Membrane comparison for wine clarification by microfiltration

DESALINATION Desalination

ELSEVIER

148 (2002) 115-120 www.elsevier.com/locate/desal

Membrane comparison for wine clarification by microfiltration Ana Urkiaga *, Libe De Las Fuentes, Marta Acilu, Janire Uriarte GAIKER Centro Tecnoldgico, Parque Tecnoldgico, Edificio 202, 48170 Zamudio (Bizkaia), Spain Tel. +34 (94) 600-23-23; Fax +34 (94) 600-23-24; email: urkiaga@gaikeKes Received 4 February 2002; accepted 5 April 2002

Abstract In this work ten different polymeric microfiltration membranes of different materials polyethersulfone (PES), cellulose mixed esters (CE), cellulose acetate (CA), polypropylene (PP) and nylon (NY) with different pore diameters and of different commercial companies have been tested for wine clarification. A stirred cell has been used in all the membrane experiments. The objective has been to find the most suitable pore diameter, material and supplier that guarantees a suitable hygienisation and clearness without altering the organoleptic properties for the assayed red 12” ordinary wine.

KeJlwords: Microfiltration; Polymeric membranes; Red wine; Physico-chemical characteristics; Adsorption

1. Introduction Wine making differs from other beverage production technologies in that the quality properties of the final product are not exactly predictable. Although different technologies have been implemented in wine manufacturing, it is still a very traditional process [ 11. One of the most common operations includes a filtration stage normally achieved by diatomeaceous earth filters. However, the already exhausted substrate will soon be considered a hazardous waste, involving *Corresponding

author.

Presented at the International July 7-12, 2002. 001 l-9164/02/$-

Congress on Membranes

disposal costs. Alternatively, membrane filtration is emerging as a very promising technology for this purpose because of its ability to perform wine clarificationlfiltrationkygienisation in one single step in continuous operation with clean in place (CP) strategies. Thus, in a previous work we proved the viability of membrane technology for wine clarification by standard sensory evaluation of Rioja Alavesa microfiltered red wine compared with traditionally produced wine [2]. The most frequent membranes pore size used in wine microfiltration are 0.1 and 0.22 pm for white wines and 0.2 pm for red wines [3-51. When a and Membrane

Processes

See front matter 0 2002 Elsevier Science B.V. All rights reserved

PII:SO01 1-9164(02)00663-X

(ICOM),

Toulouse, France,

116

A. Urkiaga et al. /Desalination

cross-flow microfiltration mode is involved, some commercial companies recommend the utilisation of the smallest pore size microfiltration membranes. Pall highly recommend their 0.1 and 0.22 pm polysulphone membranes, Sartorius the 0.1 pm PES and 0.2 pm PP, Microdyn and Vaslin Bucher the 0.2 pm polypropylene membranes, and Koch its 500 kD ultrafiltration (UF) polysulphone membranes even in red wine filtration. Many authors warn that if very small pore size membranes are used, some unwanted flavour and colour changes in the treated wine can be introduced [6,7]. Peri et al. [S] determined that the optimal cut-off in wine microfiltration probably lies around 0.1 mm, and found that it strongly depended on the membrane material and filtration conditions: initial suspended solids amount, wine variety and processing temperature. The aim of this work is to find out which are the most suitable membrane materials, among the different tested ones, and pore diameters for red wine clarification using microfiltration polymeric membranes. For this purpose different experiments at laboratory scale using a stirred cell have been carried out. Unspecific adsorption, pyhsicochemical characteristics, flux permeation and flux recovery after cleaning have been studied.

148 (2002) 115-120

and Gelman Sciences) were chosen in order to check if there were differences among manufacturers. 2.3. Microfiltration

experiments

The experiments were carried out in an Osmonics stirred cell (Sepa ST). The membrane (flat sheet type) active area was of 16.9 cm*. The assays were carried out in a batch mode. In each one the cell was filled up with wine (300 ml) and the final obtained concentrate was the 0.3% of the initial volume. For each membrane the total wine filtered volume was 900 ml (3 successive batch trials). The operation pressure was 1.2 bar and in all the cases the same stirring speed was used. During the experiments the temperature was monitored and only one degree variation observed (14.5-15.5”C). In addition to the microfiltration experiments, unspecific adsorption essays were carried out. These experiments consisted of putting in contact a lOO-ml volume of wine with each membrane for a 48-h period without pressure in a rotational stirrer at 5 r-pm. Then the membranes were several times rinsed and the permeability with DI water measured. The permeability decrease for each membrane was calculated. 2.4. Analytical methods

2. Materials and methods 2.1. Wine samples Wine was delivered by the cellar Les Vignerons de Buzet, located in Buzet-Sur-Baise, Bordeaux, France. It was a red 12” ordinary wine without filtration. 2.2. Tested membranes For the experimentation ten different microfiltration polymeric membranes were tested. Different materials (cellulose acetate-CA, polyethersulfone-PES, polypropilene-PP and nylon-NY) and pore diameters (0.2,0.45,0.8 and 5 pm) were tested. Moreover, different membrane manufacturers (Schleicher & Schuell, Alber, Lida, Millipore

Spectrophotometric analyses were carried out on a Uvikon 922 UV/VIS spectrophotometer (Kontron Instruments). Turbidity was analysed using a Hach Turbidimeter. Total anthocyanins (TA) were determined according to Ribereau-Gayon [9] and total polyphenols according to Singleton and Rossi [lo]. Total polysaccharides were determinated using the Usseglio-Tomasset [ 1 l] method which base is the precipitation of the polysaccharides with ethanol and ulterior calorimetric dosage. 3. Results and discussion The unspecific adsorption experiments (Table 1) resulted in a significative permeability decrease

A. Urkiaga et al. /Desalination

117

148 (2002) 115-120

Table 1 Decrease of the initial permeability, with DI water, after the unspecific adsorption essay for the different tested membranes Pore diameter, urn

Material

Supplier

Initial permeability, L/hm*bar

0.2 0.2 0.2 0.2 0.45 0.45 0.45 0.45 0.8 5

CA PES CA NY CA PES CA CE CA PP

Schleicher&Schuell Schleicher&Schuell Albet Lida Schleicher&Schuell Schleicher&Schuell Albet Millipore Schleicher&Schuell Gelman Sciences

10,263 14,809 5,464 5,586 10,798 13,720 11,620 7,570 13,163 9,570

(~10%) after soaking the membranes in wine for two days. The higher reduction was observed for the 0.45 pm PES membrane (25.3%), whereas the lowest one (5.46%) corresponded to the 0.45 l.trn CA. However all the materials and pore sizes have a quite similar behaviour concerning wine components adsorption. Regarding filtration experiments, Fig. 1 shows a similar visible spectrum pattern of the filtered wines when compared to the raw wine. Only 0.2 pm CA Schleicher & Schuell membrane showed a slight decrease. In Table 2 the physicochemical characteristics of the different permeate wines when compared with the feed one are compared. No difference in colour has been observed, and the trend is similar for total polyphenols with a maximum retention of 7.2% (CE 0.45), and total anthocyanins with less than 5.3% of reduction, except for 0.2 pm PES membrane (retention = 20.6%). The parameters that have shown the most important variation among the different tested membranes have been turbidity and total polysaccharides. The NY and PP membranes were the ones giving the highest turbidity values. For NY membrane this result is quite surprising, as its pore size was smallest. Moreover, the 0.45 l.trn CA (Albet) and PES showed quite high turbidity values. Total polysaccharides showed a quite

Final permeability, L/hm bar

Permeability decrease, % 10.3 12.3 9.22 11.9 5.46 25.3 9.75 11.5 12.6 13.1

9,208 12,983 4,960 4,92 1 10,208 10,247 10,487 6,702 11,498 8.319

,

t

CA 0.45 S&S

-h-CA

PES 0.45 0.2 S&S

f

PES 0.2

--!wTk&8%-+PP5 --t--CA

0.2 Albet

+x-NY 0.2 - CE 0.45 Millipore ~--I+-mc-A_8;45Aibe-.--+ Unfiltered wine

0 350

400

450

500

550

600

Wave-length

650

700

750

800

850

(nm)

Fig. 1. Visible spectra of the unfiltered wine and the different filtrates.

important decrease (31.2-82.7%). PES (0.2 l.trn), CE (0.45 l.tm), PES (0.45 l_trn) and NY (0.2 l.trn) have been by this order the membranes that have given the most important decrease. Polysaccharides with polyphenols are usually the main responsible compounds of the fouling in wine clarification with membranes [ 121. Moreover the retention of these compounds will affect to the organoleptic characteristics of the filtrated wine so their retention and their fouling effect must be reduced.

A. Urkiaga et al. /Desalination

118

148 (2002) 115-120

Table 2 Physico-chemical characteristics of the different obtained permeates Pore diameter,

Membrane material

Supplier

pm Initial wine 0.2 0.2 0.2 0.2 0.45 0.45 0.45 0.45 0.8 5

CA PES CA NY CA PES CA CE CA PP

S&S S&S Albet Lida S&S S&S Albet Millipore S&S GS

Turbidity, NTU

Colour

IC

IC’

Total polysacchar., mg/Lx 1O-’

Total polyphenols, mg galic ac./L

Total anthoc., mg/L

3.65 0.21 0.12 0.48 3.37 0.25 0.88 1.23 0.37 0.27 3.26

0.69

8.03 7.51 7.76 8.02 8.07 7.96 7.90 7.99 7.99 7.93 7.99

9.11 8.51 8.78 9.11 9.11 8.98 8.98 8.93 9.04 8.94 9.01

7.94 3.09 1.37 3.09 2.59 3.07 2.45 3.07 1.55 5.46 5.00

1.317 1,277 1,273 1,288 1,326 1,245 1,385 1,245 1,222 1,349 1.252

228 229 181 221 216 217 220 229 220 220 229

Time, min V,,,.:600 ml

0.68 0.69 0.70 0.70 0.70 0.70 0.70 0.70 0.71 0.70

Table 3 Operation times of the different tested membranes for three permeate volumes Pore diameter, urn

Membrane material

Supplier

Time, min Vpcrm.; 100 ml

Time, min V,,,,._300 ml

0.2 0.2 0.2 0.2 0.45 0.45 0.45 0.45 0.8 5

CA PES CA NY CA PES CA CE CA PP

S&S S&S Albet Lida S&S S&S Albet Millipore S&S GS

0.90 0.93

4.45 10.0 3.18 4.07 2.20 20.8 3.00 1.80 2.87 0.78

0.82 1.20 0.58 1.62 0.58 0.50 0.49 0.28

Although with some difference as in the case of the turbidity between the two tested 0.45 CA membranes, in general the same membranes of different suppliers show quite similar behaviour. On the other hand and taking into account the decrease in permeate flux with permeate volume (Fig. 2) and with time (Table 3) outstanding differences can be observed among the different membranes. For example PES membranes needed by far the longest filtration time, although their initial permeate fluxes were the highest ones. With the exception of the largest pore size [PP (5 pm)]

10.6 55.7 10.5 12.0 6.63 109 12.7 5.21 15.0 1.62

Time, min VP,,.:900 ml 22.3 177 31.1 29.2 17.5 333 30.2 12.5 50.5 2.49

that showed a very high and constant value of permeate flux along the experiment the other membranes although their initial permeate fluxes were quite different the final ones were rather similar. With regard to permeate flux the best membranes were the CE (0.45 pm), CA (S&S) (0.45 pm), CA (Albet) (0.2 pm) and NY (0.2 pm). Last but not least, for each membrane the optimal cleaning procedure was searched. Cleaning is a very important aspect of a membrane process. In this sense the improvement of the back-flushing method has been probed. Moreover, the basic

A. Urkiaga et al. /Desalination

*CA045

APP~

X CA 0.2

. CA 0.8

mNY02

I CE 0.45

. PES 0.45

-CA

cleaning after an acid cleaning with citric acid showed a worse result. The membrane with the easiest permeability recovery was the NY membrane. In Table 4 some of the cleaning procedures and permeability recovery are summarised. The PES membranes were which showed a lowest permeability recovery after the filtration experiment with only 2.20 and 5.93% (Table 5). As general conclusion and taking into account all the obtained results, all different membranes tested can be considered suitable for red wine clarification. The best membrane material seems to be cellulose acetate and both size pores, 0.2 and 0.45 urn, are suitable. However organoleptic test would definitely proved microfiltered wine quality.

PES 0.2

0.45 S&S

0 CA 0.2

S&S

16000 -; 14000 5

12000

4

10000

E,

8000

5

6000

E i!

2000 4000

-

0 0

400

200

Permeate

800

600 volume

119

148 (2002) 115-120

1000

(ml)

Fig. 2. Comparison of the permeate flux vs. the volume of filtered winefor the different tested membranes.

Table 4 Cleaning procedure and permeability recovery carried out for three different membranes Membrane

Chemical agent

Cleaning conditions

Permeability recovery (2) %

CA 0.2 (Albet)

Ultrasil 1% Citric acid 1M NaOH IM Citirc acid IM

T: 60°C; P: 0.5 bar; t: 30 min T: 60°C; P: 0.5 bar; t: 30 min T: 60°C; P: 0.5 bar; t: 30 min Backwashing T: 60 “C. P: 0.5 Bar; t: 30 min

22.3 43.6 19.6 42.8

NY 0.2

Ultrasil 2% Ultrasil 2%

T: 50°C; P: 0.5 bar; t: 30 min Backwashing T: 50 “C. P: 0.5 Bar; t: 30 min

21.4 77.4

PES 0.45 (S&S)

Ultrasil 2% Citric acid 1M NaOH 1M NaClO 10% NaClO 10% NaClO 10% Citric acid 1M NaClO 10%

T: 60°C; P: 0.5 bar; T: 60°C; P: 0.5 bar; T: 60°C; P: 0.5 bar; T: 20°C; P: 0.5 bar; T: 20°C; P: 0.5 bar; T: 20°C; P: 0.5 bar; T: 60°C; P: 0.5 bar; Backwashing T: 20

11.0 38.2 3.93 18.9 40.5 47.3 56.1 60.8

t: 30 min t: 30 min t: 30 min t: 30 min t: 30 min t: 30 min t: 30 min “C. P: 0.5 bar;

f:

30 min

-

Table 5 Differences between permeability recovery after unspecific adsorption (1) and after wine microfiltration (2) experiments Pore diameter, pm

Material

Supplier

Permeability recovery (l), % Permeability recovery (2), %

0.2 0.2 0.2 0.45 5

PES CA NY PES PP

Schleicher&Schuell Albet Lida Schleicher&Schuell Gelman Sciences

87.8 90.8 88.1 74.7 86.9

5.93 24.8 22.4 2.20 14.2

A. Urkiaga et al. /Desalination

120

4. Conclusion As general conclusion and taking into account all the obtained results under the same operational conditions for red wine clarification the best membrane material seems to be cellulose acetate and both size pores, 0.2 and 0.45 (S&S) pm, are suitable for the physico-chemical and flux reduction point of view. If only the physicochemical characteristics are taken into account the best membrane of the tested ones would be the 0.8 CA (S&S) one. In any case in this work experiments have been carried out at a small scale and using a stirred cell and not a real crossflow filtration. For this reason the obtained polysaccharides retention for example is higher than the nowadays obtained one by crossflow microfiltration (retention under the 20%) [ 13-151. This high retention can be the responsable of the observed accused flux reduction along the filtration essays. In order to prevent and reduce this fouling different methods could be applied as backflushing, backshocking or infrasonic pulsing [ 161. Anyway, in order to check the obtained results, organoleptic test all together with more pilot scale study would be needed.

Acknowledgements This work has been funded by the Basque Government, Department of Presidency.

References [l]

[2]

[3]

M. Magerstadt, Cross flow wine microfiltration by small diameter hollow fibre membranes, Filtr. Separ., 35(6) (1998) 513-514. A. Urkiaga, L. De las Fuentes, M. Acilu and P. Aldamiz-Echevania, Red wine clarification by microfiltration, J. Filtr. Sot., 3 (2001) 4-7. M. Gaillard and J.L. Berger, Ultrafiltration et microfiltration tangentielle. Resultats d’essais sur mout et sur vin, Revue des OEnologues et des Techniques Vitivinicoles, 24(95) (1984) 39-62.

148 (2002) 115-120

141 A. Urkiaga, L. De las Fuentes, M. Acilu and P. Aldamiz-Echevarria, Aplicacion de la tecnologfa de membranas en enologia, Alimentacibn, Equipos y Tecnologfa, 156 (2001) 95-104. 151 J.L. Berger, Testing of the Romicon tangential filter: applications to practical conditions for different types of Beaujolais wines, Revue des OEnologues et des Techniques Vitivinicoles, 61 (1991) 25-30. [61 M. Ferrando, C. Gtiell and F. Lopez, Industrial wine making: composition of must clarification treatments, J. Agric. Food Chem., 46 (1998) 1523. [71 CA. Sirns, R.P. Bates and R.P. Johnson, Use of ultrafiltration in the processing of muscadine and hybrid wines, Am. J. Enol. Vitic., 39 (1988) 11. PI C. Peri, M. Riva and P. Decio, Crossflow membrane filtration of wines: comparison of performance of ultrafiltration, microfiltration and intermediate cut-off membranes, Am. J. Enol. Vitic., 39 (1988) 162. [91 J. Ribereau-Gayon, The Anthocyans of Grapes and Wines, Academic Press, New York, 1982. PO1 V.L. Singleton and J.A. Rossi, Colorimetry of total phenolics with phosphomolibdic-phosphotungstic acid reagent, Am. J. Enol. Vitic., 16 (1965) 144. u11 L. Usseglio-Tomasset, Les colloi’des glucidiques solubles des mciuts et des vins, Connaissance de la vigne et du vin, 10(2) (1976) 193-226. A. Vemhet, M.P. Pellerin, J. Belleville, J. Planque and u21 M. Moutounet, Relative impact of major wine polysaccharides on the preformances of an organic microfiltration membrane, Am. J. Enol. Vitic., 50( 1) (1999) 51-56. 1131 P.J. Cameira dos Santos, V. Cheynier, J.M. Brillouet, Y. Cadot, J.L. Escudier, H.D.V. Roesink and M. Mouounet, Cross-flow filtration of wines with polymeric membranes: the inlfuence of wine making technology and backpulse on the fouling process, PrehrambenoTecnoloska-i-Biotechnoloska-Revja, 32(2/3) (1994) 77-83. [I41 M. Serrano, B. Pontens et P Ribereau-Gayon, La microfiltration tangentielle 2: applications en oenologie, J. International des Sciences de la Vigne et du Vin, 26(2) (1992) 97-l 16. 1151 E. Drioli, S. Todisco, I processi a membrana nella modema enologia, Vignevini, l-2 (1999) 3 l-45. 1161 C. Gtiell, F. Lbpez, M. A. Perez, A. Rolan, E. Moreno, Aplicaci6n de tecnicas de separaci6n por membrana en la industria enol6gica, Alimentaci6n Equipos y Tecnologia, 10 (1999) 89-96.