OA16340A - Traitement fongicide bactéricide et/ou antioxydant des denrées alimentaires par application de formulations comprenant une huile essentielle et un dialkylène glycol. - Google Patents

Abstract

La présente invention concerne le traitement fongicide, bactéricide et/ou antioxydant des denrées alimentaires, au moyen de formulations d'huile essentielle dans un dialkylène glycol.

Description

The present invention relates to new formulations for the treatment of foodstuffs, in particular fruits as well as to the method of treatment by means of said formulations by application to said foodstuffs.

It is important that said foodstuffs do not lose their organoleptic qualities and retain an attractive appearance when they are placed on the market for rapid consumption. However, after harvest, fruits, for example, are commonly stored for relatively long periods before being placed on the market. Phenomena liable to alter the appearance and taste of the fruit are in particular the proliferation of fungi and bacteria on their surface, as well as premature scalds (or "scald") due to oxidized products resulting in blackening of the fruit. the skin. These deteriorations are even more rapid at the level of micro-wounds and cuts appearing on the skin during storage or handling of the fruit.

Many methods exist in the state of the art for the treatment of fruits, which makes it possible to slow down and / or totally or partially prevent the proliferation of bacteria and fungi on their surface.

Thus, application WO 00/32053 describes a process for the fungicidal treatment of fruits and vegetables after harvesting by sprinkling or spraying a composition comprising eugenol, optionally a surfactant and optionally a solvent chosen from alcohols, glycols, water, alkyl esters of carboxylic acid and mixtures thereof, said composition being brought to a temperature of between 40 ° and 60 ° C. However, the processing requires the rapid cooling of the fruits and vegetables.

EP0795272 provides an antioxidant process for fruits and vegetables by immersing or spraying an aqueous composition comprising a terpene and / or polyphenol compound, at a temperature between 40 ° C and 60 ° C. The composition advantageously comprises a surfactant.

WO00 / 32054 mentions a composition comprising eugenol and dipropylene glycol: however this formulation is used for the anti-germinating treatment of potatoes, by dispersing or dissolving in water, then sprinkling.

However, immersion or showering at 40-60 ° C can be phytotoxic and a short application time and / or subsequent cooling of the treated fruit is necessary, thus making the process difficult to carry out.

Immersion and showering do not allow a coating of satisfactory quality.

Finally, these processes require the presence of surfactants which, in fact, affect the penetration of the active principle into the skin of the fruits, so that the active principle is little absorbed and evaporated. It is therefore necessary to use high concentrations and doses of the active ingredient to take this significant loss into account. However, this dose increase has two major drawbacks:

the level of residues which inevitably increases in foodstuffs;

the unpleasant taste and / or odor of eugenol that results from these residues; and the cost of active principle to be used, relative to the quantity effectively effective for the fruit.

Thus, it is desirable to make available new formulations for the treatment of foodstuffs which make it possible to potentiate the activity of the active principle while allowing easy application. The present inventors have therefore demonstrated that the combination of an essential oil and of dialkylene glycol made it possible to potentiate the fungicidal, bactericidal and antioxidant effect of the essential oil, thus making it possible to reduce the quantity of essential oil and of material. active, and therefore to limit residues in processed foodstuffs.

According to a first object, the present invention therefore relates to a fungicidal, bactericidal and / or antioxidant treatment process for foodstuffs comprising the application of a formulation comprising an essential oil and / or one of its constituents or their mixtures in a dialkylene glycol. .

Typically, the formulation can be in the form of a solution. Advantageously, the formulation does not contain water.

Generally, said formulation comprises from 10% to 80% (weight) of essential oil and / or one of its constituents or their mixtures and 20% to 90% (weight) of dialkylene glycol, preferably from 10 to 70% of said constituent and 30 to 90% of the dialkylene glycol.

As foodstuffs, the present invention is aimed in particular at fruits and particularly at the treatment of apples, pears, tomatoes, peaches, citrus fruits, persimmon, pomegranate, kiwi, grains.

The term "essential oil" applied here refers to the essential oil as well as one of its constituents and / or its mixtures. The term "constituent" here refers to

W active constituents, that is to say having a bactericidal, fungicidal and / or antioxidant activity, in particular fungicidal and antioxidant.

Thus, as essential oil, mention may in particular be made of mint oil, and / or thyme oil and / or oregano oil and / or clove oil, as well as their constituents, namely L-carvone, thymol, carvacrol and eugenol respectively and / or mixtures thereof.

Said oils generally comprise from 50 to 90% of said component; thus, clove oil typically contains about 80% eugenol and mint oil about 70% L-carvone.

The term “dialkylene glycol” denotes a compound of formula (I) below:

in which :

- n and m independently represent an integer from 1 to 5,

- j represents an integer varying from 1 to m and k represents an integer varying from 1 to n,

- for each value of j and for each value of k, R ?, R ₂ ^j , R3 ^k and R / identical or different, independently represent a hydrogen atom, a linear or branched hydrocarbon comprising from 1 to 10 carbon atoms , in particular a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms. Preferably, for each value of j and for each value of k, R /, R /, R3 ^k and R ₄ ^k independently represent a hydrogen atom, a methyl, an ethyl, an n-propyl or an ipropyl.

Examples of dialkylene glycol are diethylene glycol, dipropylene glycol, and dibutylene glycol. According to a particular aspect, said dialkylene glycol is dipropylene glycol.

The solution can comprise a mixture of dialkylene glycols of formula (I).

The formulations are in particular in the form of a solution. By "solution" is meant that the essential oil is soluble in dialkylene glycol. Thus, when applying the formulation according to the invention to foodstuffs, the essential oil is distributed uniformly and does not lead to the formation of clumps.

L

The formulations according to the invention exhibit a fungicidal and / or antioxidant activity comparable to concentrated formulations and this at an equivalent total dose of active principle.

The formulations according to the invention also have the advantage of reducing the phytotoxicity which can be observed during the application of essential oils and / or their constituents. Thus, the formulations according to the invention exhibit lower phytotoxicity than the concentrated formulations and this at an equivalent total dose of active principle.

In addition, it has been demonstrated by the inventors that the level of residues is significantly lower in the case of the formulations according to the invention from the first days after application, compared to the concentrated formulations of essential oils and this relative to an equivalent total dose in active principle. This lower absorption rate, especially upon application, in particular slows down the degradation of organoleptic qualities and eliminates phytotoxicity.

On the other hand, the solutions according to the invention are perfectly stable for up to several months, preferably at least one month, at low temperature, preferably down to 0 ° C. This therefore allows the end user to store the formulations in cold rooms, for example.

According to a particular embodiment, the solution can also comprise one or more emulsifiers.

According to the present invention, the term "emulsifier" means any type of agent usually used for this purpose, such as ethoxylated fatty alcohols, ethoxylated fatty acids, ethoxylated alkylphenols or any other nonionic product.

The formulations according to the invention can generally comprise from 0% to 20% by weight, in particular from 0% to 15% by weight and more particularly from 1% to 5% by weight of emulsifier.

The method according to the invention is preferably implemented for the fungicide and antioxidant treatment, and more particularly fungicide.

The application is generally carried out by thermal nebulization.

This can advantageously be carried out by means of Electrofog Xeda or any other device as described in application FR 2 566 681. The boiling temperature of said alkylene glycols being high and that of the oils greater than 230 ° C, it It is possible to carry out thermonebulization at high temperatures and obtain good quality mists. For example, the boiling point of dipropylene glycol is 232 ° C. The thermonebulization temperature is generally 40 degrees lower than the boiling temperature, and therefore in this case is around "L

192 ° C, At this temperature, a good quality mist is obtained, that is to say composed of particles of small size and low distribution, which makes it possible to distribute the essential oil and / or its constituents on the very homogeneously.

Preferably, the formulations according to the invention are applied at a temperature between 170 ° and 230 ° C, in particular between 190 ° and 215 ° C, in the case of thermonebulization. In the case of atomization, the formulations can be applied at temperature between 0 ° and 35 ° C, especially in cold storage rooms.

The amount of formulation according to the invention to be applied to food depends essentially on the method of application selected. In general, approximately 30 to 300 g, generally 100 to 200 g of formulation per tonne of foodstuffs treated, i.e. 3 to 210 gtonne, generally 10 to 140 g / tonne of foodstuffs processed, are applied per application over a period of 6 months. active ingredient, particularly around 75g / tonne of active ingredient. More generally, the applied amount of active principle is adjusted as a function of the storage time.

The application can be continuous or intermittent during the shelf life. Preferably, the application is repeated in the storage enclosure every month at reduced doses compared to the first application. The advantage of this repeated application is to also periodically clean the atmosphere of the chamber by lowering the level of spores in the air and lowering the danger of indirect contamination of healthy foodstuffs by the fungal spores conveyed by the recirculation of a polluted atmosphere.

Thus, for example, the application is repeated every month, with a dose, per application, of between 15 and 100 g, preferably 50 g of formulation per tonne of foodstuffs treated.

According to another object, the invention also relates to a process for preparing formulations according to the invention comprising the step of dissolving an essential oil and / or its constituents in a dialkylene glycol. Preferably, (the dialkylene glycol is dipropylene glycol. The solubilization can generally be carried out with stirring.

The bacterial strains affecting foodstuffs are, for example, Erwînia carotovora or Escherichia coli. As examples of species of fungi, there may be mentioned Fusarium oxysporum, Geoiricum candidum, Gloeosporium fructigenum, Penicillium digitatum, Penicillium expansum, Phytophthora parasitica, Botrytis cinerea, Monilinia fructigena, Aspergillus niger xhL

Figure 1 represents the levels of eugenol residues in the fruits treated with a formulation according to the invention (BIOX CD) and for comparison a concentrated formulation at close equivalent total dose (BIOX C) and a concentrated formulation at mid-total dose (BIOX C mid-dose).

The following examples are given by way of illustration and without limitation of the present invention.

Example 1: Determination of the effectiveness of clove oil (Biox C) and clove oil dissolved in dipropylene glycol (Biox CD) against post-harvest diseases of apples and pears

This study was carried out to evaluate the fungicidal efficacy of the Biox C formulation (containing approximately 80% eugenol) and of the Biox CD formulation (25% clove oil in 75% dipropylene glycol, i.e. comprising approximately 20 % eugenol), each of the formulations being applied by thermonebulization with Electrofog Xeda®, at a temperature of about 192 ° C, and at a concentration of 25 g per tonne for the Biox C formulation (i.e. 20 g / tonne of 'eugenol) and 80 g per tonne for the Biox CD formulation (i.e. 16 g / tonne), on apples and pears. Quasi equivalent total doses of eugenol were therefore applied.

The phytotoxicity of the treatments was also studied for the treated fruits.

Golden apples and Abate pears were harvested and then placed in cold rooms at 1 ° C. The fruits were then inoculated at room temperature. The skin of the fruit was notched on its equator to a thickness of 1 mm and a suspension of pathogenic spores was inoculated. The fruits were dried for 24 hours, then placed again in the storage chamber for the spray treatment.

Three pathogenic strains were inoculated: Botrytis cinerea, Penicillium expansum and Monilinia fructigena. Each inoculated batch was treated respectively with the Biox C formulation and the Biox CD formulation (at 25 g and 80 g of formulation per tonne of fruit respectively). An untreated lot served as a control.

The results were as follows:

Fungicidal activity: All the batches treated provided statistical control of the disease, both in terms of incidence and severity.

Phytotoxicity: some phytotoxicity symptoms were observed with the Biox C formulation. No phytotoxicity was observed with the Biox CD formulation, despite the total dose of eugenol equivalent.

Organoleptic evaluation of the treated fruits: a significant change in taste was detected for apples and pears treated with the Biox C formulation. No change in taste was detected with the Biox CD formulation, despite the total dose of equivalent eugenol. .

Determination of Eugenol Residue Levels: The objective of this study was to determine the eugenol residue levels in apples and pears after application of the Biox C and Biox CD formulations. The results are summarized in the following table:

Test duration Eugenol residues BIOXC BIOX CD A TR. [mg / kg] [mg / kg] 7 days after treatment Apples 5.18 0.91 0.2 Pears 11.7 2.97 0.07 30 days after treatment Apples 0.91 0.39 - Pears 1.24 0.52 0.06

Residue levels after treatment with the Biox C formulation at 7 days on apples were six times higher than with treatment with the Biox CD formulation, and four times higher on pears.

At 30 days after treatment, the residue levels of eugenol with the Biox C formulation on apples and pears were 2.4 times higher than the residue levels obtained with the Biox CD formulation.

FIG. 1 represents the curves of variation of eugenol residues over time with the formulations according to the invention (Biox CD) and the concentrated formulations of eugenol (Biox C). It appears from Figure 1 a sudden drop in residues obtained with the Biox CD formulation from the first days after treatment. This very low level of residues thus reduces the risk of excessive absorption by the fruit in the initial phase, which limits the consequent risks of phytotoxicity and bad taste.

With the formulation Biox CD, the residue value, from the ^20th day, about half compared to the formulation Biox C. This value guarantees the presence of an acceptable residue and the protection of the fruit for about 30 days.

It also appears from Figure 1 that the Biox C formulation used at mid-dose makes it possible to obtain the same residue as the Biox CD formulation at 30 days but with much higher residue values in the first days. These high values lead to significant absorption by the skin of the fruit, with negative impacts in terms of taste and phytotoxicity.

o 8 MAR. 2013

T-OAZENAVEs riéfé Indu5 / nej> XAOUNDE,: ena

CABINI Prc

B.P 501

Phone 22 2

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Cameroon 22 20 64 14 e@iccnei.cm

Claims (12)

1. A method of fungicidal, bactericidal and / or antioxidant treatment of foodstuffs comprising the application of an essential oil formulation and / or one of its constituents or their mixtures in a dialkylene glycol. 2. The method of claim 1 such that said formulation is in the form of a solution. 3. Method according to claim 1 or 2 such that the formulation comprises from 10% to 80% (weight) of essential oil and / or one of its constituents or their mixtures and 20% to 90% (weight) of the dialkylene glycol. 4. The method of claim 1, 2 or 3 such that the formulation comprises from 10% to 70% (weight) of said component and 30% to 90% (weight) of the dialkylene glycol. 5. Method according to any one of the preceding claims, such that the essential oil is chosen from mint oil, thyme oil, oregano oil and clove oil. 6. Method according to any one of the preceding claims, such that said constituent is selected from L-carvone, thymol, carvacrol and eugenol. 7. A method according to any preceding claim such that said constituent is eugenol. 8. Method according to any one of the preceding claims, such that the dialkylene glycol is chosen from diethylene glycol, dipropylene glycol and dibutylene glycol. 9. A method according to any preceding claim such that said dialkylene glycol is dipropylene glycol. 10. Method according to any one of the preceding claims, such that the formulation is applied by thermal nebulization. 11. Method according to any one of the preceding claims, such that between 30 and 300 g of formulation is applied per tonne of foodstuffs processed, for each application. 12. Method according to any one of the preceding claims, such that the application is repeated every month, with a dose, per application, of between 15 and 100 g, preferably 50 g of formulation per tonne of foodstuffs processed.