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DESCRIPTION

Background of the Invention

The present invention refers to the field of ice cream production and similar food products, in particular it refers to the field of the ice cream production by means of a fluid dynamic process.

Known art

Conventionally the homemade ice cream is produced in ice cream makers with substantially a mechanical and thermal process which, to be carried out, needs tens of minutes or hours.

Usually an ice cream maker for home or professional use comprises a metal container with cylindrical shape combined with a cooling system intervening to feedback adjust the temperature thereof. A vane rotor, rotationally driven by an electric motor, is housed in the cylindrical container. The rotor is coaxial to the cooled container; when the ice cream maker is working the rotor vanes scrapes continuously the inner surface of the container, carrying out the so called batch freezing.

In general, for the object of the present description, with the expression base preparation a substantially liquid mixture of the fresh ingredients of the ice cream or else a substantially liquid mixture of water and/ or milk and an industrial base in powder or paste, specifically for ice cream, or dessert, or else for similar products, such as for example sorbets, slushes, coffees, mascarpone, coffee, hazelnut creams, etc., is intended.

At first the process provides the production of a base preparation, at room temperature, containing for example water and/ or. milk, in a weight percentage -of _. :about 60%, and a base, which can be industrial or homemade. The base preparation is poured into the cylindrical container of the ice cream maker, the container in this step not being cooled and having a room temperature, as the base preparation .

Then the process provides the ice cream maker to be switched on: the vane rotor is rotated in the cylindrical container and the latter is cooled progressively until the respective inner wall reaches a temperature just lower than 0°C, for example -2°C.

The progressive reduction of the cylindrical container temperature causes the crystallization of the base preparation at the inner wall of the container itself. The layer thickness of the base preparation subjected to crystallization is usually comprised between few micron and one millimeter. The rotor vanes take away periodically the crystallized layer of the base preparation, forming again continuously. The crystals the vanes take away are blended again mechanically with the rest of the base preparation.

The afore described process is repeated for a number of cycles, taking care of maintaining the temperature of the inner wall of the cylindrical container constant just below 0°C, causing the slow cooling of the whole mass of the base preparation and the increasing of the respective viscosity, and at the same time preventing the ice crystals with great size to be formed. Further the blending of the base preparation in the container causes the inclusion of little air bubbles in the mass of the preparation itself.

The described process, after several tens of minutes, causes the formation of the homemade or domestic ice cream. The inclusion of the air bubbles imparts creaminess to the ice cream; the little size of the ice crystals imparts an optimal fine texture, perceptible at the palate, to the ice cream. ^■

Disadvanta-geously , the conventional '. vice- 1 - cream production process needs for long times which can not be compatible with the industry needs, but most of all with the needs of the retail: the ice cream seller has to produce the ice cream, and in particular every taste of ice cream, at least one hour before it is sold to the public. The forced reduction of the production times causes inevitably a reduced inclusion of air bubbles and an increase of the average size of ice crystals, with evident adverse repercussions on the quality of the produced ice cream.

As an alternative to the conventional afore described process other processes for producing ice cream have been proposed, which provide the use of cryogenic fluids. For the objects of the present description with the expression cryogenic fluid, fluids which do not change state, from liquid to gaseous, are identified, at a temperature not higher than about -100°C.

For example a process has been proposed, in which the base preparation in a liquid state is inserted into a container, mixed with liquid nitrogen and mixed up to the complete evaporation of nitrogen.

At first the temperature of liquid nitrogen is greatly below -200°C, and the boiling point is about -195°C. The interaction of the liquid nitrogen with the stirred base preparation causes the instantaneous freezing of the preparation in crystals having little size, also lower than the crystal size of the homemade ice cream, on the average; thence an ice cream having a texture comparable to the texture of the homemade ice cream is obtained. Because the heat has been taken away from the base preparation, the nitrogen reaches the boiling temperature and it evaporates in the atmosphere; the widespread cavities present in the forming ice cream, at the beginning occupied by the nitrogen, are then occupied by air, which imparts an optimal creaminess to the ice cream. . ^· . ^■ .■ ^■■ -.·.., An example of an ice cream production process with liquid nitrogen is described in the US Patent 5,098,732.

The drawbacks of the afore described process are due to the difficulties in storage and use of the liquid nitrogen, which can not be confined. The nitrogen must be held in containers in which the liquid and gaseous phases coexist; the container are provided with vents allowing a continuously outlet of the gaseous nitrogen into the atmosphere. Then, necessarily, these containers must be stored outdoor or in closed but well ventilated rooms. In case the air change is not sufficient, the nitrogen gas could saturate the environment, with evident hypoxia risks for persons. Further the liquid nitrogen, when contacting the skin, could easily cause scalds. Again, the continuous release of nitrogen from the container puts a strain on costs .

The use of liquid nitrogen for the ice cream production too necessarily needs for the introduction of convenient safety measures, concerning instruments, procedures and operator training, with evident cost increases .

An alternative process is described in the US Patent 7,781,006. The base preparation of the ice cream is emulsified in liquid carbon dioxide CO ₂ spraying the two liquids through a first nozzle in an environment confined at a pressure of about 10 atm and held therein for about 15 seconds. The obtained emulsion is expanded through a second nozzle; the pressure jump through the second nozzle, lower than 5 atm, is such to cause a phase change of the emulsion, or else to cause an expansion of the C0 ₂ sufficient to cause the instantaneous freezing of the emulsion and the consequent ice cream formation. In practice, the C0 ₂ is used as a propellant gas and at the same time as a gas cooling the emulsion. . ^■ · ^■ : _; : Ί

The main drawback of the process is-, because the C0 ₂ dissolves into the water present in the base preparation, thereby increasing the acidity thereof and giving a characteristic perception of "fizzy" to the final preparation. The acidification of the base preparation causes the accelerated denaturation of the present proteins, with a consequent high loss of quality of the produced ice cream. Further the obtained ice cream is gassy, that it is release slowly C0 ₂ , analogously to what it can be determined with bubbly water in a bottle.

Another drawback of the just described process is because of the need, in an industrial plant, of recovering and recycling the C0 ₂ so that to minimize consumptions and prevent the dispersion of this gas into the environment. Summary of the invention

Object of the present invention is then to provide a process and an apparatus for the production of ice cream, in particular with the aid of a coolant, which overcome the drawbacks of the traditional solutions and at the same time allow obtaining ice cream with features comparable to the features of homemade ice cream.

It is a further object of the present invention to provide a process and an apparatus for the production of ice cream with the aid of a preferably cryogenic coolant, which can be easily and safely applied both in industrial field and in domestic field or in retail.

It is a further object of the present invention to provide a process and an apparatus for the production of ice cream with a preferably cryogenic coolant, which allow obtaining high quality ice cream rapidly, according to the retail needs.

It is a further object of the present invention to provide a process and an apparatus for the ice cream production, in the HoReCa (Hotel-Restaurant-Cafe) field, starting from ready-made capsules. _;

In its' first aspect, therefore the invention relates to a process for the ice cream production according to claim 1. I ^■

In particular, the invention concerns a process for the production of ice cream or similar food products, comprising the steps of:

a) providing a base preparation for ice cream or dessert or similar;

b) nebulizing the base preparation through at least one first nozzle, and

c) intercepting the jet or aerosol of base preparation with at least one jet of an expanding coolant, to obtain ice cream.

The temperature of the expanding coolant is preferably lower than -30°C, more preferably lower than -50°C, for example -70°C.

Preferably the coolant is a cryogenic fluid.

Advantageously, and differently from what provided in the processes according to the above known art, in the process according to the present invention the cooling of the base preparation is not carried out by the first gas, hereinafter defined as propellant gas, which here it has the only task of conveying the preparation itself through the first nozzle. On the contrary the cooling is obtained, instantly or almost instantly, with a second fluid, defined as coolant, which impacts the aerosol of the base preparation downstream of the first nozzle (or the first nozzles if present) while expanding rapidly. In this way an ice cream, dessert or similar product, accumulable in a container, are produced.

The process allows obtaining in less than 5 minutes, for example one minute, ice c.ream having organoleptic, texture and softness characteristics, equal or equivalent to those of the homemade ice cream, for which at least one hour for the respective preparation with conventional ice cream: makers is needed, also using the- same starting raw materials. Therefore the process is advantageously implemented not only in industrial field, but in commercial field too for the retail of ice cream at bar, ice cream parlours, etc., on customer demand.

In the process according to the invention a propellant gas is used, which does not need the additivation of carbon dioxide in the ice cream, that is it does not form a fizzy ice cream, and it does not activate any acidification processes in proteins.

As it will be evident, in the present invention for the cooling of the base preparation is further used a coolant less problematic to manage with respect to the liquid nitrogen .

A further advantage is that the coolant, expanding and intercepting the aerosol exiting from the first nozzle, maximizes the turbulence and, de facto, acts also as a stirrer of the base preparation which is freezing. In this way a satisfactory air inclusion into the so produced ice cream, dessert, or similar food products is obtained.

Preferably the base preparation is composed of water and/ or milk according to a weight percent comprised in the range 40% - 70% and a base for ice cream or dessert or similar, in powder or paste, according to a weight percent comprised in the range 30% - 60%.

The base for ice cream, or dessert, or similar is generally a food product which, conveniently mixed or emulsified with water, or milk, or a mixture of water and milk in the ratio the supplier of the base itself recommended, allows producing ice cream, sorbet, coffee, slush, creams, etc. Food additives, also alcohol - based, colorants, preservatives, stabilizers, thickeners, sweeteners, etc. can be added to the base. Therefore the process according to the invention can be implemented for the production of a plurality of foods o beverages to be served cool . i r -■ < Preferably the step b) is carried out by- means of a technique selected from pneumatic or ultrasonic nebulization .

In the preferred embodiment the step b) is implemented conveying the base preparation through the first nozzle with a propellant gas selected from air, nitrogen, or an inert gas. The suggested gases revealed a little o zero chemical affinity with the base preparation and therefore they are perfect as propellant gas.

Alternatively to the pneumatic nebulization, the process provides the nebulization of the base preparation with ultrasounds, for example by means of an appropriate device with vibrating membrane of the type used in medical field.

Alternatively to the pneumatic nebulization and ultrasounds, the aerosol of the base preparation can be obtained applying a hydraulic pressure surges onto the base preparation fed by the nozzle.

Preferably the propellant gas, for example compressed air, is fed to the first nozzle at a pressure equal to, or greater than, 2 bar, more preferably greater than 5 bar, for example 10 bar or 15 bar.

Generally the pressure of the propellant gas at which the base preparation is nebulized, defined as nebulization pressure or atomization pressure, is inversely proportional to the average diameter of the preparation drops ejected from the first nozzle.

Preferably the process comprises the further step of: d) feedback adjusting the size of nebulized drops of the base preparation by changing the pressure and/ or flow rate of the first gas, and/ or the number of first active nozzles, and/ or changing the minimum through section of said first nozzle.

: In practice the nebulization pressure is adjusted according to the characteristics, of the. base preparation, for example according to the respective density or the possible presence of alcohol, etc. Therefore as the characteristics of the base preparation change, the pressure of the propellant gas and/ or the flow rate of the preparation nebulized in the time unit are feedback adjusted. Such a flow rate can be adjusted changing the number of first nozzles operative in a selected time, or else using first adjustable nozzles, of the variable geometry type. In this latter situation the minimum through section of the first nozzles and/ or the length of the first nozzles can be changed.

Preferably the average diameter of the nebulized drops of the base preparation is comprised in the range 1 - 20 μπι. As the average diameter of the drops decreases, the respective surface transferring heat to the coolant increases. Then a little average diameter, tending to the lowest limit of the mentioned range, is desirable, because it allows minimizing the flow rate of coolant needed to freeze instantly the aerosol and it allows obtaining an ice cream with fine texture.

In the preferred embodiment of the present inventions the coolant is C0 ₂ , in liquid phase or gaseous phase. During the respective expansion this fluid is subjected to a strong temperature drop according to known thermodynamic processes .

Preferably the CO2 expansion is isentropic and/ or supersonic or transonic. Generally the expansion is transonic when the Mach number is comprised in the range 0.8 < Ma < 1, and it is supersonic when Ma > 1. More preferably C0 ₂ starts its expansion from the liquid phase. The liquid CO2 falls within the definition of cryogenic fluid stated above.

It has been observed that with an isentropic expansion of liquid C0 ₂ a biphasic solid - gas jet of C0 ₂ provided with ^' the maximum kinetic energy and minimum enthalpy, is obtained. The process according to the invention can be implemented ' anyway also expanding the gaseous C0 ₂ ; in this case the heat transfer with the aerosol of base preparation is lower with respect to what is found with the liquid C0 ₂ expansion, but anyway sufficient.

With an isentropic expansion of liquid C0 ₂ the maximum weight percent of solid C0 ₂ is obtained, that is dry ice or carbon-dioxide snow, particularly useful because of the high latent heat of sublimation accompanying the phase change of expanded C0 ₂ , from solid to gas.

It has been observed that with a supersonic expansion of C0 ₂ , the efficient freezing and blending of nebulized drops of the base preparation is obtained with the maximum efficiency in terms of consumed C0 ₂ per weight unit of produced ice cream, or similar. The turbulence the C0 ₂ jet/s produced allows obtaining, for example, ice cream with a weight percent of about the 30% of embedded air.

Alternatively the expansion is transonic or subsonic; in this case the efficiency of heat transfer is lower than what can be detected with a supersonic expansion, but it can be sufficient anyway to obtain the desired food product .

Preferably the above described step c) comprises the further steps of:

e) arranging one or more convergent-divergent nozzles downstream of the first nozzle, oriented towards the aerosol of the base preparation;

f) feeding liquid or gaseous C0 ₂ to the convergent- divergent nozzles;

g) expanding the liquid or gaseous C0 ₂ through the convergent-divergent nozzles generating corresponding C0 ₂ jets in a gaseous and/or solid state, and

h) intercepting the aerosol of the base preparation with the C0 ₂ jets in a gaseous and/or solid. state.

^■ The convergent-divergent nozzles are usually identified with the name of de Laval nozzles.

As afore described, the C0 ₂ expansion could generate biphasic solid - gas jets. The percentages of gas and dry ice at the end of the expansion are determined by the thermodynamic conditions of the expansion itself.

Preferably the C0 ₂ pressure before the expansion is comprised in the range 20-70 bar. More preferably, the C0 ₂ is initially confined in an apposite container and the pressure of the gaseous phase in equilibrium with the liquid phase is equal to 55 bar at room temperature. The CO2 container is preferably a cylinder; the cylinder delivery is provided at its upper portion, where the gaseous phase of C0 ₂ is present, or else the cylinder is provided with a plunger and the delivery is at the liquid phase of C0 ₂ .

Generally the expanding C0 ₂ changes almost instantly the temperature of nebulized drops of base preparation to about -70°C.

The step h) is preferably implemented by orienting the nozzles in such a way to maximize the aerosol turbulence of the base preparation.

Preferably the method comprises the further step of: i) adjusting the C0 ₂ pressure fed to the convergent- divergent nozzles and/or feedback adjusting the C0 ₂ flow rate delivered by the convergent-divergent nozzles based on one or more of:

- the flow rate of the aerosol of the base preparation;

- the density of the aerosol of the base preparation;

the protein content of the aerosol of the base preparation ;

- the early temperature of the base preparation;

- the nebulization temperature of the base preparation.

Preferably the base preparation is nebulized in a substantially confined volume, for example an ice cream tub, an ice cream dish, or an industrial receptacle, based whether the process according to the present invention is applied in HoReCa field, or else in the retail field in restaurants, bars, ice cream parlours, etc., or else in industrial field.

In case in which the volume collecting the produced ice cream is a tub or a dish, the process provides the further step, concurrent with the steps b) and c) , of rotating the tub/ dish to obtain the blending of ice cream or dessert collected therein.

Optionally one or more garnishes could be added to the produced ice cream/ dessert successively, for example fruit pieces, concentrated fruit, dried fruit or pieces of chocolate .

Generally the process according to the present invention could be applied both in industrial field, for the continuous or batch production of great amount of ice cream or dessert per time unit, and in commercial area, in retail field, for the production on customer demand and according to his/ her preferences.

Generally the process could provide or not a further step of recovering and recycling at least part of the used C0 ₂ . This step if especially useful if the process if applied in industrial field.

In its second aspect the invention concerns to an apparatus for the production of ice cream and similar food products, according to claim 18.

In particular, the invention concerns an apparatus comprising :

- at least one first nozzle;

- means for feeding said at least one first nozzle with a base preparation for ice cream or dessert or similar, at a first nebulization pressure;

- means for intercepting the jet of base preparation , exiting from said at least one first nozzle with an expanding coolant. .'" : · The temperature of the expanding coolant is preferably lower ^' than -30°C, more preferably lower than -50°C, for example -70°C.

Preferably the coolant is a cryogenic fluid.

Generally the apparatus could comprise a plurality of first nozzles, each fed with a base preparation for a single taste of ice cream, dessert, etc., or else alternatively several first nozzles are fed with the same base preparation, for example to produce in parallel the same ice cream taste on several production lines.

Preferably the means for feeding the base preparation to the first nozzle, or first nozzles, comprise an ultrasonic device, for example of the vibrating membrane type, or a pneumatic device/ circuit.

More preferably the feeding means comprise a container for the base preparation, in fluidically connection with at least one first nozzle, and a circuit for feeding a first gas, the propellant gas, to the container. In principle the apparatus may comprise a container for the base preparation for each first nozzle to be fed, or else a container for a group of first nozzles to be fed.

In an embodiment of the apparatus according to the present invention, particularly adapted for the retail, the container of the base preparation is a capsule at least partially ready-made with a base for ice cream or similar products. For example, the apparatus user or operator provides for mixing water and/ or milk at the base contained in the capsule; alternatively the apparatus itself is provided with an inflow line of water and/ or milk to the capsule, etc.

With the term capsule is intended a disposable container ready-made with the base preparation or the base for ice cream, dessert or similar. The capsule is geometrically configured to be inserted into the apparatus, according to the invention:, to allow the ice cream delivery, and to be ejected once the ice cream has been delivered.

Preferably one or more of the first nozzles are interchangeable and/ or of the variable - geometry type. For example, the first nozzle may be easily replaced with another nozzle having different geometrical features, for example provided with a greater or smaller minimum inner diameter. Alternatively the first nozzle is of the variable - geometry type; for example the nozzle comprises a stator portion and an axially or transversally movable pin with respect to the stator portion to modify the minimum inner diameter of the nozzle and/ or the length of the nozzle. In this way it is possible to intervene on the aerosol flow rate of the base preparation ejected from the first nozzle in the time unit. The so obtained adjustment on the inner diameter of the first nozzle further allows considering possible density changes occurred in the base preparation. For example the variable - geometry nozzles are of blade type.

Independently from the presence or not of first interchangeable and/ or variable - geometry nozzles, preferably the apparatus comprises means for feedback controlling the average size of nebulized drops of the base preparation. Such controlling means in their turn comprise one or more of:

means for adjusting the feeding pressure of the propellant gas to the container of the base preparation;

- automatic means for replacing the first nozzles with other interchangeable nozzles; for example a nozzle changing mechanical device;

- means for changing at least one geometrical feature of the first nozzle, for example means for increasing or decreasing the minimum through section of the variable - geometry nozzle, and/ or the nozzle length, etc. i

As afore described, the average diameter of . the aerosol drops of base preparation/is related to the heat transfer surface between the same drops and the expanding coolant. Therefore it is useful to have means for changing the average drop diameter in a range comprised between 1 and 20 microns, so that to be able to change at one's pleasure not only the texture of produced ice cream, but the cooling conditions of aerosol too.

In an embodiment the apparatus comprises a device for heating and/or cooling the container of the base preparation.

For example, the container is heated with an electrical resistor; the generated heat can be used to heat up washing water which can be fed with prearranged frequency to first nozzles in order to clean them and prevent the clogging thereof. For example, the container is cooled with Peltier cells applied to the respective walls, or else by means of a bypass circuit for the coolant extending at the wall container. The generated cool can be used to realize desserts such as whipped cream, which could need a pre-cooling of the base preparation.

As described relating to the process according to the invention, the coolant is preferably C0 ₂ in liquid and/or gaseous state. The CO2 can be stored in container hermetically isolated with respect to the environment in which they are and therefore the apparatus can be provided with one or more C0 ₂ cylinders. Because of the impact against the aerosol of the base preparation, the C0 ₂ expanding rapidly cools instantaneously or almost instantaneously the drops of base preparation, but it does not bond chemically thereto, therefore avoiding the frizzy ice cream to be created. Alternatively to C0 ₂ the apparatus provides for the N ₂ nitrogen use, 0 ₂ oxygen or an inert gas. Obviously the C0 ₂ is preferred because of cost reasons too .

In the preferred embodiment the means for intercepting . I _. < the aerosol of the base preparation comprise one or more convergent-divergent nozzles, usually known as de Laval nozzles, directed towards the aerosol of the base preparation exiting from the at least one nozzle. The C0 ₂ , or the cooling fluid used alternatively, is fed to the convergent-divergent nozzles, in which the respective expansion and the drastic temperature decrease happen.

Preferably the convergent-divergent nozzles are of the variable - geometry type. For example, each nozzle is composed of a fixed portion and a moving portion with respect to the fixed portion to change its minimum through section the cooling fluid can use. For example the nozzles are of blade type.

Preferably the feed pressure of C0 ₂ to the convergent- divergent nozzles is comprised in the range 20-70 bar, more preferably it is comprised between 40 bar and 60 bar, for example it is equal to about 55 bar.

Preferably the apparatus comprises a controlling unit programmed for feedback adjusting at least one of:

- pressure and/or flow rate of the CO ₂ fed to each of the convergent-divergent nozzles;

- orientation and/or geometry of one or more among the convergent-divergent nozzles.

For example, the nozzles are movable and the apparatus comprises one or more actuators driving the nozzle movements; the controlling unit is of electronic type and it is connected to the nozzle actuators. Still as an example, the apparatus comprises one or more electrovalves for the interception of the C0 ₂ lines and the controlling unit drives the electrovalves to adjust the flow rate thereof and/ or the pressure of fed CO2.

In the preferred embodiments the controlling unit is programmed to obtain the supersonic expansion of C0 ₂ through the convergent-divergent nozzles. The advantages. of this technical choice have been described referring to> the process according to the present invention. Alternatively the expansion is transonic or subsonic.

Preferably the apparatus comprises a compartment for housing an ice cream dish, or an equivalent container, for example a tub, and the apparatus nozzles open into the housing compartment, that is they direct the aerosol or the C0 ₂ jet directly into the compartment, and particularly into the dish or container housed therein.

More preferably the housing compartment is provided with a swivel supporting platform of the dish (or used container) . The platform rotation, for example driven by the controlling unit, allows distributing the ice cream forming in the dish itself optimally. For example the rotation speed of the platform is comprised between 0.5 and 4 rpm. ^'

In an embodiment the apparatus comprises means for feeding one or more ice cream garnishes into said housing compartment. For example, the apparatus is provided with receptacles containing different garnishes (crushed hazelnuts, praline, chocolate pieces, etc.) and with slides to feed these garnishes by gravity into the dish full of the just produced ice cream.

The person skilled of the art will comprise that the method and the apparatus according to the present invention are usable both in industrial field for the production of great amounts of ice cream per time unit, and in HoReCa field or in domestic field, for the production of ice creams, desserts or similar in a few seconds and with high qualitative features. Examples of cool food products which can be produced by means of the process and the apparatus of the invention are, in addition to ice cream, the semifreddo, sorbets, cold coffee, slushes, creams and whipped cream.

In particular- the apparatus may advantageously,: be realized in compact and transportable size, so- that it. 'can be installed in bars, ice cream parlours or houses. For example the apparatus is provided with a cylinder of liquid C0 ₂ , of little size, and with a line for the compressed air connectable to the compressor usually present in the bar machine for the beer delivery. For the domestic field the apparatus is provided with a cylinder of compressed air and with a cylinder of liquid C0 ₂ and both the cylinders are interchangeable when they are used up.

Brief description of the figures

Further characteristics and advantages of the present invention will be more evident from the following description of its preferred embodiment, made herein below, for illustration purposes only and without limitation, with reference to the attached figures, wherein:

- - figure 1 is a block diagram referring to the method according to the present invention;

- - figure 2 is a principle scheme of the apparatus according to the present invention.

Detailed description of a preferred embodiment of the invention .

Referring to attached figure 1, the steps a) - c) of the method according to the present invention are schemati zed .

The process will be now described in detail with reference to figure 2, which represents a principle scheme of an apparatus 1 according to the present invention.

The apparatus 1 comprises at least one container 2 of the base preparation P. The container 2 could have different size according to the application field, industrial or domestic or HoReCa, in which the apparatus will operate.

In general the base preparation P can be obtained, for example, by mixing fresh ingredients of the ice creams, such as milk, sugar ¹ , eggs, etc., or mixing or. emulsifying a semifinished or ^; pretreated base for ice cream, genera ^' . iy sold in powder or paste form, with water and milk. The mixing or emulsion in water or milk can be obtained with known methods, for example by stirring or centrifuging the base and the water/ milk.

For example, the mixing is carried out before the pouring of the base preparation P into the container 2 (premixing) , or alternatively directly into the container 2. In this case the user pours the water or milk into the container 2 in which an electric whisk of the apparatus 1 (not shown) can be activated.

When desired, thickeners can be added to the base preparation P such as, for example, carob flour, agar, pectin, etc., and/ or sweeteners such as, for example, sugar, saccharose, dextrose, honey, etc. This case is indicated by means of corresponding blocks with dotted line shown in figure 1.

In HoReCa field or in private field the container 2 is preferably a capsule, of the disposable type, which can be inserted into the apparatus 1 for the production of an ice cream, sorbet, beverage taste, etc. The capsule is preferably made in plastic, or else in aluminum and it is closed hermetically by a film which can be lacerated or it is adapted to be removed by the user or the operator. Then the apparatus may comprise a punching element having the function of lacerating the capsule film during the delivery of the base preparation P; alternatively the film closing the capsule is removed by the user/ operator before the respective use of the apparatus 1.

In case in which the container 2 is a capsule, the water may be contained in its inside, in a chamber separated with respect to the chamber in which the industrial base in powder or paste is packaged. A diaphragm separates the two chambers; the diaphragm can be lacerated or broken by the user, so that to obtain the mixing of the water and the base before the capsule could., be.' : rins.erted into the apparatus 1. The same user agitates the capsule to emulsify the base into the water.

The container 2 is fluidically communicated with a feeding line 3 of propellant gas, for example air, nitrogen, an inert gas, etc. The line 3. is part of the apparatus 1 or else it is an outer line existing in the environment in which the apparatus 1 is installed.

The line 3, for example a metal braid - strengthened hose, or else a metal duct, is in its turn connected to a cylinder 4 in which the propellant gas is contained, in gaseous or liquid phase. Along the line 3 an on/ off valve 31 is arranged, preferably an electrovalve .

Alternatively to the cylinder 4, the line 3 is connected to an outer compressor (not shown) .

The nebulization is obtained by spraying the base preparation through a first nozzle 5 fluidically communicating with the inner volume of the container 2. In general the number of nozzles 5 arranged for the base preparation nebulization can be more than one per each provided container 2.

Preferably the nozzle 5 in interchangeable with other nozzles having different geometrical features. For example, the apparatus 1 comprises a selection station, comparable to a tool changing station of a numerically controlled machine, provided with a set of interchangeable nozzles; according to the nature and density of the base preparation the station selects the most appropriate nozzle.

Alternatively or in addition, the nozzle 5 has a variable geometry. For example the nozzle 5 comprises moving portions to allow the adjustment of the minimum through section.

Downstream the container 2 and upstream the nozzle 5, a valve 21 for intercepting the flow of the base preparation is. i provided. The valve 21 is preferably an electrovalve too.' . ^· ■ ^■ The apparatus comprises a controlling unit CU connected to the intercepting valve 31 and the intercepting valve 21 for the respective feedback activation and adjustment. The controlling unit CU is programmed to change the opening of the valves 21 and 31 to close, open or choke the respective gas and base preparation flow rates into the respective lines based on one or more features of the nebulized preparation or the produced ice cream IC. One detectable feature is, for example, the average diameter of the drops of the base preparation ejected from the nozzle 5. In industrial field this characteristic can be easily detect by optical means. The valves 21 and 31 are preferably arranged to allow also the pressure adjustment in the respective lines.

Preferably the apparatus 1 comprises means for adjusting the wall temperature of the container 2. These means comprise a heating element and/ or a cooling element. In the example shown in figure 2 the container 2 is surrounded by an electrical resistor 6 which can be feedback turned on and adjusted by the controlling unit CU . The heat produced by the resistor 6 is used to heat the washing water usable periodically to wash the container 2, the nozzle 5 and the possible ducts of the apparatus 1. This feature is useful especially in commercial field, when the apparatus is cleaned and turned off at the end of the day. In addition or in alternative to the resistance 6, the apparatus comprises a cooling element (not shown) active on the wall of the container 2, selected from a Peltier cell, a vaporizer of a cooling system, etc. The produced cool may serve occasionally to pre-cool the base preparation before the respective nebulization; for example the cool is useful to produce food products such as whipped cream.

With the reference numeral 7 the aerosol of the base preparation, 'exiting ^' from the nozzle 5 is ; indicated. The aerosol is composed of base preparation drops ^■ ■ who.se ^■ < average diameter is comprised in the range 1 - 20 microns. ^: The feedback adjustment of the geometry of the nozzle 5 or the respective minimum diameter, by the controlling unit CU, allows obtaining the desired average diameter for the drops of aerosol 7.

In the example shown in figure, in which the propellant gas is air or nitrogen, the nebulization pressure is equal to about 5 - 15 bar. In other words, the propellant gas in the line 3 is fed with a pressure comprised between 5 bar and 15 bar and the pressure itself presses against the free surface of the base preparation P inside the container 2; the base preparation P is pushed through the nozzle 5 by means of this pressure.

The aerosol is sprayed in a substantially confined environment, preferably a compartment 16 for accommodating a collecting container 8, anyway provided with vents to allow the propellant gas to come out. In the example of figure 2, the confined environment is defined by the inner volume of an ice cream dish or tub 8, for example of the plastic type usually used in ice cream parlours. The produced ice cream IC is collected in the dish 8.

Preferably the cup 8 is supported in an appropriate accommodating compartment 16, on a swivel platform (not shown) of the apparatus 1. The rotation in the platform plane, which is driven by the controlling unit CU too, is given to the cup 8 to allow an uniform distribution of the ice cream IC in its inside.

The apparatus 1 comprises one or more convergent- divergent nozzles 9 and 10, for example de Laval nozzles, placed at a countercheck surface 51 of the apparatus 1 against which the cup 8 is substantially displaced in abutment to obtain the confinement with respect to the surrounding environment. The convergent-divergent nozzles 9, 10 are directed to intercept the aerosoli downstream the nozzle 5 with the corresponding jets.. 'Preferably the nozzles 9 and 10 can be orientated, more preferably they are provided with actuators, controlled by the controlling unit CU, to drive the motion. Alternatively to the convergent-divergent nozzles 9, 10, the apparatus 1 may comprise a single toroidal nozzle surrounding the aerosol 7.

The convergent-divergent nozzles 9, 19 are connected to a supply 13 of a coolant, for example a cylinder, from a line 11. The line 11 is in its turn intercepted by a valve 12, preferably an electrovalve driven and controlled by the controlling unit CU.

In the example shown in figure 2, the coolant is CO ₂ stocked in the cylinder 13, in gaseous and/ or liquid form.

Preferably the stocked C0 ₂ is liquid, and therefore it is a cryogenic fluid; in this case the greatest possibilities of having the expanding C0 ₂ generating dry ice are obtained. The pressure of the gaseous phase, which usually is in equilibrium with the liquid phase in the cylinder 13, at room temperature, is comprised between 50 and 70 bar. This is the feed pressure of the C0 ₂ to the convergent-divergent nozzles 9 and 10, short of the choking intervention of the electrovalve 12 by command of the controlling unit CU.

In an embodiment the cylinder 13 is provided with a plunger which withdraws the liquid at the bottom; in another embodiment the delivery of the cylinder 13 is at the upper portion of the cylinder itself, and then it withdraws the gaseous phase of C0 ₂ .

During the passage through the nozzles 9 and 10, the C0 ₂ expands generating jets 14 and 15, containing a gaseous and/ solid phase (dry ice), which intercept the aerosol 7. The interaction between the jets 14 and 15 and the aerosol 7 of the base preparation P is substantially of thermal and kinetic type: the jets 14 and 15 freeze almost : immediately the aerosol' .7 at about -70°C and increase ^' the turbulence inside the dish 8', with the result that the aerosol 7 deposits on the bottom of the dish 8 as ice cream IC ready to be eaten.

The nozzles 9 and 10, and the pressure and flow rate of C0 ₂ are preferably selected to obtain an isentropic and supersonic expansion which, for the above described reasons, allow obtaining the better energy yield in terms of C0 ₂ usage per unit of produced ice cream IC.

Now it will be described the operation of the apparatus 1 referring to an application in HoReCa field., for example an application in the retail field in a bar.

The barman pours the base preparation P into the container 2 or, in alternative, puts a capsule 2 containing the selected base preparation P inside the apparatus 1. Further the barman arranges a dish 8 into the compartment 16 and activates the apparatus 1. The controlling unit CU drives the opening of the electrovalves 31 and compressed air is fed from the cylinder 4 into the container/ capsule 2. The controlling unit CU further drives the opening of the electrovalves 21 and in this way a spray 7 of the base preparation through the nozzle 5 is obtained. At the same time the controlling unit CU drives the opening of the electrovalves 12 and the liquid C0 ₂ flows along the inflow line 11 to the convergent-divergent nozzles 9 and 10. The C0 ₂ expands thus creating the jets 14 and 15 striking the spray 7 of the base preparation. An ice cream IC collecting on the bottom of the cup 8 is thus obtained.

If the apparatus if provided with the moving platform, the controlling unit CU can drive it to rotate the cup 8 around its own vertical axis to obtain an uniform distribution of the ice cream IC in its inside.

When the base preparation P is used up, the controlling unit CU closes the electrovalve 31, 21 and 12. If present, means for feeding possible gaxnishes into the dish: 8y ^■ -for ¹ ;example crushed hazelnuts ):;. a e' activated . The barman takes the dish 8 from the apparatus 1 and he/ she delivers it to the customer, or else' he/ she delivers another ice cream taste into the dish 8 by repeating the preceding steps with a capsule different from the preceding one.