SYSTEM AND METHOD FOR SMOKE TAINT ELIMINATION IN FRUITS AND VEGETABLES

Abstract

A method and system are described for reducing smoke taint in fruits and vegetables using limited ozone exposures ranging from 1 ppm-hour to 5000 ppm-hour of said fruits and vegetables.

Claims

1. A method for the treatment of fruits and vegetables to reduce the concentration of smoke taint compounds in said fruits and vegetables, comprising: (i) placing said fruits and vegetables in a containerized environment; (ii) raising ozone concentration levels in said containerized environment to expose said fruits or vegetables to ozone exposures varying from 1 ppm-hr to 5000 ppm-hr.

2. A method according to claim 1, wherein the fruits comprise at least one of: wine grapes, table grapes, peaches, nectarines, plums, lychees, mangoes, almonds, pistachios, apricots, dates and cherries, strawberries, raspberries, blueberries, blackberries, red currants, while currants, blackcurrants, apples and pears.

3. A method according to claim 1, wherein the smoke taint compounds include phenolic compounds selected from at least one of: guaiacol, 4-Methylguaiacol, phenol, syringol, catechol, m-cresol, p-cresol, o-cresol, 4-Methylsyringol, 4-Ethylguaiacol, and 4-Ethylphenol.

4. A method according to claim 1, wherein the smoke taint compounds include phenolic compounds selected from at least one of: Guaiacol rutinoside, Methylguaiacol rutinoside, Syringol gentiobioside, Methylsyringol gentiobioside, Cresol rutinoside, and Phenol rutinoside.

5. A method according to claim 1, wherein the smoke taint compounds include compounds selected from at least one of: formaldehyde, acetaldehyde, propional, butyraldehyde; acetone, methyl ethyl ketone; benzene, toluene, ethyl benzenes, fluorene, phenanthrene and pyrene.

6. A method according to claim 1, wherein the ozone exposure is in the range of 20 to 500 ppm-hr.

7. A method according to claim 1, wherein the ozone exposure is in the range of 30 to 100 ppm-hr.

8. A method according to claim 1, wherein the containerized environment is a mobile container that can be readily transported by ship, train or truck.

9. A method according to claim 1, wherein the containerized environment is a building or cold-storage room.

10. A method according to claim 1, wherein the containerized environment is a rotating drum or cylindrical container.

11. A method according to claim 9, wherein the exposure in the building or cold-storage room is performed using circulating-air fumigation.

12. A system to reduce the concentration of smoke taint compounds in fruits and vegetables, comprising: (i) an enclosed container (ii) an ozone generation system (iii) an ozone detection system and (iv) a fan system to regulate air flow within the container, wherein ozone levels in said container are maintained between 1 ppm and 10 ppm for periods ranging from 1 hour to 500 hours.

13. A system according to claim 12, wherein the ozone detection system is an electrochemical system.

14. A system according to claim 12, wherein the air flow is at or above 10 feet per minute around or entering the container holding fruit as described in claim 1.

15. A system according to claim 12, wherein the container walls are made from non-virgin polypropylene resins, nitrile, nylon, or latex.

16. A system according to claim 12, wherein the container is mobile and transportable by ship, train or truck.

17. A system according to claim 12, wherein the container is a building or cold storage room.

18. A system according to claim 12, wherein the container is a rotating drum or cylindrical container.

19. A system according to claim 12, wherein the fan system uses circulating air fumigation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Certain embodiments of the present disclosure will hereinafter be described in detail, by way of example only, with reference to the accompanying drawings, in which:

[0017] FIG. 1 is a diagram illustrating a system demonstrating an embodiment of the present invention.

[0018] FIG. 2 is a diagram illustrating a system configured to implement the method of the present invention.

[0019] FIG. 3 is a diagram showing results from a referenced publishing that indicates consistent decreases in Guaiacol and 4-methyl guaiacol concentrations contributing to smoke taint, and a lack of effect on the polymeric anthocyanin levels from ozone treatment. The original colored version of this figure can be seen in (Modesti, 2021)

DETAILED DESCRIPTION

[0020] In the following paragraphs, embodiments of the present disclosure will be described in detail by way of example with reference to the attached drawings. Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than as limitations on the present disclosure. As used herein, the “present disclosure” refers to any one of the embodiments of the disclosure described herein, and any equivalents. Furthermore, reference to various feature(s) of the “present disclosure” throughout this document does not mean that all claimed embodiments or methods must include the referenced feature(s).

[0021] The current invention discloses a system and method for treating smoke taint in fruits and vegetables, in particular smoke taint in wine grapes in order to improve wine quality.

[0022] Smoke tainted grapes will have phenolic compounds such as guaiacol or 4-methyl guaiacol, as well as other smoke related molecules, of at least 0.5 ug/kg of the fruit crush that must be reduced with gaseous ozone. The following are chemical structures of some phenolic compounds typically found in wood smoke resulting from the pyrolysis of ligno-cellulose:

##STR00001##

[0023] In addition to the above listed volatile phenols, smoke taint and smoke taint markers include the volatile phenols m-cresol, p-cresol, o-cresol, 4-Methylguaiacol, 4-Methyl syringol, 4-Ethylguaiacol, 4-Ethylphenol and the phenolic glycoside compounds Guaiacol rutinoside, Methylguaiacol rutinoside, Syringol gentiobioside, Methylsyringol gentiobioside, Cresol rutinoside, and Phenol rutinoside.

[0024] In addition to the above phenolic compounds, other compounds typically found in smoke include aldehydes such as formaldehyde, acetaldehyde, propional, butyraldehyde; ketones such as acetone, and methyl ethyl ketone; benzene and alkylbenzenes such as toluene and ethyl benzenes, and polycyclic aromatic hydrocarbons (PAHs) such as fluorene, phenanthrene and pyrene.

[0025] The system and method of the present invention destroy smoke compounds in smoke-tainted grapes at much lower ozone exposures than the prior art, while preserving the anthocyanin levels in grapes. The benefit of the instant invention is that 1) using lower concentrations of ozone in commercial practice will require smaller ozone generation equipment at a reduced cost, 2) the smaller ozone generators will use less energy and have lower power costs, and 3) the lower ozone concentrations mitigate the possibility of harm to humans in the event that safety practices are breached and ozone exposure occurs 4) the short exposure ozone treatments increase system throughput thereby reducing treatment costs.

[0026] The method comprises exposing fruits and vegetables in a containerized environment at ozone exposures ranging from 1 ppm-hr to 5000 ppm-hr to destroy common chemicals in wood smoke, more preferentially from exposures ranging from 200 ppm-hr to 500 ppm-hr, and most preferentially from exposures ranging from 30 ppm-hr to 50 ppm-hr. The prior art teaches exposures exceeding 5600 ppm-hr to remove smoke taint from grapes.

[0027] The method of the present invention is applicable to fruits and vegetables affected by smoke taint. Particularly, the method is applicable to fruits selected from wine grapes, table grapes, stone fruit such as peaches, nectarines, plums, lychees, mangoes, almonds, apricots, dates and cherries, berries such as strawberries, raspberries, blueberries, blackberries, red currants, white currants, blackcurrants, apples and pears. Treatment to diminish smoke taint is desired due to high consumer preference for smoke-free smell and taste. This method is also applicable to any produce vegetable such as carrots, tomatoes, eggplants, bell peppers, broccoli, and celery.

[0028] A system of the present invention is a container that is mobile and can be readily transported by ship, train or truck and that applies ozone exposures ranging from 1 ppm-hr to 5000 ppm-hr to destroy common chemicals in wood smoke, more preferentially from exposures ranging from 200 ppm-hr to 500 ppm-hr, and most preferentially from exposures ranging from 30 ppm-hr to 50 ppm-hr. The exposure range between 1 ppm-hr and 5000 ppm-hr can be satisfied, for example, if the container ozone levels are maintained at 1 ppm for 1 hour on the low end, and 10 ppm for 500 hours on the high end. FIG. 1 shows the vertical cross section of a container described herein.

[0029] Fruit is harvested and loaded into standard size harvest bins 1. The loaded bins are stacked on top of each other. With the container loaded with fruit, and the container closed. Power is brought to the container and used to energize the system devices. On-board power is used in cases where the container has a power source, such as in refrigerated shipping containers. Air flow is established through the system using an ID fan system 2. Ozone is generated using either UV light system or corona discharge 3. An electrochemical sensor 4 utilizing a porous membrane is exposed to the air ozone mixture and the ozone diffuses across a porous membrane into a cell containing electrolyte and electrodes generating an electrical signal. The signal strength is a measure of the ozone concentration in ppm or ppb on a volume basis. A controller 5 is communicatively coupled with sensor 4 to adjust the current flow to the ozone generator to maintain the required setpoint ozone concentration in the container. A data logger 6 is used to record ozone compositions and control parameters. On embodiment of the control system is the use of wireless control and data-logging through a web-based server platform enabling remote operation. The system is designed to force air and ozone the bottoms of the pallets, from bottom to top. The ductwork in the container through which the air enters 7 and exits the system 8 is placed and sized in order to create a chimney effect driving air flow uniformly in and out of the bins. A suitable power adapter to power accessory ozone generation and control systems in refrigerated shipping containers is described by Dick, P. H., and Saadat, S, et al. in United States Patent Application 20120309215, “Apparatus for Powering an Accessory Device in a Refrigerated Shipping Container”.

[0030] A catalyst system can be installed in the external fresh air exchange system 9. The catalyst would facilitate the reduction of any remaining ozone to oxygen in order to mitigate the possibility of human exposure to ozone, for instance when venting to indoor spaces. Catalysts such as platinum or Carulite (a zeolite) are suitable for this purpose. The catalyst system should be heated using electrical resistance in order to prevent water from condensing on the catalyst reducing its efficiency. A refrigeration system can also be deployed into the container if fruit cooling is desired. The container size is sized to accommodate multiple standard size harvest bin stacked on top of each other. The larger the container the greater the ozonation throughput.

[0031] The bins and container walls used should be manufactured from materials known to be resistant to ozone. Examples of materials known not to be compatible are non-virgin polypropylene resins, nitrile, nylon, and latex.

[0032] Another embodiment of this invention is where the container is a building or cold-storage room. The ozone generation, sensing, control and data logging equipment are installed and operated in order to maintain the ozone concentration inside the room. Such facilities are widely used to fumigate grapes with sulfur dioxide, and water scrubbing is often used to remove treatment gases from the air upon completion of the process. The room is unattended during ozonation.

[0033] Inside the building or cold room, palletized fruit from the field are stacked in parallel leaving a space between them, and a tarp is placed over top of the system to contain air flow, in order to create a tunnel of forced air flow through the system. A fan system is installer) to draw ozone-containing air though the pallets to ensure uniform treatment as shown in FIG. 2. The fruit is exposed to the required ozone concentration and time as described herein for smoke removal.

[0034] Another embodiment of this invention includes bins or storage containers which are perforated to allow a gaseous mixture to flow through the bins or container allowing the ozonated air mixture to contact the fruit or vegetables held within the bin or container.

[0035] Another embodiment includes a container holding fruit, and said container is of a cylindrical form and does not need circulating air flow. In this form, the fruit itself is rotated therefore the circular air flow is not needed because the process is stagnant in nature and the fruit is exposed due to its movement inside such container.

[0036] It has been found that in these scenarios and embodiments, other than the immediately preceding one, that the air flow around and entering the stagnant containers holding fruit should be preferentially at or above 10 feet per minute (10FPM) to be effective enough to penetrate the fruit held within.

Example 1

[0037] In the aftermath of the September 2020 bush fires in Sonoma and Napa Valley in California, and those in Willamette Valley in Oregon, refrigerated shipping containers with ozone generation, sensing, and control systems were deployed to these regions in attempt to mitigate wine grape smoke taint.

[0038] Post-harvest smoke-tainted grapes, and controls, in standard vineyard field harvest bins were loaded into the containers. Ozone generation, sensing, and control capabilities were added into the circulation fan of each container. A high volume of air was forced down and through the slotted channels of the container, and the air forced up through the grape containers. The systems were operated to provide a forced air chimney effect venting at the top of the container to assure uniform flow through the bins.

[0039] The grapes were exposed to uniform forced air flow ozone concentrations ranging between three and four ppm for twenty-four hours, and then removed and subjected to chemical testing. Table 1 shows the average results from a winery in Sonoma Valley.

TABLE-US-00001 TABLE 1 Impact of Ozonation on Smoke-Tainted Grapes After 24 hour forced air Molecule Control ozone treatment Guaiacol (ug/kg) 2.7 1.0 4-methyl guaiacol (ug/kg) 0.6 <0.5 Catechin (mg/L) 25 22 Tannin (mg/L) 372 366 Polymeric Anthocyanins (mg/L) 24 24

[0040] It has also been shown that this invention can decrease the above mentioned volatile and non-volatile organic compounds, as was reported in MDPII Molecules journal (Modesti, 2021)

[0041] This evidence is supported by FIG. 3 covering the taste of treated wines inside the ozone concentration and time values claimed here within.

BIBLIOGRAPHY

[0042] Antolini, A., Forniti, R., Modesti, M., Bellincontrol, A., Catelli, C., & Mencarelli, F. (2020). First Application of Ozone Postharvest Fumigation to Remove Smoke Taint from Grapes. Ozone Science & Engineering, 1-9. [0043] Bellincontro, A., Catelli, C., Cotarella, R., & Mencarelli, F. (2017). Postharvest ozone fumigation of Petit Verdot grapes to prevent the use of sulfites and to increase anthocyanin in wine. Australian Journal of Grape and Wine Research, 200-2006. [0044] Chen, Z., Sun, Y., Qi, Y., Liu, L., & Zho, Y. (2019). Mechanistic and Kinetic Investigations on the Ozonolysis of Biomass Burning Products: Guaiacol, Syringol, and Cresol. International Journal of Molecular Sciences, 1-14. [0045] Dick, P. H., Cope, D. J., Wang, H., Hoobler, R. J., Weber, M., & Volondin, A. (2008). US Patent No. 2008/0159910 A1. [0046] Dick, P. H., Saadat, S., Hayes, R., Weber, M., & Shannon, M. (2014). U.S. Pat. No. 8,867,187 B2. [0047] Segade, S. R., Vincenzi, S., Giacosa, S., & Rolle, L. (2019). Changes in stilbene compostion during postharvest ozone treatment of “Moscato bianco” winegrapes. Food Research International, 252-257. [0048] Segade, S., Vilanova, M., Giacosa, S. et al. (2017). Ozone Improves the Aromatic Fingerprint of White Grapes. Sci Rep 7, 16301. [0049] Modesti, M.; Szeto, C.; Ristic, R.; Jiang, W.; Culbert, J.; Bindon, K.; Catelli, C.; Mencarelli, F.; Tonutti, P.; Wilkinson, K. [0050] Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes. Molecules 2021, 26, 1798. https://doi.org/10.3390/molecules26061798 Academic Editor: Encarna Gómez-Plaza