EP3724312A1 - Cork powder as beverage fining agent, preparation method and use thereof - Google Patents

Abstract

The present application is related to a process for preparing and enhancing cork powder for the fining operation of beverages. The process involves the use of cork powder having a particle size smaller than or equal to 5 mm which undergoes pre-treatment to remove solvent-soluble extractives. The resulting cork powder is immersed in impregnation solvent and vacuum is consecutively applied and removed. The cork powder obtained by this process enables the removal of the aroma defects of beverages resulting from undesirable aroma compounds when present at levels exceeding the smell detection threshold, without significantly altering the quality of the beverage.

Description

DESCRIPTION

"CORK POWDER AS BEVERAGE FINING AGENT, PREPARATION METHOD

AND USE THEREOF"

Technical Field

The present application is related to a process for preparing and enhancing cork powder for the fining operation of beverages .

Background

The aroma and complex flavor of the wine result from the presence of a vast range of organic molecules (Ribereau- Gayon et al . , 2006) . Not all these molecules are desirable when present over a certain concentration in the end product. The removal of these molecules below their critical concentration of sensory detection is a hard task, especially in a complex mixture such as wine. For improving the fining process, it is necessary to remove the undesirable compound (s) until levels below their critical concentration, maintaining the maximum possible level of the other components, resulting in wine with higher quality.

The most prominent compounds are 2-isobutyl-3- methoxypyrazine (IBMP), 2-methoxypyrazine, guaiacol, 4- methylguaiacol , 4-vinylguaiacol, 4-ethylguaiacol , 4- vinylphenol, 4-ethylphenol , 2 , 4 , 6-trichloroanisol , 2- methylisoborneol , geosmin ( 4 , 8a-dimethyldecalin-4a-ol ) , methanethiol (methyl mercaptan) , ethanethiol (ethyl mercaptan) , dimethyl sulfide, diethyl dimethyl sulfide, hydrogen sulfide, acrolein (propenal), acetic acid, acetaldehyde, amyl acetate, diacetyl, ethyl acetate, isovaleric acid, 2-ethoxy-hexa-3 , 5-dien, 2-acethyl-3, 4, 5, 6- tetra-hydropyridin, 2-acethyl-3, 4, 5, 6-tetra-hydropyridin, 2-ethyl-tetra-hydropyridin, 2-acethyl-l-pyrroline, geraniol (3, 7-dimethylocta-2 , 6-dien-l-ol) , halogenated aromatics, trichlorophenol , tribromoanisole, 4 , 5-dichloroguaiacol , chlorovaniline, proanthocyanidins (known as condensed tannins), 4-aminoacetophenone, 1, 1, 6-trimethyl-l, 2- dihydronaphthalene (TDN) , isopropylmethoxypyrazine, 2,3- butanedione, 3-hydroxybutanone, 2-mercaptoethanol , 2- methoxy-3, 5-dimethylpyrazine, 2- sec-Butyl-3-methoxypyrazine and acetamide.

Cork is the bark of the cork oak tree ( Quercus suber L.), being a plant tissue, 100% natural, sustainable and renewable, which is periodically harvested from the tree usually every 9 to 12 years, depending on the cultivation region (Silva et al . , 2005) . The Quercus suber L. is a slow- growing tree that grows only in certain regions of the western Mediterranean (Portugal, Spain, southern France, part of Italy, North Africa) and China (Barberis, Dettori, & Filiggheddu, 2003; Costa, Pereira, & Oliveira, 2003; Fialho, Lopes, & Pereira, 2001) . Portugal is the largest producer of cork and processes around three quarters of all cork worldwide (Costa et al . , 2003; Fialho et al . , 2001) .

Cork tissue is compact, with no intercellular hollows, and has a regular hexagonal arrangement. This plant tissue is homogenous in terms of the type of cells: intercellular hollows are parenchyma cells with hollow insides filled with air (Pereira, 2015) . The cells are mostly coated with suberin (a natural interlinked aliphatic-aromatic polyester) comprising between 30 and 50% of its weight, and lignin (a group of aromatic polymers resulting from the oxidative coupling of 4-hydroxyphenylpropanoids ) that accounts for 15 to 30% of its weight. Other components are cellulose and hemicellulose of the cellular wall that accounts for 6 to 25% and the presence of 8 to 20% of low molecular weight compounds which include fatty acids, terpenes, long-chain aliphatic compounds and saccharides that are collectively known as extractives (Gandini, Pascoal, & Silvestre, 2006; Pereira, 2013) .

The industrial transformation of cork gives rise to 25% of cork powders as waste (Gil, 1997, Godinho, Martins, Belgacem, & Gil, 2001), which based on the production of cork in Portugal in 1997 corresponds to between 32,000 to 37,000 tons per year of cork powder and 50, 000 tons per year worldwide (Gil, 1997) . There are two different types of cork powder according to the origin: grinding powder obtained from granulation or pre-grinding; the cleaning powder, without impurities; the finishing powder from cut and sanding operations; finishing powder from agglomerated cork panels; finishing powder from agglomerated cork stoppers and disks; finishing powder from insulation cork board (Gil et al . , 1986) . The mixture of these powders is referred to as "burning powder" and is used to feed boilers due to its high heating value (Fernandes et al . , 2010; Gil, 1997) . Other applications include the use as filling agent, mixed with fining agent, to improve the quality of cork stoppers, production of linoleum, application in agglomerates, briquettes, agricultural substrate, source of chemical substances (extractives) and more recently, agglomeration with polymers (Fernandes et al . , 2010) . Being a low cost and environmentally friendly material, cork powder can be used to prepare activated charcoals with high specific surface area, comparable with commercial types of activated charcoals, or can be applied as bioadsorbents in the direct adsorption of pollutants. It can be used commercially to adsorb oil spillages (Corticeira Amorim, 2009) .

The bioadsorption (sorption of contaminants by natural adsorbents) has gained importance recently given the good performances and the low cost of materials of natural origin including cork powder (Chubar et al . , 2004a; Chubar et al . , 2004b) . For example, the removal of metal ions in residual waters is normally carried out using activated charcoal, activated alumina or polymer resins, which are expensive, non-regenerable materials (Villaescusa et al . , 2000) . For this reason, there is the need for low cost, efficient and regenerable adsorbent materials for this application. The content of fatty acids of cork makes cork a bioadsorbent for metal ions, oils, etc. In general, these bioadsorbents present selectivity for the contaminants to remove and be easily eliminated by incineration (Pagnanelli et al . , 2004) . The bioadsorbents for treating residual waters must also be inexpensive due to the large volumes of effluents involved (Volesky, 2001 ) .

Various studies have reported the advantages of cork as bioadsorbent of heavy metals , such as Cu(II), Zn(II), Cr(VI), Cr (III) , Ni (II), Pb(II), Cd(II), As(III) (Cubar et al, 2004b; Villaescusa et al . , 2000; Machado et al . , 2002; Acevedo et al . , 1995) and uranium (Psareva et al . , 2005), for removing organic pollutants in waters such as the pyrethroids fenpropathrin, permethrin, deltamethrin, fenvalerate, 1- cyhalothrin (Domingues, 2005) , bifenthrin (Domingues, 2005; Domingues et al . , 2005) and a-cypermethrin (Domingues, 2005; Domingues et al . , 2007), volatile phenols (Karbowiak et al . , 2010), paracetamol (Villaescusa et al . , 2011), chloroanisoles (Barker et al . , 2001; Capone et al . , 1999) and polycyclic aromatic hydrocarbons (PAHs) (Olivella et al . , 2011a) . There are also studies on the removal of oil from waters (Pintor et al . , 2013; Souza et al . , 2016), pesticides such as a propazine, 2 , 4-dichlorophenoxyacetic acid, alachlor, chlorpyrifos, isoproturon, metamitron, methomyl and oxamyl (Olivella et al, 2015) , furosemide (Machado et al . , 2017) .

Summary

The present application refers to a process for preparing and enhancing cork powder for the fining operation of beverages, which comprises the following steps:

- obtaining cork powder having a particle size smaller than or equal to 5 mm;

- pretreating to remove soluble extractives in an apolar solvent that is provided for use in food;

- pretreating to remove soluble extractives in a polar solvent that is provided for use in food;

- drying the treated cork powder;

- immersing the treated cork powder in a sufficient quantity of impregnation solvent for the cork powder to be fully immersed;

- applying vacuum to the treated cork powder and immersed in the solvent;

- removing the vacuum;

- leaving the treated cork powder immersed in impregnation solvent and at rest;

separating the treated cork powder and impregnation solvent .

In an embodiment, the apolar solvent in the pre-treatment is dichloromethane .

In another embodiment, the polar solvent in the pre-treatment is ethanol.

In an embodiment, the step of removing the extractives with apolar solvent lasts between 2 and 24 hours.

In yet another embodiment, the step of removing the extractives with polar solvent lasts between 2 and 24 hours.

In an embodiment, the drying of the treated cork powder occurs between 2 and 15 hours.

In an embodiment, the drying of the treated cork powder occurs at a temperature between 45 and 105°C.

In another embodiment, the impregnation solvent is water.

In yet another embodiment, the impregnation solvent is ethanol .

In an embodiment, the vacuum is applied between 70 and 1000 Pa.

In another embodiment, applying and removing the vacuum occurs at least 11 times.

In an embodiment, the cork powder is immersed in impregnation solvent and left to rest for 1 to 12 hours.

In an embodiment, the cork powder is separated from the impregnation solvent by decantation, centrifugation or filtration with or without vacuum.

The present application also refers to cork powder obtained by the process described that comprises a particle size equal to or smaller than 5 mm and is impregnated with an impregnation solvent.

In an embodiment, the cork powder is used for beverage fining in a ratio between 10 g of cork powder/ hL of beverage to 1000 g of cork powder/ hL of beverage.

In another embodiment, the cork powder remains in contact with the beverage for 1 to 144 hours.

In yet another embodiment, the cork powder is removed from the beverage by centrifugation or filtration.

General description

The present application describes the use of cork powder obtained directly from the cork industry having a particle size smaller than or equal to 5 mm, and the same cork powder after a process of impregnation with a solvent. Additionally, the present application describes a method for preparing and enhancing cork powder without soluble extractives in dichloromethane and ethanol having a particle size smaller than 5 mm and cork powder without soluble extractives in dichloromethane and ethanol and impregnated with a solvent.

The treatment that is the object of the present application, namely the removal of the extractives (low molecular weight hydrophobic substances that include, but are not limited to, fatty acids, terpenes, long-chain aliphatic compounds and sugars present in the cork and which are solubilized by solvents including, but not limited to, dichloromethane, ethanol and water, representing between 8 and 20% by weight of the cork) , the removal of air and impregnating with a solvent quite significantly increased the removal capacity of the compounds responsible for the sensory defects of the wine. These materials obtained from cork powder are highly efficient for the wine fining process with sensory defects stemming from the presence of compounds such as: 2-isobutyl- 3-methoxypyrazine (IBMP), 2-methoxypyrazine, guaiacol, 4- methylguaiacol , 4-vinylguaiacol, 4-ethylguaiacol , 4- vinylphenol, 4-ethylphenol , 2 , 4 , 6-trichloroanisol , 2- methylisoborneol , geosmin ( 4 , 8a-dimethyldecalin-4a-ol ) , methanethiol (methyl mercaptan) , ethanethiol (ethyl mercaptan) , dimethyl sulfide, diethyl disulfide, hydrogen sulfide, acrolein (propenal), acetic acid, acetaldehyde, amyl acetate, diacetyl, ethyl acetate, isovaleric acid, 2- ethoxyhexa-3 , 5-dien, 2-acethyl-3, 4, 5, 6-tetra-hydropyridin, 2-acethyl-3, 4, 5, 6-tetra-hydropyridin, 2-ethyl-tetra- hydropyridin, 2-acethyl-l-pyrroline, geraniol (3,7- dimethylocta-2 , 6-dien-l-ol ) , halogenated aromatics, trichlorophenol , tribromoanisole, 4 , 5-dichloroguaiacol , chlorovaniline, pronthocyanidins (known as condensed tannins), 4-aminoacetophenone, 1, 1, 6-trimethyl-l, 2- dihydronaphthalene (TDN) , isopropylmethoxypyrazine, 2,3- butanedione, 3-hydroxybutanone, 2-mercaptoethanol , 2- methoxy-3, 5-dimethylpyrazine, 2- sec-Butyl-3-methoxypyrazine and acetamide.

Treating beverages with the different materials obtained from cork powder, especially those treated by the processes that are the object of the present application, namely the removal of extractives, removal of air and impregnation with a solvent, does not affect the end quality of the beverage after the removal of the sensory defect.

Advantages of the material that is the object of the present application

Since cork powder is a low cost industrial waste originating from a natural, regenerable source, its use as fining agent is an environmentally friendly technique. It is also an economically viable option when compared with traditionally used fining agents, such as, for example, polyvinylpolypyrrolidone (PVPP) , inorganic fining agents such as, for example, bentonite and activated charcoals, and others. Simple treatment of cork powder, such as the removal of the extractives and the removal of air with the impregnation with solvents, enables its efficiency to increase highly to levels surpassing other products available on the market. After use, the residue formed can be eliminated by utilizing it to generate energy by burning. The cork powder enables the removal of the aroma defects resulting from undesirable aroma compounds when present in levels superior to the smell detection threshold, without significantly altering the quality of the beverage.

Description of embodiments

The present application refers to a method for preparing and enhancing cork powder, for use thereof in the removal of undesirable aroma compounds present in the matrix of beverages, especially in wine.

The cork powder used in the present technology is obtained directly from the cork industry, and used with a particle size equal to or smaller than 5 mm, obtained by sieving. In an embodiment, the cork powder presents a particle size equal to or smaller than 2 mm, obtained by sieving cork powders from the cork industry.

In another embodiment, the cork powder presents a particle size equal to or smaller than 0.075 mm, obtained by sieving cork powders from the cork industry.

In an embodiment, the cork powder is used without removal treatment of the extractives. In another embodiment, the cork powder is used after removing the soluble extractives in an apolar solvent that is prescribed for use in food. Next is an extraction with a polar solvent that is prescribed for use in food.

Dichloromethane and ethanol are chosen as preferred solvents for removing the extractives from the cork because its use is permitted for the treatment of foodstuffs, food products, food components and food ingredients (Directive 2009/32/EC) .

In an embodiment, the removal of the extractives is carried out with dichloromethane, with a volume depending on the equipment used, in a soxhlet for 2 to 24 hours, followed by extraction with ethanol, with a volume depending on the equipment used, in a soxhlet for 2 to 24 hours. The treated cork powder is dried in an oven for 2 to 12 hours at 45- 105°C .

In an embodiment, the air is removed from the cork powder without pre-treatment, or to the cork powder after removal of the extractives, and the powder is impregnated with a solvent. In an embodiment, the impregnation solvent is a water. In another embodiment, the impregnation solvent is ethanol. Initially, the cork powder is placed in a sufficient amount of solvent for the cork powder to be fully immersed.

A vacuum (between 70 and 1000 Pa) is applied to the cork powder with or without treatment, immersed in the impregnation solvent. The vacuum is repeatedly removed until the cork powder stops floating and settles on the bottom of the recipient. This procedure is performed at least 11 times. Thereafter the cork powders are left in contact with the impregnation solvent for 1 to 12 hours, at rest. The cork powder impregnated with the solvent is separated from the impregnation solvent by decantation, centrifugation or filtration with or without vacuum.

In an embodiment, vacuum (between 70 and 1000 Pa) is applied to a suspension of the cork:solvent 0.25 g:5 mL, followed by removal of the vacuum repeatedly until the cork powder stops floating and settles on the bottom of the recipient. This procedure is carried out at least 11 times.

The cork powders are left in contact with the solvent for 1- 12 hours, at rest. The cork powder impregnated with the solvent is separated from the solvent by decantation, centrifugation or filtration with or without vacuum.

The cork powders prepared are subsequently used in the removal of undesirable compounds present in the matrix of beverages. The cork powders are mixed with a beverage in a ratio between 10 g of cork powder/ hL of beverage to 1000 g of cork powder/ hL of beverage for 1 to 144 hours and subsequently removed by centrifugation or filtration. In an embodiment, the natural cork not impregnated and impregnated with the solvent, as well as the cork without extractives not impregnated and after impregnation with the solvent, is used as fining agent for removing 4-ethylphenol and 4-ethylguaiacol in red wines, by adding 250 g of cork powder per hectoliter of wine contaminated with 750 pg/L of 4-ethylphenol and 150 pg/L of 4-ethylguaiacol and a second wine containing 1500 pg/L of 4-ethylphenol and 300 pg/L of 4-ethylguaiacol (Table 1) .

Table 1 - Amount of 4-ethylphenol and 4-ethylguaiacol removed from wines with two contamination levels using the natural cork powder and cork powder after removing the extractives, without and with impregnation with a solvent (ethanol) .

The figures represent the average ± standard deviation (n=4); 4-EP- ( 4-ethylphenol ) and 4-EG- ( 4-ethylguaiacol ) .

The natural cork without impregnation had the capacity to remove significant amounts of the two volatile phenols for the two contamination levels that the wines presented. The removal of the extractives from the cork using dichloromethane and ethanol increased the removal efficiency of the cork powder for both volatile phenols, for both contamination levels (2.1 times and 6.8 times increase in the removal power for the average and high level of contamination, respectively) .

In another embodiment, the decrease in the particle size of the cork powder to amounts under 0.075 mm, enabled an increase in their efficiency in removing the 4-ethylphenol and 4-ethylguaiacol (Table 2) .

Table 2 - Amount of 4-ethylphenol and 4-ethylguaiacol removed from wines with two contamination levels using the cork powder after removing the extractives with impregnation with a solvent (ethanol) with two particle sizes.

The figures represent the average ± standard deviation (n=4); 4-EP (4-ethylphenol) and 4-EG (4-ethylguaiacol) .

In another embodiment, the increase in the application dosage of the cork powder from 250 g/hL to 500 g/hL increased the removal of 4-ethylphenol and 4-ethylguaiacol on average between 21% and 33%, respectively (Table 3) .

Table 3 - Amount of 4-ethylphenol and 4-ethylguaiacol removed from wines with two contamination levels, using the cork powder after removing the extractives and with impregnation with a solvent (ethanol), with particle sizes de 0.075 mm and with two application dosages (250 g/hL and 500 g/hL) .

The figures represent the average ± standard deviation (n=4); 4-EP ( 4-ethylphenol ) and 4-EG ( 4-ethylguaiacol ) .

In an embodiment, the application of the natural cork in the red wine, without impregnating with a solvent, did not significantly decrease the total abundance of the aroma compounds in the headspace in relation to the original wine, having noted a significant decrease to 2-methyl- 1-butanol , diethyl succinate and dodecanoic acid (Table 4) . The cork powder after removing the extractives and without impregnation with the solvent resulted in a decrease of 21% in the total abundance of the aroma compounds in the headspace in relation to the original wine with the exception of ethyl acetate, 3-methyl-l-butanol acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, phenylethanol acetate and decanoic acid (Table 4) . Impregnating with the solvent significantly reduced the total abundance of the aroma compounds in the headspace in relation to the original wine by 32% and 37% for natural cork and after the removal of the extractives (Table 4) . The reduction of the particle size of the cork powder after the removal of the extractives (<0.075 mm) and impregnated with the solvent did not result in a significant decrease of the total abundance of the aroma compounds in the headspace in relation to the original wine when compared with a cork having a particle size smaller than 2 mm. Doubling the application dosage of the cork powder without extractives impregnated with the particle size smaller than 0.075 mm results in a significant decrease in the total abundance of the aroma compounds in the headspace in relation to the dosage of 250 g/hL of the same material, exceeding 29%.

Table 4 - Total abundance of the aroma compounds in the headspace of the red wine contaminated with 750 pg/L of 4- ethylphenol and 150 pg/L of 4-ethylguaicol , TF) and after treatment with natural cork (CRN) , and after removing the extractives with dichloromethane and ethanol (CKF) before and after removing the air and impregnation with ethanol (CKNI and CKFI) and cork powders having a particle size smaller than 0.075 mm in two application dosages (250 and 500 g/hL) .

Results expressed in absolute area (area*10⁵) Figures presented as average ± standard deviation; $ ID - Identification; * RI (retention index) of: Vas, Gal , Harangi, Dobd and Vekey (1998); Bailley, Jerkovic, Marchand-Brynaert and Collin (2006) ; Czerny, Brueckner, Kirchoff, Schmitt and Buettner (2011) . Odor descriptors by: Perestrelo, Fernandes, Albuquerque, Marques and Camara (2006) ; Dragone, Mussato, Oliveira and Teixeira (2009); Jiang and Zhang (2010) . The averages in the same line followed by the same letter are not significantly different ANOVA and Tukey post-hoc test (p<0.05) . n.d., not detected.

The application of natural cork powder and after removing the non-impregnated extractives did not cause any alteration in the intensity of the color, in the luminosity parameter (L*) and red hue (a*) (Table 5) . The treatment of the wine with the cork powders impregnated with ethanol led to a significant decrease in color intensity, only being significant for the corks after removing the extractives (Table 5) . These alterations in color intensity are not due to the decrease in the concentrations in monomeric anthocyanins (Table 6) . Also for the individual phenolic acids, the overall levels do not significantly alter or their decrease was significant or small (Table 7) .

These results show that the cork powders, either in their natural form or after removing the extractives, have a low impact on the phenolic composition, however the removal of the air and impregnation with the solvent has a significant impact on the color of the wine, albeit reduced.

Table 5 - Chromatic characteristics of red wine contaminated with 750 pg/L of 4-ethylphenol and 150 pg/L of 4- ethylguaicol , TF) and after treatment with natural cork (CRN) , and after removing the extractives with dichloromethane and ethanol (CKF) before and after removing the air and impregnating with ethanol (CKNI and CKFI) and cork powders with a particle size smaller than 0.075 mm in two application dosages (250 and 500 g/hL) .

The amounts are presented as average ± standard deviation. The averages within a column followed by the same letter are not significantly different (Tukey, p<0.05) . L* - luminosity, a* - reds, b* - yellows, DE* - color difference. The figures corresponding to DE* were obtained by taking as reference the untreated (T) wine and wines treated with cork (CRN, CKNH, CKMIX, CKMIXH, CK75250, CK75500) . A.U.- absorbance units.

Table 6. Monomeric antocyanins from red wine contaminated with 750 pg/L of 4-ethylphenol and 150 pg/L of 4- ethylguaicol , TF) and after treatment with natural cork (CRN) , and after removing the extractives with dichloromethane and ethanol (CRF) before and after removing the air and impregnating with ethanol (CRNI and CRFI) and cork powders with a particle size smaller than 0.075 mm in two application dosages (250 and 500 g/hL) .

The figures are presented as average ± standard deviation. Del-3-Glc-delphinidin-3-glucoside, Cya-3-Glc- cyanidin-3- glucoside, Pet-3-Glc-petunidin-3-glucoside, Peo- 3-Glc- peonidin-3-glucoside, Mal-3-Glc-malvidin-3-glucoside, Del- 3-AcGlc- delphinidin-3-acethylglucoside, Cya-3-AcGlc- cyanidin-3-acethylglucoside, Pet-3-AcGlc- petunidin-3- acethylglucoside, Peo-3-AcGlc- peonidin-3-acethylglucoside, Mal-3-AcGlc- malvidin-3-acethylglucoside, Del-3-CoGlc- delphinidin-3-coumaryl-glucoside, Cya-3-CoGlc—cyanidin-3- coumaryl-glucoside, Pet-3-CoGlc-petunidin-3-coumaryl- glucoside, Peo-3-CoGlc-peonidin-3-coumaryl-glucoside ; Mal- 3-CoGlc-malvidin-3-cyanidin-3-coumaryl . The averages in the same line followed by the same letter are not significantly different ANOVA and Tukey post-hoc test (p<0.05) . n.d., not detected .

Table 7 - Phenolic acid (mg/L) from the red wine contaminated with 750 pg/L of 4-ethylphenol and 150 pg/L of 4- ethylguaicol , TF) and after treatment with a natural cork (CRN) , and after removing the extractives with dichloromethane and ethanol (CKF) before and after removing the air and impregnation with ethanol (CKNI and CKFI) and cork powders with a particle size smaller than 0.075 mm in two application dosages (250 and 500 g/hL) .

The figures are presented as average ± standard deviation; the averages in the same line followed by the same letter are not significantly different ANOVA and Tukey post-hoc test (p<0.05 ) . n.d. GRP 2-S-glutathionyl caftaric acid.

The effect of removing the volatile phenols from the wine by using natural cork powders and after removing the extractives, removing the air and impregnating with the solvent was carried out by sensory analysis using a panel of specialists (Table 7) . As seen, the presence of volatile phenols has a significant impact on the phenolic sensory note of the wines resulting at the same time in the decrease of the fruity and floral aroma. According to the instrumental color intensity, the color intensity evaluated sensory of wines treated with cork powder without extractives and impregnated with ethanol was less than the original wine, decreasing the color intensity evaluated sensory with the increase in the application dosage of 250 g/hL to 500 g/hL. This decrease in the color was accompanied with a significant alteration in the parameters L* and °h. Neither the natural cork powders without extractives altered the limpidity and the oxidized visual sensory attribute (Table 7) . All the cork powders applied in the contaminated wine, in the two application dosages significantly decreased the negative phenolic attribute. The aromatic fruit attribute after applying all cork powders enabled a significant recovery of the fruity aroma attribute in relation to the contaminated wine. For the floral attribute only the cork powders without extractives with an application dosage of 250 g/hL and particle sizes <2 mm and <0.075 mm enabled a significant increase of this sensory attribute. Applying the cork powders did not significantly alter the attributes acidity and body of the wine, but no significant differences were noted for the bitter, astringent, balance and persistence attributes. Applying the cork powder without extractives having a particle size <0.075 mm with an application dosage of 500 g/hL was capable of decreasing the bitter sensation. For astringency, cork powders without extractives with an application dosage of 250 g/hL and particle sizes <2 mm and <0.075 mm enabled the significant decrease in this sensory attribute. For persistence, the application of the cork powders increases this sensory attribute.

Table 8 - Average scores of each attribute after sensory analysis of wine without volatile phenols (TO) and of wine contaminated with volatile phenols (TF) of red wines after treatment with natural cork (CRN) , dichloromethanol and ethanol free of extractives (CKF) before and after removal of the air and impregnated with ethanol (CKNI and CKFI) and cork powder having a cork size under 0.075 mm in two application dosages (250 and 500 g/hL) .

¹ Results of the analysis of constancy, - C- Figures from index C for attributes; - no variance noted for this attribute for most tasters . The figures are presented as average ± standard deviation (n = 12) ; Averages in the same line followed by the same letter are not significantly different (Duncan p <0.05) . To determine the composition of headspace aromas of the red wines, a method of microextraction in solid phase (SPME) was used, employing a fiber of

Divinylbenzene/Carboxen/Polydimethylsiloxane 50/30 pm ( Filipe-Ribeiro et al . , 2017a) . The analyses were carried out four times.

To determine the levels of 4-ethylphenol and 4- ethylguaiacol , the method described by Milheiro et al . was used (2017) . The analyses were carried out four times.

The color intensity and the tone were determined in accordance with the OIV method (2009) . The chromatic characteristics of the wines L* ( limpidity) , a* (red), and b* (yellow) were determined in accordance with the OIV method (2009) . The Croma, the angle h and the color difference were calculated using the following formulae: C^* = -^(Da*)² + (Dό*)² ;

All the

determinations were carried out twice.

Determining the profile of monomeric anthocyanins , of the phenolic acids and the catechin was carried out by high efficiency liquid chromatography using a photodiode set detector utilizing the methodology of Guise, Filipe-Ribeiro, Nascimento, Bessa, Nunes, and Cosme (2014), and its quantification was carried out in accordance with Filipe- Ribeiro et al . (2017b) .

Sensory evaluation

The sensory analysis was carried out with a panel comprised of six specialists (ISO 6658, 1985) . Fifteen attributes were selected: visual (limpidity, tone, color intensity and oxidized), aroma (fruity, floral, vegetal, phenolic and oxidized aroma) and descriptors of taste and touch / texture (taste - bitter, acidity, touch / textural - astringency, body, balance and persistence) using an adapted test page based on the one recommended by OIV (http : //www. oiv. int/public/medias/3307/review-onsensory- analysis-of-wine.pdf) . The attributes were quantified using a 5-point intensity scale (ISO 4121, 2003) .

The scales were anchored with the terms "low intensity" for the score one and "high intensity" for the score five, and the scores obtained only whole numbers. The sensory analysis of the samples was carried out twice in two different testing sessions. All the evaluations were carried out from 10:00 to 12:00 p.m. in individual cabins (ISO 8589, 2007) using the glass material according to ISO 3591 (1977) .

A volume of wine of 50 mL was used to enable the testers to taste 25 mL of wine two times (ISO 3591, 1977) and were presented in random order (ISO 6658, 1985) . The consistency between the testers (C-index) was evaluated by the analysis of constancy (Dij ksterhuis, 1995) .

Examples of Application

1 - The cork powder having a particle size smaller than 2 mm was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 1500 pg/L and a concentration of 4-ethylguaiacol of 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decantation, centrifugation or filtration the wine. The content of volatile phenols in the wine decreased 110 pg/L to 4-ethylphenol and 11 pg/L to 4-ethylguaiacol . The color intensity of the wine remained constant (10.31 U.A) and the chromatic characteristics remained unaltered (L*=10.04; a*=39.45; b*=34.20) . The abundance of aromas in the headspace remained constant. The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin remained constant .

2 - The cork powder was used, having a particle size smaller than 2 mm and immersed in ethanol in a ratio of 5% (p/v), and in that the air was removed by applying vacuum (10 Pa) . The vacuum was removed for impregnation of the cork powder with ethanol. This process of applying and then removing the vacuum, was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decantation, centrifugation or filtration and the cork powder was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 1500 pg/L and 4-ethylguaiacol 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by centrifugation or filtration the wine. The content of volatile phenols in the wine decreased 888 pg/L to 4-ethylphenol and 133 pg/L to 4- ethylguaiacol . The color intensity of the wine did not significantly decrease (10.31 U.A) and the chromatic characteristics remained practically unaltered (L*=13.17; a*=43.32; b*=35.47) . The abundance of aromas in the headspace decreased slightly (32%) . The content of monomeric anthocyanins, low molecular weight phenolic acids and the catechin decreased slightly (<3%) .

3 - The cork powder having a particle size smaller than 2 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. The material obtained was applied in a dosage of 750 g/hL to a red wine containing 4-ethylphenol with a concentration of 3500 pg/L and 4-ethylguaiacol of 1250 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decantation, centrifugation or filtration the wine. The content of volatile phenols in the wine decreased 783 pg/L to 4-ethylphenol and 72 pg/L to 4-ethylguaiacol. The color intensity of the wine remained constant (10.66 U.A) and the chromatic characteristics remained unaltered (L*=9.53; a*=38.11; b*=33.54) . The abundance of aromas in the headspace decreased slightly (21%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin remained constant.

4 - The cork powder having a particle size smaller than 2 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 5% (p/v) and the air was removed by applying vacuum (175 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and removing the vacuum, was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decantation, centrifugation or filtration and the material was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 1500 pg/L and 4-ethylguaiacol 300 pg/L, and left in contact for 6 days. Afterwards, the cork was removed by centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 1037 pg/L to 4-ethylphenol and 149 pg/L to 4-ethylguaiacol. The color intensity of the wine decreased slightly (8.97 U.A) and the chromatic characteristics remained practically unaltered (L*=13.87; a*=44.37; b*=36.22) . The abundance of aromas in the headspace decreased slightly (37%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<3%) .

5 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. The product obtained was applied in a dosage of 50 g/hL to a red wine containing 4-ethylphenol with a concentration of 1500 pg/L and 4-ethylguaiacol 300 pg/L and left in contact for 3 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 873 pg/L to 4- ethylphenol and 91 pg/L to 4-ethylguaiacol. The color intensity of the wine remained constant (10.01 U.A.) and the chromatic characteristics remained unaltered (L*=10.53; a*=39.11; b*=34.54) . The abundance of aromas in the headspace decreased slightly (23%) . The content of monomeric anthocyanins, low molecular weight phenolic acids and the catechin remained constant.

6 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 1-5% (p/v) and the air was removed by applying vacuum (10 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering and the material was applied in a dosage of 1000 g/hL to a red wine containing 4- ethylphenol with a concentration of 1500 pg/L and 4- ethylguaiacol 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 931 pg/L to 4-ethylphenol and 158 pg/L to 4-ethylguaiacol. The color intensity of the wine decreased slightly (9.40 U.A) and the chromatic characteristics remained practically unaltered (L*=10.85; a*=40.72; b*=34.08) . The abundance of aromas in the headspace decreased (40%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<3% ) .

7 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 12 hours and subsequently with ethanol in a soxhlet for 12 hours. This material was immersed in ethanol in a ratio of 5% (p/v) and the air was removed by applying vacuum (200 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering. The material was applied in a dosage of 750 g/hL to a red wine containing 4- ethylphenol with a concentration of 1500 pg/L and 4- ethylguaiacol 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 1122 pg/L to 4-ethylphenol and 202 pg/L to 4-ethylguaiacol . The color intensity of the wine decreased slightly (8.34 U.A) and the chromatic characteristics remained practically unaltered (L*=14.84; a*=45.32; b*=36.17) . The abundance of aromas in the headspace decreased (69%) . The content of monomeric anthocyanins, low molecular weight phenolic acids and the catechin decreased slightly

(<5% ) .

8 - The cork powder having a particle size smaller than 2 mm was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 750 pg/L and 4- ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 85 pg/L to 4-ethylphenol and 9 pg/L to 4- ethylguaiacol . The color intensity of the wine remained constant (10.31 U.A) and the chromatic characteristics remained unaltered (L*=10.04; a*=39.45; b*=34.20). The abundance of aromas in the headspace remained constant. The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin remained constant.

9 - The cork powder having a particle size smaller than 2 mm was immersed in ethanol in a ratio of 5% (p/v) and the air was removed by applying vacuum (233 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering. The material was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 750 pg/L and 4-ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 270 pg/L to 4-ethylphenol and 43 pg/L to 4-ethylguaiacol . The color intensity of the wine did not significantly decrease (10.31 U.A) and the chromatic characteristics remained practically unaltered (L*=13.17; a*=43.32; b*=35.47) . The abundance of aromas in the headspace decreased slightly (32%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<3%) .

10 - The cork powder having a particle size smaller than 2 mm was treated successively with dichloromethane in a soxhlet for 6 hours and subsequently with ethanol in a soxhlet for 6 hours. The product obtained was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 750 pg/L and 4-ethylguaiacol 150 pg/L and left in contact for 1-10 days. Afterwards, the cork was removed by centrifuging or by decanting, filtering the wine. The content of volatile phenols in the wine decreased 169 pg/L to 4-ethylphenol and 19 pg/L to 4-ethylguaiacol. The color intensity of the wine remained constant (10.66 U.A) and the chromatic characteristics remained unaltered (L*=9.53; a*=38.11; b*=33.54) . The abundance of aromas in the headspace decreased slightly (21%) . The content of monomeric anthocyanins, low molecular weight phenolic acids and the catechin remained constant.

11 - The cork powder having a particle size smaller than 2 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 1-15% (p/v) and the air was removed by applying vacuum (15 atm) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum, was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering. The material was applied in a dosage of 250 g/hL to a red wine containing 4- ethylphenol with a concentration of 750 pg/L and 4- ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 306 pg/L to 4-ethylphenol and 61 pg/L to 4-ethylguaiacol . The color intensity of the wine decreased slightly (8.97 U.A) and the chromatic characteristics remained practically unaltered (L*=13.87; a*=44.37; b*=36.22) . The abundance of aromas in the headspace decreased slightly (37%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<3% ) .

12 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. The material obtained was applied in a dosage of 250 g/hL to a red wine containing 4-ethylphenol with a concentration of 750 pg/L and 4-ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 287 pg/L to 4-ethylphenol and 84 pg/L to 4-ethylguaiacol. The color intensity remained constant (10.01 U.A) and the chromatic characteristics remained unaltered (L*=10.53; a*=39.11; b*=34.54) . The abundance of aromas in the headspace decreases slightly (23%) . The content of monomeric anthocyanins, low molecular weight phenolic acids and the catechin remained constant.

13 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 5% (p/v) and the air was removed by applying vacuum (751 atm) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering. The material was applied in a dosage of 250 g/hL to a red wine containing 4- ethylphenol with a concentration of 750 pg/L and 4- ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 310 pg/L to 4-ethylphenol and 75 pg/L to 4-ethylguaiacol . The color intensity of the wine decreased slightly (9.40 U.A) and the chromatic characteristics remained practically unaltered (L*=10.85; a*=40.72; b*=34.08) . The abundance of aromas in the headspace decreased (40%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<3% ) .

14 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 5% (p/v) and the air was removed by applying vacuum (341 atm) . The vacuum was removed to impregnate the cork with the ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled at the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering and the material was applied in a dosage of 500 g/hL to a red wine containing 4-ethylphenol with a concentration of 750 pg/L and 4-ethylguaiacol 150 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the wine. The content of volatile phenols in the wine decreased 379 pg/L to 4-ethylphenol and 103 pg/L to 4-ethylguaiacol. The color intensity decreased slightly (8.34 U.A) and the chromatic characteristics remained practically unaltered (L*=14.84; a*=45.32; b*=36.17). The abundance of aromas in the headspace decreased (69%) . The content of monomeric anthocyanins , low molecular weight phenolic acids and the catechin decreased slightly (<5%) .

15 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 1-5% (p/v) and the air was removed by applying vacuum (10-1000 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering and the material was applied in a dosage of 250 g/hL to a beer containing 4-ethylphenol with a concentration of 1500 pg/L and 4-ethylguaiacol 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the beer. The content of volatile phenols in the beer decreased 931 pg/L to 4-ethylphenol and 158 pg/L to 4-ethylguaiacol. The chromatic characteristics remained practically unaltered. The abundance of aromas in the headspace decreased (20%) . The content of low molecular weight phenolic acids and the catechin decreased slightly (<3% ) .

16 - The cork powder having a particle size smaller than 0.075 mm was treated successively with dichloromethane in a soxhlet for 24 hours and subsequently with ethanol in a soxhlet for 24 hours. This material was immersed in ethanol in a ratio of 1-5% (p/v) and the air was removed by applying vacuum (10-1000 Pa) . The vacuum was removed to impregnate the cork with ethanol. This process of applying and then removing the vacuum was repeated until the cork powder settled on the bottom of the recipient, which on average occurred after the 11^th vacuum cycle. The excess ethanol was removed by decanting, centrifuging or filtering and the material was applied in a dosage of 150 g/hL to a cider containing 4-ethylphenol with a concentration of 1500 pg/L and 4-ethylguaiacol 300 pg/L and left in contact for 6 days. Afterwards, the cork was removed by decanting, centrifuging or filtering the cider. The content of volatile phenols in the cider decreased 931 pg/L to 4-ethylphenol and 158 pg/L to 4-ethylguaiacol. The chromatic characteristics remained practically unaltered. The abundance of aromas in the headspace decreased (20%) . The content of low molecular weight phenolic acids and the catechin decreased slightly (<3% ) .

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Directive 2009/32/EC, of the European Parliament and of the Council, of 23 April 2009, Official Journal of the European Union, L 141, 2009. Lisbon December 14, 2018

Claims

1. The process for preparing and enhancing cork powder for the fining operation of beverages, characterized by comprising the following steps:

- obtaining cork powder having a particle size smaller than or equal to 5 mm;

- pre-treatment for removing soluble extractives in an apolar solvent that is provided for use in food;

- pre-treatment for removing soluble extractives in a polar solvent that is provided for use in food;

- drying the treated cork powder;

- immersing the treated cork powder in a sufficient quantity of impregnation solvent for the cork powder to be fully immersed;

- applying vacuum to the treated cork powder and immersed in the solvent;

- removing the vacuum;

- leaving the treated cork powder immersed in impregnation solvent and left to rest;

- separating the treated cork powder and impregnated with the impregnation solvent.

2. The process according to the preceding claim, characterized in that the apolar solvent in the pre-treatment is dichloromethane .

3. The process according to claim 1, characterized in that the polar solvent in the pre-treatment is ethanol.

4. The process according to either claim 1 or 2, characterized in that the step of removing the extractives with apolar solvent lasts between 2 and 24 hours.

5. The process according to either claim 1 or 3, characterized in that the step of removing the extractives with polar solvent lasts between 2 and 24 hours.

6. The process according to any of the preceding claims, characterized in that the drying of the treated cork powder occurs between 2 and 15 hours.

7. The process according to any of the preceding claims, characterized in that the drying of the treated cork powder occurs at a temperature between 45 and 105°C.

8. The process according to any of the preceding claims, characterized in that the impregnation solvent is water.

9. The process according to any of the claims 1 to 7, characterized in that the impregnation solvent is ethanol.

10. The process according to any of the preceding claims, characterized in that the vacuum is applied between 70 and 1000 Pa.

11. The process according to any of the preceding claims, characterized in that applying and removing the vacuum occurs at least 11 times.

12. The process according to any of the preceding claims, characterized in that the cork powder is immersed in impregnation solvent and left to rest for 1 to 12 hours.

13. The process according to any of the preceding claims, characterized in that the cork powder is separated from the impregnation solvent by decantation, centrifugation or filteration with or without vacuum.

14. The cork powder obtained by the process described in any of the preceding claims, characterized by comprising a particle size equal to or smaller than 5 mm and is impregnated with an impregnation solvent.

15. The process of removing contaminants from beverages, characterized by using the cork powder described in claims 1 to 13 in a ratio between 10 g of cork powder/ hL of beverage to 1000 g of cork powder/ hL of beverage.

16. The process according to the preceding claim, characterized in that the cork powder remains in contact with the beverage for 1 to 144 hours.

17. The process according to either claim 15 or 16, characterized in that the cork powder is removed from the beverage by centrifuging or filtering.

Lisbon, December 14, 2018.