Wine Fermentation Research Articles

Quality improvement of jujube wine through mixed fermentation with Saccharomyces cerevisiae and Bacillus licheniformis

Routine analysis, electronic sensory methods, and HS-SPME-GC-MS were used to evaluate the effect of S. cerevisiae and S. cerevisiae + Bacillus licheniformis on the quality of jujube wine. The results show that all wine samples showed significant differences in color, taste, amino acids, organic acids, and aroma (p < 0.05), while the color quality of co-fermented jujube wine was better. On the sensory scale, co-fermentation improved the taste complexity of jujube wine with a unique flavor and typical aroma. HS-SPME-GC-MS analysis revealed 37 characteristic volatile compounds in co-fermented jujube wine. Therefore, using B. licheniformis in the wine fermentation process can significantly improve microbial biotransformation efficiency and flavor. Our results show that the mixed culture of B. licheniformis and S. cerevisiae could be a valuable tool to adjust volatile components and improve the aroma complexity of jujube wine.

Review on Legal Supervision System of the Chinese Wine Industry

After more than 40 years of development, China’s wine regulatory system has been constantly improved, from half-base wine standards to pure-juice fermented wine standards, and then to the establishment of a relatively complete and mature industry-standard system with product and manufacturing standards as the core and other relevant industry standards as accessories. This advancement supports that the Chinese wine industry has emerged from New World wine countries. Nowadays, according to statistics from the International Organization of Vine and Wine, China is one of the top grape producers, wine consumers, and importers globally. Still, wine production has fallen in recent years, and the balance of wine import and export trade also shows a growing trade deficit. Faced with this problem, it is worth thinking about how to improve the regulatory system to help domestic wines overcome the difficulties. In this article, we first review the development process of China’s wine legal supervision system and summarize the situation of Chinese wine production, consumption, and trade in the past 20 years. Then we elaborate on China’s current legal framework for the wine industry consisting of a series of laws, regulations, and standards, and introduce domestic wine geographical indications. Finally, some suggestions are put forward on brand building, wine testing standards, and taxation of domestic wine. This review will help someone interested in Chinese wine to have a deeper understanding of the wine from a legal supervision system perspective and promote international cooperation and communication in the wine industry. In addition, it will also provide references for the establishment of wine regulations and standards in New World wine countries or regions.

Functional divergence in the proteins encoded by ARO80 from S. uvarum, S. kudriavzevii and S. cerevisiae explain differences in the aroma production during wine fermentation.

SummaryPhenylethanol (PE) and phenylethyl acetate (PEA) are commonly desired compounds in wine because of their rose‐like aroma. The yeast S. cerevisiae produces the PE either through de novo biosynthesis by shikimate pathway followed by the Ehrlich pathway or the direct phenylalanine catabolism via Ehrlich pathway, and then converted into PEA. Previous work demonstrated that, compared to S. cerevisiae, other Saccharomyces species, such as S. kudriavzevii and S. uvarum, produce higher concentrations of PE and PEA from the precursor phenylalanine, which indicates differential activities of the biosynthetic‐involved enzymes. A previous in‐silico analysis suggested that the transcriptional activator Aro80p is one of the best candidates to explain these differences. An improved functional analysis identified significant radical amino acid changes in the S. uvarum and S. kudriavzevii Aro80p that could impact the expression of the catabolic genes ARO9 and ARO10, and hence, the production of PE from phenylalanine. Indeed, wine S. cerevisiae strains carrying the S. uvarum and S. kudriavzevii ARO80 alleles increased the production of both compounds in the presence of phenylalanine by increasing the expression of ARO9 and ARO10. This study provides novel insights of the unidentified Aro80p regulatory region and the potential usage of alternatives ARO80 alleles to enhance the PE and PEA concentration in wine.

Use of Microwave Maceration in Red Winemaking: Effect on Fermentation and Chemical Composition of Red Wines.

The objective of this study was to evaluate the effect of microwave treatment of crushed grapes on the yeast population of the must and on the development of alcoholic fermentation, as well as on the extraction of different compounds from the grapes such as polysaccharides and amino acids that can affect the organoleptic quality and stability of the wine. This study demonstrated for the first time the effect of the microwave treatment of grapes on native yeast species and their diversity, producing an increase in fermentation kinetics and a decrease in the lag phase. The microwave treatment produced a positive effect on the extraction of amino acids and polysaccharides from the grapes, resulting in significantly higher amounts of the main amino acids of the must and some major volatile compounds in the treated samples. The polysaccharides most affected by the microwave treatment were the PRAGs, the main polysaccharides liberated from grapes during the maceration.

Correlations between microbiota with physicochemical properties and volatile compounds during the spontaneous fermentation of Cabernet Sauvignon (Vitis vinifera L.) wine

Understanding the diversity and evolution of microorganisms during wine fermentation is essential for controlling its production. However, the flavors profiles associated with microbiota changes during the spontaneous fermentation have not yet been described in detail. In this study, we explored the correlations between microbial community with physicochemical properties and flavor components during the spontaneous fermentation of Cabernet Sauvignon wine. Microbial community diversity at different fermentation stages was identified using high-throughput sequencing, and physicochemical properties and volatile compounds were identified through fermentation features testing and headspace solid phase microextraction gas chromatography mass spectrometry. First, the diversity of the fungi community decreased with the fermentation process, whereas the bacteria did not change significantly until the end of the fermentation. Second, the changes of the fermentation environment had reshaped the diversity and composition of the microbial community. Finally, Aureobasidium, Cladosporium, Filobasidium, Hanseniaspora, Hannaella, Saccharomyces, Alternaria, Wickerhamomyce, Starmerella, Candida, Papiliotrema, Bradyrhizobium, Gluconobacter, Leuconostoclia, Comamonas, Acetobacter, and Massilia, were significantly correlated with changes of physicochemical properties and volatile compounds. Overall, our research results provide important insights for understanding the metabolically active microbiota, which is conducive to the expression of wine "terroir".

Biogas Production Potential from Anaerobic Co-digestion of Grape Pomace

Grape cultivation and wine production has been in practice since 7000 BC in ancient China. Today, top wine producing countries are France, Italy, and Spain, including the United States. New York State is the third largest wine producing state in the US, with over 28 million gallons produced in 2017. Wine pomace, the residue from wine making after pressing could be used for the production of electricity and heat replacing fossil resources. One alternative route could be anaerobic fermentation of wine making residues for the production of electricity and heat from the produced biogas.&#x0D; This research investigated the cumulative biogas production from anaerobic fermentation of differently prepared red wine grape pomace. Red wine grape pomace was used as received, prepared by blending using a laboratory benchtop blender, refined using a Valley beater apparatus, and cooking the refined red wine grape pomace for 2 hours at 98°C. The pH of each solution was adjusted to 8.50 with 20% Calcium Hydroxide (Ca(OH)2) solution. 300 g of each solution and 30 g of bacteria inoculate was filled into a 500 ml Erlenmeyer flask that contained a magnetic stirrer. The anaerobic fermentation experiment have been run in duplicate, lasted for up to 170 hours, at a temperature of 39°C ± 2°C.&#x0D; Untreated red wine grape pomace had the lowest cumulative biogas production of 93 ml and 151 ml.&#x0D; Blended grapes showed a cumulative biogas production of 283 ml and 243 ml respectively. Refined red wine grape pomace generated the highest biogas production with 566 ml and 864 ml, followed by refined and cooked red wine grape pomace with a biogas production of 365 ml and 830 ml. The maximum biogas composition without CO2 was 70% and the minimum biogas composition was 55%.&#x0D; Pre-treatment such as refining, blending, and heat treatment can increase biogas production and lead to a possible lower retention time in the fermentation vessel due faster biomass conversion.

Kinetics and mathematical model of killer/sensitive interaction under different physicochemical conditions of must/wine: a study from a biological point of view.

Fermentation of grape must to wine is carried out by a complex microbial mixture, which also involves spoilage yeasts of wine. The latter yeasts produce organoleptic changes that cause significant economic losses to the wine industry. SO2 is traditionally used to control this spoilage populations, but because of its harmful effects on human health, biocontrol has emerged as an alternative treatment. Although studies have been carried out to select biocontroller yeasts and examine their underlying mechanisms of action, reports on their application have not been published yet. To better understand the interaction and the successful application of biocontrol, the use of mathematical models, among other methods, is important, as they facilitate the prediction of success or failure of the antagonist. The objective of the present study was to use an existing mathematical model to obtain information about the yeast's interaction assayed and to validate its predictive use under different physicochemical conditions during the wine fermentation, and eventually predict biocontrol kinetics. The mathematical model was applied to the fermentation conditions and provided information on the kinetic parameters of the biocontrol interaction and allowed interpretations about other parameters. The model was applied in the different physicochemical conditions for the biocontrol and did not fit correctly to experimental data, and therefore an improvement was proposed which was successful and presented new hypotheses.

Implementasi Peraturan Gubernur Bali Nomor 1 Tahun 2020 Tentang Tata Kelola Minuman Fermentasi di Singaraja

In running an alcoholic beverage trading business, of course, you must have a permit. With the issuance of Bali Governor Regulation No. 1 of 2020 on The Governance of Fermented Beverages and/or Distillation typical of Bali aims to establish production standardization to ensure the safety and legality of fermented beverage products and or distillation, especially typical of Bali. The purpose of the research was to discuss the application of the Governor of Bali regulation number 1 of 2020 in the distribution permit of Balinese fermented drinks in Singaraja and to describe the obstacles faced in implementing the regulation of the Governor of Bali number 1 of 2020 concerning the governance of fermented Balinese wine in Singaraja. The research used the type of empirical research. This research approach uses a sociological approach and a factual approach. The sources of legal materials for this research consist of primary and secondary sources. Data collection techniques used are interview techniques and field observations. The results found that the implementation of Bali Governor Regulation Number 1 of 2020 concerning Governance of Balinese Fermented/Distilled Drinks in the distribution permit for Balinese fermented wine in Singaraja is just waiting for technical instructions, so until now the implementation in the field has not been running as it should. Obstacles encountered include monitoring efforts and still waiting for cooperation with companies that already have distribution permits.

Bottle Aging Affected Aromatic and Phenolic Wine Composition More than Yeast Starter Strains

Volatile and phenolic compounds play a key role in the sensory properties of wine, especially aroma and color. During fermentation, yeasts produce enzymes that affect the skin’s phenolic compounds extraction and synthesize some of the most important wine volatile compounds. Generally, selected yeasts of the Saccharomyces cerevisiae (Sc) strains are inoculated, which are responsible for carrying out the wine fermentation, enhancing and highlighting its sensory characteristics and contributing to help achieve the wine typicity, according to the winemaker’s criteria. After fermentation, all wines require aging in a bottle to modulate their composition and stability over time. Thus, four different Sc strains (Sc1–Sc4) were inoculated into tanks with Tempranillo grapes to carry out, in duplicate, their fermentation and subsequent aging in bottles (9 months), comparing the aromatic and phenolic composition between them. Results showed differences in the fermentation process (kinetic, ethanol yield), CI, TPI and content of alcohols, esters, anthocyanins, flavonols and flavanols in wines from the different Sc strains studied. Moreover, in the content in wines of most groups of aromas and phenols, except for total acetate esters and flavonols, aging in a bottle had more influence than the yeast strain used for fermentation.

Genetic bases for the metabolism of the DMS precursor S-methylmethionine by Saccharomyces cerevisiae

Dimethyl sulfide (DMS) is a sulfur containing volatile that enhances general fruity aroma and imparts aromatic notes in wine. The most important precursor of DMS is S-methylmethionine (SMM), which is synthesized by grapes and can be metabolized by the yeast S. cerevisiae during wine fermentation. Precursor molecules left after fermentation are chemically converted to DMS during wine maturation, meaning that wine DMS levels are determined by the amount of remaining precursors at bottling.To elucidate SMM metabolism in yeast we performed quantitative trait locus (QTL) mapping using a population of 130 F2-segregants obtained from a cross between two wine yeast strains, and we detected one major QTL explaining almost 30% of trait variation. Within the QTL, gene YLL058W and SMM transporter gene MMP1 were found to influence SMM metabolism, from which MMP1 has the bigger impact. We identified and characterized a variant coding for a truncated transporter with superior SMM preserving attributes. A population analysis with 85 yeast strains from different origins revealed a significant association of the variant to flor strains and minor occurrence in cheese and wine strains.These results will help selecting and improving S. cerevisiae strains for the production of wine and other fermented foods containing DMS such as cheese or beer.

Effect of ‘loss of function’ mutation in &lt;i&gt; SER1 &lt;/i&gt; in wine yeast: fermentation outcomes in co-inoculation with non-&lt;i&gt;Saccharomyces &lt;/i&gt;

In wine fermentation, improved wine complexity and sensorial properties can arise from the use of non-Saccharomyces yeast. Generally less alcohol tolerant, such strains often do not finish fermentation, therefore requiring a second inoculation with the more robust Saccharomyces cerevisiae, usually added on Day 3. This sequential approach affords non-Saccharomyces time to make an impact before being overtaken by S. cerevisiae. However, two inoculations are inconvenient; therefore the identification of a slow growing S. cerevisiae strain that can be used in a single co-inoculation with the non-Saccharomyces yeast is highly attractive. In this study we investigated the use of the naturally occurring ‘loss of function’ SER1 variant, identified in a Sake yeast, for the purposes of carrying out co-inoculated wine fermentations. The SER1-232(G &gt; C; G78R) change was introduced into the commonly used wine strain, EC1118, via CRISPR/Cas9 editing. In a chemically defined grape juice medium, the SER1(G78R) mutant grew and fermented more slowly and increased acetic acid, succinic acid and glycerol concentrations. Simultaneous inoculation with the slower-growing mutant with a Metschnikowia pulcherrima or Lachancea thermotolerans strain in sterile Sauvignon blanc juice resulted in differences in sensorial compounds, most likely derived from the presence of non-Saccharomyces yeasts. The EC1118 SER1 (G78R) mutant completed fermentation with M. pulcherrima, MP2, and in fact improved the viability of MP2 compared to when it was used as a monoculture. The SER1 (G78R) mutant also promoted both the growth of the SO2-sensitive L. thermotolerans strain, Viniflora® Concerto™, in a juice high in SO2 and its subsequent dominance during fermentation. In co-fermentations with wild-type EC1118, the Concerto™ population was substantially reduced with no significant changes in wine properties. This research adds to our understanding of the use of a novel slow-growing S. cerevisiae yeast in wine fermentations co-inoculated with non-Saccharomyces strains.

Rootstock, Vine Vigor, and Light Mediate Methoxypyrazine Concentrations in the Grape Bunch Rachis of Vitis vinifera L. cv. Cabernet Sauvignon.

Ramsey rootstock has previously been implicated in an approximate 8-fold increase of 3-isobutyl-2-methoxypyrazine (IBMP) levels in the rachis (grape bunch stem) of Vitis vinifera L. cv. Shiraz scions over own-rooted Shiraz vines at harvest. IBMP extracted from rachis during red wine fermentation can contribute potent "green" flavors. Methoxypyrazines (MPs) are normally present in Cabernet Sauvignon grapes, rachis, and wines, but it is unknown whether rootstocks can influence the MP concentration in the rachis. This study considered the effect of eight rootstocks including Ramsey and own roots on the concentrations of IBMP, 3-isopropyl-2-methoxypyrazine (IPMP), and 3-sec-butyl-2-methoxypyrazine (SBMP) in the rachis and grapes of Cabernet Sauvignon over two seasons. IBMP predominated, and its concentration in rachis and berries at harvest was significantly affected by rootstock and growing season. In the 2020 vintage, light exclusion, vine vigor, and spatial variation in vine vigor were shown to significantly affect MP concentrations in rachis.

Analysis of fungal dynamic changes in the natural fermentation broth of 'Hongyang' kiwifruit.

‘Hongyang’ kiwifruit (Actinidia chinensis Planch.) is an ideal kiwifruit wine variety. At present, there is no research on the dynamic changes of yeast during the natural fermentation of kiwifruit wine. In this study, a high-throughput was employed to analyze the fungal population composition and diversity in the samples cultured in yeast extract peptone dextrose (YPD) medium and enriched in the natural fermentation process of ‘Hongyang’ kiwifruit at four time points, day one (D1T), day three (D3T), day five (D5T), and day fifteen (D15T). Five hundred and eighty-two operational taxonomic units (OTUs) were obtained from 131 genera and 178 species samples. The diversity analysis results showed that in the early natural fermentation stage, the dominant species was Aureobasidium pullulans, and as natural fermentation proceeded, the genus Pichia became the dominant species. Pichia kluyveri was an important species at the later stages of natural fermentation. An analysis of the metabolic pathways shows that P. kluyveri plays an aromatic-producing role in the natural fermentation of ‘Hongyang’ kiwifruit. These results could provide a theoretical basis for the studies of kiwifruit fungal diversity and fungal changes during fermentation. The findings could fix a major deficiency in the production of kiwifruit fruit wine, which lacks a specific flavor-producing yeast species or strain.

Protein content of the Oenococcus oeni extracellular vesicles-enriched fraction

Malolactic fermentation is essential for the quality of red wines and some other wine styles. Spontaneous malolactic fermentation is often driven by Oenococcus oeni, and commercial starters for this purpose are also often of this species. The increasing number of microbial species and inoculation strategies in winemaking has prompted a growing interest in microbial interactions during wine fermentation. Among other interaction mechanisms, extracellular vesicles have been hypothesized to play a role in this context. Extracellular vesicles have already been described and analysed for several wine yeast species. In this work, the production of extracellular vesicles by O. oeni is reported for the first time. The protein content of these extracellular vesicles is also characterised. It shows differences and similarities with the recently described protein content of Lactiplantibacillus plantarum, a bacterial species also capable of performing malolactic fermentation of wine (and used sometimes as an alternative starter). This work further contributes to the development of the field of extracellular vesicles in food biotechnology.

Microbial Communities and Flavor Compounds during the Fermentation of Traditional Hong Qu Glutinous Rice Wine.

As a traditional Chinese rice wine, Hong Qu glutinous rice wine (HQW) is popular among consumers due to its unique flavor. However, its quality changes during fermentation, and the potential relationships between flavor and microbes have not been systematically researched. In this work, physicochemical properties (pH, total sugar, alcohol, amino acid nitrogen), flavor compounds (organic acids, free amino acids, and volatile compounds), and microbial communities were investigated. The results revealed that Pantoea, Lactiplantibacillus, Lactobacillus, Leuconostoc, and Weissella predominated the bacterial genera, and Monascus was the predominant fungal genus. Organic acids, free amino acids, and key volatile compounds (esters and alcohols) significantly increased during fermentation. The correlations analysis showed that Lactiplantibacillus was closely associated with flavor compounds formation. This study deepens our understanding of the roles of microorganisms in flavor formation on traditional HQW fermentation.

Downregulation of EHT1 and EEB1 in Saccharomyces cerevisiae Alters the Ester Profile of Wine during Fermentation.

EHT1 and EEB1 are the key Saccharomyces cerevisiae genes involved in the synthesis of ethyl esters during wine fermentation. We constructed single (Δeht1, Δeeb1) and double (Δeht1Δeeb1) heterogenous mutant strains of the industrial diploid wine yeast EC1118 by disrupting one allele of EHT1 and/or EEB1. In addition, the aromatic profile of wine produced during fermentation of simulated grape juice by these mutant strains was also analyzed. The expression levels of EHT1 and/or EEB1 in the relevant mutants were less than 50% of the wild-type strain when grown in YPD medium and simulated grape juice medium. Compared to the wild-type strain, all mutants produced lower amounts of ethyl esters in the fermented grape juice and also resulted in distinct ethyl ester profiles. ATF2, a gene involved in acetate ester synthesis, was expressed at higher levels in the EEB1 downregulation mutants compared to the wild-type and Δeht1 strains during fermentation, which was consistent with the content of acetate esters. In addition, the production of higher alcohols was also markedly affected by the decrease in EEB1 levels. Compared to EHT1, EEB1 downregulation had a greater impact on the production of acetate esters and higher alcohols, suggesting that controlling EEB1 expression could be an effective means to regulate the content of these aromatic metabolites in wine. Taken together, the synthesis of ethyl esters can be decreased by deleting one allele of EHT1 and EEB1 in the diploid EC1118 strain, which may modify the ester profile of wine more subtly compared to the complete deletion of target genes.

Development of an innovative temperature control system in a fermenter: application to the case of the wine industry

Temperature is one of the most important parameters influencing the fermentation in wine making process. Indeed, its control during this phase is fundamental to obtain a high-quality product. Fermentation is an exothermic process and for this reason a good cooling system in fermenter tanks is required. The temperature control systems usually adopted are represented by an external cooling jacket in which cold water flows. This system is based on the water circulation which is activated only when a critical temperature in the fermenter is exceeded making the control less precise. In this paper an alternative solution based on heat pipe technology is designed and its feasibility is investigated through the application of its ideal variant. This innovative temperature control system has the advantage to work on continuous mode, thus keeping the temperature in the fermenter more uniform during the whole process. Moreover, the proposed system is fully passive reducing the costs of this process phase. The results of this work demonstrated that the device application could be feasible and that it represents a promising solution.

Synthetic biology for the engineering of complex wine yeast communities.

Wine fermentation is a representation of complex higher-order microbial interactions. Despite the beneficial properties that these communities bring to wine, their complexity poses challenges in predicting the nature and outcome of fermentation. Technological developments in synthetic biology enable the potential to engineer synthetic microbial communities for new purposes. Here we present the challenges and applications of engineered yeast communities in the context of a wine fermentation vessel, how this represents a model system to enable novel solutions for winemaking and introduce the concept of a 'synthetic' terroir. Furthermore, we introduce our vision for the application of control engineering.

Profiles of Sterigmatocystin and Its Metabolites during Traditional Chinese Rice Wine Processing.

Mycotoxin pollution is widespread in cereal, which greatly threatens food security and human health. In this study, the migration and transformation of sterigmatocystin (STG) mycotoxin during the contaminated rice wine processing was systematically assessed. QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) coupled with ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UPLC−MS/MS) method was firstly established for STG analysis in rice wine. It was found that high levels of rice leaven caused a significant reduction in STG in the fermented rice and wine, which was mainly due to the adsorption of yeast cells and Rhizopus biological degradation. However, compared with rice, the levels of STG in separated fermented wine was significantly decreased by 88.6%, possibly attributed to its high log Kow (3.81) and low water solubility (1.44 mg/L). The metabolites of STG (i.e., monohydroxy STG) were identified in rice wine fermentation for the first time. Moreover, STG disturbed the metabolic profile rice wine composition mainly by glycine, serine and threonine metabolism, alanine, aspartate and glutamate metabolism, purine metabolism pathway, particularly with regard to eight amino acids and sixteen lipids. This study elucidated the STG migration and transformation mechanism during the rice wine processing. The finding provided new analytical method for mycotoxin exposure and pollutant in food production, which may support agricultural production and food security.

Moving towards in-line monitoring of phenolic extraction during red wine fermentations using infra-red spectroscopy technology. Influence of sample preparation and instrumentation

Improvements to technology which allows quantification of phenolic compounds, such as tannins, anthocyanins, and polymeric pigments, are continually being made. Currently infra-red (IR) spectroscopy technology is promising due to the rapidity and multivariate nature of the measurements and its non-destructive nature. However, most developments have been made on a laboratory scale with off-line or off-site analysis and these applications must now be adapted to become more suitable to on-site applications. As removal of solids in suspension poses a challenge with in-line systems during red-wine fermentations, an investigation was conducted to assess the effect of the presence of solids and remaining solids after rough filtration on the accuracy and reliability of predictive calibrations. Three different commercially available instruments with different spectroscopic acquisition methods were evaluated. These instruments were chosen, namely transmission Fourier transform near infra-red (T-FT-NIR), diffuse reflectance Fourier transform near infra-red (DF-FT-NIR) and an attenuated total reflectance Fourier transform mid infra-red (ATR-FT-MIR), as they are widely available and, if suitable, would provide a variety of options for winemakers, including one which is non-invasive. Spectra obtained using both a contactless DF-FT-NIR and ATR-FT-MIR were the least affected by suspended solids in a turbid system as the calibrations obtained did not show poorer performance than those developed with clean samples. The PLS calibrations optimised for the phenolic parameters: tannins (mg/L), anthocyanins (mg/L), total phenols, polymeric pigments (mg/L) and colour density, showed suitability for potential in-line implementation. The comparisons of the sample preparation and instruments are also discussed.