Search Results (492)

Non-Saccharomyces yeasts shape the aroma, freshness, and reduced-alcohol profiles of wines, yet their oenological contribution is curtailed by a poor tolerance to ethanol. Because ethanol acts on the plasma membrane, the cell’s selective barrier, this limitation is rooted in the membrane lipidome, whose remodeling has been documented but never integrated into a wine-specific, predictive framework. This review provides that synthesis, keeping the non-Saccharomyces wine yeasts as the subject and Saccharomyces cerevisiae as a reference frame. It first describes how ethanol perturbs the bilayer and how the cell compensates through unsaturated fatty acids, ergosterol, phospholipid-class balance, and membrane fluidity. It then traces the concentration- and time-dependent remodeling of the lipidome, together with the medium-chain fatty-acid, temperature, and oxygen co-stressors accompanying it, and the comparative membrane biology distinguishing these yeasts from S. cerevisiae, including the markedly reduced uptake of exogenous sterols under oxygen limitation. Finally, it weighs the nutritional, process, and non-genetically modified strain-improvement strategies that reinforce them. The same lipid descriptors recur throughout, yet are seldom measured in improved wine strains. We argue that the membrane lipidome can be read as a candidate multivariate predictive signature of ethanol tolerance and of fermentation performance, and outline the validation it still requires. Full article

Methanol formation is a critical safety concern in kiwifruit wine due to the high pectin content of kiwifruit. This study aimed to establish an effective strategy to reduce methanol formation while maintaining the fermentation performance and sensory quality of kiwifruit wine. The effects of fermentation temperature, pectinase dosage, and clarification centrifugation conditions on methanol production were investigated, and the selected process-regulation strategy was further evaluated by analyzing physicochemical properties, volatile aroma compounds, and sensory characteristics. The results showed that pectinase dosage was the predominant factor affecting methanol formation. Under the selected process conditions identified within the tested parameter ranges (fermentation at 19 °C, pectinase dosage of 0.02 g/L, and centrifugation at 2500 r/min), the methanol content decreased to 167.45 ± 2.20 mg/L, representing a 37.39% reduction compared with the control group, while the ethanol content remained at 12.66 ± 0.04% (v/v). Moreover, the wine exhibited favorable physicochemical characteristics, including improved retention of phenolic compounds and balanced organic acid composition. Aroma profiling using GC–MS and multivariate statistical analysis demonstrated that the optimized wine exhibited a volatile aroma pattern comparable to that of the control wine, indicating that methanol mitigation did not substantially impair the characteristic flavor of kiwifruit wine. Sensory evaluation further confirmed the improved overall acceptability of the processed product. This study provides a practical approach to producing safer kiwifruit wine while preserving quality attributes. Full article

To explore coffee’s effect on sweet rice wine quality, this study developed a novel fermented beverage using round glutinous rice and coffee powder as raw materials. The fermentation process was optimized using an orthogonal array design combined with fuzzy comprehensive evaluation. Flavor, physicochemical properties, and antioxidant activities were systematically evaluated via electronic tongue (E-tongue), gas chromatography–mass spectrometry (GC-MS), and gas chromatography–ion mobility spectrometry (GC-IMS). The optimal fermentation parameters were 0.6% fermentation starter (Jiuqu), 10% coffee powder, a fermentation time of 56 h, and a temperature of 28 °C. Adding coffee powder significantly increased total flavonoid content. Compared to the control group, the scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺), as well as hydroxyl radicals, increased by 18.36%, 7.40%, and 10.96%, respectively, compared to the control group. Flavor analysis identified 173 volatile organic compounds, demonstrating strong complementarity between GC-MS and GC-IMS. The addition of coffee powder preserved traditional sweet rice wine components while introducing roasted heterocyclic compounds, such as 2-methylpyrazine and 2-ethylfuran, thereby imparting nutty and roasted characteristics. E-tongue analysis revealed enhanced sensor responses for sweetness, bitterness, and saltiness, along with decreased umami. In conclusion, the addition of coffee powder is an effective strategy to enhance the in vitro antioxidant activity and enrich the flavor profile of sweet rice wine. This study provides a scientific basis for the application of coffee in traditional fermented foods. Full article

The phenomenon of global warming has been demonstrated to induce the premature ripening of grapes, resulting in a concomitant increase in sugar and a decrease in acidity. This can result in the production of wines that are characterised by an imbalance in terms of alcohol content and acidity. The utilisation of lactic acid-producing Lachancea thermotolerans yeast in fermentation represents a promising strategy for reducing the pH of must without the need for chemical acidification. However, it is important to note that the fermentation rate and lactic acid production can be influenced by several factors present in the must. The present study focused on the effect of copper, used in organic vineyards to limit mildew, on biomass and lactic acid production by two L. thermotolerans oenological strains in laboratory-scale fermentations. The methodology used is based on an innovative integrative approach combining conventional microbiological, spectroscopic, cytometric and transcriptomic analyses. The results obtained demonstrated that the addition of copper increased lactic acid production in comparison with the control condition and this effect was strain-dependent, reaching up to 16.15 g/L for strain Lt1 under conditions of high copper concentration (20 mg/L). The monitoring of microbial populations demonstrated discrepancies in the fermentation kinetics in conditions exhibiting varying concentrations of copper and showed that an increased duration of cell generation is evident under conditions exhibiting elevated copper concentrations, particularly in the context of the Lt1 strain. Furthermore, the analysis of the samples using flow cytometry revealed the oxidative status of the two strains throughout the fermentation process. Transcriptomic data indicated that metabolic pathways involved in cell communication, ribosomal and cell wall activity of L. thermotolerans were modulated by the presence of copper. The findings of this study demonstrate strain-specific effects of copper on L. thermotolerans, which may be of interest to winemakers, particularly those engaged in organic viticulture who intend to use acidifying yeasts during warm vintages. Full article

Cider is a low-alcohol fruit wine produced by partial or complete fermentation of apple juice. In recent years, its consumption has grown significantly, especially in Asia. Its distinctive flavor profile reflects a complex interplay of aroma and non-volatile components. The composition of cider is mainly influenced by three factors: raw materials, starter cultures, and production process. This review begins by outlining the composition of cider, covering both its aromatic compounds and non-volatile components. The primary aroma profile is defined by higher alcohols, esters, fatty acids, and carbonyl compounds, while sugars, organic acids, and polyphenols are the key determinants of its taste. Subsequently, it provides a detailed analysis of how the raw material, the choice of starter cultures, and the applied production processes collectively shape the cider’s flavor. Research shows that apple variety and maturity influence the levels of sugars, organic acids, and polyphenols, shaping the flavor foundation of cider. To enhance flavor diversity, inoculation strategies have shifted from single-strain fermentation with Saccharomyces cerevisiae to mixed fermentations using non-Saccharomyces yeasts and lactic acid bacteria, either simultaneously or sequentially. Currently, screening non-Saccharomyces strains has become a key strategy to increase cider flavor complexity. Precise micro-oxygenation and nutrient supply regulate microbial metabolism, thereby controlling the fermentation process and the production of specific flavor compounds. In the future, given the untapped diversity of non-Saccharomyces yeasts and lactic acid bacteria in winemaking traits, research in this direction may be key to improving cider quality. In addition, selecting apple cultivars tailored to specific cider styles and exploring pre-fermentation treatments such as cold maceration and enzymolysis may also contribute to enhancing the flavor diversity of cider. Full article

Black rice wine is a traditional cereal-based fermented beverage valued for its colour, flavour and bioactive constituents. However, product innovation is needed to meet increasing consumer demand for fruit-derived aroma, nutritional quality and functional attributes. To address this demand, we developed an integrated processing strategy combining enzymatic pretreatment of pitaya pulp with stage-specific co-fermentation, an approach that has not been systematically evaluated in rice wine systems. Pitaya pulp was first pretreated with pectinase using an orthogonal design to optimise juice yield and betacyanin retention; the enzymatically pretreated pitaya pulp was then introduced either as pulp or as fermented pitaya wine at the saccharification, tank-flushing or ageing stage. The resulting wines were compared with a pitaya-free control and three commercial black rice wines on the basis of physicochemical indices, phenolic and pigment contents, amino acid composition, mineral composition and fuzzy mathematics-based sensory evaluation. Pitaya pulp added at saccharification (Sample THJ) yielded the strongest functional and nutritional profile, with the highest total phenolic content (629.74 mg/L); high flavonoid content (152.07 mg/L); enrichment in Mg, K and Mn; and a broader taste-active amino acid profile. By contrast, pitaya pulp added during tank flushing (Sample CHJ) achieved the highest sensory score (85.3) and had the highest anthocyanin content. These findings indicate that the timing and form of pitaya addition determine the balance between functional enrichment, pigment retention and sensory quality. Co-fermentation with red-fleshed pitaya, particularly the early addition of enzymatically pretreated pitaya pulp, provides a practical route for the development of fruit-flavoured black rice wine with improved nutritional composition and consumer appeal, suggesting the potential for enhanced functional value. Full article

This paper aims to provide an overview of fermented foods involving yeast Hyphopichia burtonii and to promote its wider use. The tolerance to salt, osmotic pressure, and heat exhibited by H. burtonii is an advantageous trait for survival in the solid state. In traditionally produced salami with a salt concentration of 2.5%, H. burtonii became the dominant species after 28 days of ripening and contributed to flavor development. Fermentation starters such as Murcha, Nuruk, and Daqu are produced via salt-free solid fermentation. H. burtonii was able to survive the high-temperature conditions associated with solid-state fermentation and drying processes. These fermentation starters used to produce flavorful alcoholic beverages such as rice wine, makgeolli, and baijiu. Certain strains of H. burtonii produced aroma compounds such as ethyl caproate and 3-methylthio-1-propanol, contributing to the flavor profile of the beverage. Two strategies can be used to leverage the advantages of H. burtonii, such as its salt tolerance and aroma production. Full article

The principal critical issue in the production of Vin Santo passito wine is the high likelihood of fermentation arrests or sluggish fermentation, resulting in low sensory quality. A potential solution is to select indigenous yeasts from well-conducted spontaneous fermentations. In this study, a novel mixed starter culture consisting of two indigenous strains, Saccharomyces cerevisiae Ris III and Zygosaccharomyces rouxii Zr186, was evaluated. After selecting the strains and testing their compatibility, the mixed culture was used as a starter in the winemaking process of dried grapes, which was conducted in barrels of various sizes. The fermentations were monitored microbiologically for a period of 100 days to verify the ability of the inoculated strains to dominate and thus facilitate the fermentation process. Both strains dominated the fermentations: S. cerevisiae showed a 100% isolation rate immediately, while Z. rouxii achieved dominance within a month. The mixed starter demonstrated a 25% improvement in fermentation purity for the same barrel size. Sensory analyses revealed that the wines produced with the mixed starter were very consistent with one another, contrasting with those obtained through spontaneous fermentations, and received the highest scores for gustatory descriptors. In conclusion, this mixed culture represents an effective strategy for standardizing fermentation and improving the sensory quality of Vin Santo. Full article

The ancestral method of sparkling wine production requires no sugar addition and is based on a single alcoholic fermentation that finishes in the bottle. It has recently gained popularity among both natural and conventional producers due to its capacity to expand sparkling wine portfolios and its advantages for sparkling wine production in warm regions such as the Mediterranean basin. However, some technological and other key aspects of the process remain poorly defined. This study investigates how must settling (using pectolytic enzymes) and pre-bottling filtration influence the physicochemical composition, colloidal structure, foaming properties, volatile profile, and sensory attributes of ancestral sparkling wines. Macabeo grapes (2023 vintage) were vinified under four treatment combinations of these two operations, and the wines were analysed after eighteen months of lees ageing. Significant differences were observed in total polyphenol index, titratable acidity, macromolecular composition, and colloidal particle concentration. Non-settled wines exhibited higher colloidal loads and lower foamability, whereas settling and filtration improved foam height and stability. Volatile (GC-Headspace) analysis showed that settled wines contained higher concentrations of fruity and floral esters, while non-settled and non-filtered wines had greater levels of volatile phenols and volatile acids associated with unpleasant aromas. Sensory assessment confirmed perceptible differences between treatments, particularly in phenolic, fruity/floral, and Maillard reaction aromaticity. These findings provide insights into the impact of two critical oenological practices on wine stability and aroma and provide technologically relevant guidance for optimizing quality in this emerging sparkling-wine category. Full article

Secondary fermentation is a critical stage in the production of traditional method sparkling wines, during which yeast metabolism drives major changes in wine composition. However, the biochemical processes occurring during this phase and the influence of bottle closure systems remain poorly understood. This study evaluated the evolution of basic oenological parameters, free amino acids and volatile compounds during the first 90 days of secondary fermentation under two bottle closure systems: crown cap and tirage-cork. Fermentation time was the principal factor governing wine composition, with the most pronounced metabolic changes occurring between 30 and 45 days after bottling. Active nitrogen metabolism was evidenced by substantial amino acid redistribution, particularly involving ASN, ORN, AAA, GLU and ASP, while the accumulation of higher alcohols and other fermentation-derived volatiles reflected intense yeast metabolic activity during bottle fermentation. Although both closure systems successfully completed fermentation, tirage-cork-fermented wines showed a tendency towards faster fermentation progression and distinct patterns of amino acid and volatile compound development. Pearson correlation analysis revealed generally weak to moderate associations between amino acids and their corresponding volatile compounds, supporting the view that aroma formation results from the integration of multiple metabolic processes rather than from precursor availability alone. Overall, the results suggest that closure-associated metabolic divergence becomes detectable during the active phase of secondary fermentation and may contribute to differences in nitrogenous and aroma-related compounds. These findings suggest that bottle closure may represent an important technological variable associated with differences in the metabolic and compositional trajectories observed during the active phase of secondary fermentation. Given the limited biological replication of the present study, these observations should be interpreted with caution and warrant confirmation through studies incorporating biological replication and direct measurements of oxygen transfer. Full article

Maceration is one of the most important tools available to winemakers for shaping the chemical composition, sensory profile, and overall style of red wines. However, understanding the consequences of different maceration choices remains challenging due to the diversity of available techniques, the complexity of extraction phenomena, and the fragmented nature of the available literature, which spans a wide range of technological strategies, cultivars, vintages, winemaking conditions, and analytical approaches. This review thus provides a comprehensive overview of traditional, advanced and emerging maceration techniques used in red winemaking. Conventional approaches, including pre-fermentative cold maceration, fermentative maceration, extended post-fermentative maceration, whole-bunch fermentation, and carbonic maceration, are discussed alongside technological modifications such as cryoextraction, thermovinification, flesh-release and Accentuated Cut Edges, as well as emerging and non-thermal technologies including pulsed electric fields, ultrasound, high-pressure processing, microwaves and ohmic heating. Particular attention is given to the mechanisms governing extraction, with emphasis on how processing conditions and tissue-disruption phenomena influence grape cell wall integrity, membrane permeability, and the release of targeted constituents from different grape tissues. Finally, the advantages, limitations, and practical implications of each technique are highlighted for researchers and winemakers, indicating the need for an integrated consideration of chemical, microbiological, sensory, technological, and economic factors when optimizing red wine production. Full article

Sea buckthorn is rich in functional components but features high acidity and susceptibility to oxidative deterioration, leading to flavor defects such as sour–astringent taste and rancidity in single-fruit wine. Co-fermentation is an effective strategy for flavor and nutrition complementarity, but the dynamic evolution of volatile aroma during yeast–lactic acid bacteria combined fermentation of such wine remains unclear. This study employed ‘Zhuangyuan Huang’ sea buckthorn and ‘Marselan’ grape to produce the composite fruit wine via sequential co-fermentation, and systematically investigated dynamic aroma changes using HS-SPME-GC-MS, orthogonal partial least squares discriminant analysis (OPLS-DA), and relative odor activity value (ROAV) analysis. Results revealed that post-fermentation, total detected volatile compounds increased from 90 to 118, with esters and alcohols rising by 24 and 11 respectively, serving as core contributors to enhanced aroma richness. ROAV analysis demonstrated this process significantly reduced the contribution of off-flavor acids, boosted the importance of floral, fruity, and sweet compounds, and elevated the sensory score from 26.8 to 84.1. OPLS-DA further confirmed significant inter-stage aroma differences with excellent intergroup discrimination. These findings confirm that this sequential fermentation breaks processing bottlenecks of high-acid fruits, reveals the synergistic flavor-modulating effects of multi-microbial sequential fermentation, and provides theoretical support for process optimization and high-value processing of composite fruit wine. Full article

The use of Kluyveromyces marxianus in mixed cultures for fermentation processes has become increasingly relevant. This yeast is characterized by rapid growth, thermotolerance, broad sugar utilization, and the ability to produce aroma-active compounds. In this study, we evaluated changes in the growth and volatilome of a K. marxianus strain isolated from agave fermentation under microbial competition induced by co-cultivation interactions and nutritional limitation induced by a nutrient-deficient medium. The results indicate that these stress factors are significant drivers of metabolic changes, leading to substantial increases in the concentrations of key aromatic compounds. Stress-free conditions favor cell growth and the production of stable, reproducible volatile profiles, which is advantageous for batch-to-batch consistency (as in wine or mezcal production). While microbial competition and nutritional limitation induce reduced cell growth and loss of viability, they also lead to increased aromatic diversity, particularly the synthesis of β-phenethyl acetate, ethyl octanoate, and ethyl hexanoate. These findings demonstrate a relationship between environmental stress and the development of volatile profile complexity, offering new insights into harnessing stress-induced changes in the volatilome to optimize the sensory profile of traditional fermentations. Full article

The growing diversity of food fermentation systems has intensified interest in non-Saccharomyces yeasts due to their broad metabolic capabilities and technological potential. However, current understanding of yeast functionality remains fragmented and frequently relies on taxonomy-centered classification, which often provides limited predictive value across fermentation systems. This review critically examines how strain-specific microbial traits, food matrix composition, and process conditions collectively shape fermentation performance across brewing, wine, cereal, plant-based, and functional fermentation systems. Particular emphasis is placed on key determinants of microbial functionality, including carbon metabolism, aroma biogenesis, acidification, enzymatic activity, microbial interactions, and transformation of food-associated bioactive compounds such as glycosides, phenolics, terpenes, and matrix-bound metabolites. The available evidence demonstrates that fermentation-relevant functionality cannot be reliably inferred from species identity alone because microbial performance is strongly modulated by strain variability and matrix-dependent environmental constraints. To address these limitations, this review proposes a matrix–trait–function framework that integrates microbial metabolic capabilities with food matrix characteristics and technological objectives to support a more predictive and application-oriented approach to yeast selection in food fermentation systems. Full article

This study investigates the breeding of the German wine yeast Oppenheimer Kreuz 1894, which carries a FOT1 allele of a fungal oligopeptide transporter, with Freya, a Kveik ale yeast, to enhance fermentation performance and aroma in beer and wine. By combining Kveik traits (osmotolerance, thermotolerance, and rapid fermentation kinetics) with those of a German wine yeast (ethanol tolerance, broadened nitrogen utilization, and aroma production) and introducing FOT1 into an ale background via classical breeding, we aimed to leverage the Saccharomyces biodiversity to improve fermentation activity and expand aromatic complexity. Fermentation products and volatile aroma compounds were quantified by HPLC and HS-SPME-GC-MS. Spore clone derivatives of initial hybrid strains (F₂-generation) showed improved fermentation profiles with increased CO₂ production. In wine fermentations, the best-performing spore clone, GYBC 901, yielded a rich aromatic profile with elevated fruity and floral notes. In beer fermentations, GYBC 899 produced the most diverse and complex aroma. FOT1 was of minor relevance to the breeding outcome, whereas meiotic recombination generated a set of diverse spore clones. These results highlight the potential of strategic yeast breeding to optimize fermentation processes and tailor flavor profiles to diverse product targets. Future work will elucidate metabolic pathways underlying these phenotypes and advance the development of application-specific strains, offering avenues to enhance beverage quality and product differentiation in the fermentation industry. Full article