Impact of Saccharomyces cerevisiae and non-Saccharomyces yeasts to improve traditional sparkling wines production

The effect of selected Non-Saccharomyces yeasts and cold-contact fermentation on the production of low-alcohol marula fruit beer

The last decade has seen increased consumer demand for zero and low-alcohol beverages. Cold-contact fermentation (CCF) in combination with non-Saccharomyces can be an effective method for producing low-alcohol fruit beverages with desirable qualities. Thus, the aim of this study was to develop a CCF process to produce low-alcohol marula fruit beer using selected non-Saccharomyces yeasts. The effect of temperature (°C), and time (h) on alcohol (% v/v), pH, total titratable acidity (LAE/mL) and specific gravity (SG) was evaluated using response surface methodology. Sterile marula fruit juice was inoculated with Metschnikowia pulcherrima, Pichia fermentans, or Pichia kluyveri respectively. Higher final SG values were observed for temperatures between 8 °C and 15 °C. Above 15 °C, the SG decreased with an increase in temperature and time. Fermentation at temperatures below 10 °C produced zero to low-alcohol marula fruit beer (0.00-0.20 % v/v) with an attenuation rate above 80 %. This was confirmed by the significance of quadratic models for SG (p ≤ 0.01), and alcohol (p = 0.00) for the three selected yeasts. Overall, P. kluyveri produced the lowest alcohol levels, followed by M. pulcherrima and P. fermentans, respectively. The study confirmed that cold-contact fermentation with non-Saccharomyces yeasts can be an effective biological method to produce low-alcohol marula fruit beer in line with the emerging consumer demand for low-alcohol beverages.

Impact of Candida railenensis during fermentation on the aromatic profile of Vidal blanc icewine

Mixed culture fermentation with non-Saccharomyces yeasts and Saccharomyces cerevisiae as multi-starters has more advantages than spontaneous fermentation, and wine products with distinctive and pleasant aromas can fulfill the diverse demands of consumers. This study was carried out to illuminate the effect of sequential inoculation of indigenous Candida railenensis and S. cerevisiae on alcoholic fermentation behavior and chemical and aromatic characteristics of Vidal blanc icewine. During the mixed culture fermentation, C. railenensis was present in the initial and middle stages but was absent after 14 days. The results of basic chemical parameters showed that the glycerol content in the mixed culture-fermented icewine was higher than that of the pure fermented icewine, but the acetic acid content was the opposite. In terms of volatile aroma compounds, C. railenensis in the mixed culture fermentation reduced some metabolites such as lower alcohols, 1-hexanol, 3-methylthiopropanol, and their unpleasant notes and increased the production of some desired volatile aroma compounds such as benzaldehyde, β-damascenone, 2-furanmethanol, and 5-methyl furfural associated with rose, honey, nut, and caramel characteristics. Furthermore, C. railenensis also changed the sensory performance of icewine by participating in the fermentation of S. cerevisiae. These findings suggest that C. railenensis with positive enological properties has the ability to be used in icewine production, which has never been reported before.

Comparison of volatile compounds during biological ageing and commercial storage of Cava (Spanish sparkling wine): The role of lees

Cava is a sparkling wine produced using a traditional method that must be aged in contact with lees for a minimum period of nine months. The contact between wine and lees improves the quality of the final product, and aroma is one of the most important qualitative parameters of a wine. The aim of the work was to study the role of lees in the ageing of Spanish sparkling wine (Cava), by sampling at industrial scale the bottles, from 9 to 30 months of ageing, jointly with the winery and in real time. The volatile profile of Cava during biological ageing and commercial storage, after disgorging, was evaluated by Headspace-Solid Phase Microextraction coupled to gas chromatography-mass spectrometry. More than 60 compounds were identified from several chemical classes including esters, alcohols, terpenes, furans, norisoprenoids, and fatty acids. A reduction in volatile components was observed when the disgorging step took place. When the behaviour of aroma over time was assessed, the principal factor that discriminated between samples was the type of ageing i.e. with or without lees. Evaluation of volatiles over time revealed that furans showed a significant relationship with ageing, indicating that some components of this family could be possible markers of ageing.

Effect of Interspecific Yeast Hybrids for Secondary In-Bottle Alcoholic Fermentation of English Sparkling Wines

In sparkling winemaking, only a few yeast strains are regularly used for the secondary in-bottle alcoholic fermentation (SiBAF). Recently, advances in yeast development programs have yielded new breeds of interspecific wine yeast hybrids that ferment efficiently while producing novel flavors and aromas. In this work, the chemical and sensorial impacts of the use of interspecific yeast hybrids for SiBAF were studied using three commercial English base wines prepared for SiBAF using two commercial and four novel interspecific hybrids. After 12 months of lees aging, the chemical and macromolecular composition, phenolic profile, foaming, viscosity and sensory properties of the resulting 13 wines were assessed. Chemically, the yeast strains did not result in significant differences in the main wine parameters, while some differences in their macromolecular contents and sensory characteristics were noticeable. The foamability was mostly unaffected by the strain used; however, some effect on the foam stability was noticeable, likely due to the differences in polysaccharides released into the wines by the yeast strains. The wines exhibited different sensory characteristics in terms of aroma and bouquet, balance, finish, overall liking and preference, but these were mostly attributable to the differences in the base wines rather than the strain used for SiBAF. Novel interspecific yeast hybrids can be used for the elaboration of sparkling wines, as they provided wines with chemical characteristics, flavor and aroma attributes similar to those of commonly used commercial Saccharomyces cerevisiae strains.

The Life of Saccharomyces and Non-Saccharomyces Yeasts in Drinking Wine

Drinking wine is a processed beverage that offers high nutritional and health benefits. It is produced from grape must, which undergoes fermentation by yeasts (and sometimes lactic acid bacteria) to create a product that is highly appreciated by consumers worldwide. However, if only one type of yeast, specifically Saccharomyces cerevisiae, was used in the fermentation process, the resulting wine would lack aroma and flavor and may be rejected by consumers. To produce wine with a desirable taste and aroma, non-Saccharomyces yeasts are necessary. These yeasts contribute volatile aromatic compounds that significantly impact the wine's final taste. They promote the release of primary aromatic compounds through a sequential hydrolysis mechanism involving several glycosidases unique to these yeasts. This review will discuss the unique characteristics of these yeasts (Schizosaccharomyces pombe, Pichia kluyveri, Torulaspora delbrueckii, Wickerhamomyces anomalus, Metschnikowia pulcherrima, Hanseniaspora vineae, Lachancea thermotolerans, Candida stellata, and others) and their impact on wine fermentations and co-fermentations. Their existence and the metabolites they produce enhance the complexity of wine flavor, resulting in a more enjoyable drinking experience.

The Maillard reaction in traditional method sparkling wine

The Maillard reaction between sugars and amino acids, peptides, or proteins generates a myriad of aroma compounds through complex and multi-step reaction pathways. While the Maillard has been primarily studied in the context of thermally processed foods, Maillard-associated products including thiazoles, furans, and pyrazines have been identified in aged sparkling wines, with associated bready, roasted, and caramel aromas. Sparkling wines produced in the bottle-fermented traditional method (Méthode Champenoise) have been the primary focus of studies related to Maillard-associated compounds in sparkling wine, and these wines undergo two sequential fermentations, with the second taking place in the final wine bottle. Due to the low temperature (15 ± 3°C) and low pH (pH 3-4) conditions during production and aging, we conclude that Maillard interactions may not proceed past intermediate stages. Physicochemical factors that affect the Maillard reaction are considered in the context of sparkling wine, particularly related to pH-dependent reaction pathways and existing literature pertaining to low temperature and/or low pH Maillard activity. A focus on the origins and composition of precursor species (amino acids and sugars) in sparkling wines is presented, as well as the potential role of metal ions in accelerating the Maillard reaction. Understanding the contributions of individual physicochemical factors to the Maillard reaction in sparkling wine enables a clearer understanding of reaction pathways and sensory outcomes. Advancements in analytical techniques for monitoring the Maillard reaction are also described, and important areas of future research on this topic are identified.