Wine Spoilage Yeasts: Control Strategy

Traditionally in winemaking, sulphur dioxide (SO2) is chemically the most widely used for microflora control as antimicrobial preservative. Other tested compounds for selective yeast control are sorbic and benzoic acids. Herein, we discuss the effectiveness and the application of traditional and novel treatments and biotechnologies for chemical and biological control of wine spoilage yeasts. The versatility of the killer toxins and the antimicrobial properties of natural compounds such as carvacrol, essential oils and bioactive peptides will be considered. Some of the wine spoilage yeasts that are intended to control belong to the genera Zygosaccharomyces, Saccharomycodes and Dekkera/Brettanomyces, but also the non-Saccharomyces yeasts species dominating the first phase of fermentation (Hanseniaspora uvarum, Hansenula anomala, Metschnikowia pulcherrima, Wickerhamomyces anomalus) and some others, such as Schizosaccharomyces pombe, depending on the kind of wine to be produced

Effect of Lachancea thermotolerans on the formation of polymeric pigments during sequential fermentation with Schizosaccharosmyces pombe and Saccharomyces cerevisiae

Anthocyanins in red grape musts may evolve during the winemaking process and wine aging for several different reasons; colour stability and evolution is a complex process that may depend on grape variety, winemaking technology, fermentative yeast selection, co-pigmentation phenomena and polymerization. The condensation of flavanols with anthocyanins may occur either with the flavylium ion or with the hemiacetal formation in order to produce oligomers and polymers. The kinetics of the reaction are enhanced by the presence of metabolic acetaldehyde, promoting the formation of pyranoanthocyanin-type dimers or flavanol-ethyl-anthocyanin structures. The experimental design carried out using white must corrected with the addition of malvidin-3-O-glucoside and flavanols, suggests that non-Saccharomyces yeasts are able to provide increased levels of colour intensity and larger polymeric pigment ratios and polymerization indexes. The selection of non-Saccharomyces genera, in particular Lachancea thermotolerans and Schizosaccharomyces pombe in sequential fermentation, have provided experimental wines with increased fruity esters, as well as producing wines with potential pigment compositions, even though there is an important reduction of total anthocyaninsinfo:eu-repo/semantics/publishedVersio

Acceleration of ageing on lees in red wines by application of ultrasounds

A transfer of parietal polysaccharides and mannoproteins is produced during aging on lees [1]. This transfer of compounds to wine is carried out after cell death. It comes to breakdown of polysaccharides from cell wall (yeast autolysis). This technique increases the density in wines [2] and gives more body and structure. Interactions between yeast polysaccharides and wine tannins will result in decrease of tannic perception (decrease of astringency). Increase of varietal characteristics is produced. The main disadvantage of the ageing on lees is the time that the process requires. Usually, nine months are necessary at least for obtaining a noticeable effect in wines. The objective of this work is the acceleration of this process using ultrasounds to lyse the yeast cell wall. In addition, the influence of this technique in different red wine quality parameters was studied

Polymeric pigments formed in sequential fermentation of red fresh musts by adding flavan-3-ols

Red wine pigments are susceptible to degradation by light, SO2 and changes in pH and temperature1,2. The formation of pyranoanthocyanins and polymeric pigments during fermentation and wine aging promote the stability of such pigments3. Glycolytic metabolites (e.g. acetaldehyde and pyruvic acid) may interact with anthocyanins and flavan-3-ols to form more stable molecules4 without a drastic change in hue values. Procyanidins are molecules from the flavanoids family that may condense with anthocyanins5. The contribution of non-Saccharomyces yeasts (e.g. L. thermotolerans, M. pulcherrima and T. delbrueckii), in sequential fermentation with S. cerevisiae and S. pombe, to the production of stable pigments was assessed in this project. with the use of HPLC-DAD/MS-ESI. The red musts have been enriched with flavanols prior fermentation. Fermentative volatiles and sensorial analysis were also performed to characterize experimental wines produced

Strategies to Improve the Freshness in Wines from Warm Areas

Trends in wine consumption are continuously changing. The latest in style is fresh wine with moderate alcohol content, high acidity, and primary aromas reminiscent of grapes, whereas certain fermentative volatiles may also influence the freshness of the wine. In addition, the effects of climate change on the composition of the grapes (high sugar content and low acidity) are adverse for the quality of the wine, also considering the microbiological stability. Herein, different strategies aiming at improving wine freshness are presented, and their performance in winemaking is discussed: among them, the addition of organic acids able to inhibit malolactic fermentation such as fumaric acid; the use of acidifying yeasts for alcoholic fermentation, such as Lachancea thermotolerans; and the selection of non-Saccharomyces yeasts with β-glucosidase activity in order to release terpene glycosides present in the must

Analysis of pyranoanthocyanins, polymeric pigments and colour parameters in Port wines

Context & aim: The two major categories of Port wines, Tawny and Ruby, are defined by their ageing conditions, with associated oxidative conditions being much more pronounced in the case of the former than the latter. The main aim of this study was to determine if, independently of the producer, all Port wines can be grouped into these styles based on their chromatic and pigment characteristics. Methods: A total of 32 Port wine samples comprising eight different styles were provided by five different producers of the Douro region in Portugal for this work. All the samples were filtered prior to analysis for anthocyanin determination using an HPLC-DAD-ESI/MS, and unfiltered samples were used for the determination of colour parameters and CIE Lab coordinates. The samples were measured in triplicate for statistical analysis. Results: The chromatic analysis of the Port wines showed Ruby style Ports to have a higher colour intensity and lower hue (°) than Tawny style Ports. The PCA analysis of colour parameters and CIE Lab coordinates clearly shows two separate clusters representing Ruby styles and Tawny styles respectively. Overall, Tawny style Ports had traces of or non-detected anthocyanins monoglucosides, a few styles having < 10 mg/L in the form of malvidin-3-O-glucoside equivalent; meanwhile Ruby styles showed higher concentrations of anthocyanins as detected by HPLC, sometimes reaching values close to 100 mg/L. The major anthocyanin family found across all wines (even in trace amounts) were pyranoanthocyanins, specifically vitisin A and coumaroylated vitisin A. Main conclusions: The results prove that in terms of all the parameters studied there is a clear division between the two major styles of Port wines, which can be attributed to the differences between the ageing process of these two types of wines

Use of Hanseniaspora spp. in sequential fermentation with Saccharomyces cerevisiae to improve the aromatic complexity of Albillo Mayor white wines

Hanseniaspora spp apiculate yeasts can be found on ripe grape skins and during the first six days of the alcoholic fermentation. Generally, these yeasts have poor characteristics for its industrial application in winery as they are related with low fermentative power, low resistance to SO2 and even high volatile acidity production. However, some species have a better fermentative capacity and are producers of certain floral and fruity volatiles. This is the case of the two strains used in this study. Hanseniaspora vineae (HV) has a fermentative power around 8-10% v/v, low volatile acidity production and produces high levels of 2-phenylethyl acetate. Similarly, Hanseniaspora opuntiae (HO) also produces a low volatile acidity providing sweet and floral aromas, but has a fermentative power around 6% v/v, which means that it must be used in sequential fermentation with Saccharomyces cerevisiae (SC). In addition, several studies indicate that both species can increase the mouthfeel and wine body. The aim of this study was to evaluate the use of HV and HO in sequential fermentation with SC to improve the sensory profile of high quality white wines from the neutral grape variety Albillo Mayor. Fermentations were performed in triplicate in 150 L stainless steel barrels with grapes from the 2021 vintage. Pure SC fermentations were used as controls. After the fermentation, the polysaccharide content and the colour was measured, and an intensive study of the aromatic profile was done

Emerging Technologies to Increase Extraction, Control Microorganisms, and Reduce SO₂

This chapter reviews the main non-thermal technologies with application in enology and their impact in: the extraction of phenolic compounds from grapes, the elimination of indigenous microorganisms, and the subsequent effect in SO2 reduction. The technologies are physical processes with null or low repercussion in temperature and therefore gentle with sensory quality of grapes. High hydrostatic pressure (HHP), ultra high pressure homogenization (UHPH), pulsed electric fields (PEFs), electron-beam irradiation (eBeam), ultrasound (US), and pulsed light (PL) have interesting advantages and some drawbacks that are extensively reviewed highlighting the potential applications in current technology

White wine processing by UHPH without SO2. Elimination of microbial populations and effect in oxidative enzymes, colloidal stability and sensory quality

The use of UHPH sterilization in the absence of SO2 has been used to eliminate wild microorganisms and inactivate oxidative enzymes. A white must of the Muscat of Alexandria grape variety was continuously processed by UHPH at 300 MPa (inlet temperature: 23–25 °C). The initial microbial load of the settled must was 4-log CFU/mL for both yeast and moulds, and slightly lower for bacteria. After UHPH processing, no microorganisms were detected in 1 mL. UHPH musts remain without fermentative activity for more than 60 days.Postprint (published version

Cluster microclimate, canopy management and its influence on the berry (size and composition) quality

Sunlight and microclimate inside the clusters’ zone are key factors in berry development and must composition. Plant geometry and training system should be joined with a proper sunlight and temperature cluster microclimate and, also in the rest of the plant. Berry temperature can vary between 2 and 10 ºC or even more in inner clusters, depending on their exposure (Spayd et al., 2002). Sunlight, air ventilation within the canopy, temperature cluster and microclimate are affected by the exposure and radiation percentage received by grapes during its growth and maturation period (Deloire and Hunter 2005). In Mediterranean conditions (warm and dry climate), the use of porous systems may help plants establish a better leaf distribution inside this area (de la Fuente et al., 2015), providing more space and enhancing certain physiological processes, both in leaves (photosynthesis, ventilation, transpiration) and berries (growth and maturation). Grapes exposed to direct radiation are more sensitive to ripening and they can even suffer a dehydration process in the Mediterranean regions, where the temperature during the ripening after midday is frequently between 30-35 ºC or higher than 40 ºC (de la Fuente et al., 2015). A key point for well microclimate management inside the canopy is heat flux control, which is usually generated by three factors: surface area (SA) to PAR (direct or indirect) radiation; intensity or thermal value (related to the temperature) and time of exposure (de la Fuente, 2009; de la Fuente et al., 2013). Sprawl systems are non-positioned systems where vegetation is in multidirectional directions. Therefore, as sun position changes along the day, some leaves are first shaded and then others, so the sun leaf exposure decreases (Gutiérrez et al., 2021). The study was conducted in D.O. Uclés vineyards (lat. 39º50’8” N; long. 3º09’48.6” W; elevation 746 m above sea level) during the 2020 season, in cv. Tempranillo. The trial was designed with two training system: Vertical Shoot Positioned (VSP) and Sprawl (SP). Berry sampling was done every three days within the final 15 days before the estimated harvest date. A single sample comprised 100 berries collected from the clusters of the 10 selected vines in each block. Weight, size, must composition (reducing sugar, pH, acidity, volatile acidity, etc.) and skin composition (total and acylated monomeric pigments, TPI) were analysed. Regarding the berry composition, SP accumulated larger concentration of reducing sugars (+7.4%). No statistical differences were observed in the remaining oenological parameters measured in the berries between treatments. Nevertheless, inside total pigments and color parameters, TPI values reached significantly higher (+40%) in the SP vs VSP treatments. In the total concentration of pigments (including the acylated fraction) and pH, no differences were founded. Berry's weight and size showed some relevant differences between treatments. During the end maturity-harvest period, the berry weight (12-11%) and berry size (6-9%) were higher in SP treatment compared to VSP. These results suggest that the SP systems can induce an increment of reducing sugars, and TPI and also, can modulate the berry weight and size, helping to control overripening and berry dehydration processes. Therefore, sprawl systems (SP) represent an alternative to VSP systems in warm areas for achieving an increment of pigments, as well as for better control of the accumulation of reducing sugars, without compromising the harvest yield (higher berry weight and size)