RO125167B1 - Process for eliminating the excess of iron and copper ions from wine, through reverse osmosis - Google Patents

Description

The invention relates to a process for the elimination of excess iron and copper ions from wine, by reverse osmosis, intended to improve the vinification processes in order to preserve the initial parameters and naturalness of the wines.

It is known that, during the vinification process, the wine is enriched with iron and copper ions of exogenous origin by contact with the unprotected metal surfaces of various containers, equipment, tanks, pipes, fittings, etc. If in small quantities these polyvalent cations are harmless, when they exceed 8 ... 12 mg / l iron and 0.8 ... 1 mg / l copper, they combine with the proteins in wine and form compounds that change its color. , even the taste, disturbing it, a phenomenon known as ferric scrapping, respectively cupric scrapping.

To remove excess iron and copper ions, the best known and most widespread process is the so-called blue gluing, which consists in treating the wine with potassium ferrocyanide, which precipitates these ions, forming a deposit of ferric and cupric ferrocyanide, known and under the name Blue Prussia, a deposit that is subsequently removed by settling and microfiltration. However, this process has a number of major disadvantages, both due to the special toxicity of this substance and the resulting compounds, which require a very strict control of the technological process of deferrization, going so far as to ban it in many countries, and due to subsequent complications. related to the special operations of equipment cleaning, as well as those of storage and neutralization of hazardous residues (V. Doholici, G. Șeptilici, Physico-chemical and microbiological technological testing of wines, pp. 50-60, CERES Publishing House, Bucharest, 1981 ).

For the same purpose, a process for deferring wine with phytic acid is also known, a biological compound that acts by adsorption of iron and calcium ions, followed by their coprecipitation and removal of sludge by microfiltration (US 7335385 B2). This process has the disadvantage of reduced efficiency and the need for further treatment of the wine with calcium carbonate, to counteract the additional acidity induced by phytic acid.

Another disadvantage, common to both of the above processes, is that, using all kinds of chemicals, the initial organoleptic parameters and the naturalness of the wine are seriously affected.

The technical problem solved by the invention is the realization of a wine deferencing process which avoids the use of substances particularly dangerous for humans and the environment, and which maintains the initial organoleptic qualities and the naturalness of the wine.

The process of removing excess iron and copper ions from wine by reverse osmosis according to the invention consists of an initial phase in which the wine is passed several times through a known reverse osmosis module, with polyamide membranes with the molecular cut of 400 Dallton, separating the permeate, which contains almost all the initial amount of iron and copper ions, as well as ethyl alcohol and endogenous water from wine, from the retentate, which accumulates the non-reducing extract, total acidity, reducing sugars and, In general, the high molecular weight components, after which, in a second phase, the permeate obtained in the first phase is passed again through the reverse osmosis module, in which the 400 Dallton membranes have been previously replaced by others of 300 Dallton , through which only endogenous water and ethyl alcohol can pass, not iron and copper ions, which accumulate in the retentate, and in the final phase the retentate obtained from the first phase is united with the permeate obtained from the second phase, it is homogenized by recirculation in a closed system, it is kept for 4 ... 6 days, the final analyzes are performed, after which the wine thus processed can be stored for immediate consumption or maturation.

RO 125167 Β1

The process for removing excess iron and copper ions by reverse osmosis, 1 according to the invention, has the following advantages:

- it is a simple, clean, environmentally friendly and efficient process;

- eliminates the potential risks of misuse of chemicals that are hazardous to both humans and the environment;

- does not introduce any exogenous element into the wine;

- preserves unaltered the initial organoleptic qualities and the naturalness of the wine.7

The following is an example of a process for the removal of excess iron and copper ions from wine by reverse osmosis.9 Beforehand, wines obtained by known vinification processes are analyzed physico-chemically, determining the initial values of ferrous ion, ferric ion, total iron and 11 copper ions. The machine used consists of a known reverse osmosis module, provided with several interchangeable cartridges having polyamide membranes having a certain molecular cut; a variable flow centrifugal pump; an automatic membrane washing system; water purification filters before washing membranes; 15 fittings and pipes. The module is located between two large double-walled tanks, one for wine and one for retentation (concentrate), and the permeate (filtrate) is collected in a third tank. In both the wine and retentate tanks and the permeate tank, an inert atmosphere of carbon dioxide is maintained at a pressure of about 4 bar. 19 in phase l, in the reverse osmosis module, cartridges with membranes with a molecular cut of 400 Dallton are mounted and several successive passages of the wine are made through the 21 module, in order to obtain as much permeate as possible. In order to maintain an optimal temperature of 15 ... 18 ° C and, implicitly, the quality of the wine, which tends to heat up when it passes through the reverse osmosis module, between the double walls of the two large tanks, the water cooled to - 4 ° C. For the same purpose, but also to obtain an optimal efficiency of filtration through the reverse osmosis membrane, the pumping pressure will have to ensure a maximum pressure difference for each filter element of 0.7 bar (10 psi). 27 After about three passes, it can be seen that:

- in the retentate, the non-reducing extract, total acidity, ash, 29 reducing sugars and, in general, those components which have a high molecular weight were concentrated;

- ethyl alcohol and endogenous water from wine, in the concentration 31 corresponding to the quantity of wine, as well as a large amount of ferrous oxide (Fe O) and copper oxide (Cu O) passed into the permeate. 33

Although a fairly large amount of ferric oxide (Fe ₂ O ₃ ) and cupric oxide (Cu ₂ O) remains in the retentate, their share in total iron and total copper, respectively, is very small. At the same time, in 35 permeate also passes an insignificant amount of the total acidity, of the volatile one, as well as a small amount of the non-reducing extract, of free and total SO ₂ . 37 in phase II, in the reverse osmosis module, cartridges with membranes with a molecular cut of 300 Dallton are mounted and a single pass of the permeate 39 obtained in the previous phase is sufficient, so that only endogenous water and alcohol pass into the new permeate. ethyl, and iron and copper ions to remain in the retentate. This residual retention represents a maximum of 41% of the initial quantity of processed wine, within the normal losses of winemaking technologies. The pumping parameters are identical to those in phase a. 43 in phase II, the retentate obtained in phase a is joined with the permeate obtained in phase II, after which the homogenization of the two fractions is carried out by recirculation in a closed system 45, followed by a stationary for 4 ... 6 days. Finally, the wine thus obtained is analyzed, checking and comparing its physico-chemical parameters with the initial ones. 47

The wine processed by this process is balanced and extractive, retains its typical aroma of variety, has an unaltered freshness and can take the path of immediate consumption or maturation.

Claims (5)

1 Claim 3 Process for the removal of excess iron and copper ions from wine by reverse osmosis, characterized in that, in a first phase, the wine is passed several times 5 successively by a known reverse osmosis module, provided with 400 Dallton molecular cut polyamide membranes, separating the permeate, which contains almost all 7 the initial amount of iron and copper ions, as well as ethyl alcohol and endogenous water in wine, by retentate, which accumulates the non-reducing extract, total acidity, sugars 9 reducing agents and, in general, high molecular weight components, after which, in order to recover as much as possible of endogenous water and ethyl alcohol, but also to concentrate 11 iron and copper ions in a small amount of endogenous water, in a second phase, the permeate obtained in the first phase is again passed through the reverse osmosis module in which 13 membranes of 400 Dallton have been previously replaced by others of 300 Dallton, through which only endogenous water can pass and ethyl alcohol, not iron and copper ions that accumulate in the retentate, and finally, in the third phase, the retentate obtained from the first phase is combined with the permeate obtained from the second phase, it is homogenized by recirculation in a closed system, 17 stays 4 ... 6 days, the final analyzes are performed, after which the wine thus processed can be stored for immediate consumption or maturation.