Food or edible material: processes – compositions – and products – Contacting food in liquid or solid state with exteriorly... – Applied material is biocidal or disinfecting
Reexamination Certificate
2000-10-23
2004-04-20
Wong, Leslie (Department: 1761)
Food or edible material: processes, compositions, and products
Contacting food in liquid or solid state with exteriorly...
Applied material is biocidal or disinfecting
C426S102000, C426S321000, C426S335000, C426S541000, C426S615000
Reexamination Certificate
active
06723364
ABSTRACT:
The present invention relates to a thermal fogging process which is particularly appropriate for the thermal fogging of a liquid treatment composition over fruit and vegetables.
The thermal fogging of liquids over fruit and vegetables stored in closed spaces is now widespread in the art.
A thermal fogging device and the corresponding thermal fogging process are disclosed in particular in FR 84 10 372. This process is more specifically indicated for the thermal fogging of aqueous compositions. Although it results in the formation of a fine mist (at least 90% of the droplets formed have a diameter of less than or equal to 3 &mgr;m), the stability of this mist is not optimal. In fact, the droplets formed have a tendency to rapidly agglomerate to form large drops at the outlet of the thermal fogging device, so that the resulting coating on the fruit and vegetables is not the most even. Furthermore, according to this process of the prior art, the thickness of the coating depends on the duration of the thermal fogging.
These two characteristics render the use of the process of the prior art not very desirable in the case of the treatment of fruit and vegetables.
This is because, as the treated fruit and vegetables are intended for consumption, it is essential for a minimum of residue to remain present on their surfaces after treatment.
A thick coating of the fruit and vegetables is therefore to be avoided.
The process of the invention, by providing a thin and homogeneous coating of the fruit and vegetables and good stability of the mist formed, makes it possible to solve this problem.
The thermal fogging mist produced at the outlet of the thermal fogging device is conventionally composed of droplets exhibiting a temperature of between 150 and 200° C. which are driven with a linear velocity of at most 100 m/s. This mist is usually obtained from an aqueous liquid composition.
The inventors have discovered, surprisingly, that the stability of a thermal fogging mist composed of droplets exhibiting a temperature of greater than 200° C. which are driven with a linear velocity of greater than 110 m/s is greatly increased.
Without wishing to be restricted to any theory, it seems that, under these operating conditions, each droplet has a high electrostatic charge which would make it possible to avoid the agglomeration of the droplets with one another, while providing a monolayer and therefore particularly thin and homogeneous coating of the fruit and vegetables treated, due to electrical repulsion phenomena.
Thus, the invention relates more specifically to a process for the thermal fogging of a liquid composition for the treatment of fruit and vegetables, characterized in that a thermal fogging mist is produced composed of droplets exhibiting a temperature of 200 to 280° C. which are driven with a linear velocity of between 110 and 140 m/s.
It should be noted that the state of the art does not in any way teach that any improvement in the coating characteristics might result from an adjustment of these two parameters in the ranges indicated above. In point of fact, the values usually attributed to these two parameters do not fall in these specific ranges.
In a particularly advantageous way, the temperature of the droplets of the thermal fogging mist is between 210 and 280° C., preferably between 220° C. and 260° C.
In addition, it is preferable for the linear velocity of the droplets to be between 115 and 135 m/s and better still between 120 and 130 m/s.
Usually, in conventional thermal fogging devices, the thermal fogging mist is produced at the outlet of a cylindrical channel by injection, at the inlet of the said channel, of the treating liquid composition into a hot air jet projected at high speed into the said cylindrical channel via the said inlet.
According to a preferred embodiment of the invention, the temperature and velocity characteristics of the thermal fogging mist are obtained in a novel way by use of a nonaqueous treating liquid composition, the temperature of the hot air jet, before injection of the said composition, being set in a highly specific range and the linear velocity of the hot air jet, before injection, being adjusted above 160 m/s.
More specifically, the thermal fogging process employed involves the injection of a nonaqueous treating liquid composition into a hot air jet exhibiting a temperature of between 550 and 750° C. which is driven with a linear velocity of 160 to 400 m/s.
These conditions differ from those recommended in the prior art. According to FR 84 10 372, the hot air is heated to a much lower temperature, generally of at most 500° C.
According to the same document, the velocity for projection of the hot air into the channel, before injection of the treating composition, is generally between 100 m/s and 300 m/s. However, the velocities usually employed in this type of technique hardly ever exceed values of 130 m/s.
The linear projection velocity, before injection, is preferably between 200 and 280 m/s and better still between 220 and 250 m/s.
Likewise, a temperature of the hot air, before injection, of between 600 and 700° C. is particularly desirable. Temperature conditions of 600 to 650° C. are ideal.
According to a preferred embodiment of the invention, the diameter of the cylindrical channel into which the hot air is projected is adjusted to a value of between 12 and 25 mm, preferably between 16 and 20 mm, more particularly between 15 and 18 mm. A particularly appropriate value is about 18 mm.
This parameter makes it possible to more easily adjust the projection velocity of the hot air in the desired range of between 160 and 400 m/s.
The injection of the treating liquid composition into the hot air jet results in a fall in the temperature.
Due to the use of a nonaqueous liquid treating composition, this fall in temperature makes possible the production of a thermal fogging mist which exhibits the desired characteristics and in particular a high temperature of between 200 and 280° C.
Preferred nonaqueous compositions comprise 15 to 100% by weight of an active substance and 0 to 80% by weight (preferably 0 to 60% by weight) of a light organic solvent exhibiting a boiling point of between 70 and 130° C.
The active substance has a protective activity and/or prolongs the storage of the fruit and vegetables. This active substance can exhibit an antioxidant effect, a sprouting-inhibiting effect and/or a bactericidal effect and/or fungicidal effect.
Examples of antioxidants are ethoxyquin, diphenylamine, vitamin E and butylhydroxyanisole.
Examples of sprouting inhibitors are isopropyl chlorophenylcarbamate and some terpenes, such as carvone.
Examples of fungicides are, for example, thiabendazole, iprodione, sec-butylamine and terpenes.
The active substance of the treating composition can comprise one or more of these substances or else one or more substances exhibiting, at the same time, sprouting-inhibiting and/or anti-oxidant and/or bactericidal and/or fungicidal properties.
It is particularly advantageous to use, as active substance, a compound selected from eugenol, isoeugenol, a eugenol salt which is acceptable in foodstuffs, an isoeugenol salt which is acceptable in foodstuffs and their mixtures. In particular, alkali metal salts, such as sodium salts, lithium salts and potassium salts, are particularly preferred salts.
It should be understood that the treating composition can comprise, in addition to the active principle of eugenol or isoeugenol type, another active principle which opposes the growth of bacteria and fungi and/or which inhibits the sprouting of potatoes and onions or which exhibits antioxidant properties.
The active substance is preferably eugenol or isoeugenol, more preferably still eugenol.
One of the particularly advantageous characteristics of the active substances of eugenol and isoeugenol type is the broad spectrum of activity which is associated with them.
These compounds are effective as bactericides, fungicides and inhibitors of the sprouting of tubers (for example potato tubers) and bulbs (for example onion bulbs).
The su
Bompeix Gilbert
Sardo Alberto
Wong Leslie
Xeda International
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