A DEVICE FOR STABILIZING WINE AND OTHER VEGETABLE BEVERAGES AND THE RELATED STABILIZING METHOD

Abstract

A device and a method for stabilizing wine or other vegetable beverages by removal, in whole or in part, of agents responsible for instability, including proteins and metals, are provided. The device has a tubular container filled internally at least partly with particles of support material covered with a layer of a mesoporous nanostructured adsorbent material comprising titanium oxide, adapted to absorb proteins and metals.

Claims

1. A device for stabilizing wine and other vegetable beverages, the device comprising: a tubular container filled internally at least partly with particles of support material coated with a layer of mesoporous nanostructured adsorbent material comprising titanium oxide, the layer having a thickness between 10 and 25 μm and the mesoporous nanostructured adsorbent material having pores of size between 15 and 50 nm, BET surface area between 90 and 100 m.sup.2/g and absorbent volume of the pores between 0.4 and 0.5 cm.sup.3/g; an inlet conduit and an outlet conduit for a beverage to be stabilized, respectively positioned at the two ends of the tubular container, said inlet conduit and said outlet conduit being in fluid communication with the internal volume of the tubular container; a first closure element and a second closure element, respectively positioned at the two ends of the tubular container, said inlet and outlet conduits passing through the first and second closure elements, wherein the first and the second closure elements are adapted to occlude a respective end section of the tubular container and to prevent escaping of the mesoporous nanostructured adsorbent material contained therein; and a first filtering element positioned in an outlet section of the inlet conduit into the tubular container and a second filtering element positioned in an inlet section of the outlet conduit from the tubular container, the first and the second filtering elements having pores of dimensions adapted to retain inside the tubular container the particles of support material coated with the layer of mesoporous nanostructured adsorbent material.

2. The device according to claim 1, wherein the particles of support material are glass spheres or flakes, having size ranging from 1 to 10 mm.

3. The device according to claim 1, wherein the tubular container is made of stainless steel, glass or food-grade plastics.

4. The device according to claim 1, further comprising respective sealing gaskets applied at an interface between the tubular container and the first and second closure elements.

5. The device according to claim 1, wherein the inlet conduit and the outlet conduit are mutually connected in a closed loop.

6. A method for adsorbing proteins and/or metals from wine or other vegetable beverages, the method comprising at least one adsorption step wherein wine or other vegetable beverages is/are made to flow through a device comprising: a tubular container filled internally at least partly with particles of support material coated with a layer of mesoporous nanostructured adsorbent material comprising titanium oxide, the layer having a thickness between 10 and 25 μm and the mesoporous nanostructured adsorbent material having pores of size between 15 and 50 nm, BET surface area between 90 and 100 m.sup.2/g and absorbent volume of the pores between 0.4 and 0.5 cm.sup.3/g; an inlet conduit and an outlet conduit for a beverage to be stabilized, respectively positioned at the two ends of the tubular container, said inlet conduit and said outlet conduit being in fluid communication with the internal volume of the tubular container; a first closure element and a second closure element, respectively positioned at the two ends of the tubular container, said inlet and outlet conduits passing through the first and second closure elements, wherein the first and the second closure elements are adapted to occlude a respective end section of the tubular container and to prevent escaping of the mesoporous nanostructured adsorbent material contained therein; and a first filtering element positioned in an outlet section of the inlet conduit into the tubular container and a second filtering element positioned in an inlet section of the outlet conduit from the tubular container, the first and the second filtering elements having pores of dimensions adapted to retain inside the tubular container the particles of support material coated with the layer of mesoporous nanostructured adsorbent material, to obtain adsorption of the proteins and/or metals on the mesoporous nanostructured adsorbent material.

7. The method according to claim 6, further comprising one or more additional adsorption steps, wherein wine or other vegetable beverages is/are recirculated through the device.

8. The method according to claim 6, further comprising a washing step of the mesoporous nanostructured adsorbent material.

9. The method according to claim 8, wherein the washing step is carried out at the end of one or more adsorption steps or between two successive adsorption steps.

10. The method according to claim 6, wherein the proteins comprise chitinase and thaumatin-like proteins and the metals comprise copper, iron and/or manganese.

Description

EXAMPLES

[0034] Materials and Methods

[0035] The effectiveness of the adsorbent material and the device of the invention was tested on different varieties of white wines obtained by an industrial process and coming from different wineries, as well as on synthetic wine solutions (composition: tartaric acid 5 g/l, ethanol 12% (v/v) in deionized water, pH 3.6) to which have been added known concentrations of the metals Cu, Fe.

[0036] The method of adsorption of compounds such as “PR” type proteins and Cu, Fe metals, in continuous flow conditions, was conducted on a prototype of the device (FIG. 2), consisting of: a) glass column filled with mesoporous adsorbent material; b) graduated bottle for containing the wines or synthetic wine solutions; c) volumetric feed pump. The column, the photographic image of which is reproduced in FIG. 2, is a glass tube, 75 mm in length, with an internal diameter of 14 mm and a glass wall thickness of 1 mm. The prototype was fed by a volumetric pump with variable power supply in the range of 1.25-12 Volts, allowing the volumetric flow to be adjusted. This flow has been optimized to obtain a constant flow rate of 1.28 ml/sec at ambient temperature.

[0037] The sintered material was obtained through a treatment in a ventilated furnace equipped with a temperature control and programming system. The programmed temperature ramp provided for a multi-step heating system with an increase in the range: T=ambient −550° C. The material obtained was analyzed with the SEM/EDX system, in order to obtain an image of the sintering structure, and to verify the absence of contaminants and organic residues. FIG. 3 shows SEM images of the sintering structure obtained by heat treatment of TiO.sub.2 nanoparticles. Based on the specific area characteristics obtained for the sintered material, materials were prepared to provide an active surface of 0.45 m.sup.2, 2.25 m.sup.2, 4.50 m.sup.2, 9.00 m.sup.2, 18.00 m.sup.2, respectively, for the treatment of volumes of 50 ml in the different case studies. By way of example, the results are reported of experiments conducted on Chardonnay and Moscato wines and on synthetic wine solutions to which known concentrations of iron and copper ions (Fe.sup.2+: 2 mg/l; Cu.sup.2+: 1 mg/l) were added. The following parameters were measured: protein composition, metal content, phenolic component composition, organic acid composition, stability tests.

[0038] The absence of contaminants was also evaluated, and the treated samples were subjected to accelerated aging tests, consisting of heat stress tests to accelerate oxidation (T=35° C., 5 days' exposure), and heat stability tests to determine protein stability (T=80° C., 30 minutes' exposure and subsequent cooling to ambient T, to assess any side effects due to contact with the adsorbent material.

[0039] Results

[0040] The experiments carried out on different varieties of white wines demonstrated the stability of oenological quality parameters such as pH (Table 1), polyphenol content (FIG. 4), organic acid content (Table 2). In particular, FIG. 4 shows the concentration of total polyphenols in a white wine—Chardonnay variety, exposed to different quantities of mesoporous TiO2. A modest decrease in polyphenol content (<4%) was observed only for elevated exposed surfaces (>9.00 m.sup.2). The results were expressed in mg/1 of gallic acid. Significant differences are identified with different letters at 95% confidence level.

[0041] Moreover, the mesoporous adsorbent material showed an inhibitory activity (dose-dependent) against oxidation of wines subjected to accelerated aging tests. FIG. 5 shows the results of a test wherein Chardonnay variety wine is exposed to different quantities of mesoporous TiO.sub.2 and subjected to an accelerated aging test at a temperature of 35° C., in static mode. As the active area increases, a protective effect is observed, as indicated by the decrease in the browning index (O.D. 420 nm). Significant differences are identified with different letters at 95% confidence level.

TABLE-US-00001 TABLE 1 Verification of pH stability on Chardonnay wine treated in different adsorbent material/wine ratios. TiO.sub.2 -Active surface/50 ml wine pH wine Control 2.93.sup.a 0.45 m.sup.2 2.91.sup.a 2.25 m.sup.2 2.94.sup.a 4.50 m.sup.2 2.93.sup.a 9.00 m.sup.2 2.93.sup.a 18.0 m.sup.2 2.92.sup.a .sup.aInsignificant differences at a 95% confidence level.

TABLE-US-00002 TABLE 2 Concentration of the main organic acids in the wine, determined with the HPLC method in Chardonnay wine before (control) and after treatment in the device. Insignificant differences at a 95% confidence level. Citric acid Tartaric acid Malic acid Succinic acid Lactic acid Acetic acid SAMPLE g/L SD g/L SD g/L SD g/L SD g/L SD g/L SD Control 0.28 0.01 5.37 0.07 2.53 0.04 2.18 0.04 0.10 0.00 0.04 0.02 TiO.sub.2 0.27 0.00 5.30 0.02 2.46 0.09 2.11 0.04 0.10 0.00 0.02 0.01 18.00 m.sup.2/50 ml

[0042] As far as protein concentration is concerned, the contact of Chardonnay variety wine with mesoporous adsorbent material in static mode produced a decrease in the total protein content, of an amount proportional to the increase in the active surface placed in contact with the wine during treatment: reductions of 4.5% (0.45 m.sup.2/50 ml), 4.5% (2.25 m.sup.2/50 ml), 15.3% (4.50 m.sup.2/50 ml), 25.2% (9.00 m.sup.2/50 ml), and 42.3% (18.00 m.sup.2/50 ml) were observed, respectively. The absence of flow and stirring produced the stabilization of the wine only after a period of 5 days (FIG. 6). More specifically, FIG. 6 shows the reduction in the concentration of total proteins in Chardonnay variety wine, exposure to mesoporous material in static mode. Significant differences are identified with different letters at 95% confidence level.

[0043] The flow stabilization tests were carried out on Moscato variety wine, using an active surface of mesoporous material equal to 18.00 m.sup.2/50 ml.

[0044] Since the wine was stable to the thermal stress induced by the heat stability test, the SDS-PAGE analysis on the protein components was carried out. The results show that the treatment effectively removed the low molecular weight protein fractions (<35 MkDa), identified as proteins with a thaumatin-like protein (TLP) structure and responsible for the phenomena of instability (FIG. 7). More specifically, FIG. 7 shows the SDS-page analysis conducted on Muscat variety wine treated with the device of the invention. Legend: Line 1—control; Line CTI—wine treated with mesoporous material 18.00 m.sup.2/50 ml wine; Line ST. standard reference. The bands of interest have been highlighted with Coomassie Blue dye.

[0045] In conclusion, tests for the removal of metal species capable of catalyzing the oxidative phenomena in beverages of vegetable origin were carried out by applying the treatment in the device to various types of matrices; by way of example, the results of the experiment that involved the treatment of a synthetic wine, to which known concentrations of Cu.sup.2+ and Fe.sup.+ ions were added, are reported (Table 3). The results showed a strong adsorbent power of these metals by the mesoporous nanostructured material, with removal of 62.5% of Fe.sup.+ ions and 48% of Cu.sup.+ ions.

TABLE-US-00003 TABLE 3 ICP-OES analysis to verify the concentration of Cu and Fe metals, added in known concentrations to synthetic wine and treated on mesoporous material. TiO.sub.2.sub.− Metal Control (ppm) 18.00 m.sup.2/50 ml (ppm) Cu.sup.2+ 0.928 0.388 Fe.sup.2+ 1.9995 0.1445