Process for producing meringue by extrusion and products obtained by the process

DESCRIPTION

0001The present invention concerns a process for the production of meringue by extrusion and related products such as, in particular, small-sized meringues and meringue granules. More specifically, the invention concerns a production process for the preparation of a baking product equivalent to traditional meringue that avoids the whipping stage of the mixture and allows recycling the fine product, mostly obtained as a left-over of the final granulating operations, by reintroducing it as an ingredient of the mixing phase.

0002As is known, both in home-made and in industrially manufactured procedures, the meringue is a baking product essentially made of egg-whites and sugar whipped to a light but solid texture, that is first modeled into the desired shape, for example, by placing it into specific moulds or by extruding it into round shapes using a pastry bag, and is then oven baked until it solidifies completely, taking on a whitish color with varying golden brown hues or even other hues as a result of the addition of other ingredients.

0003Besides being used as a finished confectionary product, the meringue is an important semi-finished product of the confectionary industry and is used as a component or decoration for more complex confectionary products, or for ice-creams, ice-cream cakes and the like. Granulated or powdered to more or less fine dimensions after baking, it is a widely used component for coatings and decorations such as in ice-cream products.

0004When manufactured industrially, a traditional meringue may be made of sugar (using partly granulated sugar and partly superfine sugar) whipped with fresh egg-whites or, alternatively, with dry or powdered egg-white and an equivalent amount of water as that found in fresh egg-white (the optimal ratio between dry egg-white material and water being about 1/10, in natural egg-whites), starch as a thickener, and optionally the addition of small quantities of flavoring, such as vanilla. As an example, the composition of an industrially produced traditional meringue is as follows: <tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Typical ingredients</entry><entry namest="col2" nameend="col2" align="center">Indicative %</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">water</entry><entry namest="col2" nameend="col2" align="char" char=".">12.62</entry></row><row><entry namest="col1" nameend="col1" align="left">egg-white</entry><entry namest="col2" nameend="col2" align="char" char=".">1.26</entry></row><row><entry namest="col1" nameend="col1" align="left">superfine sugar</entry><entry namest="col2" nameend="col2" align="char" char=".">63.12</entry></row><row><entry namest="col1" nameend="col1" align="left">granulated sugar</entry><entry namest="col2" nameend="col2" align="char" char=".">16.41</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat starch</entry><entry namest="col2" nameend="col2" align="char" char=".">6.56</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">vanilla flavoring</entry><entry namest="col2" nameend="col2" align="char" char=".">0.006</entry></row></tbody></tgroup></table></tables>

0005The aforesaid ingredients are normally mixed in batches by loading a planetary mixer equipped with vertical stirrers which, by a combined movement of rotating about their own axis and also rotating about a common axis in the mixing bowl, whip the mixture to a light stiff texture by incorporating therein a large amount of air. This mix is then introduced into a production line that goes to mould the mixture into the desired shapes, which are then taken by conveyer belt to an oven with the right temperature and conveyor speed for the optimal baking of this kind of product. For some uses, the baked meringue units coming out of the oven can be used as they are, or they may undergo granulation in special machines with mill-like rotating elements thereby resulting in meringue granules of the size required for their later use as a semi-finished product. A block diagram of a process of this kind is illustrated, by way of example, in the attached Figure 1, which will be dealt with in more detail further on.

0006It is evident that this final stage of the procedure, as well as other intermediate stages of the production process, yields powders of crushed meringue granules, that are easily produced also because of the extremely fragile nature of meringue. These powders, which are too fine to be incorporated in the desired product, must be discarded and cannot be reintroduced at any stage of the production process, such that they are often sold as animal feed. The impossibility of reusing such left-overs in the described production process is due to the fact that the concerned powdery ingredient cannot be added to the whipped egg-white mixture processed in the food mixer because it would irreparably compromise the texture of the mixture, completely spoiling the characteristics of the product right from the mixing phase.

0007Albeit with different variations essentially concerning the choice and dosage of the ingredients, or the mechanical phases for shaping the mixture before baking, the known processes for the industrial manufacturing of meringue and of the various forms of granules obtained from it still involve the production of a whipped mixture as well as a considerable amount of left-overs due to the impossibility of reutilizing the powders in the initial mixing process.

0008On the basis of this prior art, an object of the present invention is, thus, to provide a meringue production method, and particularly a method for producing meringue granules, which allows to avoid the aforesaid drawbacks and offers a final product that is equivalent for quality and characteristics to the traditional one described above, but with a considerable reduction in left-overs and thus a consequent economic saving.

0009To this end, according to the present invention there is proposed to carry out the initial mixing process without envisaging whipping the egg-whites with sugar but introducing appropriate components among the ingredients such that the chosen technology still achieves the light and airy texture typical of meringues even without whipping. In this way, there is the advantage of being able to recycle the powders obtained in the later stages of the production process in the initial mixing process, without needing to discard them as a by-product.

0010The mixture proposed according to the present invention is designed and calibrated to be processed practically in a dry state, by adding a chemical yeast such as sodium bicarbonate or ammonium bicarbonate to the fundamental ingredients of traditional meringues - that is, sugar and egg-whites (or rather powdered egg-whites and water). Following thermal decomposition in the baking process, the chemical yeast triggers the production of carbon dioxide and possibly ammonia, which cause an airing of the mixture comparable with what occurs with the whipping process. This solution is combined with the adoption of an extrusion technology for the production of meringue units to be conveyed to the oven for baking, carried out in a similar manner to the making of noodles. The process involves inputting the homogeneous (but non-whipped) mixture into a screw-type extrusor from whose draw-plate small cylindrical elements of consistent mixture emerge. These cylindrical elements ial are cut into small segments and conveyed to the oven for baking.

0011In order to give the concerned mixture the necessary texture for it to be extruded through the draw-plate, the product according to the present invention also contains, in comparison with a traditional meringue mix, an ingredient like wheat flour. In order for it to be homogeneously mixed despite the largely powdery consistency, the said product also contains a certain amount of oil, and preferably sunflower seed oil.

0012The procedure according to the present invention thus enables the production of meringue by extrusion, whereby the initial mixture does not require whipping and allows incorporating without any problems large fractions of powdered product recycled from the later stages of the production process.

0013In the field of industrial production of meringue, the Italian patent No. 1246340 discloses a mechanical device for the production of pre-cut meringue that is referred to as an extrusor or extrusion mould. This is a specially designed device for obtaining - in the final meringue shape before baking - preestablished fracture lines enabling the realisation of portions of the required size by mere manual cutting, thus avoiding the inconveniences connected to the fragility of the finished product.

0014Although the shaping device described in the aforesaid document is referred to as an "extrusor", the meringue mixture that it is designed for is a traditional one, which the document describes as essentially made up of egg-whites whipped with sugar.

0015Thus, the present invention specifically provides a process for the production of meringue by extrusion comprising, in sequence, the following steps: <ul id="ul0001" list-style="none" compact="compact"><li>a) mixing a composition of ingredients including sugar, powdered egg-whites and water or, alternatively, fresh egg-whites, starch, flour, chemical yeast and oil, part of said ingredients being optionally composed of the recycling of a fine fraction of product separated during the production process;</li><li>b) extruding the mixture resulting from the previous operation via a screw-type extrusion device yielding through the draw-plate thereof homogeneous cylindrical or prismatic elements of product;</li><li>c) cutting the said elements into segments;</li><li>d) baking the said cut elements, with leavening of the product; wherein the fine powders of the product separated during the production process are recycled by reintroducing them in the mixing phase a).</li></ul>

0016According to some preferred embodiments of the invention, the proposed process is applied to the production of meringue granules, in which case after the baking step d) the following steps are carried out: <ul id="ul0002" list-style="none" compact="compact"><li>e) granulating the product obtained in the baking step d);</li><li>f) subsequently separating the finished product, in the desired granule size, from the fine powders by sifting, and recycling said fine product in the aforesaid mixing step a).</li></ul>

0017Preferably, the said mixture of ingredients of step a) includes powdered egg-whites and water, while the sugar used is superfine sugar, the starch and flour are from wheat, the chemical yeast is ammonium bicarbonate and the oil is sunflower seed oil. The said ingredients are preferably included in the following proportions in the mixture, as a percentage by weight: <tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">superfine sugar</entry><entry namest="col2" nameend="col2" align="center">42 - 64 %</entry></row><row><entry namest="col1" nameend="col1" align="left">powdered egg-whites</entry><entry namest="col2" nameend="col2" align="center">1 - 3 %</entry></row><row><entry namest="col1" nameend="col1" align="left">water</entry><entry namest="col2" nameend="col2" align="center">10 - 30 %</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat starch</entry><entry namest="col2" nameend="col2" align="center">2.5 - 8.0 %</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat flour</entry><entry namest="col2" nameend="col2" align="center">5 - 16 %</entry></row><row><entry namest="col1" nameend="col1" align="left">ammonium bicarbonate</entry><entry namest="col2" nameend="col2" align="center">0.15 - 0.7 %</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">sunflower seed oil</entry><entry namest="col2" nameend="col2" align="center">3 - 10 %</entry></row></tbody></tgroup></table></tables> Part of these ingredients may also derive from the recycling of the said fine powders. In practice, when the mixture is made in batches, the first list of ingredients of the working day will be in the proportions reported in the table above, while the ingredient lists for later batches will be recalculated bearing in mind that the later mixtures will include an amount of recycled powder, largely containing the same ingredients (excluding water). The amount of ingredients deriving from the recycled fine powders may make up from 40% to 65% percent weight of the entire mixture of step a).

0018The mixing step a) may be carried out, according to a specific embodiment, in a zed-mixer (or of the Werner and Pfleiderer type), having a container with square or rectangular cross-section and two rotating horizontal Z-shaped stirrers. This device is normally equipped with a container whose bottom is delimited by two semi-cylindrical surfaces with parallel axes, connected along a generatrix; each surface containing one of the two Z-shaped rotating stirrers. By their motion, the stirrers first force the mixture up along the walls of the container and then down centrally, where the motion of the stirrers assures a vigorous remixing of the composition. It is evident that a device like this, unlike the traditional planetary mixer, is suitable for processing non-fluid, but partially powdery, mixtures such as the one considered here, and allows achieving a homogeneous mix by making the oil reach every part of the mixture.

0019Depending on the nature of the ingredients used, with a mixing device as the one described above, it is normally advisable to start with a part of the ingredients first, run the mixer for a certain period of time and then add the remaining ingredients and complete the operation.

0020As an altemative to the described mixer, it is also possible to use other equipment as long as it can withstand high pressure and is suitable for mixing almost dry mixtures such as the one considered here. If a continuous operation is desired instead of a batch operation, then for the mixing phase it is possible to use a suitable turbo-mixer, which can discharge the mixed product directly onto the production line.

0021Preferably, the said mixture extrusion step b) is carried out at high pressure, using a draw-plate with round holes, preferably bronzed in view of the better capability of this material to withstand the high extrusion pressures involved. Each of the draw-plate holes has a larger input diameter, where the mixture to be extruded is fed in, and a smaller output diameter, with each channel including a narrowing (for example, a conical narrowing if the holes are round) at a certain point of its length and, subsequently, a tract that is of a constant section, equal to the outlet section. This tract, called a pre-chamber, is important in order to give compactness to the extruded product, and its length is one of the parameters that can be regulated to optimise the quality of the product.

0022The extrusion step is followed by a cutting step c), carried out by means of a rotating blade cutter placed immediately at the exit of the said draw-plate. Depending on the speed of the blade, more or less lengthy cylindrical segments of compact product are obtained, but an axial length equal to or slightly less than the diameter of the cylinder is generally preferable. Naturally, in the same way as with screw-type extrusors used in noodle production, the draw-plate holes may be of any shape, such as, e.g., square-shape. However, round holes have fewer practical problems and are the preferred shape when the required final product is powdered granules.

0023In the procedure according to the present invention, the baking step d) is carried out by passing the product in a tunnel oven involving two baking stages. The first stage is carried out with a burner at 230-250°C while the second stage is carried out with a burner at 120-140°C - the total baking time being 6-8 minutes. This temperature scheme is programmed so that the product undergoes a great initial heating, which immediately triggers the leavening process, followed by a more moderate heating, after the product has risen, in order to complete the baking process.

0024On exiting the baking process, if the desired final product is not the thus obtained meringue units, but the relative granules, then the already mentioned granulation operations are carried out in one or more granulating machines, each one consisting of two parallel toothed rollers which, by rotating in opposite directions to one another, crush up the segments of product passing through them. The product exiting these granulation operations is then separated by sifting into three fractions - an intermediate granular fraction making up the final product, a coarser granular fraction that is returned to the granulation operation, and a finer fraction that is recycled by reintroducing it into the aforesaid mixing step a).

0025If two granulating machines are used in sequence, for example, then the coarse fraction exiting the first machine is used to feed a second similar apparatus, while the intermediate fraction from the first machine is the desired product and the finer fraction is recycled to be used in the aforesaid mixing step a). The second granulating machine will only yield fractions of finer product to be recycled to step a) and the fraction of product of the desired size, while the coarser fraction product is fed back into the same machine.

0026According to a further aspect, the present invention concerns products with the same characteristics as those obtainable via the previously described process, both as regards meringues as a finished product and as regards the relative granules.

0027The specific characteristics of the present invention, as well as its advantages and the corresponding operating modalities will be clearer with reference to a detailed description thereof, that is presented merely by way of example and is also illustrated in the attached drawings, wherein: <ul id="ul0003" list-style="none" compact="compact"><li>Figure 1 shows a block diagram of a meringue granule production procedure according to the prior art; and</li><li>Figure 2 shows a block diagram of a meringue granule production procedure by extrusion according to the present invention.</li></ul>

0028With reference to figure 1, already recalled earlier, the mixture is whipped and sifted according to the traditional procedure, and baking only serves to preserve an already aired texture. It is evident from the diagram that, by not enabling any addition of the powders obtained as fine fractions from the granulation and sifting operations of the final product, these powders necessarily represent non-reusable waste products, thus penalizing the economic yield of the entire process.

0029On the other hand, by operating according to the procedure of the present invention, as shown schematically in figure 2, the mixture - composed of suitable ingredients - is not whipped but undergoes extrusion. After the final granulation operation (where the relative block in the diagram may represent even two or more stages in a cascade sequence), the powders produced are reintroduced into the starting product in the initial mixing phase. Such operation is not possible with the traditional procedure. In this way, a closed-circuit process is realized whereby the only outputted product is the desired final one.

EXAMPLE 1

0030Preparation of chocolate-flavored "truffle" meringue granules

0031According to a specific form of realization of the process of the present invention, a chocolate meringue is produced starting from the following ingredients: <tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" align="left"><b>Phase 1</b></entry><entry namest="col2" nameend="col2" align="center">Indicative %</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">recycled powders</entry><entry namest="col2" nameend="col2" align="char" char=".">40.7</entry></row><row><entry namest="col1" nameend="col1" align="left">whipping (powdered) egg-whites</entry><entry namest="col2" nameend="col2" align="char" char=".">1.0</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat starch</entry><entry namest="col2" nameend="col2" align="char" char=".">2.8</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat flour</entry><entry namest="col2" nameend="col2" align="char" char=".">7.9</entry></row><row><entry namest="col1" nameend="col1" align="left">ammonium bicarbonate</entry><entry namest="col2" nameend="col2" align="char" char=".">0.3</entry></row><row><entry namest="col1" nameend="col1" align="left">sunflower seed oil</entry><entry namest="col2" nameend="col2" align="char" char=".">2.7</entry></row><row><entry namest="col1" nameend="col1" align="left">cocoa 10/12</entry><entry namest="col2" nameend="col2" align="char" char=".">1.8</entry></row><row><entry namest="col1" nameend="col1" align="left"><b>Phase 2</b></entry><entry namest="col2" nameend="col2" /></row><row><entry namest="col1" nameend="col1" align="left">powdered sugar</entry><entry namest="col2" nameend="col2" align="char" char=".">33.8</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">water</entry><entry namest="col2" nameend="col2" align="char" char=".">9.0</entry></row></tbody></tgroup></table></tables>

0032The ingredients of phase 1 are weighed and loaded into a zed-mixer (Sodolve, Mod. HSM/S with a capacity of 110 liters), and then mixed for 2 minutes. Thereafter, the ingredients of phase 2 are added and the mixture is mixed for another 2 minutes.

0033The product is then loaded into the cochlea of a screw-type extrusor with a bronzed draw-plate containing round holes for high pressure operation. The diameter of the input hole is 11 mm and that of the exit hole is 4.5 mm, while the pre-chamber has a length of 20 mm. An optimal choice of these parameters consists of limiting the input hole to between 9 and 13 mm in diameter, and the output hole to between 2.2 and 5 mm, while the pre-chamber length should be between 17 and 23 mm.

0034On exiting the extrusor, the product is cut to the required size established by the speed of the cutter blades and is then carried by a conveyor belt to an oven of the Simer type with two baking stages, the first using a burner at 240°C and the second using a burner at 130°C, with a total baking time of 7 minutes.

0035On exiting the oven the product is granulated and sifted in two consecutive stages, in order to obtain: <ul id="ul0004" list-style="none" compact="compact"><li>■ powders (to be reused in the next mixing process);</li><li>■ coarser granules, to be fed back into the granulating machine;</li><li>■ the finished product.</li></ul>

EXAMPLE 2

0036Preparation of white hazelnut flavored meringue granules

0037According to another embodiment of the process of the present invention, a white hazel nut flavored meringue is produced starting from the following ingredients: <tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" align="left"><b>Phase 1</b></entry><entry namest="col2" nameend="col2" align="center">Indicative %</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">recycled powders</entry><entry namest="col2" nameend="col2" align="char" char=".">48.3</entry></row><row><entry namest="col1" nameend="col1" align="left">superfine sugar</entry><entry namest="col2" nameend="col2" align="char" char=".">30.2</entry></row><row><entry namest="col1" nameend="col1" align="left">whipping (powdered) egg-whites</entry><entry namest="col2" nameend="col2" align="char" char=".">1.0</entry></row><row><entry namest="col1" nameend="col1" align="left">water</entry><entry namest="col2" nameend="col2" align="char" char=".">8.2</entry></row><row><entry namest="col1" nameend="col1" align="left">wheat starch</entry><entry namest="col2" nameend="col2" align="char" char=".">3.0</entry></row><row><entry namest="col1" nameend="col1" align="left">ventilated wheat flour</entry><entry namest="col2" nameend="col2" align="char" char=".">6.0</entry></row><row><entry namest="col1" nameend="col1" align="left">ammonium bicarbonate</entry><entry namest="col2" nameend="col2" align="char" char=".">0.1</entry></row><row><entry namest="col1" nameend="col1" align="left">hazel nut flour</entry><entry namest="col2" nameend="col2" align="char" char=".">1.2</entry></row><row><entry namest="col1" nameend="col1" align="left">stabilizer</entry><entry namest="col2" nameend="col2" align="char" char=".">0.04</entry></row><row><entry namest="col1" nameend="col1" align="left">vanilline</entry><entry namest="col2" nameend="col2" align="char" char=".">0.06</entry></row><row><entry namest="col1" nameend="col1" align="left"><b>Phase 2</b></entry><entry namest="col2" nameend="col2" /></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">sunflower seed oil</entry><entry namest="col2" nameend="col2" align="char" char=".">1.9</entry></row></tbody></tgroup></table></tables>

0038The preparation is carried out using the same equipment as in example 1, and proceeding in the same manner. Here, too, only the desired product is obtained from the process because the powders are recycled by adding them as ingredients to the next batch to be mixed.

0039As is evident from the foregoing, with respect to the traditional procedure, the main advantage of the process according to the present invention lies in the possibility of recycling the powders obtained during the granulation and sifting operations, by reusing them as ingredients in the next batch to be mixed. This achieves a better production yield and a corresponding reduction in by-products of the entire process.

0040Moreover, the meringue granules obtained with the proposed procedure are crunchier and more compact compared to the kind obtained with the traditional method - and this can be an advantage when the product is to be employed as a semi-finished component, in particular for ice-cream products.

0041The present invention has been disclosed with particular reference to some specific embodiments thereof, but it should be understood that modifications and changes may be made by the persons skilled in the art without departing from the scope of the invention as defined in the appended claims.