NL2008464C2 - Method of coating of a bakery food product, and a coating agent for a bakery food product. - Google Patents

Description

Method of coating of a bakery food product, and a coating agent for a bakery food product.

5 The present invention relates to a method of coating of a bakery food product, and to a coating agent that is useful for said method.

In particular, the invention relates to bakery food products that are primarily made from dough, and in 10 particular to bread products.

It is well established practice to coat such bakery food products with a coating layer in order to produce a food product having an appetizing appearance and a shiny gloss .

15 A well known method to produce such a coating layer is by applying an aqueous solution of whole eggs or egg yolks on the outer surface of the bakery food product before it is baked. During subsequent baking of the bakery food product, the applied solution is dried and a desired coating layer is 20 formed. The coating layer that is obtained is herein also referred to as a 'glazing layer' , which terms have a similar meaning in the context of the invention. Correspondingly, the aqueous solution that is applied on the bakery food product may be referred to as a 'glazing agent'.

25 Another aqueous solution that is suitable for this purpose which is commonly used in this regard, is a dilution of milk or milk derivatives.

The aqueous solutions that are commonly used contain animal proteins, e.g. from eggs, from milk, or from 30 collagen. The aqueous solutions containing egg proteins, are referred to in the art as an 'egg wash'.

2 A glazing agent for bread is for example disclosed in JP2001/249009-A. Herein, whey protein is used as a protein source in the composition of the glazing agent.

Another glazing agent is disclosed in EP0878132-A2, in 5 which collagen is used as a protein source.

In summary, the prior art teaches the use of animal proteins for coating agents that are suitable to create a glazing layer on bakery food products. However, there are several 10 disadvantages that relate to the use of animal proteins in this regard.

First, animal proteins are potential allergens to humans. When present in a coating layer on a bakery food product, such allergens can provoke an allergic reaction, 15 even though the consumer is not allergic to proteins from the bakery food product itself (as vegetable proteins are significantly different from animal proteins in this context).

Second, the coating agent itself requires additives in 20 order to stabilize and preserve the aqueous solution before it is actually used. These additives may not be clean label.

Third, animal proteins are a component in the coating agent which is relatively expensive.

Fourth, the production of animal proteins imposes a 25 general burden on the environment, and as a source of proteins they are therefore ranked low on the scale of sustainability.

Fifth, certain religions or individual consumption patterns (e.g. a vegetarian or vegan diet) require that 30 animal proteins are abandoned from a daily diet.

The objective of the invention is to provide a coating agent which is suitable for coating of a bakery food product, 3 wherein the coating agent contains proteins, and lacks in whole or in part, the disadvantages of the known coating agents. Furthermore, the objective of the invention is to provide a method of applying such a coating agent on a 5 bakery food product.

According to a first aspect of the invention, the above objective is achieved by the provision of: a method of coating of a bakery food product, wherein a 10 vegetable protein, preferably gluten, is applied on an outer surface of the bakery food product and a coating layer is subsequently formed on the outer surface.

It has been found that gluten, which is a vegetable protein source that mainly contains gliadin and glutelin, 15 can be used advantageously as a protein source in coating layers on bakery food products. As gluten is derived from wheat and related grain species, its proteins are similar to the proteins contained in bakery food products, especially food products based on dough. According to the invention, 20 the gluten is present in the coating layer and does not contribute proteins that are foreign to the proteins of the food product itself. Thus, allergic reactions in consumers in respect of foreign proteins are avoided.

Furthermore, gluten is an economically viable and 25 sustainable source of protein, because the costs are relatively low in comparison with the animal proteins that are used in the prior art.

In the method according to the invention, the vegetable 30 protein may also be a soy protein or a corn protein, or a vegetable protein from potato, pea, beans, etc.

4

Furthermore, the vegetable protein in the context of the invention, may be a mixture of above mentioned vegetable proteins, possibly including gluten.

The advantages of using these vegetable proteins or 5 mixtures thereof, are the same as explained above for gluten specifically.

Preferably, in the method of the invention, the coating layer which is formed on the outer surface is substantially 10 free of animal proteins.

As such, the risk of the bakery product provoking an allergic reaction by allergens that are foreign to vegetable proteins, is eliminated.

The term 'substantially free' in the context of the 15 invention, means a relative content in weight of animal proteins which is below 10%, preferably below 5%, more preferably below 1%, and most preferably approximately 0%.

Preferably, in the method according to the invention, gluten 20 is applied on the outer surface of the bakery food product, in the form of a homogeneous mixture of hydrolyzed gluten in water .

It is noted that gluten in itself is not homogeneously dispersable in water. As part of the invention, a 25 homogeneous mixture of gluten in water was developed which is suitable for use in the invention, which is based on hydrolyzed gluten in water.

A 'homogeneous mixture of gluten in water' in the context of the present invention shall be construed as a 30 mixture of gluten particles and/or molecules in water, which is stable for at least 2 days under ambient conditions and in open air.

5

The homogeneous mixture of hydrolyzed gluten in water allows for a simple and straightforward method of applying the mixture on the outer surface of the bakery food product, for instance by spraying, rolling, brushing or dipping.

5 Advantageously, the content of gluten in the homogeneous mixture is 5 to 40 wt.%, while the content of water is preferably 25 to 75 wt.%.

With further preference in the method according to the 10 invention, the gluten is enzymatically hydrolyzed gluten.

It was found that enzymatically hydrolyzed gluten is highly suitable as a protein source for the homogeneous mixture, in accordance with the invention.

15 Other ways of improving the dispensability of the gluten can be achieved by subjecting gluten to acid hydrolysis, or by a reduction of the disulphide bonds within the gluten proteins .

In addition, the gluten may be dispersed in a solvent 20 containing acid or alcoholic dispersants, in order to further promote the dispersability of gluten in the solvent.

Preferably, in the method according to the invention, the hydrolyzed gluten has a degree of hydrolysis between 2% and 25 15%.

It was found that it is possible to achieve a stable, homogeneous mixture of gluten in water, when using hydrolyzed gluten having such a degree of hydrolysis (DH). For instance, the DH value may be between 7% and 10%.

30 Alternatively, the DH value may be outside the range of 7% to 10%, while still within the range between 2% and 15%.

With further preference, the gluten in the method according to the invention, has been hydrolyzed by a protease enzyme.

6

For that reason, the homogeneous mixture may contain an amount of protease, usually between 0.1 and 4.0 wt.%, which 5 may still be present in the mixture, e.g. when the protease is not separated from the hydrolyzed gluten after the hydrolysis reaction has been performed.

According to another preferred variant of the method 10 according to the invention, the homogeneous mixture comprises an additive for the reduction of the water activity.

Well known additives that reduce water activity are for instance dextrose, sugar, monosaccharides, disaccharides, 15 dextrins, glycerol, sorbitol and other food alcohols, and sodium chloride.

By reducing the water activity of the homogeneous mixture, the mixture is microbiologically stabilized so that it can be kept over a longer time, before it is actually 20 used and applied on a bakery food product. Furthermore, a reduced water activity is beneficial in regard of the physical and chemical stability of the mixture.

Preferably, the content of the additive in the mixture is 1 to 60 wt.%.

25

In the method according to the invention, the homogeneous mixture may further contain traces of acid which is used for lowering of the pH-value as well as for microbial and enzymatical inactivation during the preparatory process of 30 the mixture which will be discussed in more detail below. Useful acids in this regard are for instance acetic acid, lactic acid, and ascorbic acid.

7

The content of acid in the homogeneous mixture is typically 1 wt.%, or even lower.

In the method according to the invention, the homogeneous mixture is preferably prepared by a preparatory process 5 comprising the steps of: - mixing in water of a protease enzyme, and gluten; - stirring the mixture under mild heating until a hydrolyzed gluten is obtained which has a satisfactory degree of hydrolysis; 10 - inactivating the protease enzyme.

The relative amounts of water, gluten and the protease enzyme that are used in this preparatory process, fall within the preferred ranges already indicated above in view 15 of the homogeneous mixture.

Mild heating corresponds to a temperature above room temperature and below 90°C, for instance between 50°C and 60 °C .

A satisfactory degree of hydrolysis corresponds to a DH 20 in the ranges already indicated above, for instance between 2% and 15%. Typically, the time of hydrolysis could be between 30 and 60 minutes.

Inactivation of the protease enzyme is performed by common methods which include: heating of the mixture above 25 90°C during several minutes, and/or adding an amount of acid in order to lower the pH value of the mixture.

The relative amount of acid that is effective for inactivation, is typically 1 wt.% or even lower.

Alternatively, the enzyme can be inactivated by the 30 application of Ultra High Pressure techniques.

8

Usually, the preparatory process comprises an additional step of adding to the homogeneous mixture an additive for the reduction of the water activity.

The advantages of such an additive have already been 5 explained above.

Furthermore, in the method according to the invention, the homogeneous mixture is preferably applied on the outer surface of the bakery food product either before the food 10 product is baked, during the baking of the food product, or after the baking of the food product.

Advantageously, it was found that the homogeneous mixture is suitable for application on a bakery food product during various stages of making bread.

15

As an alternative to the above preferred embodiments of the method according to the invention, the gluten may be applied in the form of a powder on the surface of the bakery food product, before the product is baked.

20 The gluten in powder form may be applied by any suitable method, including the use of regular dusting equipment, or by simply rolling the bakery food product in an amount of gluten powder.

Typically, the gluten in powder form comprises gluten 25 particles having a mean particle size of 200 micrometer or smaller.

Preferably, the gluten particles have a mean particle size in the range of 5-200 micrometer, more preferably in the range of 50-150 micrometer.

30 Surprisingly, it was discovered that the gluten powder after having been applied on the bakery food product, will yield during subsequent baking under the influence of ambient moisture, thus forming a continuous film on the outer surface of the bakery product, so that eventually a coating layer is obtained.

9

The ambient moisture that comes into contact with the gluten powder, is normally already present in the air 5 contained in the oven during baking. In addition, moisture is expelled from the bakery food product itself towards the outer surface of the product, during baking.

To further improve the yielding of the gluten powder under the influence of ambient moisture, one may apply an 10 additional spray of water on the gluten particles after their application on the bakery product, and before the baking is performed.

Furthermore, the degree of moisture of the air contained in the oven, may be raised by introducing steam 15 into the oven.

Preferably, the gluten which is applied in the method according to the invention, is obtained from wheat or related grain species.

20 Moreover, it is preferred that in the method according to the invention, the bakery food product is baked, wherein the bakery food product obtained after baking comprises a coating layer on the outer surface.

The baking of the bakery food product is typically 25 performed in an oven at an appropriate temperature. For

instance, soft buns are baked for ca. 9 minutes at 260-270°C, and tin bread is baked for 30-35 minutes at 235°C

According to a further preferred method according to the 30 invention, it comprises an additional step of the application of edible particles onto the gluten after the gluten has been applied on the outer surface of the bakery 10 food product, and before the final step of baking is performed.

The edible particles may for instance be seeds, grains, flakes etc., which primarily function as a further 5 decoration of the bakery food product. It was found that the coating layer that is eventually formed on the bakery food product, has excellent glueing properties for adhering such particles onto the coating layer.

Actually, it was found that the adhesion of edible 10 particles was improved when compared to methods known from the prior art.

It is noted that when gluten in powder form is applied on the outer surface of the bakery product, it is preferred that the gluten powder is first moistened (e.g. by a spray 15 of water), before edible particles are applied upon the gluten powder.

In a second aspect, the invention also relates to a coating agent for a bakery food product, which is a homogeneous mixture of hydrolyzed gluten in water, which 20 further comprises an additive for the reduction of the water activity.

Well known additives that reduce water activity are for instance dextrose, sugar, and carbohydrates in general.

By reducing the water activity of the homogeneous 25 mixture, the mixture is stabilized so that it can be kept over a longer time, before it is actually used and applied on a bakery food product. Furthermore, a reduced water activity is beneficial in regard of preservation of the mixture .

30 Preferably, the content of the additive in the mixture is 1 to 60 wt. %.

11

As an alternative, the coating agent according to the second aspect of the invention, is a homogeneous mixture of hydrolyzed gluten in water, wherein the hydrolyzed gluten has a degree of hydrolysis in the range between 2% and 15%.

5 It was found that it is possible to achieve a stable, homogeneous mixture of gluten in water, when using hydrolyzed gluten having such a degree of hydrolysis (DH). For instance, the DH value may be between 7% and 10%. Alternatively, the DH value may be outside the range of 7% 10 to 10%, while still within the range between 2% and 15%.

Preferably, the above two alternatives of the coating agent according to the second aspect of the invention, contain a hydrolyzed gluten which is enzymatically hydrolyzed.

15

With further preference, the coating agent according to the second aspect of the invention, comprises the features of the two alternatives mentioned above, in combination.

20 Preferably, in the coating agent of the invention, the coating layer is substantially free of animal proteins.

The advantages of such a coating agent are that it allows the formation of a coating layer according to the first aspect of the invention, wherein the coating layer is 25 substantially free of animal proteins. The advantages thereof have already been explained above.

The term 'substantially free' in the context of the above coating agent, means a relative content in weight of animal proteins which is below 10%, preferably below 5%, 30 more preferably below 1%, and most preferably approximately 0%.

12

Optionally, the coating agent further contains thickeners, emulsifiers, fat based ingredients, colours and aromas.

It is thus possible to alter the viscosity of the coating agent, in order to comply with the specific required 5 yield of the coating agent when it is applied on the bakery food product.

According to a third aspect, the invention relates to a baked bakery food product, which comprises a coating layer 10 that comprises a vegetable protein, preferably gluten, as a main ingredient.

The bakery food product having such a coating layer achieves the advantages already explained above in view of the first aspect of the invention.

15 The term 'main ingredient', implies that the coating layer contains at least 50 wt.% vegetable protein, possibly at least 75 wt.%, and further possibly at least 85 wt.%.

In the bakery food product according to the invention, the 20 vegetable protein may also be a soy protein or a corn protein, or a vegetable protein from potato, pea, beans, etc.

Furthermore, the vegetable protein may be a mixture of above mentioned vegetable proteins, possibly including 25 gluten.

The advantages of using these vegetable proteins or mixtures thereof, are the same as already explained for gluten specifically.

30 Preferably, in the bakery food product of the invention, the coating layer is substantially free of animal proteins.

13

As such, the risk of the bakery product provoking an allergic reaction by allergens that are foreign to vegetable proteins, is eliminated.

The term 'substantially free' in the context of the 5 invention, means a relative content in weight of animal proteins which is below 10%, preferably below 5%, more preferably below 1%, and most preferably approximately 0%.

In addition, the baked bakery food product according to 10 third aspect of the invention may further contain edible particles which are adhered onto the coating layer.

Preferably, the baked bakery food product according to third aspect of the invention, is obtained by the method according 15 to the first aspect of the invention.

Further details of the invention will be disclosed by the example below.

20 Example I

In a temperature controlled tank, an amount of 52.8 kg water and 0.2 kg Neutrase (a commercially available form of protease) were introduced and stirred.

25 Next, 20 kg wheat gluten in powder form was admixed to obtain a homogeneous mixture, which was subsequently stirred for 60 minutes at 53°C.

Next, the temperature of the mixture was raised to 90°C, which temperature was subsequently maintained during 30 10 minutes.

Finally, the mixture was allowed to cool under stirring, while amounts of 0.75 kg ascorbic acid and 26.5 kg dextrose were added under stirring.

14

The obtained mixture is a homogeneous mixture having the qualities of a coating agent according to the second aspect of the invention.

5 The obtained mixture is transferred into a bag at 65°C-90°C, (a so-called 'hot fill' ) , which bag is subsequently closed off for storage.

The thus prepared and packaged coating agent can be kept stable in closed packaging for a prolonged period of 10 time (several months).

After opening, the coating agent is stable for 2 days at room temperature.

Optionally, the coating agent is dried after production, in order to achieve a further extended period of 15 stable storage time.

The above prepared coating agent is sprayed over the outer surface of a loaf of bread before baking.

After subsequent baking of the loaf of bread, the outer 20 surface is provided with a coating layer which contributes the following features to the loaf of bread: - an attractive, glossy appearance; - an additional flavour; - a crispy property.

25

Dependent on the type of bread that is to be produced, flakes of grains may in addition be applied onto coating agent before the loaf of bread is finally baked.

Claims (18)

A method of coating a bakery food product, wherein a vegetable protein, preferably gluten, is applied to an outer surface of the bakery food product and a coating layer is then formed on the outer surface. The method of claim 1, wherein the coating layer formed on the outer surface is substantially free of animal proteins. 3. Method according to claim 1 or 2, wherein gluten is applied to the outer surface of the bakery food product, in the form of a homogeneous mixture of hydrolyzed gluten in water. 4. A method according to claim 3, wherein the gluten is enzymatically hydrolysed. The method according to any of the preceding claims 3-4, wherein the hydrolysed gluten has a degree of hydrolysis between 2% and 15%. 25 The method according to any of the preceding claims 3-5, wherein the homogeneous mixture comprises an additive for reducing the water activity. Method according to any of the preceding claims 4-6, wherein the homogeneous mixture is prepared via a preparation process comprising the steps of: - mixing in water a protease enzyme, and gluten; - stirring the mixture under mild heating until a hydrolysed gluten is obtained that has a sufficient degree of hydrolysis; - inactivating the protease enzyme. 8. Method as claimed in any of the foregoing claims 3-7, wherein the homogeneous mixture is applied on the outer surface of the bakery food product either before baking the food product, during baking the food product, or after baking the food product . The method of claim 1, wherein the gluten is applied in the form of a powder to the surface of the bakery food product before the product is baked. A method according to any one of the preceding claims, wherein the gluten is obtained from wheat or related cereals. 11. Method as claimed in any of the foregoing claims 8-10, wherein the bakery food product is baked and wherein the bakery food product obtained after baking comprises a coating layer on the outer surface. 12. A method according to any one of the preceding claims, which comprises an additional step of applying edible particles to the gluten, after the gluten has been applied to the outer surface of the bakery food product, and before the final baking step is performed. 13. Coating agent for a bakery food product, which agent comprises a homogeneous mixture of hydrolysed gluten in water, and which further comprises an additive for reducing the water activity of the homogeneous mixture. 14. Coating agent for a bakery food product, which agent is a homogeneous mixture of hydrolysed gluten in water, the hydrolysed gluten having a degree of hydrolysis in the range between 2% and 15%. 15. Coating agent according to claim 13 or 14, which is substantially free of animal proteins. A baked bakery food product comprising a coating layer which comprises a vegetable protein, preferably gluten, as a main ingredient. 20 The baked bakery food product according to claim 16, wherein the coating layer is substantially free of animal proteins. A baked bakery food product according to claim 16 or 17, which is obtained via the method according to claim 11.