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EP-4740752-A1 - METHOD FOR EXTRACTING TANNINS FROM GRAPE SEEDS AND PLANT FOR THE IMPLEMENTATION OF THIS METHOD

EP4740752A1EP 4740752 A1EP4740752 A1EP 4740752A1EP-4740752-A1

Abstract

The present invention relates to a method for extracting tannins from grape seeds, characterized in that it comprises a phase in which a fluid mass containing grape seeds passes through an ultrasonic tube, passing through said ultrasonic tube. Said ultrasonic tube is connected to ultrasonic generators so as to transmit the ultrasound generated by said ultrasonic generators to said fluid mass containing grape seeds. Said ultrasonic generators are arranged outside said ultrasonic tube.

Inventors

  • MARTINI, BRUNO

Assignees

  • Ecotecne S.r.l.

Dates

Publication Date
20260513
Application Date
20251111

Claims (13)

  1. Method for extracting tannins from grape seeds, characterised in that it comprises a transit step of a fluid mass (M) comprising grape seeds (V) inside at least one ultrasonic duct (21), with crossing of said ultrasonic duct (21), said ultrasonic duct (21) being connected to ultrasonic generating means (20) in such a way as to transmit the ultrasounds generated by said ultrasonic generating means to said fluid mass (M) containing grape seeds (V), said ultrasonic generating means (20) being arranged outside of said at least one ultrasonic duct (21).
  2. Method according to claim 1, characterized in that said fluid mass (M) comprises a liquid as the transport fluid in which the grape seeds (V) are immersed, said liquid being hydroalcoholic or aqueous.
  3. Method according to one or more of the preceding claims, characterized in that said aqueous liquid consists of a waste liquid or fluid that exits together with the grape seeds from a fermentation phase of a winemaking process; said waste liquid consists substantially of a fraction of must.
  4. Method according to one or more of the preceding claims, characterized in that said fluid mass M is between 10% and 50% grape seeds, and preferably comprises 50% liquid and 50% grape seeds.
  5. Method according to claim 1, characterized in that it comprises the following operating steps: a) loading a fluid mass (M) comprising grape seeds (V) into a tank (11), b) withdrawing said fluid mass (M) comprising grape seeds (V) from a collection bottom (14) of said tank (11) and pumping said fluid mass (M) containing grape seeds (V) into said ultrasonic duct (21) so that said fluid mass (M) containing grape seeds (V) continuously passes through said ultrasonic duct (21) from the inlet (21a) of said ultrasonic duct (21) to the outlet (21b) of said ultrasonic duct (21), c) subjecting said fluid mass (M) comprising grape seeds (V) to ultrasounds determined by ultrasonic generating means (20) operating at frequencies between 18 kHz and 30 kHz, with a power between 5 W/litre and 2000 W/litre; d) return said fluid mass (M) comprising grape seeds (V), exiting from said ultrasonic duct (21), to the upper part (11a) of said tank (11), e) repeat phases b) to d), defining an extraction cycle, until all the fluid mass (M) comprising grape seeds (V) is subjected to ultrasound inside said ultrasonic duct (21) for a total period of time between 30 seconds and 30 minutes.
  6. Method according to one or more of the preceding claims, characterized in that said ultrasonic generator means (20) and the ultrasonic duct (21) are configured and connected in such a way that the temperature of the fluid mass (M) comprising grape seeds (V) at the inlet (21a) of said ultrasonic duct (21) is substantially equal to the temperature of said fluid mass (M) comprising grape seeds (V) at the outlet (21b) of said ultrasonic duct (21), or alternatively said ultrasonic generator means (20) and the ultrasonic duct (21) are configured and connected in such a way that a temperature difference of the fluid mass (M) comprising grape seeds (V) between the outlet (21b) of said ultrasonic duct (21) and the inlet (21a) of said ultrasonic duct (21) is between 1°C and 45°C.
  7. Method according to one or more of the preceding claims, characterized in that said ultrasound generating means (20) comprise a plurality of ultrasonic transducers of the piezoelectric type, or of the magnetostrictive type.
  8. Method according to one or more of the preceding claims, characterized in that, subsequently to said phase e) of extraction cycles, said fluid mass (M) comprising grape seeds (V) is filtered so as to separate the exhausted grape seeds (V) from a vinous fluid (T) with a very high tannin content.
  9. Plant (10) for the extraction of tannins from grape seeds, characterized in that it comprises: - a tank (11) for containing a fluid mass (M) containing grape seeds (V), said tank (11) comprising in turn: - a lid (12), having a loading mouth (13), - a collection bottom (14), having a discharge mouth (15); - a recirculation line (16) for the transit of said fluid mass (M), said recirculation line (16) extending between said discharge mouth (15) and said loading mouth (13), said recirculation line (16) comprising: - at least one ultrasonic duct (21) having an inlet mouth (21a) and an outlet mouth (21b), configured and positioned so as to be internally crossed by said fluid mass (M), - ultrasonic generating means (20) connected to said at least one ultrasonic duct (21), said ultrasonic generating means (20) being configured so as to transmit ultrasound to said fluid mass (M) containing grape seeds (V) which passes through said at least one ultrasonic duct (21); - pumping means (17) configured to withdraw said fluid mass (M) from said discharge mouth (15), to induce said fluid mass (M) to pass through said at least one ultrasonic duct (21) and to move said fluid mass (M), exiting from said at least one ultrasonic duct (21), towards said loading mouth (13).
  10. Plant according to the preceding claim, characterized in that it comprises a diverter valve (40) with at least three ways, said diverter valve (40) being configured to divert said fluid mass (M) containing grape seeds (V) from said recirculation line (16) to a separation line (30), said separation line (30) being configured to remove said grape seeds (V) from said fluid mass (M).
  11. Plant according to claim 9 or 10, characterized in that said ultrasonic generating means (20) are connected to said at least one ultrasonic duct (21) so as to allow the transmission to said fluid mass (M) of vibrations such as to determine the generation of ultrasonic cavitation in said fluid mass (M) containing grape seeds (V).
  12. Plant according to one or more of claims 9 and 10, characterised in that said ultrasonic generating means (20) comprise at least one support and transmission body (27) configured to support a plurality of ultrasonic vibration generators (28) for the vibration of said at least one ultrasonic duct (21), each portion (21c) of said at least one ultrasonic duct (21), which is fixed to a corresponding support and transmission body (27), being surrounded by at least two ultrasonic vibration generators (26).
  13. Plant according to one or more of claims 9 to 10, characterised in that said separation line (30) comprises a discharge duct (31) configured to connect said at least three-way valve (40) with separation means (32), said separation means (32) being configured to separate the grape seeds (V) from said fluid mass (M) and to collect a remaining vinous mass (T) rich in tannins.

Description

Technical field The present invention relates to a method for extracting tannins from grape seeds and a plant for implementing this method. Background Grape seeds are the seeds of grape berries, wherein a grape berry comprises skin, pulp and seeds. The fundamental feature of grape seeds is their high content of polyphenols and oils. This peculiarity makes grape seeds a valuable source for the production of antioxidants with a high content of polyphenols and edible oils (grape seed oil). Grape seeds are also used in the wine production process as, together with the skins, they are responsible for the release of polyphenols with organoleptic and sensory functions. The best known and most highly regarded polyphenol, also for its effectiveness and relevance in the organoleptic properties and colour of red wine, is undoubtedly tannin, an element found in grape skins, seeds and stems. However, grape seeds are often a source of bitter and aggressive tannins and, depending on the vintage and grape variety, are a variable that must be considered with great care. In traditional fermenters, the mechanical action and washing away of the pump-overs, combined with the action of temperature and alcohol, dissolve the protective cuticle present in the grape seeds, causing the substances contained in them to pass into the must-wine. Immature grape seeds (which in many vintages can represent significant quantities) will transfer their tannic, bitter and aggressive properties to the product, resulting in wines that are inelegant, rough, with herbaceous notes and, above all, wines that require much more refinement, with increased costs and delays in sale. To improve the quality of a wine in production, the grape seeds are sometimes removed, resulting in processing waste. However, pomace and, above all, grape seeds contain beneficial substances of great biomedical interest. In particular, pomace contains polyphenolic antioxidant molecules belonging to the families of anthocyanins, anthocyanidins, flavones, flavans, stilbenes, phenolic acids, etc. These molecules are all natural antioxidants, such as catechins, rutin, epicatechins, chlorogenic acids, quercetin and resveratrol, which are particularly important for the prevention of myocardial infarction, diabetes, ageing, senile dementia, cancer and more. There is therefore an increasing need to make the most of grape seeds for all their beneficial properties. For this reason, for example, grape seeds can be extracted in the desired quantity from the must during the vinification phase, allowing the oenologist or cellar master to extract the desired quantity of grape seeds during vinification by performing appropriate 'pumping over', with all the known advantages inherent in this type of operation, such as the elimination of unripe grape seeds and the elimination of excess grape seeds. A specific oil can also be extracted from the grape seeds; the process of separating the grape seeds for this purpose may involve separating the grape seeds from the pomace. Furthermore, the waste generated during processing could be used to make other products, such as flour. To date, therefore, grape seeds discarded from winemaking processes are used in areas far removed from the field of oenology. Summary of the invention The technical problem posed and solved by the present invention is therefore to develop a method for extracting tannins from grape seeds. In particular, one aim of the invention is to develop a plant for extracting tannins from grape seeds, specifically a plant capable of implementing an extraction method according to the present invention. Another purpose of the present invention is to develop a method for extracting tannins from grape seeds that is external and independent of a winemaking process from which the grape seeds used have been extracted and discarded. Another purpose of the present invention is to develop a method that does not involve crushed grapes but only grape seeds. Another purpose of the present invention is to develop a method and a plant for extracting tannins from grape seeds that operate with low energy consumption. This task and these purposes are achieved by a method for extracting tannins from grape seeds according to claim 1 and by a plant for extracting tannins from grape seeds according to claim 9. Preferred features of the present invention are the subject of the respective dependent claims. Further features and advantages of the invention will be apparent from the description of a preferred, but not exclusive, embodiment of the electric motor structure according to the invention, supported by the drawings provided for illustrative and non-limitative purposes in the attached tables and listed below. Brief description of the figures Reference will be made to the figures in the attached drawings, in which: ▪ Figure 1 represents a schematic view of a system according to the present invention for carrying out a method of extracting tannins from grape se