- Email: [email protected]
Aglianico wine dealcoholization tests
20th European Symposium on Computer Aided Process Engineering – ESCAPE20 S. Pierucci and G. Buzzi Ferraris (Editors) © 2010 Elsevier B.V. All rights reserved.
325
Aglianico wine dealcoholization tests Loredana Liguori, Gerardina Attanasio, Donatella Albanese, Marisa Di Matteo Dipartimento di Ingegneria Chimica e Alimentare, Università degli studi di Salerno, Fisciano 84084, Salerno, [email protected]
Abstract In the recent years, there has been a growing interest in partial or total dealcoholization of alcoholic beverages. The demand for drinks with low levels of alcohol is attributable both for health reasons and for the desire to reduce alcohol consumption in new generations. This research aims to produce a dealcoholized wine with less than 0.5% alcohol-by-volume from Aglianico. Dealcoholization tests were carried out by plant working on direct osmosis, equipped with a membrane contactor and some temperature sensors and automatic control of the process phases. The fixed alcohol content was achieved with 5 cycles, under mild condition. Chemical-physical and aromatic composition was evaluated in feed (wine) during the dealcoholization process. Keywords: direct osmosis, wine dealcoholization, chemical-physical composition, aromatic compounds, beverage.
1. Introduction Wine is one of the most popular alcoholic drinks in the world, which contributes to reducing the risk of cardiovascular diseases, thanks to a plenty of compounds playing a role of great significance from the aspect of human health. However, non-alcoholic and low alcoholic fermented beverages such as wines and beers have become of great interest because they offer traditional beer and wine flavours without certain unhealthy and socially objectionable side effects of alcohol. Furthermore, they have a lower caloric content, and the same intake of natural antidotes of cardiovascular diseases, anthocyanins and phenolic compounds (Takács et al., 2007). The technologies for the production of dealcoholized, low- and reduced-alcohol beverages have progressively improved in order to safe and get better their quality. There are several methods disclosed in the art for removing or reducing alcohol in wines. However, each process has its advantages and disadvantages, in terms of process costs and product quality. Various processes based on the use of high temperature like evaporation and cryoconcentration, employed for the concentration of fruit juices, cause strong alteration or loss of the wine aroma. Wine vacuum distillation promotes a dealcoholized wine with low volatile compounds that could be used for blending with other wines. Only the recovery of the lost volatile fraction during the process by means of distillation will give a desired organoleptic product (Gomez-Plaza et al., 1999). Another dealcoholization technique is based on spinning cone column. It is operated at mild operation temperatures (26-35°C) and takes places in two steps: aroma recovery and ethanol removal. After ethanol separation, the aromatic fraction is added back to the wine. It is a long and expensive operation (Diban et al., 2008). Other technologies such as adsorption on zeolites (Diban et al., 2008) and supercritical fluid extraction (Medina et al., 1997) are studied in the literature as possible alternatives to reduce the alcoholic content in beverages, but these both methods have some disadvantages and/or are too much onerous like for example for supercritical fluid
326
L.Liguori et al.
extraction or another they change the composition of wine. The membrane processes can be also utilized for the dealcoholization and they allow the ethanol content to be reduced under mild conditions, so the organoleptic features might remain unchanged. There are some experimental works on wine dealcoholization by pervaporation (Takács et al., 2007), reverse osmosis (Pilipovik et al., 2005; Labanda et al., 2009; Catarino et al., 2006) and osmotic distillation (Varavuth et al., 2009; Diban et al., 2008). Direct osmosis finds its application in the concentration of fruit juices, vegetable juices, skim milk, coffee extract, etc. and it can be also used for the concentration of pharmaceutical products and beverages dealcoholization. In earlier years, direct osmosis process could not be exploited commercially because of low flux due to thick membranes. With the advent of thin membranes in recent years resulted in increased flux and hence the direct osmosis process has been gaining the importance due to the concentration of heat sensitive liquid foods/natural colours (Ravindra Babu et al., 2006). It will be interesting to develop an easy, rapid and profitable plant for beverages dealcoholization based on direct osmosis. The objective of this work was to study the feasibility of applying a pilot plant working on direct osmosis using a membrane contactor to dealcoholize wine in order to produce a non alcoholic beverage similar to the original wine.
2. Experimental The dealcoholization tests were carried out in a pilot plant equipped with a polypropylene hollow fiber membrane contactor (Liqui-Cel, Extra-Flow 4x28, Celgard X50). Inside the module, hollow fibers are wrapped around a central tube; a baffle for the liquid phase is created in the middle of the contactor so maximizes surface area and improves liquid transfer efficiency. Feed stream (wine) enters the shellside port and travels into the distribution tube. Wine is forced radially over the fibers on each side of the baffle and it exits through the collection tube and the second shellside port. Pure water is introduced to the other side port and it is gradually enriched by volatile compounds, especially ethanol, due to their different concentration in the two streams. An overview on the fluid dynamics of the module is shown in fig.1.
Figure 1: Liqui-Cel Extra-Flow 4x28 Module
From theoretical calculations performed on the module’s exchange characteristics and based on operational considerations, the dealcoholization process consists of five cycles: the first two lasting 45 minutes, the others 30 minutes. Pure water flows in counter-current and temperature is monitored during all the cycles’ process. At the end of every cycle, samples were taken from each of the two streams and were evaluated for chemical-physical and aromatic compositions.
Aglianico wine dealcoholization tests
327
Alcohol content (% vol.) was evaluated according to AOAC methods (1995). On dealcoholized wine samples pH was determined through the use of pHmeter (Hanna Instrument, mod.122); instead, total acidity determinations, expressed in equivalent of tartaric acid content (g/L), were carried out by titrating 25 ml sample with 0.1N NaOH to a pH endpoint of 7.0. The reducing sugars content was measured with Fehling method, according to AOAC (1995). The total phenols amount in Aglianico wine and in dealcoholized wine samples was determined according to the Folin-Ciocalteu colorimetric method (Singleton et Rossi, 1965). Absorbances were measured at 765 nm, using Perkin Elmer UV/VIS Spectrometer Lambda Bio 40. Total phenols were expressed as gallic acid equivalents (GAE mg/L). Gallic acid standard solutions were prepared at a concentration ranging from 100 to 400 mg/L. The colour measurements of Aglianico and dealcoholized wine samples were carried out using the Glories methods (1986). Colour density and hue were calculated using the following equations (eqn. nr. 1-2) which incorporated corrected values for a 1 cm cuvette, as reported in a previous paper (Cliff M.A. et al.,2007); Colour density = [(A520-A700) + (A420- A700)] Colour hue/tint = [(A420-A700) + (A520- A700)]
(Eqn. nr.1) (Eqn. nr.2)
Another method for colour evaluation utilized L*, a* b* coordinate values in the Hunter system for each wine sample with a CR-300 Chromometer. The identification and determination of aroma compounds concentration in Aglianico wine and dehalcoholizated samples were made respectively by GC coupled to a mass spectrometer (Trace MS plus, TermoFinnigan, USA) and by GC (HP 6890, Agilent) both equipped with a capillary column (Equity 5, 300 mm x 0.25 mm x 0.25 μm, Supelco). The extraction of the aroma compounds was made according to Cocito et al, 1995. The gascromatografy conditions were: injector worked in split mode and was set at 250°C, one microlitre (1μl) was the injected volume, helium was used as carrier gas at a constant flow of 1.0 ml. The temperature program in the oven was 5 min at 50°C, an increase until to 200°C at a rate of 2°C/min and finally 5 min at 200°C. Mass detector conditions were: electronic impact (EI) mode at 70 eV, source temperature 280°C, scanning rate 1 scan/s, mass acquisition 30-350 amu. The identification was based on comparison of the GC retention times and mass spectra with authentic standards from Sigma-Aldrich when standards were available; for these compounds, calibration curves were calculated in order to the quantification. When the authentic standards were not available, the identification was based on comparison with the spectral data of the Wiley library and the chromathographic data from literature; semiquantitative analyses of these compounds were done assuming the response factors equal to the 2-octanol, used as internal standard.
3. Results and discussion The Aglianico wine ethanol content was 12.80% (v/v) and it decreased during the dealcoholization process, in such amount between 62.10 % and 83.67 % in the first three cycles, then alcohol amount reduced gradually in the last cycles until to achieve an alcohol content less than 0,5% (as shown in table 1). pH, total acidity and also reducing sugars content showed very slight variations during the dealcoholization, as reported in table 2. Total phenols amount was high, typical of red wines (Minussi R.C. et al., 2003) and it was nearly unchanged, with a slightly increase at the end of the dealcoholization, probably because of the concentration effect produced for removal of ethanol from the
328
L.Liguori et al.
corresponding red wine, according to research carried out by Belisario-Sanchez YY. et al. (2009). Colour density was similar to Versari et al. (2007) varying around 7 during the dealcoholization process, with a slight decrease in the final product. Tonality values were roughly similar in all cycles and testified the mellow state of wine (table 2). About chromatic parameters, dealcoholized wine with 0.42% alcohol content showed brightness value (L*) higher than Aglianico wine and a degree of redness similar to the original wine. The degree of redness (a*) ranged from 20.23 to 29.07 as in other studies about red wines (Cliff M.A. et al., 2007), like as b* values (table 2).
Table 1: Alcohol content (%v/v), alcohol loss (%), pH, total acidity (mean values ± standard deviation), reducing sugars and total phenols content of wine samples during the dealcoholization process. V0 is starting wine (Aglianico); V1, V2, V3, V4, V5 are wine samples respectively at the end of every cycle.
Samples
Alcohol content (% vol.)
V0
12,8
V1
Total phenols (Gallic acid mg/L)
T (°C)
Total acidity (tartaric acid g/L)
3,49
20,0
5,59 ± 0,18
0,60
3381,75
3,38
20,1
5,64 ±0,04
0,59
3616,75
20,0
5,80 ±0,04
0,57
3724,25
20,1
5,68 ± 0,04
0,54
3604,25
3,21
20,1
5,78 ± 0,03
0,56
3919,25
3,20
20,1
5,64 ± 0,02
0,57
4145,50
Alcohol loss (%)
pH
4,85
62,10
V2
3,50
72,65
3,34
V3
2,09
83,67
3,24
V4
0,75
94,14
V5
0,42
95,71
Reducing sugar (g/100 ml)
Table 2: Chromatic Glories and CIE Lab parameters (mean values ± standard deviation) of dealcoholized wine samples. Samples
Colour density
a*
b*
V0
7,61 ± 0,04
0,71 ± 0,01 14,82 ± 0,77
27,92 ± 1,52
5,68 ± 1,18
V1
7,65 ± 0,12
0,69 ± 0,01 14,98 ± 0,04
29,07 ± 0,24
8,51 ± 0,10
V2
7,73 ± 0,18
0,55 ± 0,02 17,96 ± 0,14
20,23 ± 0,6
2,15 ± 0,45
V3
7,50 ± 0,16
0,53 ± 0,01 17,91 ± 0,06
20,84 ± 1,16
1,87 ± 0,39
V4
7,54 ± 0,09
0,63 ± 0,01 19,49 ± 0,12
24,92 ± 0,17
5,24 ± 0,46
V5
7,58 ± 0,01
0,63 ± 0,00 21,92 ± 0,04
27,26 ± 0,30
9,60 ± 0,19
Tonality
L*
In order to evaluate the sensory impact owing to the aroma compounds loss by the dealcoholization process, the odour activity values (OAV) of the most significant compounds were evaluated as ratio between aromatic compounds concentration and corresponding olfactory threshold. The OAV allows to estimate the contribution of specific compound to the wine aroma. Each compound was assigned to one or several aroma series, depending on its principal odour descriptors; the solvent, floral, sweet, green, fatty, fruit and balsamic series were chosen for this purpose.
329
Aglianico wine dealcoholization tests
In figure 2 it was shown the odour activity values for each dealcoholizated cycle. Sweet and solvent aroma series suffered major changes, and V4 and V5 dealcoholizated samples were characterized by only solvent aroma serie (Genovese et al., 2007).
V5
25
V4 V3 V2
20
V1 V0
OAV
15
10
5 V0 V1 V2 0
V3 flo ral
s weet
V4 green
fatty
V5 s o lv ent
fruity
bals am ic
Figure 2: Odour activity values of odorant series of dealcoholized wine samples.
4. Conclusions The dealcoholization plant working on direct osmosis resulted efficient for removing alcohol from wine until to ethanol concentration lower than 0.5% (v/v). The final dealcoholized product has a chemical composition similar to wine of origin in terms of reducing sugars, total acidity and is rich in phenolic substances, but it is lacking in aroma. So, this should be an obstacle for the development of non alcoholic beverages, which had been reconstituted in the wine aroma for a better tasting drink. These results show that the membrane technology based on direct osmosis and used to separate the ethanol from wine keeps or increases the amount of beneficial compounds in the dealcoholized wine. It also can be used for a reduction of alcohol degree in wine industry.
References AOAC, 1995, Official methods of analysis of AOAC International, 16th ed., Arlington Y.Y.Belisario-Sanchez, A. Taboada-Rodriguez, f. Marin-Iniesta, A. Lopez.gomez, 2009, Dealcoholized wines by spinning cone column distillation: phenolic compounds and antioxidant activity measured by the 1,1-diphenyl-2-picrylhydrazyl method, Journal of Agriculture and food Chemistry, 57, 6770-6778 M. Catarino, A. Mendesa, L. Madeira, A. Ferreira, 2006, Beer dealcoholization by reverse osmosis, Desalination, 200, 397–399 CIE, 1986, Colorimetry, 2nd ed., Vienna: Central Bureau of the Commission Internationale de L’Eclairage M.A. Cliff, M.C. King, J. Schlosser, 2007, Anthocyanin, phenolic composition, colour measurements and sensory analysis of BC commercial red wines, Food Research International, 40, 92-100 C. Cocito, G. Gaetano, C. Delfino, 1995, Rapid extraction of aroma compounds in must and wine by means of ultrasound, Food Chemistry, 52, 311-320 N. Diban, V. Athes , M. Bes, I. Souchon, 2008, Ethanol and aroma compounds transfer study for partial dealcoholization of wine using membrane contactor, Journal of Membrane Science 311, 136-146
330
L.Liguori et al.
A.Genovese, A.Gambuti, P. Piombino, L. Moio, 2007, Sensory properties and aroma compounds of sweet Fiano wine, Food Chemistry, 103, 1228-1236 Y. Glories, 1984, La couleur des Vins rouges, 2a partie, Connaissance de la Vigne et du vin, 18, 253-271 E. Gómez-Plaza, J.M. López-Nicolás, J.M. López-Roca, A. Martinez-Cutillas, 1999, Dealcoholization of Wine Behaviour of the Aroma Components during the Process, Lebensm.-Wiss. u.-Technol., 32, 384-386 J. Labanda, S. Vichi, J. Llorens, E. Lopez-Tamames, 2009, Membrane separation technology for the reduction of alcoholic degree of a white model wine, Food Science and Technology, article in press. I. Medina, J. L. Martinez, 1997, Dealcoholisation of Cider by Supercritical Extraction with Carbon Dioxide, Journal of Chemical Technology & Biotechnology, 68, 14-18 R.C. Minussi, M. Rossi, L. Bologna, L.Cordi, D. Rotilio, G.M. Pastore, N. Duran, 2003, Phenolic compounds and total antioxidant potential of commercial wines, Food Chemistry, 82, 409– 416 M.V. Pilipovik, C. Riverol, 2005, Assessing dealcoholization systems based on reverse osmosis, Journal of Food Engineering, 69, 437–441 B. Ravindra Babu, N.K. Rastogi, K.S.M.S. Raghavarao, 2006, Effect of process parameters on transmembrane flux during direct osmosis, Journal of Membrane Science, 280, 185–194 V.L. Singleton, J.A. Rossi, 1965, Colorimetry of total phenolics with phosphomolybicphosphotungstic reagents, American Journal of Enology and Viticulture, 16, 144-158 L.Takács, G. Vataia, K. Korány, 2007, Production of alcohol free wine by pervaporation, Journal of Food Engineering, 78, 118–125 S. Varavuth, R. Jiraratananon , S. Atchariyawut , 2009, Experimental study on dealcoholization of wine by osmotic distillation process, Separation and Purification Technology, 66, 313–321 A. Versari, G.P. Parpinello, A.U. Mattioli, 2007, Characterisation of Colour Components and Polymeric Pigments of Commercial Red Wines by Using Selected UV-Vis Spectrophotometric Methods, South African Journal of Enology and Viticulture, 28, 1, 6-10
325
Aglianico wine dealcoholization tests Loredana Liguori, Gerardina Attanasio, Donatella Albanese, Marisa Di Matteo Dipartimento di Ingegneria Chimica e Alimentare, Università degli studi di Salerno, Fisciano 84084, Salerno, [email protected]
Abstract In the recent years, there has been a growing interest in partial or total dealcoholization of alcoholic beverages. The demand for drinks with low levels of alcohol is attributable both for health reasons and for the desire to reduce alcohol consumption in new generations. This research aims to produce a dealcoholized wine with less than 0.5% alcohol-by-volume from Aglianico. Dealcoholization tests were carried out by plant working on direct osmosis, equipped with a membrane contactor and some temperature sensors and automatic control of the process phases. The fixed alcohol content was achieved with 5 cycles, under mild condition. Chemical-physical and aromatic composition was evaluated in feed (wine) during the dealcoholization process. Keywords: direct osmosis, wine dealcoholization, chemical-physical composition, aromatic compounds, beverage.
1. Introduction Wine is one of the most popular alcoholic drinks in the world, which contributes to reducing the risk of cardiovascular diseases, thanks to a plenty of compounds playing a role of great significance from the aspect of human health. However, non-alcoholic and low alcoholic fermented beverages such as wines and beers have become of great interest because they offer traditional beer and wine flavours without certain unhealthy and socially objectionable side effects of alcohol. Furthermore, they have a lower caloric content, and the same intake of natural antidotes of cardiovascular diseases, anthocyanins and phenolic compounds (Takács et al., 2007). The technologies for the production of dealcoholized, low- and reduced-alcohol beverages have progressively improved in order to safe and get better their quality. There are several methods disclosed in the art for removing or reducing alcohol in wines. However, each process has its advantages and disadvantages, in terms of process costs and product quality. Various processes based on the use of high temperature like evaporation and cryoconcentration, employed for the concentration of fruit juices, cause strong alteration or loss of the wine aroma. Wine vacuum distillation promotes a dealcoholized wine with low volatile compounds that could be used for blending with other wines. Only the recovery of the lost volatile fraction during the process by means of distillation will give a desired organoleptic product (Gomez-Plaza et al., 1999). Another dealcoholization technique is based on spinning cone column. It is operated at mild operation temperatures (26-35°C) and takes places in two steps: aroma recovery and ethanol removal. After ethanol separation, the aromatic fraction is added back to the wine. It is a long and expensive operation (Diban et al., 2008). Other technologies such as adsorption on zeolites (Diban et al., 2008) and supercritical fluid extraction (Medina et al., 1997) are studied in the literature as possible alternatives to reduce the alcoholic content in beverages, but these both methods have some disadvantages and/or are too much onerous like for example for supercritical fluid
326
L.Liguori et al.
extraction or another they change the composition of wine. The membrane processes can be also utilized for the dealcoholization and they allow the ethanol content to be reduced under mild conditions, so the organoleptic features might remain unchanged. There are some experimental works on wine dealcoholization by pervaporation (Takács et al., 2007), reverse osmosis (Pilipovik et al., 2005; Labanda et al., 2009; Catarino et al., 2006) and osmotic distillation (Varavuth et al., 2009; Diban et al., 2008). Direct osmosis finds its application in the concentration of fruit juices, vegetable juices, skim milk, coffee extract, etc. and it can be also used for the concentration of pharmaceutical products and beverages dealcoholization. In earlier years, direct osmosis process could not be exploited commercially because of low flux due to thick membranes. With the advent of thin membranes in recent years resulted in increased flux and hence the direct osmosis process has been gaining the importance due to the concentration of heat sensitive liquid foods/natural colours (Ravindra Babu et al., 2006). It will be interesting to develop an easy, rapid and profitable plant for beverages dealcoholization based on direct osmosis. The objective of this work was to study the feasibility of applying a pilot plant working on direct osmosis using a membrane contactor to dealcoholize wine in order to produce a non alcoholic beverage similar to the original wine.
2. Experimental The dealcoholization tests were carried out in a pilot plant equipped with a polypropylene hollow fiber membrane contactor (Liqui-Cel, Extra-Flow 4x28, Celgard X50). Inside the module, hollow fibers are wrapped around a central tube; a baffle for the liquid phase is created in the middle of the contactor so maximizes surface area and improves liquid transfer efficiency. Feed stream (wine) enters the shellside port and travels into the distribution tube. Wine is forced radially over the fibers on each side of the baffle and it exits through the collection tube and the second shellside port. Pure water is introduced to the other side port and it is gradually enriched by volatile compounds, especially ethanol, due to their different concentration in the two streams. An overview on the fluid dynamics of the module is shown in fig.1.
Figure 1: Liqui-Cel Extra-Flow 4x28 Module
From theoretical calculations performed on the module’s exchange characteristics and based on operational considerations, the dealcoholization process consists of five cycles: the first two lasting 45 minutes, the others 30 minutes. Pure water flows in counter-current and temperature is monitored during all the cycles’ process. At the end of every cycle, samples were taken from each of the two streams and were evaluated for chemical-physical and aromatic compositions.
Aglianico wine dealcoholization tests
327
Alcohol content (% vol.) was evaluated according to AOAC methods (1995). On dealcoholized wine samples pH was determined through the use of pHmeter (Hanna Instrument, mod.122); instead, total acidity determinations, expressed in equivalent of tartaric acid content (g/L), were carried out by titrating 25 ml sample with 0.1N NaOH to a pH endpoint of 7.0. The reducing sugars content was measured with Fehling method, according to AOAC (1995). The total phenols amount in Aglianico wine and in dealcoholized wine samples was determined according to the Folin-Ciocalteu colorimetric method (Singleton et Rossi, 1965). Absorbances were measured at 765 nm, using Perkin Elmer UV/VIS Spectrometer Lambda Bio 40. Total phenols were expressed as gallic acid equivalents (GAE mg/L). Gallic acid standard solutions were prepared at a concentration ranging from 100 to 400 mg/L. The colour measurements of Aglianico and dealcoholized wine samples were carried out using the Glories methods (1986). Colour density and hue were calculated using the following equations (eqn. nr. 1-2) which incorporated corrected values for a 1 cm cuvette, as reported in a previous paper (Cliff M.A. et al.,2007); Colour density = [(A520-A700) + (A420- A700)] Colour hue/tint = [(A420-A700) + (A520- A700)]
(Eqn. nr.1) (Eqn. nr.2)
Another method for colour evaluation utilized L*, a* b* coordinate values in the Hunter system for each wine sample with a CR-300 Chromometer. The identification and determination of aroma compounds concentration in Aglianico wine and dehalcoholizated samples were made respectively by GC coupled to a mass spectrometer (Trace MS plus, TermoFinnigan, USA) and by GC (HP 6890, Agilent) both equipped with a capillary column (Equity 5, 300 mm x 0.25 mm x 0.25 μm, Supelco). The extraction of the aroma compounds was made according to Cocito et al, 1995. The gascromatografy conditions were: injector worked in split mode and was set at 250°C, one microlitre (1μl) was the injected volume, helium was used as carrier gas at a constant flow of 1.0 ml. The temperature program in the oven was 5 min at 50°C, an increase until to 200°C at a rate of 2°C/min and finally 5 min at 200°C. Mass detector conditions were: electronic impact (EI) mode at 70 eV, source temperature 280°C, scanning rate 1 scan/s, mass acquisition 30-350 amu. The identification was based on comparison of the GC retention times and mass spectra with authentic standards from Sigma-Aldrich when standards were available; for these compounds, calibration curves were calculated in order to the quantification. When the authentic standards were not available, the identification was based on comparison with the spectral data of the Wiley library and the chromathographic data from literature; semiquantitative analyses of these compounds were done assuming the response factors equal to the 2-octanol, used as internal standard.
3. Results and discussion The Aglianico wine ethanol content was 12.80% (v/v) and it decreased during the dealcoholization process, in such amount between 62.10 % and 83.67 % in the first three cycles, then alcohol amount reduced gradually in the last cycles until to achieve an alcohol content less than 0,5% (as shown in table 1). pH, total acidity and also reducing sugars content showed very slight variations during the dealcoholization, as reported in table 2. Total phenols amount was high, typical of red wines (Minussi R.C. et al., 2003) and it was nearly unchanged, with a slightly increase at the end of the dealcoholization, probably because of the concentration effect produced for removal of ethanol from the
328
L.Liguori et al.
corresponding red wine, according to research carried out by Belisario-Sanchez YY. et al. (2009). Colour density was similar to Versari et al. (2007) varying around 7 during the dealcoholization process, with a slight decrease in the final product. Tonality values were roughly similar in all cycles and testified the mellow state of wine (table 2). About chromatic parameters, dealcoholized wine with 0.42% alcohol content showed brightness value (L*) higher than Aglianico wine and a degree of redness similar to the original wine. The degree of redness (a*) ranged from 20.23 to 29.07 as in other studies about red wines (Cliff M.A. et al., 2007), like as b* values (table 2).
Table 1: Alcohol content (%v/v), alcohol loss (%), pH, total acidity (mean values ± standard deviation), reducing sugars and total phenols content of wine samples during the dealcoholization process. V0 is starting wine (Aglianico); V1, V2, V3, V4, V5 are wine samples respectively at the end of every cycle.
Samples
Alcohol content (% vol.)
V0
12,8
V1
Total phenols (Gallic acid mg/L)
T (°C)
Total acidity (tartaric acid g/L)
3,49
20,0
5,59 ± 0,18
0,60
3381,75
3,38
20,1
5,64 ±0,04
0,59
3616,75
20,0
5,80 ±0,04
0,57
3724,25
20,1
5,68 ± 0,04
0,54
3604,25
3,21
20,1
5,78 ± 0,03
0,56
3919,25
3,20
20,1
5,64 ± 0,02
0,57
4145,50
Alcohol loss (%)
pH
4,85
62,10
V2
3,50
72,65
3,34
V3
2,09
83,67
3,24
V4
0,75
94,14
V5
0,42
95,71
Reducing sugar (g/100 ml)
Table 2: Chromatic Glories and CIE Lab parameters (mean values ± standard deviation) of dealcoholized wine samples. Samples
Colour density
a*
b*
V0
7,61 ± 0,04
0,71 ± 0,01 14,82 ± 0,77
27,92 ± 1,52
5,68 ± 1,18
V1
7,65 ± 0,12
0,69 ± 0,01 14,98 ± 0,04
29,07 ± 0,24
8,51 ± 0,10
V2
7,73 ± 0,18
0,55 ± 0,02 17,96 ± 0,14
20,23 ± 0,6
2,15 ± 0,45
V3
7,50 ± 0,16
0,53 ± 0,01 17,91 ± 0,06
20,84 ± 1,16
1,87 ± 0,39
V4
7,54 ± 0,09
0,63 ± 0,01 19,49 ± 0,12
24,92 ± 0,17
5,24 ± 0,46
V5
7,58 ± 0,01
0,63 ± 0,00 21,92 ± 0,04
27,26 ± 0,30
9,60 ± 0,19
Tonality
L*
In order to evaluate the sensory impact owing to the aroma compounds loss by the dealcoholization process, the odour activity values (OAV) of the most significant compounds were evaluated as ratio between aromatic compounds concentration and corresponding olfactory threshold. The OAV allows to estimate the contribution of specific compound to the wine aroma. Each compound was assigned to one or several aroma series, depending on its principal odour descriptors; the solvent, floral, sweet, green, fatty, fruit and balsamic series were chosen for this purpose.
329
Aglianico wine dealcoholization tests
In figure 2 it was shown the odour activity values for each dealcoholizated cycle. Sweet and solvent aroma series suffered major changes, and V4 and V5 dealcoholizated samples were characterized by only solvent aroma serie (Genovese et al., 2007).
V5
25
V4 V3 V2
20
V1 V0
OAV
15
10
5 V0 V1 V2 0
V3 flo ral
s weet
V4 green
fatty
V5 s o lv ent
fruity
bals am ic
Figure 2: Odour activity values of odorant series of dealcoholized wine samples.
4. Conclusions The dealcoholization plant working on direct osmosis resulted efficient for removing alcohol from wine until to ethanol concentration lower than 0.5% (v/v). The final dealcoholized product has a chemical composition similar to wine of origin in terms of reducing sugars, total acidity and is rich in phenolic substances, but it is lacking in aroma. So, this should be an obstacle for the development of non alcoholic beverages, which had been reconstituted in the wine aroma for a better tasting drink. These results show that the membrane technology based on direct osmosis and used to separate the ethanol from wine keeps or increases the amount of beneficial compounds in the dealcoholized wine. It also can be used for a reduction of alcohol degree in wine industry.
References AOAC, 1995, Official methods of analysis of AOAC International, 16th ed., Arlington Y.Y.Belisario-Sanchez, A. Taboada-Rodriguez, f. Marin-Iniesta, A. Lopez.gomez, 2009, Dealcoholized wines by spinning cone column distillation: phenolic compounds and antioxidant activity measured by the 1,1-diphenyl-2-picrylhydrazyl method, Journal of Agriculture and food Chemistry, 57, 6770-6778 M. Catarino, A. Mendesa, L. Madeira, A. Ferreira, 2006, Beer dealcoholization by reverse osmosis, Desalination, 200, 397–399 CIE, 1986, Colorimetry, 2nd ed., Vienna: Central Bureau of the Commission Internationale de L’Eclairage M.A. Cliff, M.C. King, J. Schlosser, 2007, Anthocyanin, phenolic composition, colour measurements and sensory analysis of BC commercial red wines, Food Research International, 40, 92-100 C. Cocito, G. Gaetano, C. Delfino, 1995, Rapid extraction of aroma compounds in must and wine by means of ultrasound, Food Chemistry, 52, 311-320 N. Diban, V. Athes , M. Bes, I. Souchon, 2008, Ethanol and aroma compounds transfer study for partial dealcoholization of wine using membrane contactor, Journal of Membrane Science 311, 136-146
330
L.Liguori et al.
A.Genovese, A.Gambuti, P. Piombino, L. Moio, 2007, Sensory properties and aroma compounds of sweet Fiano wine, Food Chemistry, 103, 1228-1236 Y. Glories, 1984, La couleur des Vins rouges, 2a partie, Connaissance de la Vigne et du vin, 18, 253-271 E. Gómez-Plaza, J.M. López-Nicolás, J.M. López-Roca, A. Martinez-Cutillas, 1999, Dealcoholization of Wine Behaviour of the Aroma Components during the Process, Lebensm.-Wiss. u.-Technol., 32, 384-386 J. Labanda, S. Vichi, J. Llorens, E. Lopez-Tamames, 2009, Membrane separation technology for the reduction of alcoholic degree of a white model wine, Food Science and Technology, article in press. I. Medina, J. L. Martinez, 1997, Dealcoholisation of Cider by Supercritical Extraction with Carbon Dioxide, Journal of Chemical Technology & Biotechnology, 68, 14-18 R.C. Minussi, M. Rossi, L. Bologna, L.Cordi, D. Rotilio, G.M. Pastore, N. Duran, 2003, Phenolic compounds and total antioxidant potential of commercial wines, Food Chemistry, 82, 409– 416 M.V. Pilipovik, C. Riverol, 2005, Assessing dealcoholization systems based on reverse osmosis, Journal of Food Engineering, 69, 437–441 B. Ravindra Babu, N.K. Rastogi, K.S.M.S. Raghavarao, 2006, Effect of process parameters on transmembrane flux during direct osmosis, Journal of Membrane Science, 280, 185–194 V.L. Singleton, J.A. Rossi, 1965, Colorimetry of total phenolics with phosphomolybicphosphotungstic reagents, American Journal of Enology and Viticulture, 16, 144-158 L.Takács, G. Vataia, K. Korány, 2007, Production of alcohol free wine by pervaporation, Journal of Food Engineering, 78, 118–125 S. Varavuth, R. Jiraratananon , S. Atchariyawut , 2009, Experimental study on dealcoholization of wine by osmotic distillation process, Separation and Purification Technology, 66, 313–321 A. Versari, G.P. Parpinello, A.U. Mattioli, 2007, Characterisation of Colour Components and Polymeric Pigments of Commercial Red Wines by Using Selected UV-Vis Spectrophotometric Methods, South African Journal of Enology and Viticulture, 28, 1, 6-10