. Correlation analysis indicated that Saccharomyces was positively correlated with alcohol content, total acidity, and 16 core volatile compounds, while Hanseniaspora and Lachancea showed opposite correlations. These insights provide a data reference for producing high-quality wines with regional characteristics.

Exploring the potentials of indigenous Saccharomyces cerevisiae and Pichia kudriavzevii for enhancing flavour and aromatic characteristics in apricot wines.

In this study, we investigated the oenological performance of key yeast populations previously identified from apricot wine fermentation, aiming to obtain indigenous starters suitable for apricot wine production. Twenty-one isolates were characterized physiologically, and two isolates each of Saccharomyces cerevisiae and Pichia kudriavzevii were selected for laboratory-scale fermentations. Results showed that S. cerevisiae S9 exhibited significantly higher sugar consumption than S2 and CECA strains, with the former demonstrating a fructophilic character. Mixed fermentations of P. kudriavzevii N11 and N12 resulted in lower citric acid content (decreasing by 12-25%) and higher glycerol levels (increasing by 12-47%) compared to pure fermentation. In the mixed fermentation, indigenous S. cerevisiae species supported the survival of P. kudriavzevii, effectively enhancing the fruity esters and terpenes content of apricot wine. This study provides technical support for screening specialized starters for apricot wine production.

Enhancing the quality and flavor of pomelo wine through sequential fermentation with Schizosaccharomyces pombe and Saccharomyces cerevisiae: A non-targeted metabolomic analysis

This study investigated the impact of single and sequential inoculation of Schizosaccharomyces pombe (S. pombe) and Saccharomyces cerevisiae (S. cerevisiae) on the sensory attributes and metabolic profiles of pomelo wine. Our comprehensive assessment included physicochemical determination, sensory evaluation, and metabolite analysis across single and sequential fermentation groups. Results demonstrated that sequential fermentation not only moderated acidity but also enhanced umami and richness, yielding a more balanced flavor profile compared to single strain fermentations. Flavor chemistry analysis revealed that sequential fermentation effectively utilized the strengths of both yeast strains to produce a wider array of aromatic compounds, especially esters, and alcohols, which are key to pomelo wine's aroma. The metabolomic analysis further confirmed that amino acid metabolism was the most prominently activated pathway, with sequential fermentation adept at regulating amino acid levels to minimize the formation of potentially harmful byproducts. This approach preserved the desirable flavor characteristics of the wine and enhanced its safety. Overall, this research offers valuable insights into optimizing pomelo wine fermentation techniques to improve its sensory quality and market value.

Effect of the initial glucose concentration on the performance of ice wine fermentation of Vidal grape juice

Ice wine is produced from concentrated grape juice obtained by the natural freezing and pressing of grapes. The high sugar content of this juice has an impact on fermentation. To investigate the impact of the initial sugar concentration on the fermentation of ice wine, the initial sugar concentration of Vidal ice grape juice was adjusted to 370, 450, 500 and 550 g/L by the addition of glucose. The fermentation process was conducted at a temperature of 18 °C with Zymaflore ST yeast. To ensure optimal fermentation, the yeast assimilable nitrogen (YAN) in the grape juice was adjusted to 350 mg/L using a commercial nitrogen source. The initial sugar concentrations (370, 450, 500, and 550 g/L) were significantly negatively correlated with the number of viable yeast during active fermentation, the total consumption of sugar and YAN, and ethanol production (130.26, 117.83, 106.14, and 90.85 g/L) but positively correlated with the production of acetic acid (0.82–2.86 g/L) and acetaldehyde. Fermentation with initial sugar concentrations ≥ 500 g/L (500 and 550 g/L) produced ethanol (106.14 and 90.85 g/L) and excessive acetic acid (2.14 and 2.86 g/L), inhibited the esterification of n-butanol and n-hexanol, and promoted the production of isopentanol, isoamyl acetate, diethyl succinate, ethyl hexanoate and ethyl octanoate while increasing the production of 2-phenylethanol and isobutanol. The initial sugar concentration affected the production of glycerol, isobutanol, ethyl acetate, and diethyl succinate, but it did not affect the final contents of the ice wine. This study examined fermentation dynamics, including substrate consumption, yeast cell production, and the production of important metabolites such as ethanol, acetic acid, higher alcohols, and esters. Appropriate initial concentrations of YAN and sugar (below 500 g/L) and a relatively high ratio of glucose to fructose (between 1:1 and 1.7:1) is preferable for effective ice wine fermentation.

Analysis of a Commercial Red Wine Fermentation Dataset with a Wine Kinetic Model

The adoption of sensors to monitor wine fermentation enables the collection of large datasets that relate the initial juice chemistry, density and temperature patterns during fermentation to fermentation outcomes. Wine kinetic models are now being applied to commercial fermentations in real time to identify abnormal or sluggish fermentations. In this work, 222 red wine fermentations from five harvests at two commercial wineries were evaluated by a wine fermentation model. The model parameters, initial juice chemistries and fermentation outcomes were analyzed for trends and relationships between them. While the fermentations with higher initial assimilable nitrogen concentrations had higher maximum fermentation rates, this did not guarantee successful fermentation outcomes in the tailing stage of the fermentation. Neither the initial, final, minimum and maximum temperatures, nor the initial pH, titratable acidity, measured yeast-assimilable nitrogen and primary amino nitrogen concentrations had any significant correlation with the maximum fermentation rate or successful completion of the fermentation. These results suggest that the initial juice-assimilable nitrogen measurements for these juices are of limited use in predicting slower and incomplete fermentation outcomes.

Isolation and selection of yeast strain for Tac Cau pineapple (Ananas comosus) wine fermentation

Isolation and selection of yeast strain for Tac Cau pineapple (Ananas comosus) wine fermentation

Influence of Organic Nitrogen Derived from Recycled Wine Lees and Inorganic Nitrogen on the Chemical Composition of Cabernet Sauvignon Wines Fermented in the Presence of Non-Saccharomyces Yeasts Candida boidinii, C. oleophila, and C. zemplinina.

In this study, the influences of inorganic nitrogen source (INS) and organic nitrogen source (ONS) supplementation during the wine fermentation process using three non-Saccharomyces yeasts (Candida zemplinina, Candida oleophila, and Candida boidinii) were analyzed. Diamine phosphate (DAP) was used as an INS, and lees enzymatic hydrolysate was used as an ONS. Complete alcoholic fermentation and a higher concentration of volatile compounds were obtained in fermentations with ONS, mainly esters from 81 to 4564 µg/L, alcohols from 231 to 7294 µg/L, and isoamyl acetate ester compounds from 12.3-22.8 ppb, with a very marked odorant activity value (OAV). In addition, malic acid was detected due to its influence on yeast metabolism and, consequently, on aroma production. Using a Y15 enzymatic autoanalyzer, residues of 1.30 g/L in ONS and 1.35 g/L in INS were obtained on the last day of alcoholic fermentation. In summary, we obtained promising results concerning the production of wine with enhanced functionalities due to higher concentrations of some volatile and polyphenolic compounds.

Influences of Processing Methods on Elderberry (Sambucus nigra L.) Wine Quality

ABSTRACT Elderberry fruit is available in the market and is becoming more popular. However, winemaking techniques are under-studied with this fruit. This study aimed to determine the impact of three processing methods on elderberry wine quality. The methods were: No extended maceration followed by hot water treatment (EC0); 2 days of cold soak maceration followed by hot water (EC2) and boiled elderberry (EB) fruits before alcoholic fermentation. The results indicated that although the treatments did not cause significant differences in ethanol, glycerol, total acidity, volatile acidity and tannins, wine pHs were influenced by the treatments. Besides influencing the pH, EB treatment produced darker elderberry wine, whereas, EC2 wine had the lightest color. Treatments also influenced the final wine monophenol profiles and antioxidant capabilities. EB wine had the highest total anthocyanin content and antioxidant activities. EC2 wine had a significantly higher amount of total hydroxycinnamates compared to EC0 but was not different from EB-treated wine. The wine antioxidant capacities were significantly lower than in musts but were not different between treatments. Cold maceration in EC2 did not help the extraction of antioxidants in elderberry wine. The results indicated that heating through boiling might help disrupt fruit cells and assist in the extraction of anthocyanins. Cold soak enhanced certain compounds in elderberry wines. This research provided information for elderberry fruit wine fermentation with general processing methods.

Effect of co-inoculations of Saccharomyces cerevisiae and grape endophytes on the fermentation property, organic acid, and volatile aroma compounds.

Grape endophytic fungi (EFFs) have rich secondary metabolic pathways that can synthesize bioactive substances and various enzymes, which may contribute to the improvement of wine quality. In order to investigate the effect of EFFs on fermentation characteristics and chemical components, fermentations by co-inoculations of Saccharomyces cerevisiae and five EFF strains at different concentrations were performed in this study. It was found that EFFs affected the fermentation rate and are related to the genus of EFFs and inoculation amount. Among them, strains RH48 and RH34 facilitated the fermentation process at an optimal concentration of 3.5g/L. Strain RH34 had acid-increasing potential and effectively increased malic and succinic acid contents. In terms of volatile aroma compounds, CS13 3.5g/L and RH34 3.5g/L treatment showed significant enhancement of acetate esters content by 91.04% and 61.34%, respectively, whereas RH48 3.5g/L and CS13 3.5g/L showed significant enhancement of fatty acid ethyl ester content by 52.14% and 48.45%, respectively. In addition, strain CS13 at 3.5g/L also significantly increased the content of terpenes, higher alcohols, and aromatic compounds, showing great potential in improving the aroma quality (floral, fruity, etc.) of wine. The results of the present study may be useful for the innovation of wine fermentation aids and the improvement of wine quality.