HERBAL ESSENTIAL OIL FOR BIOMATERIAL PRESERVATION

Abstract

Compositions and methods for inhibiting the decomposition of agricultural products are provided. A composition comprises a breathable sachet of cyclodextrin-encapsulated plant essential oils, such as thyme oil. Another composition comprises a mixture of a plant essential oil, protein, wax and glycerine used as a coating on at least one inner surface of a defined space such as a storage, shipping or delivery container or a flower sleeve. A method comprises addition of the composition to a defined space containing, or designed to contain, an agricultural product such as a fruit, vegetable or cut flower.

Claims

1. A composition to reduce microbe-mediated decomposition of organic matter in a defined space comprising a breathable sachet of encapsulated herbal essential oil.

2. A composition to reduce microbe-mediated decomposition of organic matter in a defined space comprising a mixture of encapsulated herbal essential oil, protein, wax and glycerine.

3. The composition according to claim 2, wherein the protein is soy protein isolate.

4. The composition according to claim 2, wherein the wax is paraffin wax.

5. The composition according to claim 1 or claim 2, wherein the herbal essential oil is obtained from thyme.

6. The composition according to claim 5, wherein the essential oil obtained from thyme is thymol.

7. The composition according to claim 1, wherein the herbal essential oil is encapsulated in cyclodextrin.

8. The composition according to claim 7, wherein the cyclodextrin is selected from the group consisting of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

9. The composition according to claim 8, wherein the β-cyclodextrin is methyl-β-cyclodextrin.

10. The composition according to claim 1 wherein the sachet comprises Tyvek® membrane, Typar® membrane or Kleenguard® A40 membrane, or Homeguard® membrane.

11. The composition according to claim 1, wherein the microbe mediating decomposition is a species of Botrytis, Listeria, Clostridium, Salmonella, Shigella, Escherichia, Cryptosporidium, Giardia, Cyclospora, Pseudomonas, Xanthomonas, Zoogloea, Frauteuria, Lactobacillus, Pediococcus, and Leuconostoc.

12. The composition according to claim 11, wherein the microbe mediating decomposition is a species of the Botrytis genus.

13. The composition according to claim 12, wherein the microbe mediating decomposition is Botrytis cinerea.

14. A storage container for an agricultural product comprising the sachet according to claim 1.

15. A storage container for an agricultural product comprising a coating of the composition according to claim 2.

16-17. (canceled)

18. A method of inhibiting the decomposition of an agricultural product comprising adding a sachet according to claim 1 to a defined space comprising the agricultural product.

19. A method of inhibiting the decomposition of an agricultural product comprising applying the composition according to claim 2 to a defined space comprising the agricultural product.

20. The method according to claim 18 wherein the defined space is a storage container, a shipping container or a delivery container.

21. The method according to claim 18 further comprising adjusting the humidity in the defined space.

22. The method of claim 18, further comprising encapsulating the defined space with modified atmosphere packaging (MAP) film.

23. The method of claim 19, further comprising encapsulating the defined space with modified atmosphere packaging (MAP) film.

Description

DETAILED DESCRIPTION

[0021] The disclosure provides materials and methods for reducing, eliminating, inhibiting, preventing or delaying microbe-mediated degradation or decomposition of organic matter (i.e., biomaterial) in the form of, e.g., agricultural products such as whole or cut fruits, vegetables, flowers and other ornamentals, and landscaping products. The materials include controlled-release packaging for at least one volatile anti-microbial essential oil, such as Thyme essential oil (e.g., Thymol). Without wishing to be bound by theory, the disclosure packages the volatile active agent in a material exhibiting some permeability to aqueous vapors, but not to aqueous liquids. The organic matter, e.g., agricultural product, being preserved, or having its useful life extended, transpires in a closed or semi-closed environment with the packaged active agent. The transpired water vapor passes through the packaging, displacing the volatile essential oil inside the packaging, leading to its progressive release in a manner that promotes extended inhibition, prevention or delay of microbe-mediated degradation of the organic matter.

[0022] A “breathable” sachet as used herein means a sachet that is permeable to water vapor, but not to liquid water. An example of a breathable sachet material is a flash-spun high-density polyester fiber material such as Tyvek®. In general, house wrap materials, e.g., Typar®, Kleenguard® A40, Homeguard®, and the like, present the desired properties of permeability to water vapor, but not liquid water.

[0023] A “composition” according to the disclosure is any anti-microbial compound or mixture of compounds capable of being transported by a gas (e.g., an aqueous vapor) prior to exerting an anti-microbial effect on a microbe capable of degrading or decomposing, in part, organic matter such as agricultural products including whole and cut fruits, vegetables, flowers and other ornamentals, as well as landscaping materials.

[0024] A “microbe” refers to a microorganism, which may be eukaryotic or prokaryotic, consistent with the meaning of the term in the art. Microbes capable of mediating decomposition of organic matter (plant or animal) according to the disclosure include fungi such as yeast or a mold (e.g., gray mold), a bacterium (e.g., a gram-positive bacterium, a gram-negative bacterium, an archaebacterium), or a protozoan, such as a parasite (e.g., Cryptosporidium, Giardia duodenalis (or G. lamblia), Cyclospora cayetanensis). In general, these microbes mediating decomposition include, but are not limited to, Pseudomonadaceae, including the Pseudomonas, Xanthomonas, Zoogloea and Frauteuria genera, lactic acid bacteria, including the Lactobacillus delbrueckii group, the Lactobacillus/Pediococcus group and the Leuconostoc group, fungi, such as yeasts and molds (e.g., gray mold), and pathogenic microbes, including pathogenic bacteria and protozoan parasites. Exemplary bacterial species according to the disclosure include species of the Botrytis genus, such as Botrytis cinerea, as well as Listeria species (e.g., L. monocytogenes), Clostridium species (e.g., C. botulinum), Salmonella species (e.g., S. perfringens), Shigella species (e.g., S. flexneri, S. dysenteriae, S. sonnei) and Escherichia species (e.g., E. coli O157:H7).

[0025] “Microbe-mediated decomposition” or “microbe-mediated degradation” mean a loss in the apparent health and/or vigor of organic matter such as agricultural products. As those of skill in the art would recognize, a change in color, texture, flexibility, resilience, odor, taste, and other properties known in the art are associated with decomposition or degradation mediated by microbes. These macroscopic signs of decomposition/degradation correlate with the destruction or impairment of biological structures such as plant vessels, leaves, seed pods, and plant cells, also correlating with alterations in the biochemical composition of the organic matter.

[0026] “Organic matter” is given its ordinary and accustomed meaning of carbon-based material that is or was associated with or produced by an organism that is or was a living organism, such as an agricultural product like fruits, vegetables, flowers and other ornamentals and landscaping materials.

[0027] A “defined space” is given its ordinary and accustomed meaning of a delimited space. In the context of the disclosure, a “defined space” is typically produced by a container that provides detectable boundaries defining the environment into discrete regions, such as an inner space or space contained within a container, which is a “defined space.”

[0028] “Breathable” means that gaseous vapor, such as aqueous vapor, can be transported through, such that a “breathable” barrier material is a material that permits the passage, or breathing of vapor such as aqueous vapor.

[0029] “Sachet” is given its ordinary and accustomed meaning of a bag, case, or packet that is semi-permeable to at least one gas or vapor. Sachets are frequently used to release perfumed scents.

[0030] “Encapsulated” means to be encased within, such as when a chemical compound is encased within a compound or composition comprising a hollow or semi-hollow core. Exemplary encapsulating materials are any of the cyclodextrins capable of forming structures comprising internal spaces for entrapping or encapsulating other compounds or materials, sometimes aided by covalent attachment of the entrapped or encapsulated material to the encapsulating compound or composition, such as a cyclodextrin.

[0031] “Herb” is given its ordinary and accustomed meaning of a plant or plant material used for food, medicine, flavoring, or perfume.

[0032] “Essential oil” means a concentrated, aromatic, typically oil-like compound of a plant. Essential oils may be volatile oils.

[0033] “Permeability” is given its ordinary and accustomed meaning of the relative capacity of a material to allow passage of a liquid or gas through the material. In the disclosure, sachet materials are relatively impermeable to aqueous liquids, but exhibit partial to complete permeability to aqueous gases.

[0034] “Cyclodextrins,” also known as cycloamyloses, constitute a family of sugars formed into rings (i.e., cyclic saccharides). Typically, cyclodextrins are glucopyranose units formed into 6-(α-), 7-(β-) or 8-(γ-)membered rings creating internal spaces suitable for transporting other compounds. As those of skill in the art understand, substitution or derivatization at the 2, 3, and 6-hydroxyl positions increases the water solubility of the cyclodextrin carrier, improving the ability of the molecule to function as a compound carrier in biological environments.

[0035] The following examples illustrate embodiments of the disclosure. Example 1 discloses the effect of thyme oil (TO) encapsulated in cyclodextrin and contained within a Tyvek® sachet to inhibit, prevent or delay microbe-mediated degradation of strawberries and blueberries. Example 2 demonstrates that cyclodextrin-encapsulated thyme oil has a protective effect on a flower (Snapdragons). Example 3 shows that thyme oil encapsulated in cyclodextrin inhibits, prevents or delays microbe-mediated degradation of a vegetable in the form of snap beans. Example 4 provides data demonstrating the wide applicability of the protective technology to organic matter such as agricultural products in demonstrating a protective effect on a number of rose varieties.

EXAMPLE 1

Strawberry and Blueberry

[0036] In these experiments, fruit were harvested from local farms, cooled to 5° C. using forced air and, for strawberry, packed in 454 g plastic clam shells (18×11×7 cm) and weighed. For blueberry, 170 g plastic clam shells (10.5×10.5×3.5 cm) were used. Two Tyvek® sachets containing 0.5 g of thyme oil encapsulated in cyclodextrin (TO:CD) were adhered to the bottom of the clamshell package. There are 4 treatments, 6 repetitions/treatment for strawberry and 12 repetitions/treatment for blueberry. For the treatments with modified atmosphere packaging film (MAP), the 6 or 12 treatment repetitions were placed in a box, wrapped and heat-sealed with MAP. Experiments with strawberry (Table 1) and blueberry (Table 2) were done to evaluate the antimicrobial effectiveness of a ratio of 16:84 thyme oil (TO, from Thymus vulgaris) cyclodextrin (CD) capsules enclosed within a Tyvek® sachet on strawberries stored for 8 days, and blueberries stored for 30 days at −1° C. with 94% humidity, with or without MAP (View Fresh A bag), or TO:CD sachets. Fruit stored using MAP (VFA bag) and TO:CD sachets had significantly less decay and less weight loss.

TABLE-US-00001 TABLE 1 Effects of TO:CD sachets on strawberry fruit quality after 7 days storage at −1° C..sup.a Change in Disease weight Total Soluble Incidence after Firmness Solids (TSS) Treatment (%) 7 days (g) (N/cm.sup.2) (° Brix) −TO:CD sachet + 36.4a −1.81b 6.75b 7.22b VFA bag −TO:CD sachet − 22.4b −9.99a 7.94b 8.03a VFA bag +TO:CD sachet − 13.9c −8.21a 7.94b 7.13b VFA bag +TO:CD sachet + 11.3c −5.88b 9.39a 8.03a VFA bag .sup.aMeans in the same column with the same letter are not significantly different (P ≦ 0.05).

TABLE-US-00002 TABLE 2 Effects of TO:CD sachets on blueberry fruit quality after 30 d storage at −1° C. and 3 days at 15° C..sup.a Total Disease Soluble Incidence Change in wt Firmness Solids (TSS) Treatment (%) after 7 d (g) (N/cm2) (° Brix) −TO:CD sachet + 42a −10.2b 13.5a 12.6b VFA bag −TO:CD sachet − 40a −27.6a 12.2b 14.3a VFA bag +TO:CD sachet − 42a −25.6a 12.3ab 12.7b VFA bag +TO:CD sachet + 28b −12.8c 13.4ab 12.3b VFA bag .sup.aMeans in the same column with the same letter are not significantly different (P ≦ 0.05).

EXAMPLE 2

Snapdragons

[0037] Six to eight snapdragon stems were placed in a bunch and wrapped in MAP sleeves (PEAKfreshUSA) fitted with 3 sachets either made of thyme oil encapsulated in cyclodextrin (TO:CD) or CD alone, and then placed in a commercial hydration solution (Chrysal Clear Professional 1) for 16 hours at 5° C. in the dark. Prior to storage, a flower on each stem was inoculated with 5 μL, of Botrytis cinerea conidial spore suspension (2500 spores). After 16 hours, the snapdragons were transferred to cardboard shipping boxes fitted with either two MCP (Ethylbloc™) sachets or without the MCP sachets. The snapdragons were simulated-shipped in the dark at 5° C. for 4 days. The snapdragons were then removed from the boxes, the Ethylbloc™ sachets discarded, and the snapdragon stems placed in vases containing commercial processing solution (Chrysal Clear Professional 2) and held at 5° C. for 1 day. The flowers were then removed from the sleeves, transferred to 25° C., and the stems were cut and placed in commercial vase solution (Chrysal Clear Professional 3) and evaluated for disease incidence and flower shatter.

TABLE-US-00003 TABLE 3 Effect of TO and MCP sachets on disease incidence and flower shatter in cut snapdragons. Disease Flower Incidence (%) Shatter (%) Treatment Day 5 Day 14 Day 5 Day 14 Control 15a 62a 06 32a +TO − MCP 08b 28b 04 14b −TO + MCP 12a 48a 02 04c +TO + MCP 04b 19b 03 06c .sup.aMeans in the same column with the same letter are not significantly different (P ≦ 0.05).

EXAMPLE 3

Snap Beans

[0038] The effect of thyme oil on the resistance of Snap beans to microbe-mediated degradation over time was also investigated. Harvested Snap beans were inoculated with Botrytis spore suspension and placed in MAP bags with and without two TO:CD Tyvek sachets. Percentage of diseased beans was recorded after 3 days at 12° C., as recorded in Table 4.

TABLE-US-00004 TABLE 4 Treatment Disease (%) Control 78a TO:CD 48b

EXAMPLE 4

Roses

[0039] To assess whether the technology disclosed herein would have wide applicability to biomaterials susceptible to microbe-mediated degradation, such as the susceptibility of a variety of cut flowers to such degradation, roses were also subjected to assessments of degradation in the presence or absence of thyme oil. Four varieties of rose were used in the studies, i.e., Parisienne, Akito, Vendela and Lindsey, and these varieties were exposed to Botrytis cinerea, the causative microbe of Gray Mold Disease. Rose flowers were inoculated with a Botrytis cinerea spore suspension, enclosed in a plastic sleeve with either two sachets containing cyclodextrin, or with two sachets containing thyme oil encapsulated in cyclodextrin, and incubated at 4° C. in commercial storage solution. Flowers were wrapped in bunches of six, with three six-flower bunches per treatment regimen. The Parisienne and Akito varieties of rose were examined after 3 days at 4° C. in the presence of Botrytis cinerea, and the results are presented in Table 5. The Vendela and Lindsey varieties were subjected to six days of exposure to Botrytis cinerea at 23° C. and the results are presented in Table 6. The Aalsmeer Gold variety of rose was assessed at 2 and 4 days of exposure to Botrytis cinerea at 23° C. The vase life of the Aalsmeer Gold was also determined. The data are provided in Table 7.

TABLE-US-00005 TABLE 5 Effect of Thyme Oil Sachet on Gray Mold Disease in Cut Roses after 3 days at 4° C. Disease Severity Variety Treatment Disease Percentage Rating.sup.y Parisienne Control 50.0a 2.5a Thyme Oil Sachet 5.6b 0.28b Akito Control 16.7a 0.17a Thyme Oil Sachet 0.0b 0.0a .sup.yDisease severity is the number of disease lesions/flower

TABLE-US-00006 TABLE 6 Effect of Thyme Oil Sachet on Gray Mold Disease in Cut Roses after 6 days at 23° C. Disease Disease Vase Life Variety Treatment Percentage Severity Rating (days) Vendela Control 55.6a 1.3a 12.8a Thyme Oil Sachet 0.0b 0.6a 16.3a Lindsey Control 88.9a 1.9a 9.2a Thyme Oil Sachet 22.2b 1.0a 9.6a

TABLE-US-00007 TABLE 7 Effect of Thyme Oil Sachet on Gray Mold Disease in Cut Roses after 2 and 4 days at 23° C. Disease Severity Disease Severity Vase Life Variety Treatment Rating day 2 Rating day 4 (days) Aalsmeer Control 2.5a 3.7a 5.7b Gold Thyme Oil 1.7b 2.6b 7.9a Sachet

EXAMPLE 5

[0040] The following Example discloses the effect of coating the interior surface of a plastic flower sleeve with a composition according to the disclosure, wherein the flower sleeve contained gerbera daisies or roses. More particularly, three experiments were conducted with gerbera daisies and one experiment was conducted with two different varieties of roses. For each experiment, thyme oil/cyclodextrin (TO/CD) capsules (see, e.g. Example 1) were mixed with soy protein isolate, paraffin wax and glycerine, and the mixture was painted on the inner side of a plastic film flower sleeve. The gerbera flowers were grown in the Rutgers greenhouse and, after cutting, flowers were dipped in Floralife Quick Dip Flowers and were inoculated with a Botrytis cinerea spore solution (5 μL, 10.sup.7 spores/mL) in the center of the disk, and placed in bunches (8-12 flowers) depending upon experiment and availability of flowers. The flower sleeves were closed with rubber bands at the top, and at the bottom around the stem. Flowers were left in buckets with Floralife flower food solution at 5° C. overnight and then placed dry in shipping boxes for three days at 5° C.

[0041] Flowers were taken out of boxes and placed in vases with Floralife flower food solution and put back in the cold room overnight. The next day, the gerbera daisies were taken out of the flower sleeves and transferred to vases with Floralife flower food solution at 23° C. and evaluated for disease after 4 days. We evaluated percentage of flowers with disease, and disease severity with the following scale for disease severity: 1=no infection; 2=inoculation site; 3=entire disc; 4=petals; 5=whole flower. The results are shown in Table 8, establishing that the percentage of flowers with disease was reduced by the protective composition applied to the flower sleeve and establishing that the disease severity was reduced for those flowers maintained in the presence of TO/CD.

TABLE-US-00008 TABLE 8 Effect of Coating Flower Sleeve with Thyme Oil On Maintenance of Cut Daisies CD TO/CD P value Experiment 1.sup.a Diseased Flowers 44.3 20.6 0.014 (%) Disease Severity 1.74 1.32 0.015 Experiment 2.sup.b Diseased Flowers 65.0 41.2 0.05 (%) Disease Severity 2.2 1.49 0.001 Experiment 3.sup.c Diseased Flowers 68.9 45.3 0.023 (%) Disease Severity 2.08 1.67 0.021 .sup.aexperiment 1: 47 Gerbera daisies/treatment .sup.bexperiment 2: CD, 40 Gerbera daisies; TO/CD, 47 Gerbera daisies .sup.cexperiment 3: CD, 66 Gerbera daisies; TO/CD, 58 Gerbera daisies

[0042] The methods described above for the Gerbera daisy experiments were repeated for the experiment on the two varieties of roses (i.e., Blushing Akito and Cool Water). The flowers were grown in Columbia and shipped to facilities at Rutgers University. Botrytis cinerea spore suspension (5 μL, 10.sup.7 spores/mL), was added to the base of an inner whorl of petals.

TABLE-US-00009 TABLE 9 Effect of Coating Flower Sleeve with Thyme Oil On Maintenance of Cut Roses CD TO/CD P value Blushing Akito Diseased Flowers 68.9 49.6 0.045 (%) Diseased 5.8 1.6 0.018 Petals/Flower (%).sup.a Flower openness 4.3 4.2 0.62 Cool Water Diseased Flowers 87.2 85.1 0.79 (%) Diseased 20.5 17.4 0.081 Petals/Flower (%).sup.b Flower openness 4.67 4.45 0.032 .sup.abased on 37.1 petals per flower .sup.bbased on 37.3 petals per flower

[0043] The percentage of diseased flowers was significantly reduced in ‘Blushing Akito’ rose and the number of infected petals was also significantly reduced. In ‘Cool Water’ rose, the number of diseased flowers and the number of petals infected was much greater than with ‘Blushing Akito’ and there were no treatment effects. The natural infection rate for ‘Blushing Akito’ was very low. Only three out of the twenty-four flowers placed directly in the vase at 23° C. after shipping showed symptoms of Botrytis cinerea infection after 7 days, although there was significant petal shatter and stem topple.

[0044] From the foregoing it will be appreciated that, although specific embodiments of the disclosure have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the disclosure.