LEADBEATER, John Michael (29 Portisham Place, Strensall, York Yorkshire Y032 5AZ, GB)
BABIN, Helene Anne (19 rue Florent Tessier, Fontenay-le-Comte, Fontenay-le-Comte, F-85200, FR)
LEADBEATER, John Michael (29 Portisham Place, Strensall, York Yorkshire Y032 5AZ, GB)
CLAIMS:
1. An edible wafer in sheet form having inclusions therein of a different edible material in particulate form, the distribution of the inclusions being substantially uniform such that when wafer sheet is divided into a number of pieces n, where n is greater than or equal to 30, with each piece having a surface area of 19.5 cm 2 and the number of inclusions in each piece N p is determined, the normalized loading of inclusions per piece expressed for each piece by the equation n.N p /N t where N t is the total number of inclusions in the n pieces has a variance of 0.35 or less.
2. An edible wafer in sheet form having inclusions therein of a different edible material in particulate form, the distribution of the inclusions being substantially uniform such that when wafer sheet is divided into a number of pieces n where n is greater than or equal to 30, with each piece having a surface area of 19.5 cm2 and the mass of inclusions in each piece MI P is determined, the normalized loading of inclusions per piece expressed for each piece by the equation n.MI p /MI t where MIt is the total mass of inclusions in the n pieces has a variance of 0.35 or less.
3. An edible wafer according to claim 1 or 2 wherein the inclusions have a maximum dimension which does not exceed about 8mm and a minimum dimension which is not less than 0.2mm.
4. An edible wafer according to any of claims 1 to 3 wherein the mass of each inclusion is in the range 0.5 - lOmg, preferably 2 - lOmg.
5. An edible wafer according to any of claims 1 to 4 wherein the inclusions are sesame seeds, poppy seeds, caraway seeds, fennel seeds, cumin seeds, hemp seeds, linseed, extruded cereal balls or pieces, roasted onion pieces, cocoa nib pieces and grated or chopped nuts such as grated coconut or chopped hazelnuts.
6. An edible wafer according to claim 4 wherein the inclusions are sesame seeds.
7. An edible wafer according to claim 1 wherein the inclusions are sesame seeds and when the sheet is divided into pieces of dimensions 65 x 30 mm, the pieces have a loading of at least 5 and more preferably at least 10 sesame seeds per piece and the variance of the normalized loading over at least 30 pieces is 0.35 or less.
8. An edible wafer according to any of claims 1 to 7 wherein the normalised loading has a variance of 0.3 or less.
9. An edible wafer according to any of claims 1 to 7 wherein the normalised loading has a variance of 0.25 or less.
10. A method for the manufacture of an edible wafer in sheet form having inclusions of a different edible material in particulate form uniformly dispersed therein which method comprises uniformly dispersing the inclusions in liquid wafer batter, dispensing the wafer batter onto a plate by means of a closeable valve which incorporates a dispensing aperture with a size sufficiently greater than the maximum dimension of the inclusions as to allow batter with inclusions dispersed therein to pass freely through the aperture and applying heat to the plate to cook the batter in contact with the plate thereby forming the wafer sheet.
11. A method according to claim 10 wherein the inclusions are sesame seeds, poppy seeds, caraway seeds, fennel seeds, cumin seeds, hemp seeds, linseed, extruded cereal balls or pieces, roasted onion pieces, cocoa nib pieces and grated or chopped nuts such as grated coconut or chopped hazelnuts.
12. A method according to claim 11 wherein the inclusions are sesame seeds.
13. A method according to any of claims 10 to 12 wherein the valve is a pinch valve.
14. An apparatus for forming a edible wafer in sheet form having inclusions of a different edible material in particulate form uniformly dispersed therein, said apparatus comprising a mixer for uniformly dispersing the particulate inclusions in liquid wafer batter, dispensing means for the wafer batter which include a closeable valve incorporating a dispensing aperture with a size sufficiently greater than the maximum dimension of the inclusions as to allow batter with inclusions dispersed therein to pass freely through the aperture, at least one plate orientable with respect to the dispensing means so that the batter can be dispensed onto the plate and heating means to cook the batter in contact with the plate to form the wafer sheet.
15. An apparatus according to claim 14 wherein the valve is a pinch valve.
16. An apparatus according to claim 14 or 15 wherein the dispensing means for wafer batter is a batter arm provided with 3 to 6 pinch valves. |
EDIBLE WAFER SHEETS
FIELD OF THE INVENTION
This invention relates to edible wafers in sheet form, a method of making edible wafers in sheet form and an apparatus for making edible wafers in sheet form.
BACKGROUND OF THE INVENTION
Edible wafer is well known as a food in its own right for example in the form of wafers for eating with desserts or ice cream or as a constituent of composite foods and confectionery items. One well known example of a confectionery item including wafer is Kit-Kat ® which is made up of fingers comprising a core of laminated wafer sheets surrounded by a moulded chocolate covering.
Wafer is generally prepared by cooking a batter comprising flour and water and, depending on the intended use, the wafer may or may not contain sugar. Wafer in sheet form is made on an industrial scale by dispensing the batter in strips onto plates with the batter subsequently being distributed as a thin film over the plate and cooked in contact with the plate. Generally the plates are part of a plate oven where batter is dispensed as strips onto a series of moving plates. Each plate comprises a base plate and a counter-plate which opens to allow batter to be dispensed onto the base plate and closes over the batter once it has been dispensed thereby spreading the batter over the plate. The combination of plate and counter-plate is often referred to as "tongs". The plates move through the oven to cook the batter after which the counter-plate is opened, the cooked wafer is ejected and the plate returns for more batter to be dispensed.
The plates may carry reeding or other engraving to impart a pattern to one or both sides of the finished wafer sheet. The surfaces of the plates may also be provided with complementary shapes or profiles to provide corresponding shapes or profiles in the wafer which are generally hollow, such as figurative or fancy shapes, up to a depth of for example about 20 mm. Wafer sheets with such shapes or profiles are referred to as
hollow wafers and the term "edible wafer in sheet form" as used herein is intended to include both flat and hollow wafers.
It may be desirable in order to improve the attractiveness of wafer to the consumer to include one or more different edible materials in the wafer as particulate inclusions, but this presents problems in the production of the wafer by conventional wafer production apparatus. Wafer batter is generally dispensed on to the plates by means of a so-called
"batter arm" which is a hollow arm through which batter flows and which is provided with relatively small holes a few millimetres in diameter (typically 2.1-3.5mm) for dispensing the batter as strips onto the plates. Particles of a different edible material dispersed in the batter preclude the use of conventional batter arms because the particles would block the small dispensing holes.
An alternative method of dispensing the inclusions which avoids the need to incorporate the inclusions into the wafer batter would be to dispense the inclusions separately from the batter but this has also been found to present difficulties. If inclusions are dispensed onto the plates separately before the batter is dispensed, for example using a sprinkle depositor, the result is that inclusions are dispensed uniformly over the plate whereas batter is dispensed onto the uniformly dispensed inclusions in the form of strips, i.e. in a non-uniform distribution over the plate. Although the mechanical action of closing the tongs and the generation of steam as the batter heats up changes the distribution of the batter to make this uniform, it also has the effect of changing the distribution of the inclusions so that this becomes non-uniform.
The result is that the distribution of inclusions in the finished wafer in non-uniform so that when, as will usually be the case, the wafer is cut into smaller pieces suitable for consumption as such or for incorporation into a food or confectionery product, there will be a significant proportion of wafer pieces with few inclusions or even no inclusions at all. There may also be a significant proportion of wafer pieces with an excess of inclusions. Generally the purpose of incorporating the inclusions in the wafer is so that they will be noticeable to the consumer by virtue of the change that they effect in the organoleptic properties of the wafer. Non-uniformity of the type referred to above, particularly wafer pieces with few or even no inclusions, is unacceptable in
the commercial production of food or confectionery products and would lead to a significant level of consumer complaints.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an edible wafer in sheet form having inclusions of a different edible material therein, wherein the distribution of inclusions in the wafer is substantially uniform.
It is a further object of the invention to provide a method for the manufacture of an edible wafer in sheet form having inclusions of a different edible material therein, which provides a product in which the distribution of inclusions in the wafer is substantially uniform.
It is a still further object of the invention to provide an apparatus for forming an edible wafer in sheet form having inclusions of a different edible material therein wherein the distribution of inclusions in the wafer is substantially uniform.
SUMMARY OF THE INVENTION
According to one aspect, the present invention provides an edible wafer in sheet form having inclusions therein of a different edible material in particulate form wherein the distribution of inclusions in the wafer is substantially uniform.
The distribution of inclusions can be considered as being substantially uniform if it is such that when wafer sheet is divided into a number of pieces n, where n is greater than or equal to 30, with each piece having a surface area of 19.5 cm 2 and the number of inclusions in each piece N p is determined, the normalized loading of inclusions per piece expressed for each piece by the equation n.N p /N t , where N t is the total number of inclusions in the n pieces, has a variance of 0.35 or less.
Alternatively, the distribution of inclusions can be considered as being substantially uniform if it is such that when wafer sheet is divided into a number of pieces n, where n
is greater than or equal to 30, with each piece having a surface area of 19.5 cm 2 and the mass of inclusions in each piece MI P is determined, the normalized loading of inclusions per piece expressed for each piece by the equation n.MI p /MI t , where MI t is the total mass of inclusions in the n pieces, has a variance of 0.35 or less.
According to another aspect, the present invention provides a method for the manufacture of an edible wafer in sheet form having inclusions of a different edible material in particulate form uniformly dispersed therein which method comprises uniformly dispersing the inclusions in liquid wafer batter, dispensing the wafer batter onto a plate by means of a closeable valve which incorporates a dispensing aperture with a size sufficiently greater than the maximum dimension of the inclusions as to allow batter with inclusions dispersed therein to pass freely through the aperture and applying heat to the plate to cook the batter in contact with the plate thereby forming the wafer sheet.
According to a still further aspect, the present invention provides an apparatus for forming a edible wafer in sheet form having inclusions of a different edible material in particulate form uniformly dispersed therein, said apparatus comprising a mixer for uniformly dispersing the particulate inclusions in liquid wafer batter, dispensing means for the wafer batter which include a closeable valve incorporating a dispensing aperture with a size sufficiently greater than the maximum dimension of the inclusions as to allow batter with inclusions dispersed therein to pass freely through the aperture, at least one plate orientable with respect to the dispensing means so that the batter can be dispensed onto the plate and heating means to cook the batter in contact with the plate to form the wafer sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a generalised illustration of the batter dispensing part of an apparatus for forming wafer sheets with inclusions according to the invention.
Figures 2A and 2B are diagrammatic representations of the batter arm of the apparatus of Figure 1 with pinch valves in the open (Figure 2A) and closed (Figure 2B) positions.
Figure 3 is a bar graph of the distribution of sesame seeds in wafer produced by using a sprinkler depositor to deposit sesame seeds separately from wafer batter. Figure 4 is a bar graph of the distribution of sesame seeds in wafer produced by using a five pinch valve batter arm to deposit batter with sesame seeds homogeneously distributed therein.
Figures 5 and 6 are bar graphs corresponding to Figures 3 and 4 respectively but showing normalized distribution of the sesame seeds.
DETAILED DESCRIPTION OF THE INVENTION
The production of wafers is a well known procedure in the food and confectionery industries and recipes for such batters, generally based on flour and water and which may or may not contain sugar depending on the intended application, are also well known. For further information as to the production of wafer, reference may be made to Tiefenbacher in Encyclopaedia of Food Science, Food Technology, and Nutrition, Eds R Macrae, R K Robinson and M J Sadler, Academic Press, London (1993) pages 417 - 420. The present invention is applicable to the production of any wafer to which it may be appropriate or desirable to add inclusions of a different edible material.
Inclusions of another edible material can be included in wafer for a number of reasons but the intention will usually be to alter the sensory experience of the consumer on eating the product. In other words there should be a noticeable difference in the organoleptic properties (for example taste and/or texture) between the wafer with inclusions and the wafer without inclusions.
According to one embodiment of the invention the inclusions are seeds and examples of seeds that may be added to wafer to change the organoleptic properties of the wafer include sesame seeds, poppy seeds, caraway seeds, fennel seeds, cumin seeds, hemp seeds and linseed. Other suitable inclusions for addition to wafer include extruded cereal balls or pieces, roasted onion pieces, cocoa nib pieces and grated or chopped nuts such as grated coconut or chopped hazelnuts. However, the present invention is applicable generally to the addition of any inclusion of a different edible material to
wafer, particularly where it is necessary or desirable to achieve a uniform distribution of inclusions in the wafer.
The size of the inclusions that can be added to wafer will depend on the size and thickness of the wafer sheet and thus the size of the particle which can be accommodated as an inclusion in the wafer. For example, where it is desired that the inclusions are contained largely or completely within the wafer, then the thickness of the wafer can be considered as placing a maximum limit on the dimensions of the inclusion. The minimum size of the inclusion will be determined by the size at which the inclusion is detectable as such by the consumer, i.e. the wafer on consumption appears to be noticeably heterogeneous. The inclusions will generally have a maximum dimension no greater than 8 mm and a minimum dimension no less than 0.2 mm.
Overall the inclusions will usually have a maximum dimension which does not exceed about 8mm. The minimum dimension of the inclusions will not usually be less than 0.2mm. Spherical inclusions such as extruded cereal balls preferably have a diameter in the range 0.2 - 2.8 mm. Seeds generally have an elongated shape and are preferably in the range 0.7 to 2.8 mm in thickness and 3 to 8 mm in length. Other non- spherical inclusions which are not seeds will generally have similar overall dimensions to those stated above for seeds.
The mass of the individual inclusions will depend on the nature of the material and, in particular, its density. However, in general terms the mass of each inclusion is preferably in the range 0.5 to 10 mg, more preferably 2 to 10 mg.
The inclusions are preferably substantially uniform in dimensions and this will generally be the case with seeds for example sesame seeds. However, the present invention is also applicable to inclusions with a range or variability in their dimensions provided that they remain within a suitable range for incorporation into wafer.
One particularly preferred particulate material for incorporation as an inclusion into wafer is sesame seeds. In nature, sesame seeds vary in size but generally have a weight
in the range 1 to 4.5 mg and a maximum dimension up to 3.5 mm. Sesame seeds supplied as a food ingredient are generally unifom in size. A typical batch of sesame seeds was found to have an average weight of 3.4 ± 0.1 mg per seed, an average thickness of 1 ± 0.1 mm and an average length of 3.45 ± 0.2 mm.
As noted above, the object of incorporating inclusions in wafer will generally be to alter the organoleptic properties of the wafer and, in any particular case, there will be an optimum number of inclusions in each wafer sheet in the form in which it is to be consumed or incorporated into a composite food product to provide this desired alteration. In general, there will be a minimum number of inclusions in a wafer of given size that will produce a noticeable difference in organoleptic properties between the wafer with and without inclusions. Similarly, there will be a minimum number of inclusions in a wafer of given size, which is greater than the number required to produce a noticeable difference in organoleptic properties, which will be required to provide a character (taste and/or texture, etc.) which is clearly identifiable as attributable to the inclusions.
The organoleptic properties of the wafer with and without inclusions can be determined by sensory testing and techniques for the assessment of food and confectionery products are well known. Such techniques generally involve the use of panels of tasters who have been trained to assess foods or confectionery products of the type in question tasting the samples under controlled conditions.
One objective of achieving a substantially uniform distribution of inclusions in wafer is to ensure that when the wafer is divided into pieces of a suitable size for consumption, a suitably large proportion of the pieces contain a number of inclusions which is at or above the level determined by sensory testing as making a noticeable difference to the organoleptic properties of the wafer. Thus, for example at least 95%, preferably at least
98%, more preferably at least 99% of the wafer pieces should contain a number of inclusions which is at or above the level which makes a noticeable difference to the organoleptic properties of the wafer.
Another objective of achieving a substantially uniform distribution of inclusions in a wafer is to ensure that when the wafer is divided into pieces of a suitable size for consumption, a suitably large proportion of the pieces contain a number of inclusions which is at or above the level determined by sensory testing as modifying the organoleptic properties of the wafer to provide a character clearly identifiable as attributable to the inclusions. Thus, for example, at least 80%, preferably at least 85%, more preferably at least 90% of the wafer pieces should contain a number of inclusions which is at or above the level determined as modifying the organoleptic properties of the wafer to provide a character clearly identifiable as attributable to the inclusions.
The production of wafer with inclusions will generally involve determining the desired loading of inclusions in the wafer. This loading will generally be set at a level where the inclusions at least make a noticeable difference to the organoleptic properties of the wafer and preferably where the wafer has an organoleptic character clearly identifiable as attributable to the inclusions. In addition the loading of inclusions will generally be set at a level where it is not considered to be excessive based on the criteria set out above. It is then necessary that the distribution of inclusions in the wafer should be substantially uniform at the level which is set based on the criteria set out below.
The distribution of inclusions in wafer can be expressed as a function of the loading of inclusions and loading can be determined in different ways depending on the nature of the inclusions and the most convenient way to quantify inclusions. Thus it may be most convenient to quantify inclusions by counting the number of inclusions in sheets of wafer as manufactured and in pieces of wafer derived therefrom. Alternatively, inclusions can be quantified by mass by separating the inclusions from the wafer, for example by extraction, and weighing them. Wafer can be quantified by surface area which can be derived for a flat wafer sheet from measuring the dimensions of sheets of wafer or pieces of wafer derived therefrom. The surface area of hollow wafer can determined for example by laser line triangulation, for example using the SICK IVP range of cameras produced by SICK AG of Waldkirch, Germany.
The loading of inclusions in wafer can be expressed in the following ways: number of inclusions in a given surface area of wafer
mass of inclusions in a given surface area of wafer.
The way in which loading of inclusions is expressed will generally be determined by the ease with which the parameters number and mass can be determined for inclusions. Determining the number of inclusions may be more appropriate where the inclusions are of relatively uniform dimensions whereas determining the mass of inclusions may be more appropriate where the inclusions vary significantly in dimensions.
The uniformity of the distribution of inclusions in the wafer can be determined from the normalised loading of inclusions in individual pieces of wafer sheet when this is divided into a number of smaller pieces of a standard size of 19.5 cm 2 . Normalized loading is derived for each individual piece of wafer from one of the following equations depending on the way in which loading is expressed:
The above equations for normalised loading are derived by dividing the loading for an individual piece (expressed as either number (equation 1) or weight (equation 2) of inclusions divided by the surface area of the individual piece (19.5 cm 2 )) by the total loading for all n pieces (expressed as either total number (equation 1) or total weight (equation 2) of inclusions over all n pieces divided by total surface area of the n pieces (n x 19.5 cm 2 )).
It will be apparent that the variance for normalized loading is dimensionless and represents the extent to which the loading of inclusions in the wafer is uniform. The loading of inclusions in the wafer is determined by the organoleptic properties which it is desired to impart to the wafer and the variation in the loading of individual pieces should be as low as possible and, in particular, at least the figure set out above.
It will further be apparent that where the inclusions are of the same or substantially the same size the variance will be the same for any given wafer whether normalized loading is determined by equation 1 or 2 above. Where the inclusions are not uniform in size the variance for a given wafer may be different depending on which equation is used.
Normalized loading is determined by dividing one or more sheets of wafer into pieces of a standard size. In principle, loading can be determined for any standard size piece of wafer but both the size and the number of pieces on which measurements are based may have an effect on variance. Accordingly, to ensure reproducibility in determining variance, normalised loading should be determined on at least 30 samples of wafer of surface area 19.5 cm 2 . Subject to the surface area being as defined, the exact dimensions of the sample are not critical but a particularly convenient size of wafer pieces for determining loading of inclusions and thus for assessing whether or not the distribution is uniform is 65 x 30 mm.
Generally a larger sheet or sheets of wafer may divided into smaller pieces, and in particular, pieces of the standard size referred to above, by manual cutting or by the use of conventional wafer cutting equipment. Where it is not possible to use all of the pieces from the sheet(s) of larger size, for example because of breakage, the pieces which are used should be representative of the sheet as a whole to ensure that no selection is made that could artificially affect variance.
Usually it will be necessary to take samples from a number of wafer sheets to ensure that normalised loading is determined from at least 30 samples of surface area 19.5 cm 2 . However, if it is not possible to obtain pieces of wafer of size 19.5 cm 2 or greater,
for example because the sheets have already been cut to a smaller size, then an alternative is to make up pieces with the standard surface area of 19.5 cm 2 by combining an appropriate number of pieces of smaller size. The pieces do not need to be combined physically but loading is determined over a wafer surface area, made up of more than one piece of wafer, with a combined surface area which is equal to 19.5 cm 2 . In this case also, the wafer pieces that are combined to give the standard surface area should be selected in a manner which does not artificially affect variance and generally the standard surface area of 19.5 cm 2 should be arrived at by combining the minimum number of smaller pieces.
The normalised loading of inclusions determined in accordance with either equation 1 or equation 2 above preferably has a variance of 0.30 or less and more preferably 0.25 or less.
According to one embodiment, the wafer sheets according to the invention contain a number and distribution of inclusions which is such that when the wafer sheet is divided into pieces of dimensions 65 x 30 mm at least 80% of the pieces contain at least 10 inclusions. Preferably at least 85% of the pieces and more preferably at least 90% of the pieces contain at least 10 inclusions.
According to another embodiment, the wafer sheets according to the invention contain a number and distribution of inclusions which is such that when the wafer sheet is divided into pieces of dimensions 65 x 30 mm at least 95% of the pieces contain at least 5 inclusions. Preferably at least 98% of the pieces and more preferably at least 99% of the pieces contain at least 5 inclusions.
A particularly preferred embodiment of the invention is constituted by wafer sheets containing sesame seeds as inclusions. When such wafer sheets are divided into pieces of dimensions 65 x 30 mm, the pieces preferably have a loading of at least 5 and more preferably at least 10 sesame seeds per piece and the variance of the normalized loading as determined by equation 1 above over at least 30 pieces is 0.35 or less.
In the method according to the present invention, a conventional wafer forming method is modified so that instead of being dispensed onto plates from small holes in a batter arm, the batter is dispensed by means of a closable valve which incorporates a dispensing aperture with a size sufficient to allow batter with inclusions dispersed therein to pass freely through the aperture without the inclusions causing the valve to jam and without the valve damaging the inclusions e.g. cutting them in half. A particularly suitable type of valve for use according to the invention is a pinch valve.
Pinch valves are well known for use in many types of manufacturing process and are based on the principle that the flow of a liquid passing through a flexible tube can be constrained, i.e. the valve is closed, by deforming the tube from the outside in such a way that flow of liquid is no longer possible. Generally the flexible tube is a flexible sleeve within a rigid tube and the valve is closed by "pinching" the flexible tube to prevent the flow of liquid. Pinching is effected by application of pressure to the outside of the flexible sleeve for example air pressure or water pressure. The valve may be designed in such a way that it is usually closed and actuation of the valve relieves the pressure to open the valve. Alternatively the valve may be designed in such a way that it is usually open and actuation of the valve applies pressure to close the valve. Pinch valves which are generally open and which can be actuated as desired to stop flow of wafer batter with inclusions are preferred for use according to the invention. Preferably the valve is actuated, i.e. pressure on the flexible sleeve is either applied or relieved by means of a pneumatic valve supplying air to the flexible sleeve, acting in response to appropriate control means.
Since wafer is an edible product and is intended for consumption as such or for incorporation into a composite food or confectionery product, the materials from which the pinch valve is constructed, in particular the flexible sleeve, as well as all other parts of the wafer forming apparatus which come into contact with the wafer or the wafer batter must be constructed of food quality materials, i.e. materials suitable for and approved for use in the processing of food products.
The method and apparatus according to the present invention are illustrated in Figures 1 and 2 of the accompanying drawings. Figure 1 is a generalised illustration of the batter
dispensing part of a wafer forming apparatus according to the invention. Batter from a batter supply line (not shown) is supplied to holding tank 2 which is also supplied with inclusions in particulate form, for example sesame seeds, from an inclusions tank 1. Batter and inclusions are mixed in the holding tank with a mixer (not shown) to form a homogeneous mixture of batter and inclusions. The mixture of batter and inclusions is fed via a pump 3 to a batter and inclusions input line 5 which communicates directly with a batter arm 9.
The batter arm 9 has affixed thereto five pinch valves indicated generally as 7 which are open to the interior of the batter arm so that when the valves are open batter and inclusions from the batter arm can flow through the valves. For example, the pinch valves can be screw threaded and affixed to nipples which are also screw threaded provided in the batter arm. The pinch valves are controlled by compressed air from line 4 so that the pressure of compressed air in the line closes the valve and when the pressure of the compressed air is released the valve opens allowing batter and inclusions to flow through the valve. The size of the pinch valves is such that, when they are open, batter containing inclusions can flow through the valve without obstruction.
The five pinch valves 7 attached to the batter arm are shown diagrammatically in Figures 2A and 2B with Figure 2A showing the valves in the open position (batter and inclusions able to flow) and Figure 2B showing the valves in the closed position (batter and inclusions unable to flow). Opening and closing of the valves is controlled by the flow of compressed air in line 4.
A number of oven plates 6 are shown in Figure 1 and these plates pass under the batter arm with pinch valves in a direction of travel indicated by 8. The oven plates have a base plate onto which batter and inclusions can be deposited and a counter-plate pivotally mounted with respect to the base plate at one side thereof parallel to the direction of travel, so that the combination of plate and counter-plate constitutes baking tongs. Each oven plate approaches the batter arm and the pinch valves in the open position, i.e. with the base plate exposed. The pinch valves are oriented on the batter arm at a shallow angle so that they point slightly down towards the base of the oven
plate. The flow of compressed air to the pinch valves is controlled by control means (not shown), for example a pneumatic valve, which is coordinated with the motion of the oven plates and the actuation of the pump 3 so that as each oven plate passes below the pinch valves five strips of batter and inclusions are deposited on the base part of the oven plate in a direction parallel to the direction of travel of the oven plate. The pump 3 is controlled so that it is actuated only whilst the pinch valves are open. Coordination of the actuation of the pump and the pinch valves with the travel of the oven plates can be achieved, for example, by means of computer software of the type commonly employed in the food processing industry.
After the oven plate has passed the pinch valves and the batter and inclusions has been deposited on the base part of the oven plate, the counter-plate closes causing the batter and inclusions to be uniformly distributed over the base part of the oven plate, the generation of steam as the batter heats up also causing movement of the batter across the plate. The oven plates with batter and inclusions then pass to an oven (not shown) where the batter is cooked to form the wafer. The wafer is then ejected and the oven plate is returned to the batter arm and pinch valves to complete the cycle and commence a further cycle.
The oven, the oven plates and the mechanism controlling the travel, opening and closing thereof have been omitted from Figure 1 in the interests of simplifying the drawing. These parts are standard components of a conventional apparatus for making wafer.
The apparatus depicted in Figure 1 has five pinch valves attached to the batter arm but this is shown purely for purposes of illustration and the present invention is not limited to the use of any particular number of pinch valves which will be determined by practical considerations such as the size of the apparatus and the size of wafer sheets to be produced. The minimum number of pinch valves is one and the maximum number will be determined by the width of the plate and the number of pinch valves needed to create an even spread of batter. The preferred number of valves will generally be from 3 to 6.
The invention is further illustrated by the following example.
EXAMPLE
Experiments were carried out to compare the distribution of sesame seeds across wafer sheets using a sprinkle depositor and a 5 pinch valve batter arm. The trials were carried out on a 25 plate wafer oven. Prior to the trial, measurements on the density and weight of individual sesame seeds were taken to calculate the amount of seeds needed to obtain inclusion of 7g of seeds in the final wafer sheet. Weight of 1 sesame seed = 0.0034g
Hence 5 g of seeds is equivalent to approximately 1450 seeds Density of sesame seeds (in bulk) = 0.98 g/ml Density of wafer batter = 1.15 g/ml
The recipe for the wafer batter is shown below in kilograms:
Flour 4.295
Water 5.593
Fat 0.043 Sodium bicarbonate 0.009 Tocopherol 0.060
TOTAL 10.000
The following oven settings were maintained throughout the trials: Oven temperature 135 - 14O 0 C
Baking Time 120 s.
The apparatus was generally as described above with reference to Figure 1. To deposit inclusions with the 5 pinch valve batter arm, the inclusions were homogeneously mixed with the batter in a separate vessel prior to deposition. Once the inclusions were fully dispersed in the batter this was added to a holding tank and then pumped through the batter arm by means of a pump. 3.9% by weight based on the total weight of seeds and batter of sesame seeds were added to the batter which resulted in a final wafer weight
of 74g, compared to a wafer weight of 67g without inclusions, i.e. 7g of seeds were added to the final wafer sheet.
The batter arm was specifically designed to allow inclusions to be added into the batter. Pinch valves were obtained from AKO UK Ltd, Daventry, UK. Use of five pinch valves ensured formation of complete wafer sheets on deposition of the batter. Pinch valves were assembled onto the batter arm via screw fittings. The pinch valves were operated by air and supplied with compressed air to regulate the start/stop of deposit.
The pressure inside the pinch valves was released via a software control while the batter pump was on to allow the batter to flow freely through the outlets of the batter arm and to be deposited on to each plate in turn.
For purposes of comparison, wafer containing inclusions was also prepared using the same batter and oven but with the inclusions being deposited on the plates using a sprinkler arm prior to deposit of the batter. The same batter as described above but without inclusions was pumped from a holding tank through a regular batter arm (10 holes, diameter 3mm) and deposited onto the plates. Since the holes in a conventional batter arm are smaller that the apertures in a pinch valve, 10 holes in the batter arm depositing 10 strips of batter deposited an equivalent amount of batter to the 5 pinch valves depositing 5 strips of batter plus seeds.
Prior to the deposition of the batter, inclusions (sesame seeds) were sprinkled onto the plates via a sprinkle depositor which fully extended into the oven. The sprinkle depositor was specifically designed for the project and was made up of a hopper to collect the inclusions, a channelled tray to transport inclusions to the oven and a vibrator to control the feed of the inclusions onto the plate by varying the frequency and amplitude of the vibrations. From the hopper, inclusions passed through a gate which could be adjusted at different heights depending on the throughput of the inclusions. Inclusions fell freely onto the plates from the channelled tray which was cut at an angle to drop seeds across the full width of the moving plates. The start/stop of deposit was controlled by the oven signal feed where the leading edge of the plate was in-line with the batter arm. The frequency of vibration of the depositor controlled the weight of inclusions added onto the plates and it was found that with a constant
frequency of 57.1Hz, 6.8 - 7g of inclusions were added to each wafer sheet (the same as for the experiment using the five pinch valve batter arm).
After baking, the wafers produced in both experiments were cut into 65 x 30 mm (19.5 cm 2 ) pieces. 10 wafer sheets were tested at a time and the number of sesame seeds in each 65 x 30 mm piece was counted. Parts of the wafers in both experiments were discarded due to breakage, leaving around 550 pieces to be counted.
Figure 3 is a bar graph showing the distribution of sesame seeds throughout 10 wafer sheets (547 pieces) using the sprinkle depositor with frequency as the ordinate and amount (number) of seeds as the abscissa.
Figure 4 is a bar graph showing the distribution of sesame seeds throughout 10 wafer sheets (558 pieces) using the five pinch valve batter arm with frequency as the ordinate and amount (number) of seeds as the abscissa.
Figures 5 and 6 are bar graphs corresponding to Figures 3 and 4 respectively but showing normalized distribution determined by equation 1 above as the abscissa.
It is apparent from a comparison of Figures 5 and 6 that a significantly narrower distribution of sesame seeds in the wafer sheets is achieved with the use of the five pinch valve batter arm than with the sprinkler depositor.
As part of the study, an external sensory panel assessed the amount of sesame seeds required in each wafer piece to give a noticeable difference in the organoleptic properties of the wafer and a clear flavour difference characteristic of the sesame seeds.
The results were as follows:
5 sesame seeds per piece - each wafer piece had a noticeable difference in flavour as compared to wafer with no sesame seeds although the panel were not necessarily able to define the flavour.
10 sesame seeds per piece - the panel could detect a clear flavour difference as compared to wafer with no sesame seeds which they were able to describe as sesame.
The sensory data show the importance of the reduced variance in the normalized loading of sesame seeds obtained as between the five pinch valve batter arm and the sprinkle depositor. The five pinch valve batter arm resulted in at least 90% of the wafer pieces having at least 10 sesame seeds (and thus having a clear sesame flavour) as compared to 73.1% for the sprinkle depositor. The five pinch valve batter arm resulted in 99% of the wafer pieces having at least 5 sesame seeds (and thus having a noticeable flavour difference) as compared to 90% for the sprinkle depositor. In other words, using the sprinkle depositor 10% of wafer pieces had less than 5 seeds and thus no noticeable flavour difference which is unacceptable for commercial production and would lead to consumer complaints.
Results in terms of number of seeds per piece are shown in the following Table:
TABLE
Comparison of Data using Sprinkle Depositor and 5 Pinch Valve Batter Arm
The variance (s 2 ) of the two sets of data were then calculated using the equation
n Variance = _ l=\ where n is the number of samples, s is the standard deviation n -\ and x is the mean of the data set.
Variance for the Sprinkle Depositor = 0.392
Variance for the 5 Pinch Valve Batter Arm = 0.194.
95% confidence interval level for s 2 can be calculated from the equation
(n -ϊ)s 2 (n -ϊ)s 2
3Co 975 fa " 1 ) Xo 025 C" - 1 ). and for the sprinkler depositor this is between 0.349 and 0.443 whilst for the 5 pinch valve batter arm it is between 0.177 and 0.224.