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New Trends in Aging on Lees
C H A P T E R
11 New Trends in Aging on Lees Antonio Morata, Felipe Palomero, Iris Loira and Jose A. Sua´rez-Lepe Department of Chemistry and Food Technology, Technical University of Madrid, Madrid, Spain
11.1 INTRODUCTION The current wine market is characterized by a certain homogeneity and a saturation of competing products. Therefore, new techniques and technologies not only reduce costs but aid to obtain highly distinguishable and quality products that are much sought after. Many research groups in enological microbiology and winemaking have focused their efforts on achieving these overall objectives, motivated by an industry that understands that the differentiation of its products at a moderate cost can significantly increase a brand’s competitiveness. In this context, it is important to note that there is a particular component subject to hedonistic tendencies, fashions, and popular trends in the consumption of wine. Wooded wines with great extraction, high alcohol content, and long periods of aging in barrels have been replaced by others in which primary or varietal fruit aromas are further respected through better integration and balance with wood volatiles. Traditionally, aging on lees (AOL) has been used to improve the sensory profile and mouthfeel of white wines, especially for those that are barrel fermented. But it is also a helpful technique for red wines, improving the softness of tannins as a result of the interaction between mannoproteins and cell wall polysaccharides with wine phenols (Escot et al., 2001). This parameter can be modulated depending on the yeast strain used for AOL (Loira et al., 2013). The reductive effect of lees and the release of some antioxidant components of cell structures like glutathione (GSH) protect the aromatic compounds, thus preserving the fruitiness and freshness, even after long periods of AOL. Antioxidant activity of lees surface, have shown a protective role on thiols during the aging (Gallardo-Chaco´n et al., 2010). The high ability of yeast lees to scavenge oxygen has also been reported (Salmon et al., 2000); and the antioxidant role of yeast lees can also improve the color stability of wines (Escot et al., 2001; Palomero et al., 2007). Moreover, it has been observed that red wines aged on lees show a high limpidity, even when cell wall polysaccharides increase the colloidal load in wines. Lees polysaccharides has the ability to protect wines from protein haze (Dupin et al., 2000). In addition, wine lees have been described as good binding agents for certain volatile compounds such as ethyl esters and fusel alcohol acetates (Rodrı´guez-Bencomo et al., 2010). Although at first this feature may seem something negative for wine quality, it was found that, in general, the nature of this linking is transitory and the union is reversed with the passage of time; that is, the volatile compounds temporarily bound to the yeast cell wall can be released back into the wine. During yeast growth, cell wall porosity depends on the nutritional composition of the media (De Nobel et al., 1990). Then, autolysis occurs after the death of the yeast cell affecting the degradation of the cell wall by auto-enzymatic activity and the release of cytoplasmic contents and coverings fragments. The release of cell wall polysaccharides during fermentation and the dependence of that process on yeast strains has been reported (Escot et al., 2001). The released polysaccharides can reach 100 mg/L. Saccharomyces cerevisiae cell wall is formed by a net of fibrillary polysaccharides containing globular mannoproteins ( 40%). Fiber polysaccharides are mainly β-glucans ( 60%) and chitin ( 2%) formed by N-acetylglucosamine units (Magnelli et al., 2002). Glucans can be β1,3- or β1,6- branched structures (Fig. 11.1). It has been reported that AOL and yeast autolysis is a slow process requiring 7 9 months before there are any repercussions in the sensory profile of wine. Not all yeasts behave in the same way with regard to autolysis and it is possible to use yeast selection to obtain optimal strains of S. cerevisiae with short autolysis periods, or in other
Red Wine Technology. DOI: https://doi.org/10.1016/B978-0-12-814399-5.00011-6
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11. NEW TRENDS IN AGING ON LEES
terms (Palomero et al., 2007), with a greater release of cell wall components. The release of yeast cell wall polysaccharides into the media can be monitored by using liquid chromatography coupled with refractive index detection (LC-RID) in model media or wines. Using this technique, it is possible to study the strains that are able to release higher amounts in a shorter time, and therefore, to select those with shorter autolysis periods (Figs. 11.1A and B and 11.2). A typical problem when using traditional AOL for red wines involves microbiological instability, because generally after red wine fermentation, together with the maceration of solids (skins and seeds), the lees are quite dirty, containing not only the yeast cells that have been fermenting the must, but also colloidal particles and cell wall fragments from grapes as well as a broad microbial population formed by yeast and bacteria species. Hence, this gross lees aging is prone to produce microbial developments and sensory deviations with associated reductive off-flavors. Reductive off-smells can include unpleasant molecules like diethyl sulfide (garlic) or dimethyl sulfide (stewed cabbage). To control this, an initial improvement is to simply use fine lees cleaning the colloidal particles settling the wine. However, this is just a partial solution because some contaminant load will still remain and at the same time, a large fraction of the yeast cells is removed. A better solution is the external production of a biomass with the yeast that is required to perform the AOL; this technique has several advantages: (1) the yeast
Chitin (0.5 of dry weight) β (1—3) and (1—6) Glucan microfibres Mannoprotein Membrane protein Periplasmatic enzyme
112 kDa 47 kDa 23 kDa 12 kDa 6 kDa
MV
FIGURE 11.1 Plasmatic membrane and cell wall structure of Saccharomyces cerevisiae. Adapted from Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy.
(A)
5
(B)
4
3 Seventh month
2
Seventh month
Sixth month
Sixth month
1
0 0
1
2
3
4
5
6 7 Minutes
8
9
10
0
1
2
3
4
5 6 7 Minutes
8
9
10
FIGURE 11.2 LC-RID chromatograms of polysaccharides releasing for 2 yeast strains 5CV (A) and 2EV (B) of Saccharomyces cerevisiae during the autolysis analyzed after 6 and 7 months of aging on lees. Chromatograms from duplicate processes. Pullulanes were used as molecular size markers in kDa. LC-RID, Liquid chromatography coupled with refractive index detection.
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biomass can be produced using a yeast species or strain with improved performance for AOL being selected by a fast autolysis and positive sensory impact; (2) even non-Saccharomyces yeasts can be used; (3) the addition will be just pure yeasts cells so there will be no collateral contaminants—no bacteria, undesired yeasts or colloidal particles; and (4) the wine can be partially cleaned before the addition of lees to obtain an even safer process, including settling and filtration procedures. The lees can be produced in an external fermenter under aerobic conditions to enhance biomass production and the yeast cells can later be purified by rinsing with water and subsequent centrifugation to get a pure biomass (Sua´rez-Lepe and Morata, 2009). Moreover, it is possible to apply it as not only a fresh biomass but it can also be applied after a drying process (e.g., lyophilization) to facilitate storage and dosage. Red wines aged on lees frequently show an intense fruity smell even when they are barrel matured for long periods. Glutathione, a cell wall peptide component formed by three amino acids and currently used as antioxidant in enology, is one of the factors responsible for this effect (Comuzzo et al., 2015a,b). The direct release of GSH during AOL or the application as an active yeast by-products affects the protective effect on fruity and varietal aromas (Rodrı´guez-Bencomo et al., 2014). The selection of yeasts that are able to release high contents of GSH during AOL is one way to enhance this protection (Sua´rez-Lepe and Morata, 2012). AOL can be used synergistically with barrel aging or oak chips, improving the aromatic richness of wines (Loira et al., 2013). Moreover, the reductive effect of AOL by increasing the GSH content helps to balance the oxidative effect of barrel aging, reducing the aggressive repercussions of the use of new barrels. It is interesting to note the high degree of chance and empiricism underlying the link between wine and wood. Do you ever wonder why a barrel of wine is shaped the way it is? The answer is that originally, they were only used as a container for trade of goods. At the time, wood was robust enough, cheap, and an abundant material, and such geometry allowed its heavy weight (volume) to be effortlessly moved by rolling it, upright if on rails or on its side on smooth surfaces. It was some time later that the positive influence of the container over the content, was perceived and recognized. This influence is due to the migration of certain chemicals, whether or not volatile, and mostly known and fully identified molecules that enrich the wine’s sensory profile (Sanz et al., 2012). Conventional wine aging in French or American oak barrels is a slow and costly process, where a large volume of wine must be immobilized in storage for varying periods before being marketed. The aromatic potential of the barrels is not unlimited, and therefore, their purchase, maintenance, and replacement, constitute a significant proportion of the variable costs for wineries. Even though these drawbacks are even more important if AOL is performed, this novel technique in red winemaking is gaining popularity since it allows the production of wines with distinctive sensory attributes. In order to solve some of the previously mentioned inconveniences, oak chips, staves, or fragments of variable sizes and shapes are usually used by winemakers globally in stainless steel tanks (Spillman, 1999). Its direct addition to the wine coupled with micro-oxygenation techniques, increases color stability and enhances the diffusion and integration of oak aromas into the wine. This procedure significantly reduces aging periods and allows wineries to release their wines into the market sooner. On the other hand, these techniques are not free of problems. The migration of oak constituents primarily depends—among other factors involved—on the exposed surface area. The quantity, shape, and size of chips can sometimes produce an excessive wood aroma extraction when the dosage is incorrect. The repeatability of the processes is not always good since a great variation between batches has been a matter of concern for some winemakers. Besides the traditional woods commonly employed to age wines irrespective of the presence of lees, woods other than oak and chestnut have been studied (see Section 11.4). The simultaneous use of chips or barrel aging with AOL helps to improve the aromatic profile with a more softening impact than just single barrel aging (Loira et al., 2013). Furthermore, cell wall polysaccharides released from the yeast during AOL soften the tannin dryness contributed by the barrel, promoting a faster and better integration of barrel tannins (Rodrigues et al., 2012; Loira et al., 2013). Another application of lees concerns the yeast cell wall adsorption capacity, which has been studied in order to remove some specific and undesirable wine compounds such as ochratoxin A and 4-ethylphenols (Caridi et al., 2012; Palomero et al., 2011). In fact, AOL has been proposed as a palliative treatment to mitigate excessive oak aromas from wines (Chatonnet et al., 1992). In contrast, yeast lees adsorb anthocyanins and other grape phenols during fermentation that can be partially released during aging and autolysis stages if they are not removed (Morata et al., 2003).
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11.2 USE OF NON-SACCHAROMYCES YEASTS Non-Saccharomyces yeasts are a trend in current enology (Morata and Sua´rez Lepe, 2016), with applications in grape sanitization, fermentation, stabilization, and aging. Traditional Saccharomyces yeasts commonly used in AOL (Fig. 11.3A) can also be substituted with non-Saccharomyces yeast and this has some advantages. Saccharomycodes ludwigii (Fig. 11.3B), Schizosaccharomyces pombe (Fig. 11.3C), and even Brettanomyces bruxellensis (Fig. 11.3D) have been described for of their optimal release of polysaccharides during AOL (Palomero et al., 2009; Kulkarni et al., 2015). S. pombe also releases 3 7 times more polysaccharides than commercial S. cerevisiae during fermentation (Domizio et al., 2017). The use of osmophilic non-Saccharomyces yeasts can accelerate the release of cell wall polysaccharides and mannoproteins (Palomero et al., 2009). This behavior is as a result of their special structure and the composition of their cell walls. In some osmophilic yeasts like S. pombe, a multilayer cell wall formed by α-galactomannose with α-1,3 glucan fibers has been described (Kopecka` et al., 1995) (Fig. 11.4). The average composition is 9% 14% α-galactomannan, 18% 28% α-1,3-glucan, 42% β-1,3-glucan, and 2% β-1,6-glucan (Manners and Meyer, 1977; Kopecka` et al., 1995). A three-layer structure with an external and internal electron dense structure and a less dense layer in the middle can be observed by transmission electron microscopy (Humbel et al., 2001). The thick multilayer structure of S. pombe contains more polysaccharides and cell wall globular proteins than S. cerevisiae cells, allowing a higher release of polymers during the AOL processes. When the release of cell wall polysaccharides has been recorded by LC-RID during the AOL across different non-Saccharomyces yeast species, it was observed that the contents were much greater when S. pombe was used (Palomero et al., 2009; Kulkarni et al., 2015). Moreover, polysaccharides were released in a shorter time (Fig. 11.5) and with higher molecular sizes (Palomero et al., 2009). This last peculiarity can influence the tactile sensation of polysaccharides in the mouth
FIGURE 11.3
Optical microscopy of yeasts. (A) Saccharomyces cerevisiae. (B) Saccharomycodes ludwigii. (C) Schizosaccharomyces pombe. (D) Brettanomyces bruxellensis.
Chitin (0.5 of dry weight) α Galactomanose β (1—6) Glucan, minor part β (1—3) Glucan, mayor part Mannoprotein α (1—3) and β (1—3) Glucan microfibres Membrane protein Periplasmatic enzyme
FIGURE 11.4 Plasmatic membrane and cell wall structure in Schizosaccharomyces pombe. Adapted from Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy.
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Polysaccharides (mg/L)
120
Saccharomycodes ludwigii
100 80
Schizosaccharomyces pombe
60
Saccharomyces cerevisiae
40 20 0 0
1
2
3
4
5
Months
FIGURE 11.5
Cell wall polysaccharides released by several yeast species during AOL. AOL, Aging on lees.
and, in fact, wines were positively perceived by tasters (Palomero et al., 2009). Another interesting fact is a twostage kinetics in the release of cell wall polysaccharides with a maximum peak and a first plateau after 1 month, but later a second maximum and plateau at 4 and 5 months for S. ludwigii and S. pombe, respectively (Fig. 11.5; Palomero et al., 2009). Moreover, the maximum value in S. cerevisiae is lower than the first plateau for S. ludwigii and S. pombe. Therefore, the use of some non-Saccharomyces is a powerful tool to enhance mouthfeel by increasing polysaccharide content. Several wine related species of non-Saccharomyces yeasts, such as, for example, Kloeckera apiculata and Candida stellata, have been reported to produce high amounts of extracellular β-glucanase enzymes (Strauss et al., 2001), and therefore, could be considered a means to hasten the breakage of the yeast cell wall.
11.3 ACCELERATED AGING ON LEES Several techniques have been described as useful to accelerate the breakage of the yeast and the fragmentation of cell walls. Among them, β-glucanases enzymes (Palomero et al., 2007), HHP (high hydrostatic pressure) (Nida, 2010), HPH (high pressure homogenization) (Comuzzo et al., 2015a,b), US (ultrasound) (Kulkarni et al., 2015; Liu et al., 2016), MW (microwaves) (Liu et al., 2016), and PEF (pulsed electric fields) (Martı´nez et al., 2016) have all reported advantages for a faster release of polysaccharides and/or cytoplasmic proteins when yeast cells are processed using them. β-glucanases enzymes produce the hydrolysis of β-glucans, thus facilitating the cell wall disruption and consequently increasing the release of polysaccharides. Yeast lysis time can be reduced from several months to a few weeks in comparison to conventional natural autolysis (Palomero et al., 2007). The presence of some collateral enzymatic activities such as β-glycosidases can affect anthocyanin stability (Palomero et al., 2007). However, some authors reported no effect on the release of polysaccharides when commercial β-glucanases enzymes (4 g/HL) were added to the lees (3% v/v of fine lees) (Del Barrio-Gala´n et al., 2011). It is likely that there may be some influence of the doses of enzyme versus lees concentration or of the conditions in which the aging was carried out. Regarding the influence of this enzyme addition to the aromatic quality of the wine, it was found that using β-glucanases during AOL at a dose equal to or higher than 30 mg/L allows the obtaining of wines with a higher content of certain volatile compounds, mainly ethyl esters and 2-phenylethanol, but also interestingly hexanol and trans-3-hexenol, even though these last two compounds are not involved in yeast metabolism (Masino et al., 2008). Lees pressurization at 100 MPa affects cell wall structure, promoting depolymerization and facilitating yeast lysis and polysaccharides release (Nida, 2010). The use of HPH at 150 MPa produces similar levels of colloids polysaccharides, proteins, and free amino acids than thermal autolysis but increases ethyl esters and reduces fatty acids (Comuzzo et al., 2015a,b). The use of US is an effective technology to disrupt the cells facilitating the depolymerization of cell coverings and releasing mannoproteins and cell wall polysaccharides. When US is employed for a few minutes to a yeast
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biomass at a power of 400 W and a frequency of 24 KHz, with a sonotrode S24D14D (Ø14 mm, length 100 mm) the breakage of cell coverings and the release of cytosolic contents facilitating the autolysis process can be observed by optical microscopy (Fig. 11.6). The effect of US can be enhanced when inert abrasives such as sand or glass beads are used together (Liu et al., 2016). The application of US to non-Saccharomyces produces a fast lysis of cells (Fig. 11.7) and it can be observed that US treated non-Saccharomyces produces 2 4 times more polysaccharides than conventional Saccharomyces yeasts (Kulkarni et al., 2015). Maximum concentrations after US treatments are observed after 2 3 weeks in all yeast species, so the use of US is a powerful tool to accelerate yeast lysis and to speed up AOL especially when used together with non-Saccharomyces yeasts. Thermal treatments are traditionally used to produce yeast derivatives used in enology such as inactivated yeasts or cell wall mannoproteins. The use of emerging heating systems including MW facilitates yeast cell disruption in a short time, thus increasing the release of polysaccharides (Liu et al., 2016).
Polysaccharides (mg/L)
FIGURE 11.6 (A) Control. (B) Ultrasound treated lees.
500
Saccharomycodes ludwigii
400 Schizosaccharomyces pombe 300 Brettanomyces bruxellensis
200 100 0 0
1
2
3
4
5
6
7
- Saccharomyces cerevisiae - Candida pulcherrima - Kluyveromyces marxianus - Lachancea thermotolerans - Metschnikovia pulcherrima - Torulopsis stellata
Weeks
FIGURE 11.7 Release of polysaccharides by both Saccharomyces and non-Saccharomyces yeasts during aging on lees accelerated by ultrasound. Adapted from Kulkarni, P., Loira, I., Morata, A., Tesfaye, W., Gonza´lez, M.C., Sua´rez-Lepe, J.A., 2015. Use of non-Saccharomyces yeast strains coupled with ultrasound treatment as a novel technique to accelerate ageing on lees of red wines and its repercussion in sensorial parameters. LWT Food Sci. Technol. 64, 1255 1262.
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TABLE 11.1
β-Glucanases enzymes
Main emerging technologies available to accelerate and/or improve wine aging on lees: features and observed results Mechanism of action
Advantages
Drawbacks
Hydrolysis of βglucans forming part of the yeast cell wall
Shorter duration of the autolytic Slight loss of color process (2 3 weeks). (undesired β-glucosidase Conventional autolysis activity) (nonaccelerated AOL): .5 months Faster and higher release of Increased risk of polysaccharides from the cell wall contamination by altering microorganisms (e.g., Brettanomyces)
References Palomero et al. (2007), Masino et al. (2008), and Ferna´ndez et al. (2011)
Enrichment of the aromatic profile Homogeneity in the size of the released polysaccharides High investment costs in equipment acquisition
Nida (2010)
Inflicts damage on cytoplasmic membrane favoring depolymerization
Higher release of polysaccharides
HPH
Cavitation, turbulence and shear, which occur when the yeast suspension is forced through the homogenization valve
Increase of ethyl esters and reduction of fatty acids
Comuzzo et al. (2015) and Popper and Knorr (1990)
US
Sound waves used to cause thinning of cell membranes, localized heating and production of free radicals
Faster and higher release of Possible slight oxidation of polysaccharides from the cell wall the wine
Kulkarni et al. (2015) and Liu et al. (2016)
HHP
Industrial application in continuous processes
No negative effects on the sensory quality of the wine Possible influence in wine color stability (higher amounts of acetaldehyde)
PEF
Increase in metal ions (Fe, Cr, Zn, and Mn) concentrations
Martı´nez et al. (2016) and Yang et al. (2016)
Increased color stability
Decrease in total anthocyanin content
Del Barrio-Gala´n et al. (2011)
Prolonged aging on lees
Residual dissolved oxygen in the medium (problems of overoxygenation)
Enrich wine in polysaccharides from wood (not from the yeast cell wall)
Difficulty in controlling the proper transfer of compounds (dose and contact time dependent)
Electroporation and electric breakdown
Acceleration of autolysis
Destabilization of the lipid bilayer and proteins of the cell membranes
Faster and higher release of mannoproteins No negative effect on wine quality has been reported
Microoxygenation
Use of nontoasted oak chips
Controlled addition of oxygen into the wine in small doses leads to wine components transformation
Transfer of wood compounds to wine
Del Barrio-Gala´n et al. (2011)
Artificially accelerate the aging process in barrel HHP, High hydrostatic pressure; HPH, High pressure homogenization; US, Ultrasounds. AOL, Aging on lees; PEF, Pulsed electric fields.
The PEF inactivation mechanism is mainly based on the electroporation of the cytoplasmic membrane that leads to disorders in the membrane’s electrical potential, osmotic imbalance, and, finally, cell lysis (Barba et al., 2018, Page 115). This nonthermal and efficient method in the use of energy technology has little effect on wine composition (Yang et al., 2016). These days, its main drawback is the release of metal ions from the electrode that may significantly increase Fe, Cr, Zn, and Mn concentrations. However, further research in this field is needed to properly understand all the implications surrounding electrode degradation.
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A. YEAST LEES BIOMASS 1. Growth of Saccharomyces cerevisae (G37) in YPED medium YPED medium enriched with glucose (up to 100g/L)
3. The Yeast was lyophilised
2. The yeast biomass was washed and centrifuged (1157 rcf for 2 min) B. WOOD AROMATISATION OF YEAST H H H C C O H H H
1. Obtaining wood extract in 10g of freeze-dried S.cerevisiae (G37)
250 mL ethanol 99% v/v Acacia
Chestnut Cherry
Oak 2. Wood aromatization of yeast lees
Each wood at a time
40 min at 45ºC
35 g of wood chips 100 min at 45ºC
C. WINE ON Aromatized yeast
… Wood-inflused yeast in 1 month at 17ºC
1 g wood-aromatized yeast biomass : 500 mL wine Red wine obtained from Tempranillo grapes from Vinos de Madrid
Oak
Chestnut
Acacia
Cherry
FIGURE 11.8 Lees impregnation with wood-extract procedure.
Another suggested alternative to increase the content of polysaccharides in wine is the use of nontoasted oak chips (for example: 4 g/L) with the aim of extracting these polymers from the wood (Del Barrio-Gala´n et al., 2011). Despite these polysaccharides having a different origin, they can act in the same manner as polysaccharides released from yeast cell walls. That is, increasing the wine’s mouthfeel and body, as well as reducing astringency and bitter flavors. The yeast cell disruption and the nonthermal permeabilization of cell membrane provoked by the aforementioned emerging technologies have been shown to be effective for wine microbial inactivation (Garcı´a et al., 2013; Ganeva et al., 2014; Abca and Akdemir Evrendilek, 2014). But, at the same time, they are also useful to accelerate the lees yeast lysis with the subsequent release of protective colloids and biological material (e.g., mannoproteins, polysaccharides, peptides, amino acids, fatty acids, nucleotides, etc.) from the cytoplasm or the coating structures (cell wall and cytoplasmic membrane) to the wine (Martı´nez et al., 2016). Regarding complementary techniques to AOL, micro-oxygenation (5 mL/L/month of O2) applied to AOL improves the color stability of the wine through the formation of new pigments that may increase or remain constant until the end of the barrel aging process (Del Barrio-Gala´n et al., 2011). These micro-oxygenated 1 AOL wines are characterized by higher color intensities and blue tonalities. Similarly, the use of nontoasted oak chips is an effective technique to accelerate the transfer of wood components to the wine in order to improve aromatic complexity and mouthfeel without the need of aging in barrels.
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11.4 LEES AROMATIZATION
By adjusting the appropriate dose, it is possible to obtain the desired wood characteristics in the wine in shorter periods of time thanks to the greater transfer surface on the chips. Table 11.1 summarizes the main novel techniques that can be coupled with AOL to improve results or speed up the AOL process.
11.4 LEES AROMATIZATION
Trihydroxymetoxyfavlonol
Krempferide
Isosakuramnetin
Kaempferol Apigenin + Pinocembrin
Butein
Aromadendrin
Fisetin
Ellagic acid
Coniferaldehyde
Naringenin Quercetin
60
Taxifolin Ferulic acid
80
p -Hidroxibenzaldehyde
Gallic aldehyde
mAU
Protocatechuic aldehyde
Acacia
p-Vanillin
Cherry Chestnut
Dihidroxirobinetin
Oak
2,4-Dihidroxibenzaldehyde
MIX
Robinetin
Siringaldehyde
Sinapaldehyde
A new technique proposed to incorporate wood aromatic compounds from several tree species is the use of yeast lees as a carrier for the wood extracts during AOL (Palomero et al., 2015). The woods studied were oak, chestnut, cherry, and acacia. A biomass of a yeast strain previously selected according to its good autolytic behavior was used to conduct the experiments. Once the yeast was soaked with an ethanol wood-extract and dried, the wood-aromatized yeast biomasses for each type of wood were poured into a red wine made from Vitis Vinifera L.cv. Tempranillo grapes from D.O. Vinos de Madrid. One gram of these biomasses was added to 500 mL of wine. Untreated yeasts were used as a control. Wines were left in contact with the lees for 1 month. All the treatments were performed in triplicate. Fig. 11.8 illustrates the processes carried out during the experimental stage.
40
20
0 10
20
30
40
50
60
min
FIGURE 11.9 Phenolic compounds (HPLC/DAD chromatograms) detected on wood-aromatized yeast, and for an equal part mixture of all wood types (MIX).
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The analysis of polyphenols and volatile compounds (by HPLC/DAD and GC-MS, respectively) performed following the methodology described in Palomero et al. (2015) on both the wines and the woody yeast biomasses confirmed that the adsorption/diffusion of these compounds from the wood to the yeast, and then to the wines occurs. Finally, a sensory assessment of all wines was undertaken by 10 expert tasters. Some of the 34 wood phenols adsorbed by yeast cell walls, and then detected by HPLC/DAD, are graphically presented in Fig. 11.9. All of these compounds have been found and described previously (Sanz et al., 2012). The data confirmed sorption phenomena occurred and that the phenolic composition of the studied woods were significantly different. This technique confirms its potential usefulness because of the great concentration of phenolics aldehydes observed in the chestnut samples. Compounds such as vanillin and syringaldehyde are some of the most distinctive wood odorants in barrel-aged wines. The concentration of vanillin, the phenolic aldehyde with the lowest sensory threshold, could be enhanced significantly through the use of chestnut instead of oak (Palomero et al., 2015). As reported previously by other authors, there are some specific compounds only found in one type of wood and therefore, could potentially be used as identification markers (Ferna´ndez de Simo´n et al., 2014; Sanz et al., 2012). In this sense, one of the clearest examples can be seen in Fig. 11.9 for the highest peak corresponding to robinetin, only found in aromatized acacia samples (and in the mixture). Table 11.2 summarizes the main volatile compounds (of the 71 volatile molecules identified that are mainly formed during wood toasting) found in the wood-aromatized yeasts. Both lactones and carbohydrate derivatives (such as furfural and 5-hydroxymethylfurfural), lignin-derived volatile phenols, and phenolic aldehydes (such as vanillin) concentrations are significantly higher in chestnut-infused yeast. Generally, large differences have been observed between the quantitative values for the kinds of wood used in our experiments. Our data correlate well with the findings of Ferna´ndez de Simo´n et al. (2014).
TABLE 11.2
Main volatile compounds (μg/g) in aromatized yeast biomasses
Compound
Acacia
Cherry
Chestnut
Oak
Furfural
0.56
0.75
3.05
0.82
5-Methylfurfural
0.23
0.37
1.18
0.21
5-Hydroxymethylfurfural
4.51
2.68
6.01
1.89
Trans-whiskylactone
nd
nd
0.25
0.34
Cis-whiskylactone P lactones and carbohydrate derivativesa
nd
nd
0.14
0.13
84.74
94.04
102.95
66.41
Phenol
0.17
0.21
0.20
0.15
2-Phenylethanol
4.29
5.31
6.28
3.21
4-Methyl guaiacol
0.59
0.71
4.74
0.16
4-Ethyl guaiacol
0.09
0.09
0.21
0.17
4-Vinylguaiacol
0.45
0.54
0.69
0.58
Eugenol P volatile phenolsa
0.19
0.31
0.87
0.65
11.99
16.03
26.39
15.87
Vanillin
35.9
19.5
Syringaldehyde
98.2
2,4-Dihydroxybenzaldehyde
38.5
nd
nd
nd
nd
1.12
nd
nd
p-Anisaldehyde P phenolic aldehydes, ketones and othera
197
124
200
a
Summations include other compounds not shown. Note: Bold indicates to summary of a family of compounds. Results in wines with wood-aromatized yeast lees.
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238
179
252
214
624
488
173
11.4 LEES AROMATIZATION
TABLE 11.3
Phenolic composition (μg/L) of red wines enriched with wood-aromatized yeast leesa
Compound
Acacia
Cherry
Chestnut
Oak
Gallic acid
23.8 6 0.5a
24.4 6 1.0a
28.9 6 3.5b
26.4 6 2.3ab
Vanillic acid
1.8 6 0.0a
1.9 6 0.7a
3.2 6 1.0b
2.4 6 0.7ab
Ellagic acid
4.2 6 0.3a
3.8 6 0.7a
11.8 6 0.6c
7.7 6 1.7b
(1)-Catechin
59.7 6 1.8a
53.6 6 7.2a
57.9 6 1.0a
55.4 6 6.2a
Procyanidin B2
11.4 6 0.7b
8.4 6 0.9a
11.3 6 1.1b
8.6 6 2.8ab
(2)-Epicatechin
5.7 6 0.2a
5.2 6 0.5a
5.7 6 0.3a
5.2 6 0.6a
Myricetin-3-glucuronide
11.6 6 0.5bc
12.9 6 0.8c
10.3 6 0.9ab
9.5 6 1.2a
Quercetin-3-galactoside
9.2 6 0.6bc
8.6 6 1.7abc
7.2 6 0.7ab
6.5 6 2.0a
Quercetin-3-glucoside
5.6 6 0.2b
5.2 6 1.2ab
4.5 6 0.3ab
3.9 6 1.0a
Quercetin
1.5 6 0.1a
2.0 6 0.1b
1.8 6 0.1ab
1.6 6 0.1a
Dihydrorobinetin
0.9 6 0.0a
nd
nd
nd
10.6 6 0.0a
nd
nd
nd
nd
1.7 6 0.0a
nd
nd
Robinetin Aromadendrin
Values are mean 6 standard deviation (n 5 3). Values in the same row with different letter denotes a statistical difference (p , 0.05). nd: not detected.
a
TABLE 11.4
Main volatile compounds (μg/L) in red wines aged for 1 month with wood-aromatized yeast leesa
Compounds
Acacia
Cherry
Chestnut
Oak
Furfural
65.3 6 7.4b
55.3 6 3.0ab
66.4 6 19.2b
68.2 6 5.9b
5-Methylfurfural
5.83 6 1.22a
5.40 6 1.61a
6.93 6 0.68a
6.23 6 1.18a
5-Hydroxymethylfurfural
224 6 19.4ab
249 6 158ab
301 6 83.9ab
307 6 84.9b
Trans-β-methyl-γ-octolactone
nd
nd
18.8 6 4.3b
19.7 6 1.1b
Cis-β-methyl-γ-octolactone
nd
nd
19.4 6 12.4b
24.2 6 10.7b
4-Methylguaiacol
2.9 6 0.3abc
2.3 6 0.7ab
4 6 0.5c
3.3 6 1.1bc
4-Ethylguaiacol
0.47 6 0.05b
0.51 6 0.14b
0.55 6 0.07b
0.44 6 0.28b
4-Vinylguaiacol
2.99 6 0.22b
3.18 6 0.12b
4.04 6 0.82b
3.91 6 0.77b
Phenol
0.96 6 0.08a
1.06 6 0.16a
0.96 6 0.03a
1.03 6 0.24a
4-Ethylphenol
0.47 6 0.04a
0.52 6 0.18a
0.68 6 0.03a
0.69 6 0.24a
4-Vinylphenol
500 6 43.7b
506 6 118b
532 6 90.3b
643 6 114b
Eugenol
1.6 6 0.1a
2.2 6 1a
1.9 6 0.3a
1.9 6 0.0a
Vanillin
1132.7 6 18.6c
864.5 6 201.9b
3840.3 6 167.6e
704.3 6 87.6b
Vanillyl ethyl ether
1721 6 303a
1783 6 361a
3569 6 79.9b
2786 6 410ab
Syringaldehyde
2009.7 6 476.3a
2938.4 6 863.8c
4812.7 6 478.4d
1940.6 6 378.2b
Acetosiringone
338 6 34.3ab
403 6 39.3ab
654 6 118c
283 6 25.7a
p-Anisaldehyde
nd
28.1 6 12.9b
nd
nd
Values are mean 6 standard deviation (n 5 3). Values in the same row with different letter denotes a statistical difference (p , 0.05). nd: not detected.
a
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The phenolic composition of Tempranillo wines was significantly different between treatments. Table 11.3 shows some of the phenolics found in the wines. As previously observed during dried yeast phenolic analysis, robinetin and dihydrorobinetin were only found in wine samples aged with acacia-infused yeast. A similar conclusion can be established for aromadendrin in the case of cherry wood. A great ratio of gallic and ellagic acid was seen in chestnut samples compared with oak ones. Some authors have claimed that these compounds could contribute to the chemical recognition of chestnut wood (Ferna´ndez de Simo´n et al., 2014). It is probable that these compounds will be easily perceived in wines aged in chestnut vessels. Generally, the volatile composition of the initial wine was significantly modified before treatments. As previously seen, there are no methyl-octolactone isomers in acacia and cherry (Tables 11.2 and 11.4), and no statistical differences were observed between chestnut and oak for these compounds. Phenolic aldehydes and phenyl ketones were detected to be at higher levels in wines aged with chestnutinfused yeast lees (Table 11.4). These compounds impart vanilla-like aromas into the wines; and woods with higher concentrations would be useful in order to reduce aging costs (Palomero et al., 2015). No differences were observed with regard to color intensity and chromatic parameters, a fact that is reasonable when taking into account that wines were left in contact with lees only for 1 month. All the kinds of wines with wood-infused yeast were reported to be more complex than the control wine, so wine aroma was improved with the aging treatment. Chestnut aromatized biomasses released the highest amounts of wood-related compounds like phenolic aldehydes, and it is perhaps for this reason that they were valued with the highest scores for plum, currant, spicy, roasted, and nutty aromas.
11.5 CONCLUSIONS AOL is an interesting technique for the biological aging of red wines, softening phenolic fraction and decreasing astringency, with a protective effect on color and varietal smells. The use of selected Saccharomyces yeasts or some non-Saccharomyces species accelerates this slow process, improving industrial application. In the same way, lees processing using emerging technologies, such as HHP, HPH, US, MW, PEF, etc., accelerates the process, increasing industrial feasibility. Moreover, this is a technique that can be synergistically used with barrel aging or wood chips to increase aromatic quality.
References Abca, E.E., Akdemir Evrendilek, G., 2014. Processing of red wine by pulsed electric fields with respect to quality parameters. J. Food Process. Preserv. 39 (6), 758 767. Barba, F.J., Ahrne´, L., Xanthakis, E., Landerslev, M.G., Orlien, V., 2018. Innovative Technologies for Food Preservation. Inactivation of Spoilage and Pathogenic Microorganisms, first ed Academic Press, Elsevier Ed, London, UK. Caridi, A., Sidari, R., Pulvirenti, A., Meca, G., Ritieni, A., 2012. Ochratoxin A adsorption phenotype: an inheritable yeast train. J. Gen. Appl. Microbiol. 58 (3), 225 233. Chatonnet, D., Dubourdieu, D., Boidron, J.N., 1992. Incidence des conditions de fermentation et d’e´levage des vins blancs secs en barriques sur leur composition en substances ce´de´es par le bois de cheˆne. Sci. Aliments 12, 665 685. Comuzzo, P., Battistutta, F., Vendrame, M., Pa´ez, M.S., Luisi, G., Zironi, R., 2015a. Antioxidant properties of different products and additives in white wine. Food Chem. 168, 107 114. Comuzzo, P., Calligaris, S., Iacumin, L., Ginaldi, F., Palacios Paz, A.E., Zironi, R., 2015b. Potential of high pressure homogenization to induce autolysis of wine yeasts. Food Chem. 185 (15), 340 348. Del Barrio-Gala´n, R., Pe´rez-Magarin˜o, S., Ortega-Heras, M., 2011. Techniques for improving or replacing ageing on lees of oak aged red wines: the effects on polysaccharides and the phenolic composition. Food Chem. 127 (2), 528 540. De Nobel, J.G., Klis, F.M., Munnik, T., Priem, J., Van Den Ende, H., 1990. An assay of relative cell wall porosity in Saccharomyces cerevisiae, Kluyveromyces lactis and Schizosaccharomyces pombe. Yeast 6, 483 490. Domizio, P., Liu, Y., Bisson, L.F., Barile, D., 2017. Cell wall polysaccharides released during the alcoholic fermentation by Schizosaccharomyces pombe and S. japonicus: quantification and characterization. Food Microbiol. 61, 136 149. Dupin, I.V.S., McKinnon, :B.M., Ryan, C., Boulay, M., Markides, A.J., Jones, G.P., et al., 2000. Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: Their release during fermentation and lees contact and a proposal for their mechanism of action. J. Agric. Food Chem. 48, 3098 3105.
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Escot, S., Feuillat, M., Dulau, L., Charpentier, C., 2001. Release of polysaccharides by yeasts and the influence of released polysaccharides on colour stability and wine astringency. Aust. J. Grape Wine Res. 7, 153 159. Ferna´ndez, O., Martı´nez, O., Herna´ndez, Z., Guadalupe, Z., Ayestara´n, B., 2011. Effect of the presence of lysated lees on polysaccharides, color and main phenolic compounds of red wine during barrel ageing. Food Res. Int. 44 (1), 84 91. Ferna´ndez de Simo´n, B., Sanz, M., Cadahı´a, E., Martı´nez, J., Esteruelas, E., Mun˜oz, A.M., 2014. Polyphenolic compounds as chemicals markers of wine ageing in contact with cherry, chestnut, false acacia, ash and oak wood. Food Chem. 143, 66 76. Gallardo-Chaco´n, J.J., Vichi, S., Urpı´, P., Lo´pez-Tamames, E., Buxaderas, S., 2010. Antioxidant activity of lees cell surface during sparkling wine sur lie aging. Int. J. Food Microbiol. 143, 48 53. Ganeva, V., Galutzov, B., Teissie, J., 2014. Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells. Appl. Biochem. Biotechnol. 172 (3), 1540 1552. Garcı´a, J.F., Guillemet, L., Feng, C., Sun, D.W., 2013. Cell viability and proteins release during ultrasound-assisted yeast lysis of light lees in model wine. Food Chem. 141 (2), 934 939. Humbel, B.M., Konomi, M., Takagi, T., Kamasawa, N., Ishijima, S.A., Osumi, M., 2001. In situ localization of β-glucans in the cell wall of Schizosaccharomyces pombe. Yeast 18, 433 444. Kopecka`, M., Fleet, G.H., Phaff, H.J., 1995. Ultrastructure of the cell wall of Schizosaccharomyces pombe following treatment with various glucanases. J. Struct. Biol. 114, 140 152. Kulkarni, P., Loira, I., Morata, A., Tesfaye, W., Gonza´lez, M.C., Sua´rez-Lepe, J.A., 2015. Use of non-Saccharomyces yeast strains coupled with ultrasound treatment as a novel technique to accelerate ageing on lees of red wines and its repercussion in sensorial parameters. LWT Food Sci. Technol. 64, 1255 1262. Liu, L., Loira, I., Morata, A., Sua´rez‑Lepe, J.A., Gonza´lez, M.C., Rauhut, D., 2016. Shortening the ageing on lees process in wines by using ultrasound and microwave treatments both combined with stirring and abrasion techniques. Eur. Food Res. Technol. 242, 559 569. Loira, I., Vejarano, R., Morata, A., Ricardo-da-Silva, J.M., Laureano, O., Gonza´lez, M.C., et al., 2013. Effect of Saccharomyces strains on the quality of red wines aged on lees. Food Chem. 139, 1044 1051. Magnelli, P., Cipollo, J.F., Abeijon, C., 2002. A refined method for the determination of Saccharomyces cerevisiae cell wall composition and β-1,6glucan fine structure. Anal. Biochem. 301, 136 150. Manners, D.J., Meyer, M.T., 1977. The molecular structures of some glucans from the cell walls of Schizosaccharomyces pombe. Carbohydr. Res. 57, 189 203. ´ lvarez, I., Raso, J., 2016. Release of mannoproteins during Saccharomyces cerevisiae autolysis induced by Pulsed Martı´nez, J.M., Cebria´n, G., A Electric Field. Front. Microbiol. 7 (1435), 1 8. Masino, F., Montevecchi, G., Arfelli, G., Antonelli, A., 2008. Evaluation of the combined effects of enzymatic treatment and aging on lees on the aroma of wine from Bombino bianco grapes. J. Agric. Food Chem. 56 (20), 9495 9501. Morata, A., Sua´rez Lepe, J.A., 2016. New biotechnologies for wine fermentation and ageing. In: Ravishankar Rai, P.V. (Ed.), Advances in Food Biotechnology. John Wiley & Sons, Ltd, West Sussex, United Kingdom, pp. 293 295. Morata, A., Go´mez-Cordove´s, M.C., Suberviola, J., Bartolome´, B., Colomo, B., Suarez, J.A., 2003. Adsorption of anthocyanins by yeast cell walls during the fermentation of red wines. J. Agric. Food Chem. 51, 4084 4088. Nida, R.H., 2010. Application of High Pressure Technologies in Over Lees Aging of Red Wines and Repercussions in Sensorial Parameters. MS thesis. Vinifera-European Master of Viticulture and Enology. Palomero, F., Bertani, P., Ferna´ndez de Simo´n, B., Cadahı´a, E., Benito, S., Morata, A., et al., 2015. Wood impregnation of yeast lees for winemaking. Food Chem. 171, 212 223. Palomero, F., Morata, A., Benito, S., Gonza´lez, M.C., Sua´rez-Lepe, J.A., 2007. Conventional and enzyme-assisted autolysis during ageing over lees in red wines: Influence on the release of polysaccharides from yeast cell walls and on wine monomeric anthocyanin content. Food Chem. 105, 838 846. Palomero, F., Morata, A., Benito, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2009. New genera of yeasts for over-lees aging of red wine. Food Chem. 112, 432 441. Palomero, F., Ntanos, K., Morata, A., Benito, S., Sua´rez-Lepe, J.A., 2011. Reduction of wine 4-ethylpohenol concentration using lyophilised yeast as a bioadsorbent: influence on anthocyanin content and chromatic variables. Eur. Food Res. Technol. 232, 971 977. Popper, L., Knorr, D., 1990. Application of high pressure homogenization for food reservation. Food Technol. 44, 84 89. Rodrigues, A., Ricardo-Da-Silva, J.M., Lucas, C., Laureano, O., 2012. Effect of commercial mannoproteins on wine colour and tannins stability. Food Chem. 131, 907 914. Rodrı´guez-Bencomo, J.J., Ortega-Heras, M., Pe´rez-Magarin˜o, S., 2010. Effect of alternative techniques to ageing on lees and use of non-toasted oak chips in alcoholic fermentation on the aromatic composition of red wine. Eur. Food Res. Technol. 230 (3), 485 496. Rodrı´guez-Bencomo, J.J., Andu´jar-Ortiz, I., Moreno-Arribas, M.V., Simo´, C., Gonza´lez, J., Chana, A., et al., 2014. Impact of glutathioneenriched inactive dry yeast preparations on the stability of terpenes during model wine aging. J. Agric. Food Chem. 62, 1373 1383. Salmon, J.-M., Fornairon-Bonnefond, C., Mazauric, J.-P., Moutounet, M., 2000. Oxygen consumption by wine lees: impact on lees integrity during wine ageing. Food Chem. 71, 519 528. Sanz, M., Ferna´ndez de Simo´n, B., Cadahı´a, E., Esteruelas, E., Mun˜oz, A.M., Herna´ndez, M.T., et al., 2012. Polyphenolic profile as a useful tool to identify the wood used in wine ageing. Anal. Chim. Acta 732, 33 45. Spillman, P.J., 1999. Wine quality biases inherent in comparisons of oak chip and barrel systems. Aust. N. Z. Wine Ind. J. 14, 25 33. Strauss, M.L.A., Jolly, N.P., Lambrechts, M.G., Van Rensburg, P., 2001. Screening for the production of extracellular hydrolytic enzymes by non-Saccharomyces wine yeasts. J. Appl. Microbiol. 91 (1), 182 190. Sua´rez-Lepe, J.A., Morata, A., 2009. Nuevo me´todo de crianza sobre lı´as en vinos tintos. Oficina espan˜ola de patentes y marcas, ES2311372 B2. October 07, 2009, Spanish Patent, p. 10905. Sua´rez-Lepe, J.A., Morata, A., 2012. New trends in yeast selection for winemaking. Trends Food Sci. Technol. 23, 39 50. Yang, N., Huang, K., Lyu, C., Wang, J., 2016. Pulsed electric field technology in the manufacturing processes of wine, beer, and rice wine: a review. Food Control 61, 28 38.
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Further Reading Escott, C., Vaquero, C., del Fresno, J.M., Ban˜uelos, M.A., Loira, I., Han, S.-Y., et al., 2017. Pulsed light effect in red grape quality and fermentation. Food Bioprocess Technol. 10 (8), 1540 1547. Morata, A., Loira, I., Vejarano, R., Gonza´lez, C., Callejo, M.J., Sua´rez-Lepe, J.A., 2017. Emerging preservation technologies in grapes for winemaking. Trends Food Sci. Technol. 67, 36 43. Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy. Suarez-Lepe, J.A., Morata, A., 2015. Levaduras para vinificacio´n en tinto. AMV Ediciones. Madrid, Spain (Chapter 8) 277 291. in Spanish.
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11 New Trends in Aging on Lees Antonio Morata, Felipe Palomero, Iris Loira and Jose A. Sua´rez-Lepe Department of Chemistry and Food Technology, Technical University of Madrid, Madrid, Spain
11.1 INTRODUCTION The current wine market is characterized by a certain homogeneity and a saturation of competing products. Therefore, new techniques and technologies not only reduce costs but aid to obtain highly distinguishable and quality products that are much sought after. Many research groups in enological microbiology and winemaking have focused their efforts on achieving these overall objectives, motivated by an industry that understands that the differentiation of its products at a moderate cost can significantly increase a brand’s competitiveness. In this context, it is important to note that there is a particular component subject to hedonistic tendencies, fashions, and popular trends in the consumption of wine. Wooded wines with great extraction, high alcohol content, and long periods of aging in barrels have been replaced by others in which primary or varietal fruit aromas are further respected through better integration and balance with wood volatiles. Traditionally, aging on lees (AOL) has been used to improve the sensory profile and mouthfeel of white wines, especially for those that are barrel fermented. But it is also a helpful technique for red wines, improving the softness of tannins as a result of the interaction between mannoproteins and cell wall polysaccharides with wine phenols (Escot et al., 2001). This parameter can be modulated depending on the yeast strain used for AOL (Loira et al., 2013). The reductive effect of lees and the release of some antioxidant components of cell structures like glutathione (GSH) protect the aromatic compounds, thus preserving the fruitiness and freshness, even after long periods of AOL. Antioxidant activity of lees surface, have shown a protective role on thiols during the aging (Gallardo-Chaco´n et al., 2010). The high ability of yeast lees to scavenge oxygen has also been reported (Salmon et al., 2000); and the antioxidant role of yeast lees can also improve the color stability of wines (Escot et al., 2001; Palomero et al., 2007). Moreover, it has been observed that red wines aged on lees show a high limpidity, even when cell wall polysaccharides increase the colloidal load in wines. Lees polysaccharides has the ability to protect wines from protein haze (Dupin et al., 2000). In addition, wine lees have been described as good binding agents for certain volatile compounds such as ethyl esters and fusel alcohol acetates (Rodrı´guez-Bencomo et al., 2010). Although at first this feature may seem something negative for wine quality, it was found that, in general, the nature of this linking is transitory and the union is reversed with the passage of time; that is, the volatile compounds temporarily bound to the yeast cell wall can be released back into the wine. During yeast growth, cell wall porosity depends on the nutritional composition of the media (De Nobel et al., 1990). Then, autolysis occurs after the death of the yeast cell affecting the degradation of the cell wall by auto-enzymatic activity and the release of cytoplasmic contents and coverings fragments. The release of cell wall polysaccharides during fermentation and the dependence of that process on yeast strains has been reported (Escot et al., 2001). The released polysaccharides can reach 100 mg/L. Saccharomyces cerevisiae cell wall is formed by a net of fibrillary polysaccharides containing globular mannoproteins ( 40%). Fiber polysaccharides are mainly β-glucans ( 60%) and chitin ( 2%) formed by N-acetylglucosamine units (Magnelli et al., 2002). Glucans can be β1,3- or β1,6- branched structures (Fig. 11.1). It has been reported that AOL and yeast autolysis is a slow process requiring 7 9 months before there are any repercussions in the sensory profile of wine. Not all yeasts behave in the same way with regard to autolysis and it is possible to use yeast selection to obtain optimal strains of S. cerevisiae with short autolysis periods, or in other
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terms (Palomero et al., 2007), with a greater release of cell wall components. The release of yeast cell wall polysaccharides into the media can be monitored by using liquid chromatography coupled with refractive index detection (LC-RID) in model media or wines. Using this technique, it is possible to study the strains that are able to release higher amounts in a shorter time, and therefore, to select those with shorter autolysis periods (Figs. 11.1A and B and 11.2). A typical problem when using traditional AOL for red wines involves microbiological instability, because generally after red wine fermentation, together with the maceration of solids (skins and seeds), the lees are quite dirty, containing not only the yeast cells that have been fermenting the must, but also colloidal particles and cell wall fragments from grapes as well as a broad microbial population formed by yeast and bacteria species. Hence, this gross lees aging is prone to produce microbial developments and sensory deviations with associated reductive off-flavors. Reductive off-smells can include unpleasant molecules like diethyl sulfide (garlic) or dimethyl sulfide (stewed cabbage). To control this, an initial improvement is to simply use fine lees cleaning the colloidal particles settling the wine. However, this is just a partial solution because some contaminant load will still remain and at the same time, a large fraction of the yeast cells is removed. A better solution is the external production of a biomass with the yeast that is required to perform the AOL; this technique has several advantages: (1) the yeast
Chitin (0.5 of dry weight) β (1—3) and (1—6) Glucan microfibres Mannoprotein Membrane protein Periplasmatic enzyme
112 kDa 47 kDa 23 kDa 12 kDa 6 kDa
MV
FIGURE 11.1 Plasmatic membrane and cell wall structure of Saccharomyces cerevisiae. Adapted from Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy.
(A)
5
(B)
4
3 Seventh month
2
Seventh month
Sixth month
Sixth month
1
0 0
1
2
3
4
5
6 7 Minutes
8
9
10
0
1
2
3
4
5 6 7 Minutes
8
9
10
FIGURE 11.2 LC-RID chromatograms of polysaccharides releasing for 2 yeast strains 5CV (A) and 2EV (B) of Saccharomyces cerevisiae during the autolysis analyzed after 6 and 7 months of aging on lees. Chromatograms from duplicate processes. Pullulanes were used as molecular size markers in kDa. LC-RID, Liquid chromatography coupled with refractive index detection.
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biomass can be produced using a yeast species or strain with improved performance for AOL being selected by a fast autolysis and positive sensory impact; (2) even non-Saccharomyces yeasts can be used; (3) the addition will be just pure yeasts cells so there will be no collateral contaminants—no bacteria, undesired yeasts or colloidal particles; and (4) the wine can be partially cleaned before the addition of lees to obtain an even safer process, including settling and filtration procedures. The lees can be produced in an external fermenter under aerobic conditions to enhance biomass production and the yeast cells can later be purified by rinsing with water and subsequent centrifugation to get a pure biomass (Sua´rez-Lepe and Morata, 2009). Moreover, it is possible to apply it as not only a fresh biomass but it can also be applied after a drying process (e.g., lyophilization) to facilitate storage and dosage. Red wines aged on lees frequently show an intense fruity smell even when they are barrel matured for long periods. Glutathione, a cell wall peptide component formed by three amino acids and currently used as antioxidant in enology, is one of the factors responsible for this effect (Comuzzo et al., 2015a,b). The direct release of GSH during AOL or the application as an active yeast by-products affects the protective effect on fruity and varietal aromas (Rodrı´guez-Bencomo et al., 2014). The selection of yeasts that are able to release high contents of GSH during AOL is one way to enhance this protection (Sua´rez-Lepe and Morata, 2012). AOL can be used synergistically with barrel aging or oak chips, improving the aromatic richness of wines (Loira et al., 2013). Moreover, the reductive effect of AOL by increasing the GSH content helps to balance the oxidative effect of barrel aging, reducing the aggressive repercussions of the use of new barrels. It is interesting to note the high degree of chance and empiricism underlying the link between wine and wood. Do you ever wonder why a barrel of wine is shaped the way it is? The answer is that originally, they were only used as a container for trade of goods. At the time, wood was robust enough, cheap, and an abundant material, and such geometry allowed its heavy weight (volume) to be effortlessly moved by rolling it, upright if on rails or on its side on smooth surfaces. It was some time later that the positive influence of the container over the content, was perceived and recognized. This influence is due to the migration of certain chemicals, whether or not volatile, and mostly known and fully identified molecules that enrich the wine’s sensory profile (Sanz et al., 2012). Conventional wine aging in French or American oak barrels is a slow and costly process, where a large volume of wine must be immobilized in storage for varying periods before being marketed. The aromatic potential of the barrels is not unlimited, and therefore, their purchase, maintenance, and replacement, constitute a significant proportion of the variable costs for wineries. Even though these drawbacks are even more important if AOL is performed, this novel technique in red winemaking is gaining popularity since it allows the production of wines with distinctive sensory attributes. In order to solve some of the previously mentioned inconveniences, oak chips, staves, or fragments of variable sizes and shapes are usually used by winemakers globally in stainless steel tanks (Spillman, 1999). Its direct addition to the wine coupled with micro-oxygenation techniques, increases color stability and enhances the diffusion and integration of oak aromas into the wine. This procedure significantly reduces aging periods and allows wineries to release their wines into the market sooner. On the other hand, these techniques are not free of problems. The migration of oak constituents primarily depends—among other factors involved—on the exposed surface area. The quantity, shape, and size of chips can sometimes produce an excessive wood aroma extraction when the dosage is incorrect. The repeatability of the processes is not always good since a great variation between batches has been a matter of concern for some winemakers. Besides the traditional woods commonly employed to age wines irrespective of the presence of lees, woods other than oak and chestnut have been studied (see Section 11.4). The simultaneous use of chips or barrel aging with AOL helps to improve the aromatic profile with a more softening impact than just single barrel aging (Loira et al., 2013). Furthermore, cell wall polysaccharides released from the yeast during AOL soften the tannin dryness contributed by the barrel, promoting a faster and better integration of barrel tannins (Rodrigues et al., 2012; Loira et al., 2013). Another application of lees concerns the yeast cell wall adsorption capacity, which has been studied in order to remove some specific and undesirable wine compounds such as ochratoxin A and 4-ethylphenols (Caridi et al., 2012; Palomero et al., 2011). In fact, AOL has been proposed as a palliative treatment to mitigate excessive oak aromas from wines (Chatonnet et al., 1992). In contrast, yeast lees adsorb anthocyanins and other grape phenols during fermentation that can be partially released during aging and autolysis stages if they are not removed (Morata et al., 2003).
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11.2 USE OF NON-SACCHAROMYCES YEASTS Non-Saccharomyces yeasts are a trend in current enology (Morata and Sua´rez Lepe, 2016), with applications in grape sanitization, fermentation, stabilization, and aging. Traditional Saccharomyces yeasts commonly used in AOL (Fig. 11.3A) can also be substituted with non-Saccharomyces yeast and this has some advantages. Saccharomycodes ludwigii (Fig. 11.3B), Schizosaccharomyces pombe (Fig. 11.3C), and even Brettanomyces bruxellensis (Fig. 11.3D) have been described for of their optimal release of polysaccharides during AOL (Palomero et al., 2009; Kulkarni et al., 2015). S. pombe also releases 3 7 times more polysaccharides than commercial S. cerevisiae during fermentation (Domizio et al., 2017). The use of osmophilic non-Saccharomyces yeasts can accelerate the release of cell wall polysaccharides and mannoproteins (Palomero et al., 2009). This behavior is as a result of their special structure and the composition of their cell walls. In some osmophilic yeasts like S. pombe, a multilayer cell wall formed by α-galactomannose with α-1,3 glucan fibers has been described (Kopecka` et al., 1995) (Fig. 11.4). The average composition is 9% 14% α-galactomannan, 18% 28% α-1,3-glucan, 42% β-1,3-glucan, and 2% β-1,6-glucan (Manners and Meyer, 1977; Kopecka` et al., 1995). A three-layer structure with an external and internal electron dense structure and a less dense layer in the middle can be observed by transmission electron microscopy (Humbel et al., 2001). The thick multilayer structure of S. pombe contains more polysaccharides and cell wall globular proteins than S. cerevisiae cells, allowing a higher release of polymers during the AOL processes. When the release of cell wall polysaccharides has been recorded by LC-RID during the AOL across different non-Saccharomyces yeast species, it was observed that the contents were much greater when S. pombe was used (Palomero et al., 2009; Kulkarni et al., 2015). Moreover, polysaccharides were released in a shorter time (Fig. 11.5) and with higher molecular sizes (Palomero et al., 2009). This last peculiarity can influence the tactile sensation of polysaccharides in the mouth
FIGURE 11.3
Optical microscopy of yeasts. (A) Saccharomyces cerevisiae. (B) Saccharomycodes ludwigii. (C) Schizosaccharomyces pombe. (D) Brettanomyces bruxellensis.
Chitin (0.5 of dry weight) α Galactomanose β (1—6) Glucan, minor part β (1—3) Glucan, mayor part Mannoprotein α (1—3) and β (1—3) Glucan microfibres Membrane protein Periplasmatic enzyme
FIGURE 11.4 Plasmatic membrane and cell wall structure in Schizosaccharomyces pombe. Adapted from Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy.
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Polysaccharides (mg/L)
120
Saccharomycodes ludwigii
100 80
Schizosaccharomyces pombe
60
Saccharomyces cerevisiae
40 20 0 0
1
2
3
4
5
Months
FIGURE 11.5
Cell wall polysaccharides released by several yeast species during AOL. AOL, Aging on lees.
and, in fact, wines were positively perceived by tasters (Palomero et al., 2009). Another interesting fact is a twostage kinetics in the release of cell wall polysaccharides with a maximum peak and a first plateau after 1 month, but later a second maximum and plateau at 4 and 5 months for S. ludwigii and S. pombe, respectively (Fig. 11.5; Palomero et al., 2009). Moreover, the maximum value in S. cerevisiae is lower than the first plateau for S. ludwigii and S. pombe. Therefore, the use of some non-Saccharomyces is a powerful tool to enhance mouthfeel by increasing polysaccharide content. Several wine related species of non-Saccharomyces yeasts, such as, for example, Kloeckera apiculata and Candida stellata, have been reported to produce high amounts of extracellular β-glucanase enzymes (Strauss et al., 2001), and therefore, could be considered a means to hasten the breakage of the yeast cell wall.
11.3 ACCELERATED AGING ON LEES Several techniques have been described as useful to accelerate the breakage of the yeast and the fragmentation of cell walls. Among them, β-glucanases enzymes (Palomero et al., 2007), HHP (high hydrostatic pressure) (Nida, 2010), HPH (high pressure homogenization) (Comuzzo et al., 2015a,b), US (ultrasound) (Kulkarni et al., 2015; Liu et al., 2016), MW (microwaves) (Liu et al., 2016), and PEF (pulsed electric fields) (Martı´nez et al., 2016) have all reported advantages for a faster release of polysaccharides and/or cytoplasmic proteins when yeast cells are processed using them. β-glucanases enzymes produce the hydrolysis of β-glucans, thus facilitating the cell wall disruption and consequently increasing the release of polysaccharides. Yeast lysis time can be reduced from several months to a few weeks in comparison to conventional natural autolysis (Palomero et al., 2007). The presence of some collateral enzymatic activities such as β-glycosidases can affect anthocyanin stability (Palomero et al., 2007). However, some authors reported no effect on the release of polysaccharides when commercial β-glucanases enzymes (4 g/HL) were added to the lees (3% v/v of fine lees) (Del Barrio-Gala´n et al., 2011). It is likely that there may be some influence of the doses of enzyme versus lees concentration or of the conditions in which the aging was carried out. Regarding the influence of this enzyme addition to the aromatic quality of the wine, it was found that using β-glucanases during AOL at a dose equal to or higher than 30 mg/L allows the obtaining of wines with a higher content of certain volatile compounds, mainly ethyl esters and 2-phenylethanol, but also interestingly hexanol and trans-3-hexenol, even though these last two compounds are not involved in yeast metabolism (Masino et al., 2008). Lees pressurization at 100 MPa affects cell wall structure, promoting depolymerization and facilitating yeast lysis and polysaccharides release (Nida, 2010). The use of HPH at 150 MPa produces similar levels of colloids polysaccharides, proteins, and free amino acids than thermal autolysis but increases ethyl esters and reduces fatty acids (Comuzzo et al., 2015a,b). The use of US is an effective technology to disrupt the cells facilitating the depolymerization of cell coverings and releasing mannoproteins and cell wall polysaccharides. When US is employed for a few minutes to a yeast
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biomass at a power of 400 W and a frequency of 24 KHz, with a sonotrode S24D14D (Ø14 mm, length 100 mm) the breakage of cell coverings and the release of cytosolic contents facilitating the autolysis process can be observed by optical microscopy (Fig. 11.6). The effect of US can be enhanced when inert abrasives such as sand or glass beads are used together (Liu et al., 2016). The application of US to non-Saccharomyces produces a fast lysis of cells (Fig. 11.7) and it can be observed that US treated non-Saccharomyces produces 2 4 times more polysaccharides than conventional Saccharomyces yeasts (Kulkarni et al., 2015). Maximum concentrations after US treatments are observed after 2 3 weeks in all yeast species, so the use of US is a powerful tool to accelerate yeast lysis and to speed up AOL especially when used together with non-Saccharomyces yeasts. Thermal treatments are traditionally used to produce yeast derivatives used in enology such as inactivated yeasts or cell wall mannoproteins. The use of emerging heating systems including MW facilitates yeast cell disruption in a short time, thus increasing the release of polysaccharides (Liu et al., 2016).
Polysaccharides (mg/L)
FIGURE 11.6 (A) Control. (B) Ultrasound treated lees.
500
Saccharomycodes ludwigii
400 Schizosaccharomyces pombe 300 Brettanomyces bruxellensis
200 100 0 0
1
2
3
4
5
6
7
- Saccharomyces cerevisiae - Candida pulcherrima - Kluyveromyces marxianus - Lachancea thermotolerans - Metschnikovia pulcherrima - Torulopsis stellata
Weeks
FIGURE 11.7 Release of polysaccharides by both Saccharomyces and non-Saccharomyces yeasts during aging on lees accelerated by ultrasound. Adapted from Kulkarni, P., Loira, I., Morata, A., Tesfaye, W., Gonza´lez, M.C., Sua´rez-Lepe, J.A., 2015. Use of non-Saccharomyces yeast strains coupled with ultrasound treatment as a novel technique to accelerate ageing on lees of red wines and its repercussion in sensorial parameters. LWT Food Sci. Technol. 64, 1255 1262.
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TABLE 11.1
β-Glucanases enzymes
Main emerging technologies available to accelerate and/or improve wine aging on lees: features and observed results Mechanism of action
Advantages
Drawbacks
Hydrolysis of βglucans forming part of the yeast cell wall
Shorter duration of the autolytic Slight loss of color process (2 3 weeks). (undesired β-glucosidase Conventional autolysis activity) (nonaccelerated AOL): .5 months Faster and higher release of Increased risk of polysaccharides from the cell wall contamination by altering microorganisms (e.g., Brettanomyces)
References Palomero et al. (2007), Masino et al. (2008), and Ferna´ndez et al. (2011)
Enrichment of the aromatic profile Homogeneity in the size of the released polysaccharides High investment costs in equipment acquisition
Nida (2010)
Inflicts damage on cytoplasmic membrane favoring depolymerization
Higher release of polysaccharides
HPH
Cavitation, turbulence and shear, which occur when the yeast suspension is forced through the homogenization valve
Increase of ethyl esters and reduction of fatty acids
Comuzzo et al. (2015) and Popper and Knorr (1990)
US
Sound waves used to cause thinning of cell membranes, localized heating and production of free radicals
Faster and higher release of Possible slight oxidation of polysaccharides from the cell wall the wine
Kulkarni et al. (2015) and Liu et al. (2016)
HHP
Industrial application in continuous processes
No negative effects on the sensory quality of the wine Possible influence in wine color stability (higher amounts of acetaldehyde)
PEF
Increase in metal ions (Fe, Cr, Zn, and Mn) concentrations
Martı´nez et al. (2016) and Yang et al. (2016)
Increased color stability
Decrease in total anthocyanin content
Del Barrio-Gala´n et al. (2011)
Prolonged aging on lees
Residual dissolved oxygen in the medium (problems of overoxygenation)
Enrich wine in polysaccharides from wood (not from the yeast cell wall)
Difficulty in controlling the proper transfer of compounds (dose and contact time dependent)
Electroporation and electric breakdown
Acceleration of autolysis
Destabilization of the lipid bilayer and proteins of the cell membranes
Faster and higher release of mannoproteins No negative effect on wine quality has been reported
Microoxygenation
Use of nontoasted oak chips
Controlled addition of oxygen into the wine in small doses leads to wine components transformation
Transfer of wood compounds to wine
Del Barrio-Gala´n et al. (2011)
Artificially accelerate the aging process in barrel HHP, High hydrostatic pressure; HPH, High pressure homogenization; US, Ultrasounds. AOL, Aging on lees; PEF, Pulsed electric fields.
The PEF inactivation mechanism is mainly based on the electroporation of the cytoplasmic membrane that leads to disorders in the membrane’s electrical potential, osmotic imbalance, and, finally, cell lysis (Barba et al., 2018, Page 115). This nonthermal and efficient method in the use of energy technology has little effect on wine composition (Yang et al., 2016). These days, its main drawback is the release of metal ions from the electrode that may significantly increase Fe, Cr, Zn, and Mn concentrations. However, further research in this field is needed to properly understand all the implications surrounding electrode degradation.
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A. YEAST LEES BIOMASS 1. Growth of Saccharomyces cerevisae (G37) in YPED medium YPED medium enriched with glucose (up to 100g/L)
3. The Yeast was lyophilised
2. The yeast biomass was washed and centrifuged (1157 rcf for 2 min) B. WOOD AROMATISATION OF YEAST H H H C C O H H H
1. Obtaining wood extract in 10g of freeze-dried S.cerevisiae (G37)
250 mL ethanol 99% v/v Acacia
Chestnut Cherry
Oak 2. Wood aromatization of yeast lees
Each wood at a time
40 min at 45ºC
35 g of wood chips 100 min at 45ºC
C. WINE ON Aromatized yeast
… Wood-inflused yeast in 1 month at 17ºC
1 g wood-aromatized yeast biomass : 500 mL wine Red wine obtained from Tempranillo grapes from Vinos de Madrid
Oak
Chestnut
Acacia
Cherry
FIGURE 11.8 Lees impregnation with wood-extract procedure.
Another suggested alternative to increase the content of polysaccharides in wine is the use of nontoasted oak chips (for example: 4 g/L) with the aim of extracting these polymers from the wood (Del Barrio-Gala´n et al., 2011). Despite these polysaccharides having a different origin, they can act in the same manner as polysaccharides released from yeast cell walls. That is, increasing the wine’s mouthfeel and body, as well as reducing astringency and bitter flavors. The yeast cell disruption and the nonthermal permeabilization of cell membrane provoked by the aforementioned emerging technologies have been shown to be effective for wine microbial inactivation (Garcı´a et al., 2013; Ganeva et al., 2014; Abca and Akdemir Evrendilek, 2014). But, at the same time, they are also useful to accelerate the lees yeast lysis with the subsequent release of protective colloids and biological material (e.g., mannoproteins, polysaccharides, peptides, amino acids, fatty acids, nucleotides, etc.) from the cytoplasm or the coating structures (cell wall and cytoplasmic membrane) to the wine (Martı´nez et al., 2016). Regarding complementary techniques to AOL, micro-oxygenation (5 mL/L/month of O2) applied to AOL improves the color stability of the wine through the formation of new pigments that may increase or remain constant until the end of the barrel aging process (Del Barrio-Gala´n et al., 2011). These micro-oxygenated 1 AOL wines are characterized by higher color intensities and blue tonalities. Similarly, the use of nontoasted oak chips is an effective technique to accelerate the transfer of wood components to the wine in order to improve aromatic complexity and mouthfeel without the need of aging in barrels.
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By adjusting the appropriate dose, it is possible to obtain the desired wood characteristics in the wine in shorter periods of time thanks to the greater transfer surface on the chips. Table 11.1 summarizes the main novel techniques that can be coupled with AOL to improve results or speed up the AOL process.
11.4 LEES AROMATIZATION
Trihydroxymetoxyfavlonol
Krempferide
Isosakuramnetin
Kaempferol Apigenin + Pinocembrin
Butein
Aromadendrin
Fisetin
Ellagic acid
Coniferaldehyde
Naringenin Quercetin
60
Taxifolin Ferulic acid
80
p -Hidroxibenzaldehyde
Gallic aldehyde
mAU
Protocatechuic aldehyde
Acacia
p-Vanillin
Cherry Chestnut
Dihidroxirobinetin
Oak
2,4-Dihidroxibenzaldehyde
MIX
Robinetin
Siringaldehyde
Sinapaldehyde
A new technique proposed to incorporate wood aromatic compounds from several tree species is the use of yeast lees as a carrier for the wood extracts during AOL (Palomero et al., 2015). The woods studied were oak, chestnut, cherry, and acacia. A biomass of a yeast strain previously selected according to its good autolytic behavior was used to conduct the experiments. Once the yeast was soaked with an ethanol wood-extract and dried, the wood-aromatized yeast biomasses for each type of wood were poured into a red wine made from Vitis Vinifera L.cv. Tempranillo grapes from D.O. Vinos de Madrid. One gram of these biomasses was added to 500 mL of wine. Untreated yeasts were used as a control. Wines were left in contact with the lees for 1 month. All the treatments were performed in triplicate. Fig. 11.8 illustrates the processes carried out during the experimental stage.
40
20
0 10
20
30
40
50
60
min
FIGURE 11.9 Phenolic compounds (HPLC/DAD chromatograms) detected on wood-aromatized yeast, and for an equal part mixture of all wood types (MIX).
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The analysis of polyphenols and volatile compounds (by HPLC/DAD and GC-MS, respectively) performed following the methodology described in Palomero et al. (2015) on both the wines and the woody yeast biomasses confirmed that the adsorption/diffusion of these compounds from the wood to the yeast, and then to the wines occurs. Finally, a sensory assessment of all wines was undertaken by 10 expert tasters. Some of the 34 wood phenols adsorbed by yeast cell walls, and then detected by HPLC/DAD, are graphically presented in Fig. 11.9. All of these compounds have been found and described previously (Sanz et al., 2012). The data confirmed sorption phenomena occurred and that the phenolic composition of the studied woods were significantly different. This technique confirms its potential usefulness because of the great concentration of phenolics aldehydes observed in the chestnut samples. Compounds such as vanillin and syringaldehyde are some of the most distinctive wood odorants in barrel-aged wines. The concentration of vanillin, the phenolic aldehyde with the lowest sensory threshold, could be enhanced significantly through the use of chestnut instead of oak (Palomero et al., 2015). As reported previously by other authors, there are some specific compounds only found in one type of wood and therefore, could potentially be used as identification markers (Ferna´ndez de Simo´n et al., 2014; Sanz et al., 2012). In this sense, one of the clearest examples can be seen in Fig. 11.9 for the highest peak corresponding to robinetin, only found in aromatized acacia samples (and in the mixture). Table 11.2 summarizes the main volatile compounds (of the 71 volatile molecules identified that are mainly formed during wood toasting) found in the wood-aromatized yeasts. Both lactones and carbohydrate derivatives (such as furfural and 5-hydroxymethylfurfural), lignin-derived volatile phenols, and phenolic aldehydes (such as vanillin) concentrations are significantly higher in chestnut-infused yeast. Generally, large differences have been observed between the quantitative values for the kinds of wood used in our experiments. Our data correlate well with the findings of Ferna´ndez de Simo´n et al. (2014).
TABLE 11.2
Main volatile compounds (μg/g) in aromatized yeast biomasses
Compound
Acacia
Cherry
Chestnut
Oak
Furfural
0.56
0.75
3.05
0.82
5-Methylfurfural
0.23
0.37
1.18
0.21
5-Hydroxymethylfurfural
4.51
2.68
6.01
1.89
Trans-whiskylactone
nd
nd
0.25
0.34
Cis-whiskylactone P lactones and carbohydrate derivativesa
nd
nd
0.14
0.13
84.74
94.04
102.95
66.41
Phenol
0.17
0.21
0.20
0.15
2-Phenylethanol
4.29
5.31
6.28
3.21
4-Methyl guaiacol
0.59
0.71
4.74
0.16
4-Ethyl guaiacol
0.09
0.09
0.21
0.17
4-Vinylguaiacol
0.45
0.54
0.69
0.58
Eugenol P volatile phenolsa
0.19
0.31
0.87
0.65
11.99
16.03
26.39
15.87
Vanillin
35.9
19.5
Syringaldehyde
98.2
2,4-Dihydroxybenzaldehyde
38.5
nd
nd
nd
nd
1.12
nd
nd
p-Anisaldehyde P phenolic aldehydes, ketones and othera
197
124
200
a
Summations include other compounds not shown. Note: Bold indicates to summary of a family of compounds. Results in wines with wood-aromatized yeast lees.
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179
252
214
624
488
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11.4 LEES AROMATIZATION
TABLE 11.3
Phenolic composition (μg/L) of red wines enriched with wood-aromatized yeast leesa
Compound
Acacia
Cherry
Chestnut
Oak
Gallic acid
23.8 6 0.5a
24.4 6 1.0a
28.9 6 3.5b
26.4 6 2.3ab
Vanillic acid
1.8 6 0.0a
1.9 6 0.7a
3.2 6 1.0b
2.4 6 0.7ab
Ellagic acid
4.2 6 0.3a
3.8 6 0.7a
11.8 6 0.6c
7.7 6 1.7b
(1)-Catechin
59.7 6 1.8a
53.6 6 7.2a
57.9 6 1.0a
55.4 6 6.2a
Procyanidin B2
11.4 6 0.7b
8.4 6 0.9a
11.3 6 1.1b
8.6 6 2.8ab
(2)-Epicatechin
5.7 6 0.2a
5.2 6 0.5a
5.7 6 0.3a
5.2 6 0.6a
Myricetin-3-glucuronide
11.6 6 0.5bc
12.9 6 0.8c
10.3 6 0.9ab
9.5 6 1.2a
Quercetin-3-galactoside
9.2 6 0.6bc
8.6 6 1.7abc
7.2 6 0.7ab
6.5 6 2.0a
Quercetin-3-glucoside
5.6 6 0.2b
5.2 6 1.2ab
4.5 6 0.3ab
3.9 6 1.0a
Quercetin
1.5 6 0.1a
2.0 6 0.1b
1.8 6 0.1ab
1.6 6 0.1a
Dihydrorobinetin
0.9 6 0.0a
nd
nd
nd
10.6 6 0.0a
nd
nd
nd
nd
1.7 6 0.0a
nd
nd
Robinetin Aromadendrin
Values are mean 6 standard deviation (n 5 3). Values in the same row with different letter denotes a statistical difference (p , 0.05). nd: not detected.
a
TABLE 11.4
Main volatile compounds (μg/L) in red wines aged for 1 month with wood-aromatized yeast leesa
Compounds
Acacia
Cherry
Chestnut
Oak
Furfural
65.3 6 7.4b
55.3 6 3.0ab
66.4 6 19.2b
68.2 6 5.9b
5-Methylfurfural
5.83 6 1.22a
5.40 6 1.61a
6.93 6 0.68a
6.23 6 1.18a
5-Hydroxymethylfurfural
224 6 19.4ab
249 6 158ab
301 6 83.9ab
307 6 84.9b
Trans-β-methyl-γ-octolactone
nd
nd
18.8 6 4.3b
19.7 6 1.1b
Cis-β-methyl-γ-octolactone
nd
nd
19.4 6 12.4b
24.2 6 10.7b
4-Methylguaiacol
2.9 6 0.3abc
2.3 6 0.7ab
4 6 0.5c
3.3 6 1.1bc
4-Ethylguaiacol
0.47 6 0.05b
0.51 6 0.14b
0.55 6 0.07b
0.44 6 0.28b
4-Vinylguaiacol
2.99 6 0.22b
3.18 6 0.12b
4.04 6 0.82b
3.91 6 0.77b
Phenol
0.96 6 0.08a
1.06 6 0.16a
0.96 6 0.03a
1.03 6 0.24a
4-Ethylphenol
0.47 6 0.04a
0.52 6 0.18a
0.68 6 0.03a
0.69 6 0.24a
4-Vinylphenol
500 6 43.7b
506 6 118b
532 6 90.3b
643 6 114b
Eugenol
1.6 6 0.1a
2.2 6 1a
1.9 6 0.3a
1.9 6 0.0a
Vanillin
1132.7 6 18.6c
864.5 6 201.9b
3840.3 6 167.6e
704.3 6 87.6b
Vanillyl ethyl ether
1721 6 303a
1783 6 361a
3569 6 79.9b
2786 6 410ab
Syringaldehyde
2009.7 6 476.3a
2938.4 6 863.8c
4812.7 6 478.4d
1940.6 6 378.2b
Acetosiringone
338 6 34.3ab
403 6 39.3ab
654 6 118c
283 6 25.7a
p-Anisaldehyde
nd
28.1 6 12.9b
nd
nd
Values are mean 6 standard deviation (n 5 3). Values in the same row with different letter denotes a statistical difference (p , 0.05). nd: not detected.
a
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The phenolic composition of Tempranillo wines was significantly different between treatments. Table 11.3 shows some of the phenolics found in the wines. As previously observed during dried yeast phenolic analysis, robinetin and dihydrorobinetin were only found in wine samples aged with acacia-infused yeast. A similar conclusion can be established for aromadendrin in the case of cherry wood. A great ratio of gallic and ellagic acid was seen in chestnut samples compared with oak ones. Some authors have claimed that these compounds could contribute to the chemical recognition of chestnut wood (Ferna´ndez de Simo´n et al., 2014). It is probable that these compounds will be easily perceived in wines aged in chestnut vessels. Generally, the volatile composition of the initial wine was significantly modified before treatments. As previously seen, there are no methyl-octolactone isomers in acacia and cherry (Tables 11.2 and 11.4), and no statistical differences were observed between chestnut and oak for these compounds. Phenolic aldehydes and phenyl ketones were detected to be at higher levels in wines aged with chestnutinfused yeast lees (Table 11.4). These compounds impart vanilla-like aromas into the wines; and woods with higher concentrations would be useful in order to reduce aging costs (Palomero et al., 2015). No differences were observed with regard to color intensity and chromatic parameters, a fact that is reasonable when taking into account that wines were left in contact with lees only for 1 month. All the kinds of wines with wood-infused yeast were reported to be more complex than the control wine, so wine aroma was improved with the aging treatment. Chestnut aromatized biomasses released the highest amounts of wood-related compounds like phenolic aldehydes, and it is perhaps for this reason that they were valued with the highest scores for plum, currant, spicy, roasted, and nutty aromas.
11.5 CONCLUSIONS AOL is an interesting technique for the biological aging of red wines, softening phenolic fraction and decreasing astringency, with a protective effect on color and varietal smells. The use of selected Saccharomyces yeasts or some non-Saccharomyces species accelerates this slow process, improving industrial application. In the same way, lees processing using emerging technologies, such as HHP, HPH, US, MW, PEF, etc., accelerates the process, increasing industrial feasibility. Moreover, this is a technique that can be synergistically used with barrel aging or wood chips to increase aromatic quality.
References Abca, E.E., Akdemir Evrendilek, G., 2014. Processing of red wine by pulsed electric fields with respect to quality parameters. J. Food Process. Preserv. 39 (6), 758 767. Barba, F.J., Ahrne´, L., Xanthakis, E., Landerslev, M.G., Orlien, V., 2018. Innovative Technologies for Food Preservation. Inactivation of Spoilage and Pathogenic Microorganisms, first ed Academic Press, Elsevier Ed, London, UK. Caridi, A., Sidari, R., Pulvirenti, A., Meca, G., Ritieni, A., 2012. Ochratoxin A adsorption phenotype: an inheritable yeast train. J. Gen. Appl. Microbiol. 58 (3), 225 233. Chatonnet, D., Dubourdieu, D., Boidron, J.N., 1992. Incidence des conditions de fermentation et d’e´levage des vins blancs secs en barriques sur leur composition en substances ce´de´es par le bois de cheˆne. Sci. Aliments 12, 665 685. Comuzzo, P., Battistutta, F., Vendrame, M., Pa´ez, M.S., Luisi, G., Zironi, R., 2015a. Antioxidant properties of different products and additives in white wine. Food Chem. 168, 107 114. Comuzzo, P., Calligaris, S., Iacumin, L., Ginaldi, F., Palacios Paz, A.E., Zironi, R., 2015b. Potential of high pressure homogenization to induce autolysis of wine yeasts. Food Chem. 185 (15), 340 348. Del Barrio-Gala´n, R., Pe´rez-Magarin˜o, S., Ortega-Heras, M., 2011. Techniques for improving or replacing ageing on lees of oak aged red wines: the effects on polysaccharides and the phenolic composition. Food Chem. 127 (2), 528 540. De Nobel, J.G., Klis, F.M., Munnik, T., Priem, J., Van Den Ende, H., 1990. An assay of relative cell wall porosity in Saccharomyces cerevisiae, Kluyveromyces lactis and Schizosaccharomyces pombe. Yeast 6, 483 490. Domizio, P., Liu, Y., Bisson, L.F., Barile, D., 2017. Cell wall polysaccharides released during the alcoholic fermentation by Schizosaccharomyces pombe and S. japonicus: quantification and characterization. Food Microbiol. 61, 136 149. Dupin, I.V.S., McKinnon, :B.M., Ryan, C., Boulay, M., Markides, A.J., Jones, G.P., et al., 2000. Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: Their release during fermentation and lees contact and a proposal for their mechanism of action. J. Agric. Food Chem. 48, 3098 3105.
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Further Reading Escott, C., Vaquero, C., del Fresno, J.M., Ban˜uelos, M.A., Loira, I., Han, S.-Y., et al., 2017. Pulsed light effect in red grape quality and fermentation. Food Bioprocess Technol. 10 (8), 1540 1547. Morata, A., Loira, I., Vejarano, R., Gonza´lez, C., Callejo, M.J., Sua´rez-Lepe, J.A., 2017. Emerging preservation technologies in grapes for winemaking. Trends Food Sci. Technol. 67, 36 43. Palomero, F., Benito, S., Morata, S., Caldero´n, F., Sua´rez-Lepe, J.A., 2008. New yeast genera for over lees ageing in red wines. In: XXX World Congress of the International Organization of Grape and Wine (OIV). 16 19 June, Verona, Italy. Suarez-Lepe, J.A., Morata, A., 2015. Levaduras para vinificacio´n en tinto. AMV Ediciones. Madrid, Spain (Chapter 8) 277 291. in Spanish.
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