Process and apparatus for making particles of frozen food products.

The invention relates to a method and apparatus for preparing frozen food particles flowing easily. One of the possible areas of application, but wherein the present invention is not limited is that of preparation of particles of frozen food products, high fluidity, to be added to, or deposited on processed food or untreated, such as the deposition on a base cake or pastry molded in advance or, for example, the addition of these particles to the prepared dishes, ice cream, desserts or other culinary preparations. Alternatively, the particulate product can be packaged frozen as a final product itself sold for individual and industrial and commercial consumers.

The use of frozen products for high-flow trim, to be deposited on a cake base or pastry molded in advance can bring many advantages over conventional methods. For example, current commercial practice in the preparation of frozen pizza is to produce and process fittings hot or chilled. Such seals are generally composed of tomato sauce, cheese cut into cubes or flakes, ham cubes, pineapple, mushrooms, salami, ground beef, etc. These pads are made from raw materials or processed products that can be found in the trade. These products are generally deposited on a pizza base, in frozen form or hot.

One drawback of the current method is that these fittings are to be developed from relatively expensive products and high quality, and consequently, they are an important part of the total cost of the finished product. In many cases, the product properties can be changed only in a limited degree, not to the point of reaching an optimum level. For example, grated products into cubes or slices do not flow relatively as they are usually sticky or gooey and it is difficult to allocate result accurately. Similarly, some fruit or vegetables into cubes or slices lose moisture to normal handling temperatures and may be wet or saturated water retaining their evil colors, giving them some nice and unappetizing appearance. In addition, a large number of fittings can be retained only for a limited time, of the order of a few days at the temperature of ice. This means that the manufacturer can often take advantage of market price fluctuations by buying raw materials at a minimum price.

It is an object of the present invention is to provide a method and apparatus to make a free-flowing frozen food product which can be used in the form of a final product marketable intrinsically or in a food preparation comprising the advantages food preparation methods used so far.

According to the present invention, the process consists in preparing the frozen food particles free flowing, consisting of the following stages: raw material supply, freezing the supplied material to a temperature at which it is in a brittle state, then fragmentation frozen material, brittle, to produce particles of high fluidity of the frozen food product.

The food product is delivered, preferably at a controlled rate and its surface is controlled to permit the execution of the freezing phase of the supply to a predetermined speed.

Product freezing phase is preferably carried out by direct heat exchange between the product and a cryogenic substance, although it is also possible according to the invention to use indirect heat exchange, such as putting the product food in contact with a low temperature surface, the temperature of the surface is lowered by putting the opposite side in contact with a cryogenic substance.

In the method preferred direct heat exchange, it is possible to use several ways to perform the heat exchange in question. For example, the food product freezing phase may consist of immersing the product in a bath of cryogenic liquid substance such as liquid nitrogen, to thereby freeze the food product. Alternatively, the freezing phase may comprise spraying a cryogenic substance in direct contact with the food product, gradually as it passes through or is maintained in a freezing zone. In another possible variant, the freezing step may include depositing the product on a solid cryogenic substance, such as for example a bed of dry ice, to thereby freezing said food product.

The temperature reached by the product during the freezing phase is preferably higher than the temperature below which the product of the natural oohésion is insignificant compared to the cohesive force produced by the crystallization. This is to d-iempêcher that the frozen product is excessively brittle or crumbly.

The frozen product of the fragmentation phase is preferably carried out so as to obtain free-flowing particles of a frozen food product with a particle size below a predetermined maximum size. The method further comprises, preferably, a calibration phase of said free-flowing particulate frozen product so as to separate the fine particles of larger size, required to form the final food product particles. The fines can be recycled to supplement the food stocked initially.

The present invention also provides an apparatus for preparing frozen food particles, high fluidity, from a food product initially supplied, said apparatus comprising: a freezing device for freezing the food product at a temperature at which thereof either brittle state, and a splitting device for splitting the frozen food product, breaking from the freezing device, so as to produce particles of free-flowing frozen food product.

In the case where the food product in question is constituted by a liquid or semi-liquid product, the apparatus preferably comprises a feeding device for sending the product in the freezing device, the latter preferably comprising a pumping device operating at a pumping rate which can be selectively adjusted to regulate the flow of the food product supply to the freezing device. Similarly, the pumping device may, preferably, operable to feed the product to the freezing device in a stream at least a predetermined diameter so that this food product flow into the freezing device has a controlled surface exposed to heat exchange to ensure freezing.

If the food product has a viscous consistency, the apparatus preferably comprises a feeding device composed of an extruder to extrude the viscous food product by at least one opening, said extruded product coming out of the or openings being routed to the freezing device. The extruder may conveniently comprise an orifice plate through which the food product is discharged, the orifice in the plate having a diameter of the order of 5 to 25 mm.

The apparatus may further comprise a temporary storage element for receiving the frozen food product at the outlet of the freezing device, and an associated power supply device to said temporary storage element, operative to power the frozen product storage the fractionation apparatus at a controlled rate.

In a possible embodiment, the fractionation apparatus comprises a fractionation crusher having a tank, where the inner walls and the core are located inside, which ring may carry out a relative movement in the tank so as to grind the product food frozen in the space between the core and the inner walls. In this case, the tank may be provided with a plurality of holes of predetermined size, through which the frozen food product and fractionated particles are removed thus allowing to retain oversize particles of the frozen food product in the space situated inside the mill. The minimum interval of predetermined separation between the outer surface of the core and the inner walls of the tank is preferably maintained at all times during the relative movement of the core within the vessel so that the frozen product in this space is not ground into unwanted particle size.

The particles of fractionated frozen product from the fractionator may be routed to a set of calibration orifices acting to separate the particles of insufficient size of the particles of larger size, intended to constitute the final particles of high fluidity of the product frozen food.

The method and apparatus consistent with the various possible preferred embodiments are now described in more detail, partly in conjunction with the accompanying drawings board where:<ul><li>Fig.1 is a block diagram of a preferred method for preparing frozen particles free-flowing foodstuff, according to the invention,</li><li>Fig. 2 is a schematic representation of a first possible embodiment of an apparatus according to the invention,</li><li>Fig. 3 is a view similar to that of Fig.2, illustrating a second possible form of preferred embodiment of the apparatus according to the invention,</li><li>4 is a view similar to Fig.2 illustrating a third possible form of preferred embodiment of the apparatus according to the present invention and,</li><li>Fig. 5 is a schematic view of the fractionation apparatus and sizing part of the preferred apparatus, object of the present invention.</li></ul>

The product to be treated accordingly. the method or apparatus which is the subject of the invention may be selected from a wide range of food products. It can be made in solid form: fruit, vegetable, boned meat, fish without bones or similar. The solid food product may be whole or pre-cut to a suitable size for processing by the method and apparatus object of the invention. Alternatively, the product may consist of substances in the semisolid state, too soft to be cut or flowable under excessive pressure when handling by the usual methods. These semi-solid products include soft fruit, margarine and processed cheese. In addition, the food can be a semi-liquid product difficult or impossible to treat by the methods used for food particles, for example of the semi-liquid products include fruit pulp, the fruits in juice, semi-liquid dairy products. In addition, the product may be in a liquid form which could not previously be treated as particles, for example liquid food products including sauces, concentrates, egg yolk, etc.

The method and apparatus of the present invention can also be used for the treatment of the finer fractions of food by-products of other processes which had hitherto often overlooked. These products can be treated in accordance with the invention by adding a wetting agent or mixable with a liquid carrier and then routed in the form of a food product intended for the process or apparatus in question, either individually or in combination with other products to be treated. For example, fine food and very small particles produced in the preparation of pizzas for packing can be recycled with the addition of a small amount of water or by cheese mixture heat-treated in order to be mixed with the other starting materials.

Another type of food product that can be used as starting material is made of chipboard or soft products such as tights and fragments such as soft cheese fragments, bacon, etc.

It will be understood that the food product to be treated can be fed in its natural form or with the addition, for example, thickeners, stabilizers, water, oil, diluents, preservatives or dyes or other foodstuffs.

In summary, the initial food product can be in liquid, semi-liquid, paste, semi-solid or solid. It may be composed of a single element or a number of elements mixed together. For example, it may be a solid, semi-liquid, pasty or semisolid added mixed solid particles of the same product or other products.

The routing of the food product intended for the first phase of freezing the process or at 10 of the apparatus freezing device can be achieved in any suitable manner. According to Figure 1, for example, from food products can come from a storage device 11, such as hoppers 12, 13 (for solids) or 14.15 tanks (for semi-solid, semi liquid or liquid). The product provided by the storage device₁₁may cross at best a blending stage 16 where additives or other food product is added to the product. Mixing adjuvants or other food products can be achieved by any suitable conventional manner using known techniques or methods.

The transfer of the food product towards the freezing stage 10 takes place at a controlled rate depending on the capacity of the freezing stage 10. The method and apparatus may be adapted to operate continuously or batchwise. Similarly, the transfer of the foodstuffs to the freezing stage 10 is carried out so as to control the surface of the product fed to the freezing stage 10 so as to perform this freezing at a predetermined rate. The freezing rate depend in part on the surface of the food product as it has an effect on the heat exchange capacity when freezing. For example, it is useful to avoid large agglomerated fragments or lumps of food, likely to freeze excessively the outer layers by allowing insufficient freezing in the heart of the fragments.

The apparatus object of the present invention, illustrated in Figures 2 to 4, comprises a feed device 17 for feeding the food product to the freezing device 10.

If one refers to the fig.2, the feeder 17 illustrated is suitable for chunks, solids, food product or solid foods into slices or precut. The feeder 17 includes a feed conveyor 18, the flanks 19 are raised to contain the food product and hold it in the carrier 18. A scraper 20 is provided to take off the conveyor 18 any solid food material fragment that not freely fall into the freezing device 10. in this particular embodiment, the solid food pieces should already be calibrated to provide a suitable surface for the heat exchange in the freezing device.

If Referring to Fig.3 where the food product is a viscous consistency or can be considered as semi-solid, the feed device 17 comprises an extruder 21 for extruding the viscous food product in a plurality of orifices from which the product comes out and is fed into the freezing device 10. the extruder may include an orifice plate 22, schematically illustrated in Fig.3, through which the product is discharged by suitable means any. The orifices of the plate 22 may be generally circular and of a diameter between 5 and 50 mm and preferably between 5 and 25 mm, the outgoing extruded elements being generally constituted by cylindrical sections nets of equal diameter that of the orifice. It is considered that orifice diameter in the range of 10 to 15 mm would be suitable for a number of normally processed food products. However, one can expect that the dimensions and optimal shapes of the orifices vary according to different food products. As illustrated, the extruded product can be gravity fed directly into the freezing device 10.

If one refers to the rig.4, in this case, the apparatus is suitable for liquid or semi-liquid. The supply device 17 includes a pumping device 23 operating at a selectively adjustable flow rate so as to control product feed rate of the reservoir 15 to the freezing device 10. The pumping member 23 expels the food product to the manifold 24 with a plurality of nozzles 25 acting to unload a predetermined diameter of the material flow, so that the food product to flow into the freezing apparatus 10 had a surface. controlled exposed to the heat exchange to ensure freezing.

The freezing phase of the supplied product is preferably carried out by direct heat exchange or indirectly between the food product and a cryogenic substance as refrigerant. This cryogenic substance may be a liquid such as liquid nitrogen or liquid carbon dioxide or can also be a gas or a solid, such as C0₂ solid in the form of dry ice or dry ice. Of course, phase combinations can be used such cryogenic substances, for example by injecting liquid C02 in a freezing zone it will form a mixture of C0₂ gaseous and solid carbon dioxide snow, the food product being conveyed through the freezing zone in a heat exchange relationship with the C0₂ gas and dry ice.

The heat exchange of the food product to the cryogenic substance to achieve the freezing of the product can be by direct contact of the food with the cryogenic substance. For example, if one refers to Figs.2 to 4, the frozen product phase comprises immersion in a bath 30 of liquid cryogen substances such as liquid nitrogen to thereby freeze the food product. Alternatively, the frozen product phase may include a cryogenic spray substance in direct contact with the product during transit or keeping in the freezer freezing device 10. Another variant includes depositing the food product on cryogenic substance consisting of a dry bed of ice C0₂ n lide to thereby freeze the product.

The use of a cryogenic substance to the oongéla- tion is preferred because such a freezing system is relatively fast in comparison with mechanical refrigeration systems. Such rapid freezing is desirable so that the food can be frozen before they could agglomerate into large fragments or lumps.

The temperature at which the food product is frozen and at which it leaves the freezing device 10 is chosen so that the food product, frozen or fragile. Generally, this temperature is lower than that obtainable with a system of conventional mechanical refrigeration. However, the temperature is preferably controlled such that the frozen food product exiting the freezing device 10 is not too brittle or émiettable. As a result, the temperature should preferably be higher than the temperature below which the product of the natural cohesion is insignificant in comparison to the cohesive force caused by crystallization. Similarly, the freezing of the product at an extremely low temperature is considered a waste of heat extraction capacity of the cryogenic substance. The optimum temperature of the frozen food product at the end of the freezing stage varies depending on the different products. A deemed that the temperature is in the range of 0 to -196 ° C and, for most products, it is 0 to -100 ° C.

The product of the freezing phase of the process and the freezing apparatus 10 of the installation according to the preferred embodiment is constituted by fragments of frozen food products. For example, in the case of a viscous food product sent to the stage of freezing into an extruded product, the product freezes and in its extruded form and therefore the flow from freezing stage is compound by generally cylindrical food product sections. In the case of liquids and semi-liquids poured or injected into the freezing stage, the product stream may consist of chunks of frozen product, spherical or irregularly shaped. On Figs.2 to 4 wherein the product is immersed in a bath 30 of liquid cryogenic substance, the frozen food product may be recovered from the bath 30 by means of a sieve conveyor 31 which discharges the frozen product of the freezing device 10 .

The flow discharged from the freezing stage can be routed to a storage 32 (Fig.1). For example, the product can be stored in containers and transferred to a conventional freezer to be kept therein for a relatively long time before further processing. Conventional freezers maintain the high fluidity of the frozen product but the temperature may be greater than that where the product is brittle. It may consequently be necessary that the storage is followed by a reduction in temperature to make the brittle product to complete the process according to the invention.

Alternatively, the flow of frozen food product, breaking at the end of the freezing stage, may be conveyed to a temporary storage 33 (Figs.2 to 4). A feeding device 34, associated with the temporary storage 33, is operable to supply the frozen product of the temporary storage 33 to the fractionator 35 at a controlled rate. For example, the temporary storage 33 may comprise a hopper 36, receiving the frozen product of the conveyor 31, with a feeding device 34 associated with the hopper 36. The feeding of the frozen product from the hopper 36 to the fractionator 35 can be by gravity, from a discharge opening at the lower part of the hopper 36. the product can be channeled towards the discharge orifice and to avoid the formation of product in the vaults portion funnel, the hopper 36 may be vibrated or otherwise subject to periodic disturbances. A grid 37 is provided at the lower part of the hopper 36 so that the frozen fragments transported by gravity from the hopper discharge port does not exceed the capacity of the fractionation device 35.

The frozen food product, brittle, is then fractionated in the fractionation stage 35 to produce the food product particles free-flowing frozen. The fractionation is done without the frozen and brittle product is cut into smaller particles or fine.

As the splitting operation is performed on a frozen product to a temperature at which it is made brittle, the particles produced by the fractionation operation includes a significant proportion of splitting surfaces in a given product. These splitting surfaces give a pleasant and appetizing aspect that color retention is excellent.

The fracturing device 35 of the subject apparatus of the invention may have the form of a horizontal or vertical mill 40. If one refers to Figure 5, the crusher 40 includes a tank 41 provided with internal walls 42 and a core 43 disposed within the tank 41. This core 43 can perform relative movement in the tank 41 to divide the frozen food product in the space 45 between the core 43 and the walls internal 42. in particular, the tank 41 is preferably fixed and the core 43 rotates or oscillates inside. The tank 41 is provided with a plurality of discharge ports at its lower portion, these orifices 46 having a predetermined diameter and the particles 47 of frozen food product, fractional, a particle size smaller than the diameter of the orifices pass through. With this, the fragments and oversized particles are retained in the space 45 of the fractionation mill 40 until they are split into fairly small product particles to pass through the holes 46.

The core 43 of the mill 40 moves or oscillates concentrically or eccentrically in the tank 41, with a predetermined minimum separation between the outer surface of core 43 and the inner walls 42 of the tank 41 maintained at all times during movement of said core so that the frozen product 44 is not crushed or ground into fragments of undesirable size.

It is therefore clear that the splitting phase of the frozen produif 44 comprises the production of particles 47 of free-flowing frozen food product having a particle size less than a predetermined maximum size, defined by the diameter of the orifices 46 of the tank 41. the preferred method of embodiment of the invention comprises a calibration phase of the frozen food product particles to high fluidity in the calibration stage 50 to separate undersized particles fragments of greater size required to form particles tranfert final product. The undersized particles can be recycled to supplement the product on arrival, either directly or via a mixing stage 16 or after passing through a storage stage 51. Of course, if necessary, the particles 47 of the fractionation stage 35 may be the final product without the need to pass the particles through the calibration stage 50.

If one refers again to Fig.5, the 50 calibration stage may comprise a set of calibration orifices 52 through which the particles of the frozen food product and fraction 57 from the fractionator ₃₅ are routed. The set of calibration orifices 52 includes openings 53 of relatively small diameter in order to separate undersized particles 54 larger particles 55, required to form the final particles of high fluidity of the frozen food product.

The set of calibration orifices 52 may be constituted by a grid, a screen, an orifice plate or the like, where the particle stream 47 passes through the openings 46. In fact, this helps to retain fines. The particles of insufficient size 54, can be collected in a container 56 and, as indicated above, can be recycled and used to supplement the flow of initial food product. Through the use of ports 46 and 53 of different diameters, it is possible to closely control the final product 55 at the particle size distribution as undersized particles 54 are recycled for further processing.

The method and preferred apparatus of the present invention, described above, allow to obtain a final product consisting of small pieces of frozen food product, hard, irregularly shaped, whose size depends on the diameter of the openings 46 of the mill 40_"and the size of the orifices 53 of the set of calibration orifices 52. It has been found that a final particle size between 5 and 12 mm and preferably between 8 and 12 mm in overall diameter suited for a number of cushioning products.

The final product 55 has high fluidity and suitable to be filed or added frozen to other food products, treated or untreated. This high fluidity can itself be coated with other food products through conventional general methods. Likewise the final product 55 can be packaged as a commercial product, used as such in the frozen state by individuals, industry or trade. An example of use of the final product particle consists of filing in small portions using an automated process on a cake base or pre-molded pastries or similar products.

The final product is also suitable for storage in the frozen state, high fluidity, in suitable containers, such as boxes or plastic bags for industrial freezers operating at temperatures generally comprised within the range of -15 to -30 ° C.

The initial food product may be formed by a raw material in the raw state or processed, cheap, can be changed to improve its desirable properties through the incorporation of appropriate food additives such as stabilizers, extenders, binders, seasonings etc., so that one obtains a final product equivalent or even higher than the equivalent product ordinarily used by the specialized industry, for example the manufacturing industry of prefabricated pizza.

It is possible to increase the bulk volume of a product, improve its water retention characteristics, taste and color and change its freezing characteristics to better suit the manufacturing operations and storage. Similarly, if necessary, it is possible to alter the melting characteristics to obtain an improved product after the consumer has made the cooking phase. We will see in all the product properties can be tailored to achieve a variety of desired end results.

One of the specific examples of the use of the method and device is the use of pulp of cheap pineapples instead of pineapple slices with a higher cost, such as are commonly employed in prefabricated pizza. The use of cheap pineapple pulp enables the production of frozen pineapple cubes, high fluidity.

Another example of the use of the method and device is the use of processed cheese, cheap, inferior, instead of Mozzarella with a higher cost, as a topping for pizza. The volume of this lower quality cheese can be increased by means of diluents, taste can be improved and some of its other properties can be modified before it is divided into small frozen particles, high fluidity. Its properties can be modified so that the small particles can retain their general shape during cooking by having only just the desired degree of fusion.

Other examples of the use of the invention include the production of frozen fish good fragments, high fluidity, from an inferior fish stuffing.

This method can also be used to produce frozen pieces of fruit high fluidity, such as strawberries, apricots, apples, raspberries, peaches, etc. from a pulp cheap fruit instead of whole fruit. Further savings can also be realized using all or only a portion of the pulp of apples cheap as a base and by adding the necessary part of the fruit and (or) of the seasoning to simulate a particular fruit prior to step freezing and fractionation (reduced product diced).

It can be seen that the invention may, in general, raise the quality of certain food products cheap and lower quality to make them marketable as is or make them even more attractive than some other premium equivalent products and a higher cost.

Finally, we must understand that various changes, modifications and (or) additions may be made to the construction and arrangement of elements or phases, as have been described, without thereby departing from the scope of this invention.