GB2474838A - Wafer and process for producing a wafer - Google Patents

Abstract

A transglutaminase (TGase) enzyme is used in the production of wafers to increase the strength and/or hardness of the wafer. A process for making a wafer comprises the steps of making a batter by mixing at least flour, water and a transglutaminase enzyme and either baking the batter on at least one hot surface or cooking the batter in an extruder. Wafer batter comprising flour, water and a transglutaminase enzyme along with a wafer made from said batter are also described. The transglutaminase may be present at 0.05 to 4 % by weight of flour used and the resulting wafer may be at least 5% harder than an equivalent wafer formed without the enzyme.

Description

WAFER

Field of the invention

The present invention relates to the use of a transglutaminase enzyme in the production of wafers.

Background of the invention

Wafers are baked products which are made from wafer batter and have crisp, brittle and fragile consistency. They are thin, with an overall thickness usually from < 1 to 6 mm and typical product densities range from 0.1 to 0.3 g/cm3.

Wafers are manufactured by preparing a batter containing mainly flour and water to which other minor ingredients may be added. A batter for use in the manufacture of commercial flat wafers typically contains 35 to 50 wt % flour. Common formulations may also comprise at least one of the following ingredients: fat and/or oil, an emulsifier such as lecithin, sugar, whole egg, salt, sodium bicarbonate, ammonium bicarbonate, skim milk powder, soy flour, yeast, and/or enzymes such as xylanases or proteases, for example.

Wafers may be distinguished from other biscuits/cookies in that wafers are the result of baking a batter whereas biscuits/cookies are usually baked out of a dough. Batter is a liquid suspension that will flow through a pipe whereas biscuit dough is rather stiff to permit rolling and flattening and normally has a water content of less than 50 parts per 100 parts of flour.

Two basic types of wafer are described by K.F. Tiefenbacher in "Encyclopaedia of Food Science, Food Technology and Nutrition p 4 17-420 -Academic Press Ltd London -1993": 1) No-or low-sugar wafers. The finished biscuits contain from zero to a low percentage of sucrose or other sugars, typically up to 10 % by weight sugars based on the weight of the wafer. Typical products are flat and hollow wafer sheets, moulded cones or fancy shapes.

2) High-sugar wafers. More than 10 % of sucrose or other sugars are responsible for the plasticity of the freshly baked sheets. They can be formed into different shapes before sugar recrystallization occurs or before sugar matrix re-solidification. Typical products are moulded and rolled sugar cones, rolled wafer sticks and deep-formed fancy shapes.

No-or low sugar wafers have a different texture and taste compared to high sugar wafers. When layered with a filling, they are used as the centre of well known chocolate confectionery products such as KIT KAT®.

In a common method of no-or low-sugar wafer manufacture, the batter is fed by pumping to a heated baking surface comprising a series of wafer baking moulds corresponding to the type of wafer desired, each wafer baking mould consisting of two heated engraved metal plates, also known as baking irons having upper and lower sections arranged to open and close, one of which may be moved relative to the other.

The baking moulds are disposed one after the other, continuously circulating through a wafer oven by travelling from one end to the other and which are opened and closed in the front entrance of the wafer oven for the depositing of the batter and removal of the individual wafers. The wafer baking moulds pass through a baking oven for a determined time at a certain temperature, for instance 1-3 minutes at 140 °C to 180 °C, to produce large flat wafer sheets with a low moisture content.

The surfaces of wafers are precisely formed, following the surface shape of the plates between which they were baked. They often carry a pattern on one surface or on both.

After cooling, the wafers are processed according to the requirements of the final product.

Wafers may also be produced by extrusion processes. WO 2008/031798 describes an example of such a process which comprises extruding a cereal-based or starch-based mix through a circular die to give an expanded non-planar extrudate; unfolding the extrudate to a flat sheet; stretching the continuous extruded and expanded sheet and subsequently cutting the sheet to a number of flat wafer products of the desired size.

Enzymes may also be used in wafer manufacture. For example endo-proteinases (such as neutral bacterial proteinase from Bacillus subtilis or papain from Carica papaya) may be used to hydrolyse the peptide bonds in wheat gluten, which has the effect of preventing the formation of gluten lumps, and xylanase (pentosanase) may be used to hydrolyse the xylan backbone in arabinoxylan (pentosan), which has the effect of decreasing the water binding capacity of wheat pentosans, redistributing water among other flour components and reducing batter viscosity. Combinations of these enzymes may also be used, mainly to decrease batter viscosity, make batters more homogenous, increase machinability, allow standard flour grades to be employed and/or increase the flour level in batter. These preparations have become widely accepted (Food Marketing & Technology, April 1994, p. 14).

Transglutaminases are a family of enzymes (EC 2.3.2.13) that catalyze the formation of a covalent bond between a free amine group (e.g., protein-or peptide-bound lysine) and the gamma-carboxamid group of protein-or peptide-bound glutamine.

Industrially, transglutaminase is used in a variety of processes to catalyze the formation of inter-and intra-molecular glutamyl-lysine crosslinks in food proteins such as soy proteins, milk proteins, egg proteins, and wheat proteins. Thus it can modify the physicochemical properties of foods including viscoelasticity and texture.

For example, it has been used as a binding agent to improve the texture of processed meat and fish products, in milk and yogurt production to make these products creamier, in noodle production to make them firmer, and in bread dough to strengthen the gluten network through the formation of glutamyl-lysine crosslinks. None of the available art describes the use of transglutaminase in wafer production.

A relatively frequent problem associated with manufacturing wafers is related to the hardness and strength of the wafer sheets in that they may be easily broken and there can be difficulties in releasing wafers from their baking plates. Wafers of a similar density (i.e. made with a similar flour:water ratio, similar recipe and similar baking conditions) tend to have a similar hardness. However, flours with low protein content, with high starch damage, and wholemeal flours tend to produce wafers that are very fragile, brittle and often stick to the baking plates.

One way to increase the hardness and strength of the wafer is to add gluten, but this is not a realistic solution because gluten strands in the batter give the batter a viscous and stringy consistency making processing difficult. In particular, during the manufacture of wafers in multiple-plate ovens (e.g. 50-plate ovens) batter is deposited onto moving plates in a continuous process. The batter is deposited using a batter arm that commonly consists of a pipe with holes facing the plate allowing the deposition of strips of batter. If batter is not cleanly deposited through the batter arm holes onto the plates when they are open, then batter may dribble over the closed plates or there may not be good coverage of each plate. This can lead to burning of the batter as it passes through the oven. Batter which is too viscous and tailing due to gluten formation results in such poor processing conditions. Moreover when the batter is too thick the batter flow rate is reduced through the holes and as a consequence a lower amount of batter is deposited. Accordingly it is more difficult to produce complete wafers.

Another way to reinforce the structure of a wafer is to add high amylose starch to the batter recipe; however this will increase the cost of producing wafers and so is not commercially attractive.

Accordingly, there is a need for a wafer which overcomes the problems discussed above, in particular in relation to the strength of the wafer and the processability of the wafer.

Summary of the invention

According to a first aspect the invention provides a process for making a wafer comprising the steps of: -making a batter by mixing at least flour, water and a transglutaminase enzyme and -baking the batter on at least one hot surface or cooking the batter in an extruder.

The use of a transglutaminase enzyme strengthens the gluten structure in the wafer and surprisingly improves the strength and hardness, and finally processability of the baked wafer sheet. Also surprisingly, the use of transglutaminase in wafer production does not lead to processing difficulties of the batter due to gluten strand formation.

Advantageously, it can give a harder bite to the wafer sheet, thus modifying the texture without any major changes to the method of producing the wafer. It also improves the release of wafers from the baking plates and reduces wafer breakages. Further the use of a transglutaminase enzyme improves the texture and processability of wafers made from flours not exactly designed for wafers (e.g. high starch damage flours, low protein-content flours, wholemeal flours), by strengthening the wafer structure.

According to a further aspect the invention provides the use of a transglutaminase enzyme in the production of a wafer to increase the strength and the hardness of a wafer.

In further aspects, the invention provides a wafer batter comprising flour, water and a transglutaminase enzyme; a wafer which is obtained from such a wafer batter or produced as described above; and a food product comprising a wafer as described herein and another edible material.

Brief description of the drawings

Fig. 1 shows a typical force versus distance graph obtained from a puncture test, used to measure the hardness and crispiness of wafers.

Detailed description of the invention

The invention consists of using transglutaminase in a wafer batter recipe to: -increase the hardness and/or strength of the wafer and improve its processability in terms of improved release of wafers from the baking plates and reduced wafer breakages; -improve the quality of wafers produced using alternative grade flour.

The method of the invention is useful for the production of any type of wafer and any suitable wafer batter recipe known to the skilled person may be used. For a baked wafer, a typical wafer batter may comprise around 35 to 50 wt % flour and water.

Thus, the flour:water ratio is generally no greater than approximately 1:1.

For an extruded wafer, a typical wafer batter may comprise 50-99 wt %, more preferably 80-99 wt % flour. Thus, the flour:water ratio is preferably at least about 4:1.

Common formulations may also comprise at least one of the following ingredients: fat and/or oil, an emulsifier such as lecithin, sugar, whole egg, salt, sodium bicarbonate, ammonium bicarbonate, milk, milk powder, e.g. skim milk powder, fruit powders, cocoa powder, malt extract, bran (flour and'or bits), flavouring and/or colouring agents, soy flour, leavening agents, e.g. yeast, and/or enzymes such as xylanases or proteases, for example. The ingredient mix may further comprise pieces of edible material.

Examples of such pieces can consist of parts of nuts, nut paste, almonds, sugar, chocolate, crunchy material, aerated material amongst others. It may also include seed husks which can be found in plain flour, for instance. Accordingly, the present invention allows for a great variability in the recipe.

Thus, a typical baked wafer batter may comprise 35-50 wt % flour, 0-10 wt % sugar, 0.05-1.8 wt % salt, 0-6 wt % oil or fat and from 50 to 65 wt % water. A typical extruded wafer batter may comprise 50-99 wt % flour, 0-50 wt % sugar, 0.05-1.8 wt % salt, 0-6 wt % oil or fat and from 0 to 25 wt % water.

Preferred are no-or low sugar wafers, which are wafers containing from 0 to 10 % by weight sweetener, preferably from 0 to 8 % by weight sweetener, and more preferably from 0 to 5 % sweetener based on the weight of the wafer. The sweetener may be sucrose or another sugar or a starch hydrolysate of any Dextrose Equivalents (DE) or an inulin hydrolysate or mixtures of two or more of these sweeteners. Examples of sugars other than sucrose are, for example, glucose, lactose, maltose or fructose and crystalline hydrate formers such as isomaltose, trehalose, or raffinose.

Any type of flour may be used in the method of the invention, including cereal flour, such as wheat, corn, barley, oats, rice, pea flour or combinations thereof It may comprise whole grain flour. The method is particularly useful for producing wafers made from alternative grades of flour (i.e. those not designed for wafers). These include flours with high starch damage, flours with low protein content and wholemeal flours. By high starch damage, we mean those flours having 6 % or more damaged starch based on the weight of the flour. By low protein content, we mean flours having a protein content of 8 % by weight or lower based on the weight of the flour. The use of transglutaminase in wafer batters made with these flours results in cross-linking of proteins present in the flour which reinforces the structure of the final wafer.

The wafer may be a flat wafer either having geometric shapes or cartoon character shapes, as well as alphabet letters or numbers, for example. It can also be a three dimensional shaped wafer such as, for example, a cone, a cup, a dish. Wafer texture results from the generation of gas cells in a gel structure mainly composed of gelatinised starch. For baked wafers, the high temperature of the baking plates induces a rapid gelatinisation of starch granules present in the flour and production and expansion of the gas bubbles inside the gelatinous matrix. These gas cells are, in the common practice, mainly generated from gassing agents such as added bicarbonates or from steam produced by heating. Therefore the wafer can be seen as a solid foam of gelatinised and dried starchlflour with dispersed gas cells (which can form an almost continuous phase in certain cases). Typically, the wafers of the invention have a thickness between 0.5 and 10 mm, preferably between 1 and 5 mm, more preferably between 1.5 and 3 mm.

According to the invention a wafer batter is treated with transglutaminase (EC 2.3.2.13). Transglutaminase can be obtained from various sources, such as for example from plants and animals including pig liver and the blood clotting protein activated Factor XIII, or from fungi, such as actinomycetes or myxomycetes, or from microorganisms, such as for example those belonging to the genus Streptoverticillium, various Streptomyces, Bacillus subtilis, various Actinomycetes and Myxomycetes. In general, transglutaminases from animal sources require calcium ions for activity.

Recombinant forms of transglutaminase enzymes may be obtained by genetic engineering methods as heterologous proteins produced in bacterial, yeast, and insect or mammalian cell culture systems. The principal requirement of any transglutaminase employed in the present invention is that it has activity to catalyze the transfer of the gamma-carboxamide group of a glutaminyl residue in a protein or peptide to the epsilon-amino of a lysyl residue of the same or a different protein or peptide, thereby forming a gamma-carboxyl-epsilon-amino crosslink. Any enzyme having transglutaminase activity may be employed in the methods of the present invention.

Transglutaminase activity may be determined using known procedures. One such technique comprises colorimetric procedures, like the use of benzyloxycarbonyl-L-glutaminyl-glycine and hydroxylamine to form a gamma-carboxyl-hydroxamic acid if transglutaminase is present. An iron complex of the hydroxamic acid can be formed in the presence of ferric chloride and trichloroacetic acid. U sing the absorbance at 525 nm with appropriate standards, the activity of enzyme present may be determined; see, US 5,681,598.

Preferably use is made of food-grade organisms, for example Aspergillus niger or Bacillus subtilis. Particularly preferred enzymes for use in accordance with the invention are enzymes which have received Generally Recognised As Safe (GRAS) notification by the Food and Drug Administration (FDA) or other equivalent body. An example of such an enzyme is VeronTG from AB Enzymes.

Transglutaminase may be added to a wafer batter at a concentration of from 0.05 to 4 % by weight based on the weight of the flour. The skilled person will be able to select an appropriate concentration of transglutaminase based on their knowledge. Preferred concentrations may range from 0.05 % to 1.2 %, preferably from 0.4 % to 0.6 % by weight based on the weight of the flour.

Any method known to the skilled person may be adapted simply by the addition of transglutaminase to the wafer batter at any time prior to cooking of the batter. The inventive method is therefore particularly useful because minimal modifications of known methods are required.

Transglutaminase may be added to the wafer batter at any time prior to baking or cooking of the batter. For example, transglutaminase may be added at the start of the mixing of the ingredients directly to the water, or may be first mixed with the flour prior to addition of the flour to the water, or may be added later during the mixing of the ingredients, or may be added immediately prior to baking of the wafer.

Accordingly, the transglutaminase may be added at the start of mixing of the ingredients or subsequently. For both baked and extruded wafers, the batter is prepared in any manner known to the skilled person. Thus, the ingredients may be mixed for from 2 minutes to 10 minutes. Then the batter may be held for from 30 minutes to 1 hour, preferably approximately 45 minutes. The mixing and holding steps are usually carried out at room temperature, for example from 20 to 35 °C, preferably approximately 25 °C.

For baked wafers, the batter may be baked for approximately 1 to 5 minutes, preferably from 2 to 2.5 minutes. The baking temperature is preferably from 140 to 180 °C.

Surprisingly, transglutaminase does not adversely affect the processability of the wafer batter due to increased gluten strand formation, even if added at the start of the mixing of the ingredients.

Alternatively, for extruded wafers, the batter may be prepared by mixing the dry ingredients or both the dry and liquid ingredients and feeding these into a cooker-extruder, for example a twin, screw extruder. Water and/or steam and/or a sugar solution and/or a fat solution may be injected in the extruder, typically at a low feed rate. The moisture in the extruder is typically between 10-25 %. The water content of the mix at this stage usually does not exceed 15 %. It is typically between 5-15 %. The ingredient mix is then cooked in the extruder. Cooker extruders are continuous machines gathering several unit operations (conveying, mixing, melting/cooking, expanding, shaping) into one machine, as described in W02008/03 1798. Thus, the ingredient mix may be fed and cooked in a twin, or single screw extruder with specific screw configuration and heating elements regulated to ensure a certain temperature profile. Cooking the mixture may be carried out at 80 to 180 °C, typically from 130 to °C, under 8 to 15 MPa, for 5 to 180 seconds, preferably from 5 to 80 seconds, in subsequent sections of the extruder where the mixture is heated, compressed and sheared so that it forms a cooked thermoplastic mass. The mean residence time is around 40 seconds. Under these conditions, the material melts due to the combination of mechanical friction produced by the screw(s) and the thermal energy given through the barrel. The melt is then conveyed to the die where it is subjected to pressure.

The thermoplastic mass may be extruded by having it pushed by the extruder screw or twin screw through the openings of a die provided for at the end of the extruder. The geometry of the die may be chosen to give a defined shape to the wafer product, e.g. circular die or any other planar or non-planar die. Furthermore, when the water-containing extrudate, initially at high pressure and temperature, arrives at the die, water vaporises causing the extrudate to expand rapidly creating a foam structure.

Traditionally, the extruded product directly expands or puffs by the instantaneous conversion of compressed liquid vapour into steam as the product flows through the die and into an ambient environment (moisture flash off process). Using a circular die ensures that expansion occurs all around the die. Thus an expanded, extruded non-planar structure is produced. The non-planar structure may then be unfolded to give a sheet of extruded material which may be subjected to stretching/pulling and/or moulding to obtain a product of the desired thickness and structure. It may be subjected to drying (e.g. to a final residual water content of approximately 1 to 4 %) and/or cutting.

In these ways, the use of transglutaminase provides the benefit of strengthening the gluten structure in the wafer without affecting the processability of the batter.

These methods may result in the production of a wafer which is at least 5 %, or more preferably at least 10 % or 12 %, harder than the same wafer that has not undergone the transglutaminase treatment. Thus, the invention also provides a wafer which is obtainable by one of the methods described above according or from a wafer batter described above, which is at least 5 %, or more preferably at least 10 % or 12 %, harder than the same wafer that has not undergone the transglutaminase treatment. By "the same wafer that has not undergone the transglutaminase treatment" we mean a wafer having the same composition and prepared by the same method as the wafer which is harder, with the exception that no transglutaminase is included in the wafer batter.

These wafers maintain the crispiness expected from wafers.

Hard and strong wafers are solid, firm and rigid and less easily broken, bent or penetrated than standard wafers. They are able to withstand more force or pressure than standard wafers. Thus, hardness is an attribute that relates to the magnitude of the force or the work needed to cause a fracture in the wafer. Crispness is an attribute that relates to the number of mechanical fractures that occur upon application of a certain force and to the magnitude of the force needed to cause a fracture. Ways to quantify hardness and crispness are known in the art, notably from Mitchell, J. R. et al. in Journal of the Science of Food and Agriculture, 80, 1679-1685, 2000.

The hardness and crispness of wafers or expanded extruded cereal products may be evaluated by a penetration test (also known as a puncture test or crush test) which is performed by using a texture analyser able to record force/distance parameters during penetration of a probe into the wafer or product. The instrument forces a cylindrical probe into a stack of five wafers and the structural ruptures (force drops) are recorded over a certain distance. The frequency of force drops allows discrimination between wafer textures whereby the higher the number of force drops, the higher the crispness.

The conditions used for this test were: Texture Analyser TA.HD, Stable Micro Systems, England; Load cell 50 kg; 4mm diameter cylinder stainless probe; Penetration rate lmmls; Distance 8mm; Record of force drops greater than 0.2N; Trigger force greater than 0.5N; Acquisition rate 500 points per second.

Van Hecke E. (1991), ("Contribution a l'étude des propriétés texturals des produits alimentaires alvéolés. Mise au point de nouveaux capteurs. Ph.D. Thesis, Université de Technologie de Compiegne") proposed a method based on 4 parameters to characterise force-deformation curve. Differences in textures of wafers products may be associated with these parameters: -hardness, given by: -the average puncturing force Fm (N) = Aid and by -the area under the force deformation curve A(N.mm) -crispiness work, Wc -which is defined as Crispness Work, Wc (N.mm). N.mm (Newton millimetre) is the non-SI work unit used.

Wc (N.mm) = (Aid) (No/d) Where No; total number of peaks d = distance of penetration (mm) A = Area under the force-deformation curve (N.mm) The above equation could be simplified to Wc = AINo.

The slope and the value of Wc will vary depending on the batter recipe. At similar weight, wafers having the same dimensions and baked under the same conditions tend to have similar hardness, which corresponds to the A value (area under the force-deformation curve (N.mm)) for the calculation of Wc.

The wafers described herein may be presented to the consumer as a wafer by itself, but may also be further processed to form a confectionery or savoury food product or a pet food. Therefore, the present invention also comprises a food product comprising a wafer as described herein and another edible material. The other edible material may be a confectionery, savoury or pet food material. For example, suitable confectionery materials include chocolate, jelly, compound chocolate, ice-cream, sorbet, nut paste, cream, cream-based products, cake, mousse, nougat, caramel, praline, jam, a low-fat or low-calorie filling, a fruit jam, a real fruit filling, or combinations thereof. Suitable savoury materials include fish or meat paste, cheese-based materials, vegetable puree, or combinations thereof. One or more other edible materials may be included as a filling for the wafer or the wafer may be the centre or part of the centre of the food product. The wafer may be in direct contact with the food material in the presence or absence of a moisture barrier.

Examples

The following example is illustrative of the products and methods of making the same falling within the scope of the present invention. It is not to be considered in any way limitative of the invention. Changes and modifications can be made with respect to the invention. That is, the skilled person will recognise many possible variations in this example covering a wide range of compositions, ingredients, processing methods, and mixtures, and can adjust the naturally occurring levels of the compounds of the invention for a variety of applications.

A wafer batter was made according to a typical recipe which comprises: Component Parts Flour 100.00 Water 105.90 Veron W (AB Enzymes) 0.04 Salt 0.26 The flour used was obtained from Nestle India (Ponda Factory) code 012310108 (supplier Narasu) and had the following characteristics: Protein % 9.3 Moisture % 13.7 Ash% 0.6 Protein % on db 10.8 Ash%ondb 0.70 WA(600line) 61.3 Starch damage % 6.25 Hagberg Falling number sec 713 The batter was made in a beaker by adding the small ingredients to the water which was at a temperature of 35 °C. The mixture was stirred with a spatula to dissolve the small ingredients. The flour (t = 21 °C) was added to the water and stirred with a spatula to incorporate all of the flour in the water. It was then mixed for 30 seconds with a Silverson mixer at 5500 rpm, continually moving the beaker to try to break the flour agglomerations. After 30 seconds the mixer was stopped and the contents of the beaker mixed with a spatula to incorporate any remaining flour on the beaker walls.

Mixing was continued for 1 minute using the Silverson (at 5500rpm) with continuous movement of the beaker to obtain a homogenous batter. Mixing was stopped and half of the batter was held in a beaker and labelled as Sample 1, while the other half of the batter was transferred to another beaker and transglutaminase added to it in proportion of 0.2 % by weight, based on the weight of the batter. This batter was labelled as Sample TG. The transglutaminase used was VeronTG from AB Enzymes.

Both batters were held for 40 minutes at room temperature after which were baked in a small kitchen Hebenstreit oven using the following conditions: * Bottom plate temperature: 180 °C * Lower plate temperature: 175 °C * Baking time: 2 minutes.

The wafers were then sealed in metallic bags and later on used for texture analysis.

A puncture test (also known as a penetration test or crush test) was used for measuring hardness and crispness of wafers. This test was performed by using a texture analyser able to record force/distance parameters during penetration of a probe into the wafer.

The instrument forces a cylindrical probe into a vertical stack of five circular wafers of diameter 45mm, the principal axis of the probe being directed normal to the surface of the stack of wafers. The structural ruptures (force drops) are recorded over a certain distance. The force required to penetrate the wafer stack allows discrimination between wafer textures whereby the higher the force required, the harder the wafer. The frequency of force drops allows discrimination between wafer textures whereby the higher the number of force drops, the higher the crispness. All tests were carried out at ambient temperature (21 °C).

The conditions used for this test were: Texture Analyser TA.HD, Stable Micro Systems, England; Load cell 50 kg; 4mm diameter flat-tipped stainless steel cylindrical probe; Penetration rate lmmls; Distance 8mm; Record of force drops greater than 0.2N; Trigger force greater than 0.5N; Acquisition rate 500 points per second.

The mechanical properties of the different wafers were analysed using a method based on the following 5 parameters which were used to characterise force-deformation curve.

A = Area under the force-deformation curve (N.mm) Wc = Crispness Work (N.mm) No = total number of peaks (i.e. frequency of force drops of at least 0.2 N) d = distance of penetration (mm) Fm = Average Puncturing Force (N) Hardness corresponds to the A value (area under the force-deformation curve (N.mm) and the average puncturing force.

Crispness work (or "work of crushing"), Wc, is defined as: Wc(N.mm) (Aid) = A (No/d) No The lower the value of Wc, the more crispy is the perceived texture of the wafer.

For each test, a data set of force versus distance is obtained. Fig. 1 shows a typical force versus distance graph. It may be noticed that the force undergoes sudden drops as the probe progresses through the specimen. These force drops are recorded, and placed in categories according to minimum value, i.e. the number of force drops of at least 0.2 N, 0.4 N, 0.6 N, 0.8 N, 1.0 N, 1.2 N, 1.4 N or 1.6 N is noted. From this determination, the frequency, with respect to distance, of such force drops is calculated. For example, it may be determined that there occur force drops of at least 0.2 N with a frequency of times per millimetre, and have dimensions of mm'.

The test was repeated eight times, and thence an average Wc value was determined from the Wc values calculated from each of the individual data sets of force versus distance. Data were analysed using a software macro' provided with the instrument, via which were obtained both the maximum force over the whole deformation range and the average force in the deformation range 1 -4 mm.

The data is shown in Table 1 below. The data for sample 1 (prepared without transglutaminase) is shown in the top half of the table, whilst the data for sample TG (prepared with transglutaminase) is shown in the bottom half of the table. The left column of data shows the average puncturing force (N Mean F 1:2); the second column of data shows the area under the curve (N.mm Area F-D 1:2); the third to tenth columns of data show the number of force drops of at least 0.2 N, 0.4 N, 0.6 N, 0.8 N, 1.0 N, 1.2 N, 1.4 N or 1.6 N respectively; the penultimate column of data shows the count peak; and the right hand column of data shows the calculated value of Wc.

Table 1

________ ______ N N.rrrn nm-i nm-i nm-i nm-i nm-i nm-i rrrri-i nm-i ______ Nrirn ________ ______ MeiFi: P,iaF-Di: d2 d.40 dff d.8 di.O di.2 d14 di.6 Q:xJntP Wc Ti _____________ ________ _______ i5.i 125.123 3.753 287 2)2 2252 2(1)2 i.6 1.376 i.i 30 4.17 ________ _______ 12337.S33 3.628 275 2252 i.6 1.501 i.37( 1.251 i.i 3.401 ________ _______ 13.737 i.679 2752 1.751 1.376 111)1 0.876 0.87( 0.876 0.876 4.i ________ _______ 16.748 133.752 2752 212 1.876 1.376 0.876 0.87( 0.751 0.625 6.0 rri _______ i6i9 i08.783 3.753 287 2377 1876 1151 i.SOi i.i iAlUi nlei _______ i55 i2i.8 3.878 31 2W2 187 115 i.SOi i i.25i 3 ni _______ 1221)3 97.453 3.i27 262 2127 187 150 i.i 0 0.876 a9 ________ _______ i64 13121)1 411)3 262 2(1)2 211)2 211)2 1.751 1 1.251 4.

________ _______ i3B4 110.548 a503 2.62 2252 211)2 137 1.251 1(X) 0.751 a95 ________ _______ 16379 13(11853 3.12 2.25 1.751 137 125 1(1)1 1 (Xl) 111)1 25 523 rri _______ 1813 i463 3 3. 2627 2627 2502 2iZ 18 1.376 5.

nlei _______ i53 1251 3 2.8 2127 211)2 211)2 187 1 i.6 31 4 nçei _______ 13.554 i08 3 2 i.6 i.6 1.50 1.37 ii i.i 24 4.5 STIe1 Aiiege 149 119 3 2. 2.1 1.8 L 1 1. 1.1 27.6 Sn:iIej 9xlev L9 152 0. 0. O. 0.4 0. 0 0 0.3 3.1 0 SIe1 rvkfiai 153 1220 35 2. 2.1 1.9 L 1 1.1 1.1) 4.

ITpTG ___ __ __ __ __ __ ___ ITpTG _____ 17. i42 3.503 225 2. 1.876 150 1.251 1251 0.876 28 51 nTG ______ 17353 i3EJ3 3.628 275 2. 2127 175 1.501 1.376 1.376 47 nTG _______ i9A4 1553 3.37 2E 2. 2127 211)2 1.62 1.501 1.501 27 57 nTG _______ i3B95 iil14 3.87 23, 2. 1.376 iff)1 0.87( 0.751 0.751 31 3 rrpTG _______ 14682 117285 3.Th3 3A) 2 2127 1.876 1.501 i1 i1 30 a9 TTG _____ 1713 136.886 411)3 ao 2. 2252 2(1)2 i.6 1.376 1.376 32 428 TTG _____ i81 145. 4.628 aa ai 2502 2(1)2 i.6 1.376 1251 37 3 ITpTG _______ 1528 iX1 4.128 28, 21 1.501 1.376 1(1)1 0.876 0.876 34 3.7C STpbTG _______ i621 i.464 3.753 3.12 21 1.876 i.6 i.6 1251 1251 31 4.3i SaTIe1G Auege 16.67 133.1 3.85 2.84 2.35 L97 1.6 1.40 L21 L15 3L00 4.3 Sie1G 9deii 1.80 14. 037 04 0 0.3 03 0. 0.25 0.2 3O8 0.7 STe1G Fvfia1 17. I36 3 2.9 2. 2.1 L 1.5 1.3 1.3 31) 4 The results are presented in the tables below.

Table 2. ANOVA results for wafer hardness given by average puncturing force.

Sample No. samples Sum Average Variance Sample 1 13 194.2 14.9 3.6 SampleTG 9 150.1 16.7 3.2 Table 2 shows ANOVA results for wafer hardness given by average puncturing force.

The hardness of the wafers containing transglutaminase was significantly higher than the standard wafers (P-value 0.044062) and the increase in hardness observed was approximately 12 %.

Table 3. ANOVA results for wafer hardness given by average area under the curves (Force vs. Penetration Distance or Time).

Sample No. samples Sum Average Variance Sample! 13 1550.9 119.3 232.4 SampleTG 9 1198.7 133.2 206.8 Table 3 shows ANOVA results for wafer hardness given by average area under the curves. The hardness of the wafers containing transglutaminase was significantly higher than the standard wafers (P-value 0.04404) and the increase in hardness observed was approximately 12 %.

Table 4. ANOVA results for wafer crispness Wc.

Sample No. samples Sum Average Variance Sample 1 13 57.3 4.41 0.61 SampleTG 9 39.4 4.37 0.51 Table 4 shows ANOVA results for wafer crispness Wc. The two types of wafers showed approximately the same crispness (P-value 0.9 18903).

Claims (9)

1. Claims 1. Process for making a wafer comprising the steps of: -making a batter by mixing at least flour, water and a transglutaminase enzyme, and -baking the batter on at least one hot surface or cooking the batter in an extruder.
2. 2. Process for making a wafer according to claim 1 wherein the transglutaminase is used at a concentration of from 0.05 to 4 % by weight based on the weight of the flour.
3. 3. Process for making a wafer according to claim 1 or 2 wherein the wafer is a no-or low-sugar wafer.
4. 4. Process for making a wafer according to any of claims 1 to 3 wherein the flour is wheat flour.
5. 5. Use of a transglutaminase enzyme in the production of a wafer to increase the strength andi'or hardness of a wafer.
6. 6. A wafer batter comprising flour, water and a transglutaminase enzyme.
7. 7. A wafer which is obtainable by a method according to any of claims 1 to 4 or from a wafer batter according to claim 6.
8. 8. A wafer according to claim 7 which is at least 5 % harder than the same wafer that has not undergone the transglutaminase treatment.
9. 9. A food product comprising a wafer according to claim 7 or 8 and another edible material.