Compositions for preventing fungal decay of post-harvest fruits, vegetables and flowers, methods and uses thereof

Abstract

The present invention relates to a composition for preventing fungal decay of post-harvest fruits, vegetables and flowers, its method and use.The composition of the present invention contains beta-cyclocitral (β-cyclocitral) as the only active ingredient, inhibits or retards the growth of fungi on post-harvest fruits, vegetables and flowers, and provides excellent results in the preservability and shelf life of these products.Furthermore, the method of preventing fungal decay of post-harvest fruits, vegetables and flowers of the present invention comprises applying the composition directly to the product or to the surface of a container or package by different means or techniques.

Description

[Technical field]

[0001] The present invention relates to protecting post-harvest fruits, vegetables and flowers from attack by organisms that cause decay, such as fungi.In particular, the present invention relates to compositions that contain beta-cyclocitral as an active ingredient, and their use for preventing fungal decay in post-harvest fruits, vegetables and flowers.The present invention also relates to a method for preventing fungal decay in post-harvest fruits, vegetables and flowers. [Background technology]

[0002] Fruits and vegetables are important components of the human diet worldwide. They are known for their high water content and for providing consumers with abundant amounts of amino acids, minerals and vitamins. They are reported to be best consumed fresh. However, damage during harvesting and handling, physiological changes during storage and pathological attacks are known to reduce their shelf life and affect their nutritional quality and health benefits [1].

[0003] Post-harvest losses can be defined as the deterioration in both quantity and quality of a food product from harvest to consumption. Quality losses include those that affect the nutritional / caloric composition, acceptability, and edibility of a given product.[2]

[0004] In general, post-harvest losses of fruits and vegetables are influenced by many factors [3]. These factors include losses due to physical, physiological, mechanical and hygienic conditions. Fruits and vegetables are primarily characterized by high metabolic activity and are known to have a short shelf life. As a result of these factors, a significant percentage of losses occur between the harvest and consumption of the produce [4,5].

[0005] In addition, other factors such as insect and mite damage, diseases caused by non-infectious pathogens and pathological spoilage also cause postharvest losses of fruits and vegetables. However, among them, pathological spoilage is the most serious, followed by mechanical damage. The combination of pathological spoilage and mechanical damage causes serious damage to fresh produce [6,7].

[0006] Environmental factors such as temperature, relative humidity and oxygen balance, especially during storage, are also major contributors to spoilage; environmental conditions such as temperature and humidity also make fruits and vegetables more susceptible to pathological attack.

[0007] Fruits and vegetables are also susceptible to damage from microbial attack. Microbial spoilage and deterioration usually begins around the wound and is exacerbated by moisture and insect migration into storage. It has been reported that 10-50% of produce losses and food waste occur after harvest.[1]

[0008] Microbial spoilage is mainly caused by fungi, bacteria, yeasts and molds. However, the majority of fruit and vegetable losses during the postharvest period are due to diseases caused by fungi and bacteria. Fruits and vegetables are prone to attack by these organisms due to their fleshy nature [8]. Many of the fungal pathogens are already present in unripe fruits, but remain quiescent during fruit development until certain stages of fruit ripening and senescence

[17] .

[0009] Food losses due to fungal spoilage are common in fresh produce such as fruits and vegetables, and sources of contamination range from pre-harvest (irrigation water, soil, contaminated seeds) to post-harvest (handling, storage and transport, cross-contamination).

[0010] Fungal decay can also occur in other products such as flowers. Once decay has occurred, the flowers are hardly fit for commercialization. Cut flowers are a highly perishable commodity and are often traded over long distances, as production centers are mainly located near the equator, while the main consumers are in Europe and North America. The main problems throughout the post-harvest period are temperature control, hydration and flower fertilization management, and the presence of fungal pathogens (especially Botrytis)

[18] . Due to multiple uncertainties along the supply chain, microbial contamination leading to spoilage and post-harvest losses can occur at any stage of the continuum from the farm or field to the consumer. Therefore, post-harvest treatment is essential to minimize microbial spoilage of fresh fruits, vegetables [9] and flowers and to reduce the risk of pathogen contamination.

[0011] A variety of post-harvest physical, chemical and gaseous treatments can be applied to maintain the fresh-food quality with high nutritional value and to meet fresh-food safety standards. These post-harvest treatments are usually combined with appropriate storage temperature controls.

[0012] For many years, the most common option has been chlorination in the form of washing with dissolved hypochlorite. Alternative chemical treatments include chlorine dioxide (ClO2), alcohols, copper sulfate (CuSO4), organic acids, hydrogen peroxide (H2O2), ozone gas (O3), and peracetic acid (PAA).

[0013] A common challenge with most chemical treatments is efficacy in dosage and duration without adversely affecting the product. Additional concerns with certain treatments are poor chemical stability (H2O2, PAA, O3), plant safety concerns (ClO2, PAA, O3), and toxicity of residuals (CuSO4, ClO2) [11,12].

[0014] Strategies needed to control these fungi are evolving, taking into account increasing rates of fungicide resistance, tightening regulations on chemical use, and market forces that impose new challenges for food preservation

[10] .

[0015] Although the most effective way to control spoilage of fruits and vegetables is achieved through chemical additives, negative consumer perceptions and stricter regulations on the use of disinfectants have led to increased interest in new alternatives to protect food by replacing synthetic agents with natural compounds

[13] .

[0016] Natural antifungals can be obtained from a variety of sources, including plants, animals and microorganisms. Plant secondary metabolites are an important source of antifungal bioactive substances, particularly essential oils, phenolic compounds, flavonoids and alkaloids.

[14]

[0017] Fraternale Daniele et al. (2014) ("Essential oil composition and antifungal activity of aerial parts of Ballota nigra ssp foetida collected at flowering and fruiting times". Natural Product Communications,9(7)) described a comparative study of the antifungal activity of extracts of Ballota nigra L. ssp. Foetida, derived either from the fruits or flowers of the perennial plant. The main components of the extracts were: β-caryophyllene, caryophyllene oxide, germacrene-D.

[0018] Medjahed, F., et al. (2016) ("Chemical profile and antifungal potential of essential oils from leaves and flowers of Salvia algeriensis (Desf.): A comparative study". Chilean journal of agricultural research, 76(2), 195-200) described a study of the biological activity of essential oils from Salvia algerensis. The oil from the leaves was more active than the oil from the flowers and showed activity against the fungi Alternaria and Fusarium. The main components of the leaf oil were benzaldehyde, eugenol and phenylethyl alcohol. In the flowers, the main components were viridiflorol, globulol and α-cadinene.

[0019] CN110946848A discloses a composition bactericide with bacteriostatic or bactericidal activity that contains several plant essential oils.The composition contains a complex mixture of linalool, terpylenol, geraniol, β-cyclocitral, nerol, myrcene, ocimene, ionone and 2H-β-ionone.

[0020] WO2016 / 170531A1 discloses microcapsules comprising a core containing a complex mixture of essential oils or derivatives thereof and a shell containing an interpolymer complex of at least one polyacid and at least one other polymer; wherein the interpolymer complex is crosslinked with at least one multivalent cationic moiety. The microcapsules can be used to prevent or inhibit crop damage due to infection of crops just before harvest or after harvest.

[0021] Plant-derived compounds, chitosan, lactoferrin and biocontrol agents (lactic acid bacteria, antagonistic yeasts, and their metabolites) can control fungal spoilage in a wide variety of foods

[13] .

[0022] An example of the state of the art regarding the use of natural compounds to protect food is EP3380413A1. Patent application EP3380413A1 describes an antimicrobial solution containing three active substances of plant origin: citral, hexanal and 2-(E)-hexenal, in order to retard the spoilage phenomena associated with the development of spoilage microorganisms (molds, yeasts, bacteria, spoilage agents) in fruit and vegetable products. In particular, the antimicrobial solution is sprayed on the surface of the transport packaging. However, the use of natural compounds such as hexanal and 2-(E)-hexenal leads to changes in the taste and quality of the food.

[0023] There is therefore a need to find natural compounds that inhibit or retard fungal growth in post-harvest fruits, vegetables and flowers, and that do not affect the organoleptic properties or quality and extend the shelf life of said products. Summary of the Invention

[0024] After extensive and thorough research, the present inventors have surprisingly found that beta-cyclocitral (β-cyclocitral) can provide excellent results in the preservation of post-harvest fruits, vegetables and flowers.Because of its fungicidal activity, beta-cyclocitral (β-cyclocitral) can be used in place of or in combination with current treatment agents to inhibit or retard fungal growth, and preserve and extend the shelf life of post-harvest fruits, vegetables and flowers.

[0025] Therefore, the present invention solves the above-mentioned technical problems existing in the art.

[0026] In a first aspect, the present invention relates to a composition for preventing fungal decay of post-harvest fruits, vegetables and flowers, which contains beta-cyclocitral (β-cyclocitral) as the only active ingredient. The inventors have found that beta-cyclocitral (β-cyclocitral) provides excellent results in the preservation of post-harvest fruits, vegetables and flowers. Specifically, this compound inhibits or retards the growth of fungi on post-harvest fruits, vegetables and flowers. As a result, the preservability is improved and the shelf life of these products is extended. In addition, the organoleptic properties of fruits and vegetables are maintained intact.

[0027] Fruits, vegetables and flowers that are to be prevented from fungal decay within the scope of the present invention include, for example, the following species: pome, stone and soft fruits (apple, pear, plum, peach, cherry, mango, strawberry, raspberry and blackberry), citrus fruits (orange, lemon, grapefruit, mandarin), vegetables (spinach, lettuce, asparagus, cabbage, carrot, tomato, pepper, avocado, cucumber and eggplant), ornamental flowers (roses, orchids, tulips, daffodils, marigolds, petunias, bougainvillea and lilies) and edible flowers (citrus flowers, clover, daisy, dandelion, hibiscus, honeysuckle, lavender, lilac, mum, nasturtium, pansy, sunflower and violet). This list is not meant to be limiting in any way.

[0028] The composition of the present invention can be in any dosage form commonly used in the art as long as it is suitable for the purpose of the present invention.When formulating the composition of the present invention, it may add an inert carrier as necessary, and may be in a suitable dosage form such as suspension, emulsion, powder, wettable powder, granular wettable powder, granule, microcapsule, capsule or tablet.

[0029] In addition, the composition contains a further active ingredient, which is eucalyptol. Eucalyptol (1,8-cineole) is an essential oil that is widely used in the field of medicine (antibacterial, expectorant, anti-inflammatory, antihypertensive, etc.). Eucalyptol has relatively strong antibacterial properties against many important pathogenic and spoilage bacteria

[19] . Thanks to this property, it has been tested for use in combination with β-cyclocitral to inhibit or delay the growth of fungi in fruits, vegetables and post-harvest fruits.

[0030] According to the present invention, the combination of beta-cyclocitral (β-cyclocitral) and eucalyptol is shown to be effective against fungal decay of post-harvest fruits, vegetables and flowers.Preferably, the ratio of β-cyclocitral to eucalyptol present in the composition of the present invention is 1:1.

[0031] In a second aspect, the present invention relates to a method for preventing fungal decay of post-harvest fruits, vegetables and flowers comprising applying a composition comprising beta-cyclocitral (β-cyclocitral) as an active ingredient to the post-harvest products, the composition being effective when in direct contact with the fruits, vegetables and flowers or when in close proximity to the fruits, vegetables and flowers without direct contact.

[0032] In one embodiment, the composition used in the methods of the invention comprises an additional active ingredient which is eucalyptol.

[0033] In another embodiment, the compositions used in the methods of the present invention are applied directly to harvested fruits, vegetables and flowers, or to the surfaces of the containers or packaging of harvested fruits, vegetables and flowers, by spraying.

[0034] In another embodiment, the composition used in the method of the present invention is applied by a sticker coated with the composition, which is applied to the surface of the harvested fruits, vegetables and flowers or on the packaging material of the fruits, vegetables and flowers.

[0035] In another embodiment, the compositions used in the methods of the invention are applied directly to harvested fruits, vegetables and flowers or to the containers or packaging of harvested fruits, vegetables and flowers using a controlled release diffuser containing the carrier and the composition.

[0036] The support may be a particulate porous material, a cellulosic material, or a wax-based material.

[0037] The particulate porous material may be selected from the group consisting of zeolites, silica, porous carbon, and mixtures thereof. The composition is releasably loaded into the pores of said particulate porous material. A typical method for loading the composition of the present invention onto the particulate porous material includes spraying the composition or a solution of the composition onto the particulate porous material, and then stirring the solid mixture or suspension to obtain the composition-loaded particulate porous material.

[0038] When the carrier is a cellulosic material, the composition is impregnated into the cellulosic material. A typical impregnation method is to immerse the material in the composition of the present invention or to spray the composition of the present invention onto the material.

[0039] When the carrier is a wax-based material, the composition is impregnated into the wax-based material. A typical impregnation method is to immerse the material in the composition of the present invention or to spray the composition of the present invention onto the material.

[0040] The wax-based materials may be chosen from animal and vegetable waxes (especially beeswax, carnauba wax, candelilla wax, sugarcane wax, rice bran wax, sunflower wax) and petroleum-derived waxes (especially paraffin, microcrystalline waxes).

[0041] In a third aspect, the present invention relates to the use of a composition comprising beta-cyclocitral (β-cyclocitral) as an active ingredient for preventing fungal decay of post-harvest fruits, vegetables and flowers.

[0042] Fungal rot can be produced by fungi belonging to any of the following families: Sclerotiniaceae, Davidiellaceae, Glomerellaceae, Trichocomaceae, Pleosporaceae, Nectriaceae, Endomycetaceae, and Mucoraceae.

[0043] More specifically, the fungus is Rhizopus, Aspergillus, Penicillium, Alternaria, Fusarium, Cladosporium, Botrytis, Geotrichum, Colletotrichum, Monilinia or a combination thereof.

[0044] The following figures are described below, which illustrate exemplary embodiments and are not intended to limit the scope of the invention: [Brief description of the drawings]

[0045] [Figure 1] Figure 1 shows the analytical curves of the % inhibition of Monillia sp. exposed to three different doses of β-cyclocitral (β-CC). The analytical curves were constructed to determine the MID using three different doses of β-CC (20, 50 and 100 μL). The linear regression model was y=c+bx, where c is the intercept and b is the slope of the fitted line. The strength of correlation in each case was judged by the ratio of explained variance, R2, and the significance (p<0.05) of the F-test derived from the analysis of variance (ANOVA) accompanying the regression. The linear model was y=1.01X+4.2047, with an R2 of 0.8982. Based on the model, the dose that inhibits 50% of the hyphal fungus was found to be 45.34 μL of β-CC. [Diagram 2] 1 shows the results of scanning electron microscopy of Monillia sp. spores exposed to the composition of the present invention (A) and unexposed (B) and cultured at 25° C. for 48 hours. Differences were observed in the morphology of Monillia sp. spores. [Diagram 3]1 shows the spore germination inhibition effect of Rhizopus sp. samples exposed to 50 μL of β-CC (A) versus a control (B). [Figure 4] 1 shows scanning electron microscopy results of Rhizopus sp. spores exposed to the composition of the present invention (A) and unexposed (B) and incubated at 25° C. for 48 hours. Differences were observed in the morphology of the exposed Rhizopus sp. spores. [Diagram 5] Strawberries exposed to the composition of the present invention (A) showed less fungal contamination compared to unexposed strawberries (B). [Figure 6] Shown are inedible (A1) and suitable (A2) cherries that had been previously exposed to a composition of the invention, as well as inedible (B1) and suitable (B2) cherries (control fruit) that had not been exposed to a composition of the invention. [Figure 7] The rose exposed to the composition of the present invention (A) shows less mottling compared to the unexposed rose (B). [Figure 8] Sucrose, glucose and fructose content (mg / g) of strawberries exposed to β-CC, β-CC / eucalyptol and unexposed strawberries (control) are shown. [Figure 9] The total sweetness index (TSI) of strawberries exposed to β-CC, β-CC / eucalyptol, and unexposed strawberries (control) are shown. [Figure 10] The sweetness index (SI) of strawberries exposed to β-CC, β-CC / eucalyptol, and unexposed strawberries (control) is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Example 1. In vitro testing of fungi isolated from strawberry (Monilinia sp.) exposed to the composition of the present invention (β-cyclocitral only) The fungus growing on strawberries was isolated and cultured on potato dextrose agar (PDA, Condalab, Madrid Spain) and was identified as Monilinia sp.

[0047] Antifungal activity was measured by the vapor agar contact method previously described by Sekiyama et al.

[15] Fungi were cultured on potato dextrose agar (PDA) at 27°C for 1 week. Fungal spores were then inoculated into the center of the PDA plate and placed aseptically in an open chamber.

[0048] A controlled release diffuser was used as described in Examples 1 and 2. In this example, three doses of β-cyclocitral (β-CC) were used: 20, 50 and 100 μL.

[0049] The diffuser was introduced into the chamber, 6 cm away from the PDA plate, and properly sealed. Incubation in the chamber was carried out at 27°C for 3-5 days. The inhibitory activity was evaluated by measuring the diameter of the colonies formed by the test strains. The minimum inhibitory dose (MID) was defined as the lowest concentration (mg / L in air) of the volatile compound that inhibited colony formation of the test strain by 50%.

[0050] The results obtained are shown in Figure 1. At concentrations of 50 μL and above, inhibition of 60% or more was obtained, and at concentrations of 100 μL, inhibition of 80-100% was achieved.

[0051] Scanning electron micrographs were taken of the fungus Monilinia sp. exposed and unexposed to 50 μL of β-cyclocitral. Electron micrographs were taken at 100 kV using a JEOL 1400 plus electron microscope (Japan) equipped with a GATAN ORIUS 200 high-resolution CCD camera.

[0052] The mycelium was fixed in a 1% (w / v) osmium tetroxide solution in distilled water for 1 h at room temperature. The mycelium was washed eight times with acetone (30, 50, 70, 80, 90, 95, 100, 100%) for 15 min each, and finally dehydrated by immersion in tert-butyl alcohol solution for 30 min three times. The samples were freeze-dried. They were then sputter-coated with platinum-palladium (10 nm) using a Hitachi E-1030 ion sputter (Hitachi).

[0053] The scanning electron microscope images obtained are shown in Figure 2. Morphological differences were observed in Monilinia sp. spores exposed to β-CC. Spores exposed to β-CC for 72 hours (A) had clearer membranes and showed slight decomposition compared to unexposed spores (B).

[0054] Example 2. In vitro study of fungi isolated from strawberry (Monilinia sp.) exposed to a mixture of β-cyclocitral (β-CC) and eucalyptol. The fungus growing on strawberries was isolated and cultured on potato dextrose agar (PDA, Condalab, Madrid Spain) and was identified as Monilinia sp.

[0055] Fungal spores were then inoculated into the center of the compartments on PDA (40 mm diameter) and a small piece of cellulose supplemented with different volumes of β-cyclocitral (β-CC) (the composition of the present invention) and eucalyptol was placed in one of the empty compartments. The plates were incubated at 27°C for 3-5 days and the mycelium growth area and % inhibition were measured.

[0056] Table 1 shows the % inhibition of Monilinia sp. exposed to 25 μL of β-CC, 25 μL of eucalyptol, and a mixture of eucalyptol and β-CC at two different doses (25 μL and 12.5 μL).

[0057] Eucalyptol alone did not show any inhibitory effect and proliferation was similar to the control (unexposed), but when mixed with β-CC, the % inhibition rate of β-CC increased to 86.41% compared to 78.22% for β-CC alone. It can be seen that the activity of β-CC is still high (~70%) when the dosage was reduced to 50% (12.5 μL β-CC).

[0058] [Table 1]

[0059] Example 3. In vitro testing of other filamentous fungi (Phytophtera nicotiana, Taphrina deformans, Colletotrichum, and Rhizopus sp.) exposed to the composition of the present invention (β-cyclocitral only) The inhibitory effect on spore germination of other filamentous fungi, specifically Phytophtera nicotiana, Taphrina deformans, Colletotrichum and Rhizopus sp., was investigated using the steam-agar contact method described in Example 1 with minor modifications as follows: The fungi were grown on potato dextrose agar (PDA) at 27°C for one week. A three-compartment petri dish was used, one compartment filled with PDA and the other two were left empty.

[0060] Fungal spores were then inoculated into the center of the compartments on PDA (40 mm diameter) and a small piece of cellulose supplemented with 50 μL of β-cyclocitral (β-CC) (a composition of the present invention) was placed in one of the empty compartments. The plates were incubated at 27°C for 3-5 days and the mycelium growth area and % inhibition were measured.

[0061] The results obtained for each fungus are shown in Table 2. 100% growth inhibition was obtained for all fungi when the samples were exposed to the composition of the present invention.

[0062] [Table 2]

[0063] Furthermore, Figure 3 shows the results obtained for Rhizopus sp samples.

[0064] Scanning electron micrographs were taken of the fungus Rhizopus sp. exposed to 50 μL of β-cyclocitral and of the unexposed fungus Rhizopus sp. The electron micrographs were taken according to the method described in Example 1.

[0065] Figure 4 shows the scanning electron microscope images obtained. Differences were observed in the morphology of Rhizopus sp. spores exposed to β-CC. Spores exposed to β-CC for 72 h (A) had membranes that were more clearly defined, thinner, and had a different structure and less uniformity compared to unexposed spores (B).

[0066] Example 4. In vivo study of strawberries exposed to the composition of the present invention (β-cyclocitral only) Mature strawberries were brought directly from a local market and delivered to the laboratory within two hours. They were then divided into two groups and each group was placed in a box.

[0067] One group of strawberries was not exposed to any product (control), and another group of strawberries was exposed to a controlled release diffuser containing the composition of the present invention. The controlled release diffusers were prepared by dividing cellulose sheets (0.2 cm thick) into 2 x 1 cm pieces and impregnating them with 50 μL of pure β-cyclocitral (β-CC). These sheets were inserted into polyethylene bags (3 x 3 cm) and then heat sealed.

[0068] The diffuser was placed in the center of one box, 10 cm from the surface of the strawberries. To maintain a homogenous atmosphere, both boxes were covered with plastic bags. The boxes were kept in an acclimation chamber (20°C, dark) until signs of fungal decomposition appeared (approximately 7 days).

[0069] FIG. 5 shows the results obtained, showing less decay in strawberries exposed to the composition of the invention (A) compared to the control strawberries (B).

[0070] Example 5. In vivo study of cherries exposed to the composition of the present invention (β-cyclocitral only) Ripe cherries were brought in directly from Spanish farms and sent to the lab within 24 hours. They were then split into two groups and each group was placed on a plate.

[0071] One group of cherries was not exposed to any product (control) and another group of cherries was exposed to a controlled release diffuser containing the composition of the present invention. The controlled release diffusers were prepared by cutting cellulose sheets (0.2 cm thick) into 2 x 1 cm pieces and impregnating them with 50 μl of pure β-cyclocitral (β-CC). These sheets were inserted into polyethylene bags (3 x 3 cm) and then heat sealed.

[0072] A diffuser was placed at the bottom of one of the plates. The two plates were covered with a plastic bag to maintain a homogenous atmosphere. The box was kept in an acclimation chamber (20°C, dark) for 6 days.

[0073] Finally, the cherries (control and exposed to the composition) were divided into two groups: edible fruits (no signs of fungus) and inedible fruits (signs of fungus).

[0074] FIG. 6 shows the results obtained, showing that about 65% of the cherries exposed to the composition of the invention were suitable for consumption (A2), whereas about 23% of the cherries not exposed to the composition were suitable for consumption (B2).

[0075] Example 6. In vivo study of roses exposed to the composition of the present invention (β-cyclocitral only) The roses were brought directly from a local market and sent to the lab within 12 hours. They were divided into two groups, each of which was placed in a jar filled with tap water.

[0076] One group of roses was not exposed to any product (control) and another group of roses was exposed to a controlled release diffuser containing the composition of the present invention. The controlled release diffusers were prepared by dividing cellulose sheets (0.2 cm thick) into 2 x 1 cm pieces and impregnating them with 50 μL of pure β-cyclocitral (β-CC). These sheets were inserted into polyethylene bags (3 x 3 cm) and then heat sealed.

[0077] The diffuser was placed in the center of the jar, 20 cm from the petal surface. To maintain a homogenous atmosphere, the two jars were covered with plastic bags. The jars were kept in an acclimation chamber (20°C, dark) until signs of fungal decomposition appeared (approximately 7 days).

[0078] FIG. 7 shows that the rose exposed to the composition of the present invention (A) had less mottling compared to the unexposed rose (B).

[0079] Example 7. Sensory analysis of strawberries exposed to a composition of the present invention (β-cyclocitral only) and a mixture of β-cyclocitral and eucalyptol (volatile organic compounds) To verify that the sensory characteristics of fruit are not altered by the use of the composition of the present invention, the following test was carried out.

[0080] The presence of volatile organic compounds (VOCs) was analyzed in three groups of samples: unexposed strawberries (control), strawberries exposed to β-cyclocitral (50 μL), and strawberries exposed to β-cyclocitral / eucalyptol (50 μL) for 5 days.

[0081] On the fifth day of storage, the entire strawberry sample was transferred to a 500 mL headspace bottle and immediately sealed. The sample was incubated at 22° C. for 2 hours.

[0082] After equilibration, the bottom of the container was enclosed around the fruit. Air purified through an activated carbon filter (BDH, 10–14 mesh) was forced into the container (750 ml min -1 ), pulled out from the container (700 ml min -1 ). VOCs were captured on Porapack™ (porous polymeric adsorbent) 50 / 80 mesh (50 mg; Supelco, Bellefonte, USA) fixed to a glass tube (5 mm outer diameter) with two plugs of silanized glass wool. The Porapack™ tube was washed with redistilled diethyl ether (2 ml) and conditioned by heating at 130° C. for 4 h under a stream of purified nitrogen.

[0083] The VOCs collected on the Porapak™ were eluted with 750 μL of redistilled diethyl ether and the samples were stored at −20° C. until chromatographic analysis.

[0084] Four samples (1 μL) from each treatment and control were analyzed using an Agilent 7820A Gas Chromatograph (Agilent Technologies, Santa Clara, CA, USA) equipped with a cool column injector, a flame ionization detector (FID), and an HP-1 capillary GC column (50 μm i.d. × 0.32 mm × 0.52 μm film thickness). Hydrogen was the carrier gas. The oven temperature was maintained at 30 °C for 0.1 min, followed by 10 °C min -1 The temperature was programmed to rise to 250° C. at 100° C. and then held for 38 minutes.

[0085] Mass spectra were obtained by electron impact ionization at 70 eV; the ion species was normal ion (MF-Linear) and the TIC range was 0 m / z to 600 m / z. Spectral data were compared with the mass spectra of the NIST Hewlett-Packard 59942C original library.

[0086] The results obtained are shown in Table 3. No changes were observed in the VOCs released through the fruit, thus confirming that the fruit exposed to the composition of the invention did not change its VOC profile and maintained its organoleptic characteristics.

[0087] [Table 3]

[0088] Example 8. Sensory analysis of strawberries exposed to a composition of the present invention (β-cyclocitral only) and a mixture of β-cyclocitral and eucalyptol (free sugars, total sweetness index (TSI) and sweetness index (SI)). To verify that the sensory characteristics of fruit are not altered by the use of the composition of the present invention, the following test was carried out.

[0089] Free sugar content, total sweetness index (TSI) and sweetness index (SI) were calculated.Three groups of samples were analyzed: unexposed strawberries (control), strawberries exposed to β-cyclocitral (50 μL), and strawberries exposed to β-cyclocitral / eucalyptol (50 μL) for 5 days.

[0090] On the fifth day of storage, the whole strawberry sample was mashed using a pest and mortar, 10 g was transferred into a Falcon tube and centrifuged at 10000 g for 30 min at 4°C.

[0091] 200 μL of the supernatant was added to a 1.5 mL vial, and 800 μL of distilled water was added. The vials were mixed and immediately analyzed on an HPLC system (Agilent, model-e2695, USA) equipped with an Aminex Column 87H. The system was kept at 50 °C and the flow rate was 0.6 ml min -1 The mobile phase was HPLC water with an IR detector, the injection volume was 5 μL, and the concentrations of the separated sugars were measured according to the corresponding standards: glucose, sucrose and fructose.

[0092] The total sweetness index (TSI) is calculated according to the following formula

[16] : TSI = 1.00 x sucrose + 0.76 x glucose + 1.50 x fructose

[0093] The sweetness index (SI) is calculated using the following formula: SI = 1.00 x glucose + 2.30 x fructose + 1.35 x sucrose

[0094] Free sugars were estimated using analytical curves of authentic standards of glucose, fructose and sucrose and expressed as (mg / ml).

[0095] The results obtained are shown in Figures 8, 9 and 10. No changes were observed in the concentrations of glucose, fructose and sucrose (Figure 8). The values ​​obtained for TSI and SI are very similar for the three samples analyzed (Figures 9, 10).

[0096] It was therefore confirmed that the fruit exposed to the product did not change its sweetness profile and maintained its organoleptic characteristics.

[0097] (References) [1] Enyiukwu, DN, Bassey, IN, Nwaogu, GA, Chukwu, LA, & Maranzu, JO “Postharvest Spoilage and Management of Fruits and Vegetables: A Perspective on Small-Holder Agricultural Systems of the Tropics”. Greener Trends in Plant Pathology and Entomology, vol. 3, no. 1, pp. 01-17 (2020). [2] Kiaya, V. 2014. "Post-harvest losses and strategies to reduce them". Technical Paper on Postharvest Losses, Action Contre la Faim (ACF) 25. [3] Yahaya, S. M., and Mardiyya, A. Y.. 2019. "Review of post-harvest losses of fruits and vegetables". Biomed. J. Sci. Tech. Res 13.4: 10192-10200. [4] Hayatu, M. 2000. "Post-Harvest Physiological Studies of Some Selected Members of Family Solanaceae". Unpublished M. Sc thesis. Bayero University, Kano: 2-25. [5] Sani M.Y, Alao, S.E.A. 2006. “Assessment of post-harvest fungi of Tomato (Lycopersicon esculentum) and Pepper (capsicum annum) from selected irrigated areas of Kano State”. Journal of Bioscience 2: 53-56. [6] Mustapha, Y., Yahaya, S.M. 2006. “Isolation and Identification of Postharvest fungi of Tomato (L. esculentum) and Pepper (Capsicum annum) sample from selected Irrigated sites in Kano”. Biological and Environmental Science Journal for the Tropics 3: 139-141. [7] Food and Agricultural Organization. 2011. FAO Statistical-Database. Rome, Italy. [8] Elias, S.N.K., Shaw, M.W., Dewey, F.M. 2010. “Persistent symptomless, systemic and seed-borne infection of lettuce by Botrytis cinerea”. European Journal of Plant Pathology 126(1): 61-71. [9] Olaimat, A.N., Holley RA. 2012. “Factors influencing the microbial safety of fresh produce: a review”. Food Microbiology 32, 1-19.

[10] Davies, C. R., Wohlgemuth, F., Young, T., Violet, J., Dickinson, M., Sanders, J. W., ... & Avery, S. V. 2021. “Evolving challenges and strategies for fungal control in the food supply chain”. Fungal biology reviews, 36, 15-26.

[11] Bastarrachea, L.J., Alborzi, S., Tikekar, R.V., 2019. “Control strategies for postharvest microbiological safety of produce during processing, marketing, and quality measures (Chapter 12)”. In: Biswas, D., Micallef, S.A. (Eds.), Safety and Practice for Organic Food. Academic Press, London, UK, pp. 259-270.

[12] Deng, L.-Z., Mujumdar, A.S., Pan, Z., Vidyarthi, S.K., Xu, J., Zielinska, M., Xiao, H.-W., 2019. “Emerging chemical and physical disinfection technologies of fruits and vegetables: a comprehensive review”. Crit. Rev. Food Sci. Nutr. 60, 2481-2508.

[13] Ribes, S., Fuentes, A., Talens, P., Barat, J.M. 2017. “Prevention of fungal spoilage in food products using natural compounds: a review”, Critical Reviews in Food Science and Nutrition.

[14] Ciocan, I. D., Bara, I. 2007. “Plant products as antimicrobial agents”. Universitatii Ale Stiintifice Analele Al I Cuza. 8:151-156.

[15] Sekiyama, Y., Mizukami, Y., Takada, A., et al. 1994. “Effect of mustard extract vapour on fungi and spore-forming bacteria”. Journal of Antibacterial and Antifungal Agent. 24:171-8.

[16] Magwaza, L.S., Opara, U.L..2015. “Analytical methods for determination of sugars and sweetness of horticultural products-A review”. Scientia Horticulturae, Volume 184, Pages 179-192.

[17] Alkan, N. and Fortes, A.M. 2015 “Insights into molecular and metabolic events associated with fruit response to post-harvest fungal pathogens”. Frontiers Plant Science, Volume 6, article 889.

[18] Loyola, C. E.; Dole, J. M.; Dunning, R. 2019 “South and Central America cut flower production and postharvest survey”. HortTechnology, Volume 29, no 6, pages 898-905.

[19] Safaei-Ghomi, J., & Ahd, A. A. 2010. “Antimicrobial and antifungal properties of the essential oil and methanol extracts of Eucalyptus largiflorens and Eucalyptus intertexta”. Pharmacognosy magazine, 6(23), 172.

Claims

1. A composition for preventing fungal decay of post-harvest fruits, vegetables and flowers, comprising β-cyclocitral as the only active ingredient.

2. The composition of claim 1 , wherein the composition further comprises eucalyptol.

3. 3. A method for preventing fungal decay of harvested fruits, vegetables and flowers which comprises applying a composition according to claim 1 or 2 to said harvested fruits, vegetables and flowers.

4. 4. The method of claim 3, wherein the composition is applied by spraying directly onto the harvested fruits, vegetables and flowers or onto the surface of a container or packaging of the harvested fruits, vegetables and flowers.

5. 4. The method of claim 3, wherein the composition is applied by means of a sticker coated with the composition, the sticker being attached to the surface of the harvested fruits and vegetables or onto packaging materials for the fruits and vegetables.

6. 4. The method of claim 3, wherein the composition is applied directly to the harvested fruits, vegetables and flowers or to a surface of a container or package of the harvested fruits, vegetables and flowers using a controlled release diffuser containing a carrier and the composition.

7. The method of claim 6 , wherein the support is selected from the group consisting of a particulate porous material, a cellulosic material, or a wax-based material.

8. 8. The method of claim 7, wherein the support is a particulate porous material selected from the group consisting of zeolites, silica, porous carbon and mixtures thereof, and the composition is releasably loaded within the pores of the particulate porous material.

9. The method of claim 7 , wherein the carrier is a cellulosic material and the composition is impregnated into the cellulosic material.

10. The method of claim 7 , wherein the carrier is a wax-based material and the composition is impregnated into the wax-based material.

11. 3. Use of the composition according to claim 1 or 2 for preventing fungal decay of post-harvest fruits, vegetables and flowers.

12. 12. The use according to claim 11, wherein the fungal rot is produced by fungi belonging to the families Sclerotiniaceae, Davidiellaceae, Glomerellaceae, Trichocomaceae, Pleosporaceae, Nectriaceae, Endomycetaceae and Mucoraceae.

13. 13. The use according to claim 12, wherein the fungus is selected from the group consisting of Rhizopus, Aspergillus, Penicillium, Alternaria, Fusarium, Cladosporium, Botrytis, Geotrichum, Colletotrichum, Monilinia or combinations thereof.

Images