Abstract:
A process for shaping a frozen confectionery product is provided, the process comprising: extruding a frozen confection from a filling means comprising a nozzle and a cutting means into a cavity which is in fluid communication with the nozzle; moving the cavity relative to the filling means so that the cutting means shears the frozen confection and thereby cuts it; and removing the frozen confection from the cavity, characterized in that the cross-section of the cutting means, when viewed along the direction of relative motion of the cavity and the cutting means is not a straight line. An apparatus for performing the process is also provided.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a process and apparatus for producing frozen confectionery products that are shaped in three dimensions. In particular, it relates to an extrusion process. 
       BACKGROUND TO THE INVENTION 
       [0002]    There is a demand for frozen confectionery products with interesting and distinctive shapes. Products that are shaped in two dimensions have been known for many years. They are usually produced by an “extrude and cut” process, in which partially frozen ice cream is extruded though a nozzle and cut by a wire into portions of uniform thickness. The two dimensional shape arises from the shape of the nozzle, but there is no possibility of shaping in the third dimension using this process. 
         [0003]    Three-dimensional shaped products can be produced by moulding. However, moulding processes have drawbacks, in particular the tendency of the ice cream to stick to the mould. U.S. Pat. No. 4,413,461 discloses a method of shaping ice cream. The problem of ice cream sticking to the mould is solved by blowing air between the mould and the ice cream or by use of a release film between the mould and the ice cream. EP-A-0827696 discloses a method for moulding three dimensional food products in which the mould is at a very low temperature, thereby reducing the adhesion between the product and the mould. However, both of these solutions add cost and complexity to the process. Therefore there remains a need for a simple method of producing frozen confectionery products that are shaped in three dimensions. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    We have developed a simple process for making frozen confectionery products that are shaped in three dimensions, based on the extrude and cut process. Accordingly, in a first aspect the present invention provides a process for shaping a frozen confectionery product, the process comprising:
       extruding a frozen confection from a filling means comprising a cutting means and a nozzle into a cavity which is in fluid communication with the nozzle;   moving the cavity relative to the filling means so that the cutting means shears the frozen confection and thereby cuts it; and   removing the frozen confection from the cavity
 
characterized in that the cross-section of the cutting means, when viewed along the direction of relative motion of the cavity and the cutting means, is not a straight line.
       
 
         [0008]    Products obtained and obtainable by the process of the invention are also provided. 
         [0009]    In a second aspect the present invention provides an apparatus for shaping a frozen confectionery product, the apparatus comprising:
       a cavity,   a filling means comprising a nozzle and a cutting means, wherein the filling means abuts the cavity so that the nozzle is in fluid communication with the cavity;   means for moving the cavity relative to the cutting means so that the cutting means shears the frozen confection and thereby cuts it;   means for removing the frozen confection from the cavity;
 
characterized in that the cross-section of the cutting means, when viewed along the direction of relative motion of the cavity and the cutting means, is not a straight line.
       
 
         [0014]    The relative movement between the cutting means and the cavity shears the frozen confection and thereby cuts the flow of frozen confection, in a manner analogous to that of the cutting wire in the conventional extrude and cut process. A process in which relative motion between a flat-ended nozzle and a flat-topped cavity cuts the frozen confection instead of the wire or blade cutter of the conventional extrude and cut process is known from WO-A 99/65325. In this case, the cutting means is the flat end of the nozzle, i.e. the cross-section of the cutting means, when viewed along the direction of relative motion of the cavity and the cutting means, is a straight line. However, this document addresses the unrelated problem of producing extruded products that contain large amounts of inclusions, and makes no mention of the possibility of producing products that are shaped in three dimensions. 
         [0015]    In the present invention, the cutting means is not a flat-ended nozzle, so the cut surface of the frozen confection is not planar. Thus the process of the invention allows frozen confections that are shaped in three dimensions to be formed. It is necessary that the cutting means be in close proximity to the opening of the cavity while the cavity is moved relative to the cutting means and the frozen confection is cut. The cutting step requires that the cutting means has translational symmetry along the direction of relative motion of the cavity and cutting means (i.e. it has a constant cross-section when viewed along this direction). For example the cutting means can be a shaped nozzle end. Thus shapes such as a half cylinder can be produced by the process of the invention, but not, for example, a hemisphere. 
         [0016]    The nozzle is in fluid communication with the cavity, allowing frozen confection to pass from the filling means into the cavity, and preventing frozen confection from leaking out between the nozzle and the cavity. The frozen confection which is filled into the cavity is of a consistency such that it can be extruded from the nozzle and filled into the cavity, but which is solid enough that it retains its shape on removal from the cavity. The frozen confection is preferably partially frozen ice cream, typically at a temperature of about −5 to −15° C., most preferably from −9 to −12° C. 
         [0017]    The cutting means may be a flange around the end of the nozzle which covers the opening of the cavity, thereby preventing frozen confection from overflowing out of the cavity during filling. Preferably the flange is slightly larger than the cavity opening. The nozzle may be narrower than the opening of the cavity, and the flange therefore covers most of the opening of the cavity. A narrow nozzle is suitable for frozen confections which are not highly viscous, so that the frozen confection flows into the cavity and fills it. In another embodiment, the nozzle has the same cross-sectional shape as the opening of the cavity (when viewed along direction of extrusion) then the nozzle closes the cavity and therefore constitutes the cutting means itself. This embodiment is preferred for frozen confections which are highly viscous or of relatively solid consistency, in order to ensure that the cavity is completely filled. Nonetheless, in this case a flange may also be present, in order to make doubly sure that no frozen confection leaks out of the cavity. 
         [0018]    Preferably the separation between the cutting means and the opening of the cavity is less than 0.5 mm, more preferably less than 0.1 mm. 
         [0019]    Preferably the cutting means is concave, and the opening of the cavity is correspondingly convex, when viewed along the direction of relative motion of the nozzle, so that the cut surface of the frozen confection is convex. 
         [0020]    Preferably the cavity is formed by a mould block and a base. More preferably the base of the cavity is openable, thereby to facilitate removal of the frozen confection. 
         [0021]    Optionally the base of the cavity also has a cross-section which is not a straight line when viewed along the direction of relative motion of the cavity and the cutting means. This enables the other side of the product to be shaped in an analogous manner. 
         [0022]    Preferably a plurality of cavities is located in a rotating carousel and the thickness of the carousel varies radially across the cavity, thereby providing the shape of the cavity, and hence the shaped product. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         [0023]    The present invention will be further by reference to the figures wherein: 
           [0024]      FIG. 1  shows the conventional extrude and cut process. 
           [0025]      FIG. 2  is a cross-sectional view of a nozzle and corresponding cavity according to the invention. 
           [0026]      FIG. 3  shows a top view of the cavity of  FIG. 2 . 
           [0027]      FIG. 4  shows a side view of the nozzle and cavity at different stages through the process of the invention. 
           [0028]      FIG. 5  shows a preferred embodiment where the cavities are located in a rotating carousel. 
           [0029]      FIG. 6  compares a product shaped by the conventional extrude and cut process with a shaped product produced according to the present invention. 
       
    
    
       [0030]      FIGS. 1(   a ) and ( b ) are schematic diagrams showing the conventional “extrude and cut” process. Extrude and cut-type processes for producing frozen confection products are well-known in the field of frozen confectionery manufacture and are described in, for example, “The Science of Ice Cream”, C. Clarke, Royal Society of Chemistry, Cambridge, UK, 2004, p 93-94. Frozen confections (which include ice cream, water ice, frozen yoghurt and the like) are made by freezing and optionally aerating a pasteurised mix of ingredients such as water, fat, sweetener, protein (normally milk proteins), and optionally other ingredients such as emulsifiers, stabilisers, colours and flavours. The frozen confection  1  can then be formed into products by extrusion through a nozzle  2 . The frozen confection  1  is cut into pieces  4  by the cutter  3 . The extruded and cut frozen confection pieces  4  drop onto a conveyor  5 , which transports them through a hardening tunnel. 
         [0031]      FIG. 2  is a cross-sectional view of a filling means and cavity according to the invention, viewed along the direction of relative motion of the filling means and cavity. The frozen confection is extruded through a nozzle  12  as before. However, the end of the nozzle  16  is not flat, as in  FIG. 1 , but is shaped. In the embodiment shown, it is scalloped, though any suitable shape may be used. Adjacent to the nozzle end  16  is a cavity  18 . In the embodiment shown, the cavity is formed by a mould block  20  and a base  22 . The base need not be flat, but may also be shaped in cross-section. In the embodiment shown the base is concave, though any suitable shape may be used. Once the cavity has been filled, the cavity is moved relative to the nozzle in a direction perpendicular to the paper. The nozzle end has a flange  24  which surrounds and seals the cavity as it is filled with the frozen confection, so that the frozen confection cannot flow out of the cavity. 
         [0032]      FIG. 3  is a top view of the cavity  18  in the mould block  20  shown in  FIG. 2 . A cavity having straight sides and rounded ends when viewed from above is shown. However any suitable shape may be chosen, for example circular, oval, star-shaped, or even the shape of an animal, cartoon character, face, hand, foot etc. These sorts of 2D shaped products have been produced for many years by the conventional extrude and cut process, using a nozzle with the appropriate cross-section. 
         [0033]      FIG. 4  shows side views of the nozzle and cavity through the process according to the invention. In this view, the shaped cross-sections of the nozzle end and cavity are not visible. In  FIG. 4(   a ) the nozzle  12  and cavity  18  are aligned while the cavity is filled. The flange  24  prevents leakage of the frozen confection from the cavity during filling. Once the cavity is filled with frozen confection  11 , the cavity  18  is moved relative to the nozzle  12  as shown in  FIGS. 4(   b ) and ( c ). Since the nozzle end is in close proximity to the opening of the cavity, the relative movement between the nozzle end and the cavity shears the frozen confection and thereby cuts the flow of frozen confection, in a manner analogous to that of the cutting wire in the conventional extrude and cut process shown in  FIG. 1 . Thus the end of the nozzle constitutes the cutting means. The base  22  and mould block  20  may also have cross-sections which are not straight lines, when viewed along the direction of relative motion of the cavity and cutting means. This enables the other side of the product to be shaped by an analogous process.  FIG. 4  shows an embodiment wherein the base  22  is fixed relative to the nozzle so that the bottom of the cavity  18  is opened when the mould block  20  is moved ( FIG. 4(   d )). This allows the shaped frozen confection to be removed ( FIG. 4(   e )) by applying a downward force e.g. by blowing with air, or gently pushing the frozen confection with a plunger  26  from above through the opening at the top of the cavity. When a plunger is used, its end should correspond to the shape of the top of the frozen confection, so that the top of the frozen confection is not altered. When the shaped frozen confection is removed from the cavity, it may land on a plate  25 , which should similarly be shaped to correspond to the bottom of the frozen confection, so that the shape of the bottom of the frozen confection is not altered. Alternatively, the frozen confection may be ejected in to a bath of a cryogenic fluid (such as liquid nitrogen) in order to harden the frozen confection, so that it may subsequently be handled without losing its shape. Once removed, the confections may be taken for further processing, for example hardening, coating in chocolate and packaging. 
         [0034]    In the embodiment shown in  FIGS. 2-4 , the frozen confection is extruded vertically downwards; however this is not essential. The frozen confection could, for example, be extruded horizontally. 
         [0035]      FIGS. 5(   a ) (perspective view) and  5 ( b ) (side view) show a preferred embodiment where the mould block in which the cavities  18  are located is a rotating carousel  30 . The nozzle is located at a filling station (not shown); the rotation of the carousel is indexed so that each cavity in turn is placed beneath the nozzle at the filling station. Once the cavity has been filled, the carousel rotates to the next index point, bringing the next cavity into position at the filling station. Further round the carousel is a removing station (also not shown) where the frozen confections are removed from the cavity, for example by the method shown in  FIGS. 4(   d ) and ( e ).  FIG. 5(   b ) shows a side view of the carousel  30 . The cross-sectional shape of the cavity  18  is achieved by varying the thickness of the carousel mould block radially across the cavity. 
         [0036]      FIG. 6  compares a product shaped by the conventional extrude and cut process (( a )-( c )) with a shaped product produced according to the present invention (( d )-( f )). Both products are shaped when viewed from above ( FIGS. 6(   a ) and  6 ( d )). The side views show that the conventional product has a rectangular cross-section ( FIG. 6(   b )), whereas the product produced according to the present invention has a shaped cross-section ( FIG. 6(   e )). The perspective views ( FIGS. 6(   c ) and  6 ( f )) show the three-dimensional shapes of the products. 
         [0037]    The various features and embodiments of the present invention, referred to in individual sections above apply, as appropriate, to other sections, mutatis mutandis. Consequently features specified in one section may be combined with features specified in other sections, as appropriate.