Pre-fermentative cold maceration in presence of non-Saccharomyces strains: Evolution of chromatic characteristics of Sangiovese red wine elaborated by sequential inoculation

Dosing oxygen from the early stages of white winemaking: Effect on oxidation-reduction potential, browning stability, volatile composition, and sensory properties

This study investigated the effect of controlled oxygen addition during alcoholic fermentation (4 mg/L, at 2nd, 4th, 6th, 10th, 14th, 16th, 20th day) and aging on lees (2 mg/L, every 15 days for 3 months) in a stainless-steel tank for white wine production from a nearly neutral grape. Under less reductive conditions (Ox), alcoholic fermentation was completed in 27 days, whereas one extra week was required under more reductive conditions (no-Ox). The greatest amount of dissolved oxygen in Ox wine triggered the increase of redox potential (EH) starting from the end of alcoholic fermentation and throughout aging (169 and 150 mV in Ox and no-Ox wine, respectively), also improving the wine resistance to browning. Oxygen addition from the early stages of winemaking significantly modulated volatile composition and sensory attributes, which may contribute to the diversification of wine style.

Effect of Sequential Fermentation with Lachancea thermotolerans/S. cerevisiae on Aromatic and Flavonoid Profiles of Plavac Mali Wine

In this study, the effects of sequential fermentation of Lachancea thermotolerans/S. cerevisiae on the production of Plavac Mali wines were investigated in comparison with the commonly used inoculation of the commercial Saccharomyces cerevisiae strain and spontaneous fermentation. A total of 113 aroma compounds and 35 polyphenolic compounds were analyzed. Sequential inoculation resulted in a decrease in alcohol content and pH (up to 0.3% v/v and 0.12 units, respectively) and an increase in total acidity (0.6 g/L, expressed as tartaric acid). The wines produced by spontaneous fermentation exhibited the greatest diversity of volatile compounds and the highest concentration of C13 norisoprenoids, lactones, and other compounds. These wines exhibited maximum hydroxycinnamic acids, prodelphinidin monomer units, epigallocatechin, B1, B3, and B4 dimers, and total flavan-3-ols. Sequential inoculation decreased the content of the aromas and polyphenols in the wines. The practical significance of this procedure lies in the selective effect on aroma compounds, the decrease in green aromas, undetectable volatile phenols, and the decrease in bitter and astringent compounds such as gallic acid, flavan-3-ol monomers (catechin and epicatechin), and dimers (B1, B2, B3, and B4). This work demonstrates the potential of sequential and spontaneous fermentation to improve the aromatic characteristics and overall quality of Plavac Mali wines.

Effect of the inoculation strategies of selected Metschnikowia agaves and Saccharomyces cerevisiae on the volatile profile of pineapple wine in mixed fermentation

To investigate the effects of inoculation ratio, concentration, and sequence of selected Metschnikowia agaves P3-3 and commercial Saccharomyces cerevisiae D254 on the volatiles of pineapple wine in mixed fermentation, the growth and fermentation ability of two yeast strains were monitored, and the physicochemical characteristics (including reducing sugar, total acidity, volatile acidity, and ethanol content) and volatile profile of pineapple wines produced by different inoculation strategies were analysed using chemical method and headspace-solid phase microextraction with gas chromatography-mass spectrometry (HS-SPME-GCMS), respectively. Results indicate that although the proliferation of M. agaves P3-3 was repressed by S. cerevisiae D254, changes in inoculation methods influenced yeast-yeast interactions and modulated the physicochemical properties and volatile profile of pineapple wine. Inoculation sequence and concentration of two strains were more important to volatile profile of pineapple wine than inoculation ratio. Simultaneous inoculations with 1 × 10⁷ CFU/mL M. agaves P3-3 and sequential inoculations increased the total acidity level, but their volatile acidity was lower than that with 5 × 10⁶ CFU/mL M. agaves P3-3. Simultaneous inoculations with 5 × 10⁶ CFU/mL M. agaves P3-3 retained more types of variety volatiles. However, the appropriate increase in the inoculation concentration of the cells and sequential inoculation increased the fermentative volatiles, especially ester levels.

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Changes in the Aromatic Compounds Content in the Muscat Wines as a Result of the Application of Ultrasound during Pre-Fermentative Maceration

This research focuses on the aromatic composition of Muscat of Alexandria wines after the application of ultrasound for 40 or 80 min during a 4 h pre-fermentative maceration process. Two methods of ultrasound application were compared in this study: probe ultrasound and bath ultrasound, for periods of 10–20 min per hour. Increases of more than 200% were obtained for some of the compounds from the skins, such as two of its terpenes, citronellol and nerol. On the other hand, increases in alcohol and ester values were registered with the application of ultrasound for 40 min. However, a significant decrease in these compounds was recorded when the ultrasound process was extended. In fact, when ultrasound was applied for 80 min, content values were even lower than those registered for the wine produced without the application of ultrasound. At the sensory level, the effect resulting from probe and bath ultrasound application for different times were compared, where most of the judges successfully discriminated the wines resulting from the application of ultrasound bath. According to data, the wines resulting from the application of ultrasound bath for 80 min presented the most significant differences, which affected the aromas of white fruit, tropical fruit, stone fruit, flowers and citrus.

Non-Saccharomyces Commercial Starter Cultures: Scientific Trends, Recent Patents and Innovation in the Wine Sector

For 15 years, non-Saccharomyces starter cultures represent a new interesting segment in the dynamic field of multinationals and national companies that develop and sell microbial-based biotechnological solutions for the wine sector. Although the diversity and the properties of non- Saccharomyces species/strains have been recently fully reviewed, less attention has been deserved to the commercial starter cultures in term of scientific findings, patents, and their innovative applications. Considering the potential reservoir of biotechnological innovation, these issues represent an underestimated possible driver of coordination and harmonization of research and development activities in the field of wine microbiology. After a wide survey, we encompassed 26 different commercial yeasts starter cultures formulated in combination with at least one non-Saccharomyces strain. The most recent scientific advances have been explored delving into the oenological significance of these commercial starter cultures. Finally, we propose an examination of patent literature for the main yeasts species commercialised in non-Saccharomyces based products. We highlight the presence of asymmetries among scientific findings and the number of patents concerning non-Saccharomyces-based commercial products for oenological purposes. Further investigations on these microbial resources might open new perspectives and stimulate attractive innovations in the field of wine-making biotechnologies.

Color Stabilization of Apulian Red Wines through the Sequential Inoculation of Starmerella bacillaris and Saccharomyces cerevisiae

Mixed fermentation using Starmerella bacillaris and Saccharomyces cerevisiae has gained attention in recent years due to their ability to modulate the qualitative parameters of enological interest, such as the color intensity and stability of wine. In this study, three of the most important red Apulian varieties were fermented through two pure inoculations of Saccharomyces cerevisiae strains or the sequential inoculation of Saccharomyces cerevisiae after 48 h from Starmerella bacillaris. The evolution of anthocyanin profiles and chromatic characteristics were determined in the produced wines at draining off and after 18 months of bottle aging in order to assess the impact of the different fermentation protocols on the potential color stabilization and shelf-life. The chemical composition analysis showed titratable acidity and ethanol content exhibiting marked differences among wines after fermentation and aging. The 48 h inoculation delay produced wines with higher values of color intensity and color stability. This was ascribed to the increased presence of compounds, such as stable A-type vitisins and reddish/violet ethylidene-bridge flavonol-anthocyanin adducts, in the mixed fermentation. Our results proved that the sequential fermentation of Starmerella bacillaris and Saccharomyces cerevisiae could enhance the chromatic profile as well as the stability of the red wines, thus improving their organoleptic quality.

Barley-sorghum craft beer production with Saccharomyces cerevisiae, Torulaspora delbrueckii and Metschnikowia pulcherrima yeast strains

The use of different yeast strains contributes to obtain insights into beer products with diverse sensory characteristics. In this study, three yeast species of different genera were selected to evaluate their fermentation performance and sensory profile for barley-sorghum beer production. Baley-sorghum wort was produced with 12.5°P and fermented with Saccharomyces cerevisiae, Torulaspora delbrueckii and Metschnikowia pulcherrima yeast strains. Differences were observed in terms of fermentation time and ability to ferment maltose. S. cerevisiae attenuated initial maltose concentration within 72 h, while M. pulcherrima and T. delbrueckii performed fermentation within 120 and 192 h, respectively. Both yeast strains simultaneously produced 11% and 23% lower ethanol concentrations, compared to S. cerevisiae with 37.9 g/L. Wort fermented with T. delbrueckii showed residual maltose concentration of 19.7 ± 4.1 g/L, resulting in significantly enhanced beer sweetness. S. cerevisiae produced significantly increased levels of higher alcohols, and obtained the highest scores for the sensory attribute body perception. Beer produced with T. delbrueckii contained significantly lower fermentative 2,3-butanediol and 2-methyl-1-butanol volatiles; this beer also showed reduced body perception. Beer conditioned with T. delbrueckii was significantly preferred over M. pulcherrima. Besides S. cerevisiae with high fermentative power, T. delbrueckii and M. pulcherrima were found to have reduced maltose fermenting abilities and provide significantly different sensory attributes to barley-sorghum beers.

Microbial Resources as a Tool for Enhancing Sustainability in Winemaking

In agriculture, the wine sector is one of the industries most affected by the sustainability issue. It is responsible for about 0.3% of annual global greenhouse gas emissions from anthropogenic activities. Sustainability in vitiviniculture was firstly linked to vineyard management, where the use of fertilizers, pesticides and heavy metals is a major concern. More recently, the contribution of winemaking, from grape harvest to bottling, has also been considered. Several cellar processes could be improved for reducing the environmental impact of the whole chain, including microbe-driven transformations. This paper reviews the potential of microorganisms and interactions thereof as a natural, environmentally friendly tool to improve the sustainability aspects of winemaking, all along the production chain. The main phases identified as potentially interesting for exploiting microbial activities to lower inputs are: (i) pre-fermentative stages, (ii) alcoholic fermentation, (iii) stage between alcoholic and malolactic fermentation, (iv) malolactic fermentation, (v) stabilization and spoilage risk management, and (vi) by-products and wastewater treatment. The presence of proper yeast or bacterial strains, the management and timing of inoculation of starter cultures, and some appropriate technological modifications that favor selected microbial activities can lead to several positive effects, including (among other) energy savings, reduction of chemical additives such as sulfites, and reuse of certain residues.

Influence of Saccharomyces and non-Saccharomyces Yeasts in the Formation of Pyranoanthocyanins and Polymeric Pigments during Red Wine Making

Yeast are able to modulate many sensory parameters of wines during red must fermentation. The effect on color and on the formation of derived pigments during fermentation has been studied thoroughly since the 90s. Yeast can increase grape anthocyanin’s color by acidification by hyperchromic effect (increase of flavylium molecules). Recent studies with non-Saccharomyces species, as Lachancea thermotolerans, described the intense effect of some strains on anthocyanin’s color, and subsequent, stability, by strongly reducing wine’s pH during fermentation. Moreover, selected yeast strains of Saccharomyces have been shown to release metabolites such as pyruvic acid or acetaldehyde that promote the formation of vitisin A and B pyranoanthocyanins during must fermentation. Schizosaccharomyces pombe, because of its specific metabolism, can produce higher concentrations of pyruvate, which enhances the formation of vitisin A-type derivatives. The hydroxycinnamate decarboxylase activity that some Saccharomyces strains express during fermentation also promotes the formation of vinylphenolic derivatives. Some non-Saccharomyces species, such as S. pombe or P. guilliermondii can also improve the production of these derivatives compared to selected strains of Saccharomyces cerevisiae. Lastly, some yeasts are also able to modulate the formations of polymeric pigments between grape anthocyanins and flavonoids, such as catechins and procyanidins.

Effects of Granucol activated carbons on sensory properties of sea-buckthorn (Hippophae rhamnoides L.) wines

The paper introduces some experimental data on activated carbons of Granucol series that can improve the colour of sea-buckthorn wines and stabilize them during storage. Such treatment is necessary because sea buckthorn contains reactive phenolic compounds that trigger non-enzymatic oxidative browning in sea-buckthorn wine. A di- rect regulation of the amount of phenolic compounds can improve sensory characteristics of sea-buckthorn wines, as well as increase their shelf-life. The research featured table dry wine made of 10 varieties of sea buckthorn grown in the Altai region. The chromatic characteristics were studied according to the existing guidelines of the International Organization of Vine and Wine (OIV, France). The index of yellowness served as an additional indicator for the co- lour assessment of the sea-buckthorn wines. Another objective indicator of colour assessment was the index of the displacement of the colour of x and y coordinates that corresponded with the green-red and yellow-blue chromatic axes. When 20–60 mg/100 ml of Granucol activated carbon was used during the winemaking process, it significantly improved the harmony of the sea-buckthorn wines. In particular, it had a positive effect on the colour characteristics. Granucol carbon reduced such unfavourable taste characteristics as excessive roughness (the total amount of polyphe- nolic compounds fell by 1.5–2 times) and significantly improved the aroma by erasing the yeasty and fusel odours.

Anthocyanins and Anthocyanin-Derived Products in Yeast-Fermented Beverages

The beverages obtained by yeast fermentation from anthocyanin-rich natural sources (grapes, berries, brown rice, etc.) retain part of the initial pigments in the maturated drink. During the fermentation and aging processes anthocyanins undergo various chemical transformations, which include reactions with glycolytic products (especially pyruvate and acetaldehyde) or with other compounds present in the complex fermentation milieu (such as vinylphenols obtained from cinnamic acids by means of a yeast decarboxylase) yielding pigments which can be more stable than the initial anthocyanins. Overall, these compounds contribute to the organoleptic traits of the mature product, but also to the overall chemical composition which make the yeast fermented beverages important sources of dietary antioxidants. In this review, we focused on the studies regarding the changes underwent by anthocyanins during yeast-mediated fermentation, on the approaches taken to enrich the fermented beverages in anthocyanins and their derived products, and on the interrelations between yeast and anthocyanin which were of relevance for obtaining a high-quality product containing optimum amounts of anthocyanin and anthocyanin-derived products.

The Impact of Non-Saccharomyces Yeast on Traditional Method Sparkling Wine

The interest in non-Saccharomyces yeast for use in sparkling wine production has increased in recent years. Studies have reported differences in amino acids and ammonia, volatile aroma compounds (VOCs), glycerol, organic acids, proteins and polysaccharides. The aim of this review is to report on our current knowledge concerning the influence of non-Saccharomyces yeast on sparkling wine chemical composition and sensory profiles. Further information regarding the nutritional requirements of each of these yeasts and nutrient supplementation products specifically for non-Saccharomyces yeasts are likely to be produced in the future. Further studies that focus on the long-term aging ability of sparkling wines made from non-Saccharomyces yeast and mixed inoculations including their foam ability and persistence, organic acid levels and mouthfeel properties are recommended as future research topics.