NL1018991C2 - Moistureproof edible coating for foods. - Google Patents

Description

Title: Moisture-resistant edible coating for foods.

The present invention relates to a moisture-resistant edible food coating.

The shelf life of foodstuffs is increased, apart from factors that prevent deterioration, by measures that reduce the diffusion of moisture through the product. For example, a moisture-proof packaging around a bread prevents it from drying out quickly.

The use of a coating with moistureproofing properties is particularly advantageous for composite foods, where the water content in the various components is different and may not change significantly during storage. A moisture-resistant coating layer in or on a foodstuff must consist solely of edible components and must also be edible as a whole.

To achieve this, a number of products, often based on fat (including chocolate and mayonnaise), are used to keep different components separate from each other in compound foodstuffs with different moisture content. In practice, however, the moisture resistance of these so-called moisture barriers is found to be too low, too low in application or too short in duration. A moisture-resistant protective layer consisting of, for example, chocolate can be affected by temperature. Mayonnaise can penetrate or be absorbed into the surrounding foodstuff, which eventually makes the moisture-resistant protective layer thinner. For that reason, the moisture-repellent effect and applicability of a number of existing, edible moisture barriers is limited and improvement is desirable.

25 Much research in the field of edible moisture barriers, including for coating tablets, has been conducted by the pharmaceutical industry. For example, British Patent Application 756082 describes that the moisture sensitivity of tablets can be reduced by mixing the moisture-sensitive powders with a solution of a prolamine in alcohol and subsequently processing them into tablets.

Shellac, often in combination with hydroxypropyl cellulose, is also a widely used biopolymer for applying a moisture-resistant coating to foodstuffs (see, inter alia, U.S. Pat.

4,820,533). The combination of shellac and prolamine has also been used for this purpose (EP 0 090 559).

Prolamines, which can be obtained from the alcohol-soluble protein fraction from grains, are used extensively as a film-forming component of a moisture-resistant and edible coating. One of the most important commercial prolamines is zein, the group of alcohol-soluble proteins from corn. However, the commercial use of zein as a component of moisture-resistant protective layers has a major drawback at the moment. Moisture-resistant protective layers based on zein are found to be too brittle in practice. To reduce the breaking of protein-containing moisture barriers, a polyalcohol or a polyglycol can be added, as described in EP 0 465 801. However, this solution has the disadvantage that the moisture-resistant properties of the coating layer are greatly limited.

There is a strong need for edible coating layers with a better moisture-proofing effect, with a longer lifespan, with a broader applicability, with a higher temperature stability and with a greater elasticity. This need is largely driven by the growth of the composite food market, including convenience foods. In such foods, moisture-containing components are combined with dry components. The occurrence of moisture transport or moisture diffusion through the foodstuff considerably reduces the taste and texture of the foodstuff, and in particular of the dry components, in a short time.

3

It is an object of the invention to obviate the above problems. It has surprisingly been found that this is possible by preparing a coating layer based on prolamine in combination with a lipid and a salt of a fatty acid. In more detail, the invention provides a composition for a moisture-resistant edible food coating which composition comprises a prolamine, an alcohol, a lipid and a salt of a fatty acid. Such a coating layer has the advantage that it has a very high moisture resistance and has a high mechanical strength. In addition, the new coating layer is highly impermeable to water and water vapor. Another important and surprising advantage of the invention is that the proposed moisture-resistant coating layer can withstand heating without causing significant damage to the coating layer. The coating layer can therefore be applied to, for example, dough that has yet to rise or that expands during the baking process.

As stated, the invention relates to a composition for a moisture-resistant edible food coating. The invention provides a method for preparing such a composition and a method for obtaining a moisture-resistant edible coating on foods. Specifically, the invention describes a moisture-resistant edible coating layer with favorable properties that were previously not achieved. The present moisture-resistant edible coating layer has the special advantage that it combines high mechanical strength with improved moisture-resistant properties and heat stability. In addition, a coating layer according to the invention has a high integrity and flows during preparation and storage of a foodstuff to which it is applied essentially not with its environment, but remains a separate phase and thus forms a stable barrier.

4

The invention also relates to foodstuffs on which such a moisture-resistant edible coating layer has been applied or in which it has been incorporated. These foods have, inter alia, the property that differences in moisture content in various components of the foodstuff are maintained longer, so that storage for a longer period of time is possible without reducing taste and the texture of (the components of) the foodstuff.

Very suitable for use in the compositions for the moisture-resistant coating layer are prolamines. According to the invention, the prolamine used is preferably wheat or rye gliadin, maize zein, barley hordein, millet or rice prolamine, oats avenine and sorghum kafirin.

Prolamines can be obtained, inter alia, by extracting the flour obtained by grinding the cereal grains with a 70-100 percent alcoholic solution in water. To this can be added between 0 and 2 weight percent of a reducing agent, for example sulfite. The extraction can take place at a temperature between 20 and 80 ° C. A hot alcohol extraction is preferably performed for the extraction of kafirin and zein. Alcohols with which extraction can take place include methanol, ethanol, propanol and butanol. Criteria for the choice of the alcohol used for extraction is that it must efficiently separate a prolamine from the other protein fractions and that a prolamine of a desired purity is obtained.

A particular advantage of a prolamine for use in a moisture-resistant coating layer according to the invention is that it is poorly soluble in water. It has been found that in particular zein, kafirin and hordein can be used with advantage. A prolamine is preferably present in the moisture-repellent coating composition in an amount of 10-90 weight percent based on the weight of the composition.

5

In the preparation of a composition for a moisture-resistant coating layer according to the invention, a prolamine is preferably dissolved in alcohol. During the evaporation of the alcohol the protein precipitates out and after complete evaporation of the alcohol a surface film consisting of a network structure of crystallized protein remains on the surface on which the solution was applied. The choice of the alcohol used for the preparation of the composition and the application of the moistureproof coating to the food may be different, but also the same as that used for the extraction of the prolamine. An important criterion for the choice of the alcohol to be used as a constituent for the composition of the moisture-resistant coating layer is that it must serve as a solvent for prolamine and that it must not leave any toxic or health-damaging residues after evaporation. Alcohols that may form part of the moisture-resistant coating composition include methanol, ethanol, propanol, isopropanol, butanol, pentanol, or a combination thereof.

A large number of lipids is suitable for use in a coating layer composition according to the invention. Lipid 20 is understood to mean glycerol esterified with at least one, but preferably three, fatty acids. If the lipid is liquid at room temperature, this is referred to as an oil. If the lipid is solid at room temperature, it is called a fat. An advantage of using oil or fat in a composition for a moisture-resistant edible coating layer according to the invention is that this increases the elasticity of the final coating layer. The presence of oil or fat reduces the brittle structure of the coating layer.

Preferably in a composition according to the invention oils are used such as soybean oil, sunflower oil, peanut oil, rapeseed oil, olive oil, palm oil and sesame oil. The person skilled in the art can also adjust the structure of the 6 coating layer by adding fats with a melting temperature between 30-60 ° C. For example, palm fat with a melting temperature of 45 ° C or soy fat with a melting temperature of 37 ° C can be used. It will be clear that the use of combinations of oils and / or fats is also possible.

The choice for the type of oil or fat is mainly dictated by the application that is intended. For example, a foodstuff that has yet to rise and will then be baked in an oven will choose a different composition than a foodstuff that does not change in volume and is stored at 5 ° C.

The lipid is preferably present in a composition for a moisture-resistant coating layer according to the invention in an amount of 0.1-50% by weight calculated on the weight of the composition.

An important component of a composition according to the invention is a salt of a fatty acid. An important advantage of this salt of a fatty acid is that it greatly strengthens the network in the moisture-resistant coating layer. The salt of a fatty acid is dispersed in the alcohol together with the prolamine and is preferably distributed homogeneously throughout the coating layer. The salt is preferably a divalent metal salt, such as a magnesium, zinc or calcium salt. The fatty acid is preferably a higher fatty acid with a length of 14-20 carbon atoms such as stearate, palmitate, oleate or arachidate. A desirable property of the salt of a fatty acid is that it is poorly soluble in alcohol, water and alcohol-water mixtures. The melting temperature of the salt of a fatty acid is preferably above 100 ° C in order to ensure the stability of the coating layer during a baking process. The degree of saturation or unsaturation of the fatty acid is suitably selected depending on the desired properties. The salt of a fatty acid is preferably present in a composition for a moistureproof coating layer according to the invention in an amount of 7 0.1-50% by weight based on the weight of the composition. Magnesium stearate is preferably used. Magnesium stearate greatly reduces the permeability of the water-repellent coating layer for water and water vapor.

A component that can be used with additional advantage in a composition according to the invention is an emulsifying fatty acid. The presence of an emulsifying fatty acid is particularly desirable if a stable mechanically strong coating layer is to be obtained. A special advantage of the use of an emulsifying fatty acid is that a very homogeneous coating layer is hereby obtained. However, the presence of an emulsifying fatty acid is not essential in all cases.

The emulsifying fatty acid is preferably present in a composition for a moisture-resistant coating layer according to the invention in an amount of 0.01-10% by weight calculated on the weight of the composition.

Preferably a fatty acid is chosen with a chain length of 6-12 carbon atoms, such as hexanoic acid and lauric acid. There is a great preference for a fatty acid with a chain length of 10-12 carbon atoms. Fatty acids with a shorter chain length can produce an unpleasant odor, although this has no effect on the moisture-resistant properties of the coating layer.

In order to prepare a composition for a moisture-resistant coating layer, a prolamine and a salt of a fatty acid are preferably dry-blended according to the invention. This can be done, for example, with a spatula, but other ways are also possible. Desirably, the salt of a fatty acid in dry form is mixed with prolamine because then a particularly homogeneous coating layer is obtained. The mixture of a prolamine and salt of a fatty acid is dispersed in an alcohol by adding the alcohol to the prolamine and salt of a fatty acid mixture. With continuous stirring, the dispersion thus obtained can optionally be heated to 80 ° C. The temperature is preferably raised to 60 ° C in order to obtain the complete solution of the zein. During the preparation of the composition, a certain amount of alcohol will evaporate. The loss of alcohol is preferably topped up during and at the end of the preparation. Finally, an emulsifying fatty acid is optionally added to the mixture and, optionally, oil or melted fat is added slowly and with stirring.

The composition thus obtained can be applied to a foodstuff by means of ironing, spraying, spraying, spraying, dipping, brushing and / or rolling. This is preferably done at a temperature of around 60 ° C, depending on the melting point of the oil or fat used as a component. The composition applied to the foodstuff is then preferably allowed to dry. This can be done at room temperature or during a baking process. Preferably, the alcohol is substantially completely evaporated from the composition. After evaporation of the alcohol, a moisture-resistant edible coating layer remains on the foodstuff that has the properties described above.

The minimum thickness of the coating layer is determined by the grain size of the salt of a fatty acid used in the composition. Depending on the application, a thicker or thinner coating layer will be desired. A minimum thickness of ~ 50 microns is possible. The maximum achievable thickness is a few millimeters. When using very finely ground powders of salt of a fatty acid, coating layers with a thickness of less than ~ 50 micrometres are possible. Preferably, the coating layer has a thickness between 50 and 500 micrometers.

Foods on which or in which the moisture-resistant edible coating can preferably be processed are composite foods in which regulation of moisture migration is desired to maintain product quality. The moisture-resistant coating layer 9 will often be applied between different layers in the foodstuff or between different components. It is possible to provide moisture-sensitive parts of a foodstuff with a moisture-resistant coating beforehand and then to process it in the foodstuff.

For example, a coating according to the invention can be applied to the bottom of a ready-made pizza, with the result that the tomato sauce applied thereto does not soak the bottom. In another case, it is also possible to provide the bread or cheese with a prepacked bread roll with a coating according to the invention, as a result of which bread and cheese are no longer sensitive to moisture from any vegetables present.

Foods on which or in which a moisture-resistant edible coating layer according to the invention can be incorporated include tart and pastries with a filling, including flan, pizza, quiche, waffle or pancake; - bread with a filling, including sausage bread and almond bread; - fruits, chocolate, nuts, muesli, cereals, cornflakes, candy, wafers, or (pancakes that are processed in custard, ice, milk, frosting, soft cheese, pudding, syrup, yogurt or other liquid products; - invested bread and toast, including pre-packaged sandwiches and sandwiches - filled products including Evergreen ™, Switch ™, or muesli bars;

Furthermore, the moisture-resistant edible coating layer can be used to prevent the absorption of moisture by a food, whether or not compounded, from the air. This includes cookies and other products with a low water activity, or products intended for consumption in a tropical climate. The moisture-resistant edible coating layer can also be applied in or applied to products whose shelf life must be improved during long transport. Furthermore, the coating layer can be applied to or in products where regulation of moisture migration is desired to maintain or even improve the specific characteristics of this product, such as for example crispy cruesli. Non-edible parts of composite foodstuffs such as packaging material, separation paper, napkins or sticks and the like can also be provided with a coating according to the invention.

The invention will now be further elucidated with reference to the following examples, which are not to be construed as limiting.

Example 1. Moistureproof edible coating layer (coating) for pizza

A moisture-resistant edible coating according to the invention was prepared to retain the moisture from the filling of a chilled pizza during storage at 4 ° C. In order to not be bound to specific ingredients on a pizza, the water activity (Aw) of various ingredients was measured for a chilled pizza. The Aw was determined using standard methods on an Aqualab AQ CXII water activity meter. The highest Aw that was measured was 1. In the test, a starch gel was used with this Aw. When this gel is placed on the pizza base, a water film is created under the gel.

The composition of the coating layer is shown in Table 1.

The composition of the pizza dough is shown in Table 2 and the preparation process is shown in Table 3 and Table 4. In this example, the coating layer is applied with a brush to the raw dough. The coating layer thus undergoes a baking step.

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Table 1: Zeine / lauric acid / oil coating for chilled pizza.

Ingredient weight (g) Details

Zeine 10.0 Fluka, Maize Zein, Mr 25,000-29,000

Mg stearate 3.0 Fluka, pract., 3.8-5% Mg

Ethanol 15% 96%

Lauric acid 0.5 Aldrich, purity 95.5%

Oil / fat 3.0 Soybean oil

Table 2: Recipe pizza dough.

Ingredient weight (g)

Flower 2000

Water 1020

Baking powder (ammonium bicarbonate, (NH-OHCCl) 40

Acid sodium pyrophosphate (Na 2 H 2 P 2 O 7) 20

Salt (NaCl) 40

Bold (lard) 100

Potassium sorbate 8

Lactic acid 8

Cysteine solution (1 g / l) 40

Total dough mass 3276 5

The dough is kneaded in a spiral kneader, Sinmag SM10. Further process steps are described in the table below (Table 3).

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Table 3: The process

Process step Details

Dry mixing ingredients 1 min.

Add water temperature 0 ° C

Slow mixing (spiral kneader, Sinmag SM10) 4 min.

Quick kneading (spiral kneader, Sinmag SM10) 10 minutes to 20 ° C

Roll out (touring machine, Rondo Seewer) 2.20 mm (setting)

Prove / rest for 10 minutes at 10 ° C

Cut out round pizza shape

The baking was carried out in a Rototherm industrial oven according to the conditions shown in the table below (Table 4).

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Table 4: The baking process: Settings Rototherm industrial oven.

Time valve *

Steam 2 min. 1 liter

Bake for 5 minutes at 210 ° C

Baking 1 min. 210 ° C 100% * Valve position of Rototherm industrial oven.

After baking, the starch gel was placed on the pizza bottom and the product with coating layer and without coating layer (control) was stored at 10 ° C for a period of 25 days. After 25 days, the Aw of the pizza crust with coating had risen from 0.93 to 0.96. This increase still results in a pizza with a crispy bottom. According to the experts, a pizza crust with an Aw well above 0.97 is no longer crispy / crispy. With the pizza check (without coating), the pizza crust has already accepted the Aw of the gel after 1 day of storage. With the described coating layer, the quality of a pizza can thus be improved and the shelf life can be extended considerably.

2013

Example 2. Coating layer (coating) for biscuit

The coating described in Table 5 has been used to protect biscuit when stored at 20 ° C and 80% relative humidity (RH).

Table 5: Zeine / oil coating for coating biscuit

Ingredient weight (g) Details

Zeine 5.0 Fluka, Maize Zein, Mr 25,000-29,000

Mg stearate 3.0 Fluka, pract., 3.8-5% Mg

Ethanol 7.5 96%

Oil / fat 16.0 (75% soy fat 45 * and 25% palm fat 37 *) * Melting point in ° C of the fat and / or oil.

The coating was applied to cookies called Knappertjes ™ (Verkade, Zaandam, NL) by means of brushes. After applying the coating, the biscuit is dried at 160 ° C for 10 minutes. Then these cookies and control cookies (uncoated Knappertjes ™, which had also undergone the same treatment) were stored in a climate chamber at 20 ° C and 80% RH. The increase in weight was measured during the storage period. As Table 6 shows, the water absorption of the coated cookie is considerably lower than that of an uncoated control cookie.

Table 6: Weight gain of coated and uncoated Crunches ™ during storage at 20 ° C and 80% RH.

Weight gain in time 3 hours 19 hours 115 hours 214 hours

Control cookie 0.23 g 0.60 g 0.74 g 0.78 g

Zein / oil coating coated cookie 0.04 g 0.16 g 0.27 g 0.55 g

Example 3. Coating coffee cakes for desserts

A coating with a composition as described in Table 7 has been used to coat coffee cookies (Albert Heijn, Zaandam, NL).

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Table 7: Zeine / oil coating for coating coffee cookies.

Ingredient weight (g) Details

Zein 29 Fluka, Maize Zein, Mr 25,000-29,000

Mg stearate 9 Fluka, pract., 3.8-5% Mg

Ethanol 43 96%

Stearic acid 2

Oil / fat 17 Soybean oil

After applying the coating, the coffee cookies are dried at 160 ° C for 10 minutes. These cookies and control cookies 5 (uncoated coffee cookies that have undergone the same treatment) are stored in custard. The Aw increase of the product was measured during the storage period. As can be seen from Table 8, the coating used gives a considerable increase in resistance to moisture absorption.

Table 8. Increase in Aw of coffee cookies during storage in custard Aw increase in time 0 hours 22 hours 46 hours

Check cookie 0.28 0.51 0.78

Zeine-coated cookie 0.20 0.39 0.57

Claims (20)

A composition for a moisture-resistant edible coating for foodstuffs comprising a prolamine, an alcohol, a lipid and a salt of a fatty acid. A composition according to claim 1 wherein the salt of a fatty acid has a chain length of 14-20 carbon atoms. A composition according to any one of the preceding claims wherein the salt of a fatty acid is magnesium stearate. A composition according to any one of the preceding claims also comprising an emulsifying fatty acid with a chain length of 10-12 carbon atoms. A composition according to claim 4 wherein the emulsifying fatty acid is lauric acid. A composition according to any of the preceding claims wherein the prolamine is a gliadin, zein, hordein, avenin, kafirin or a combination thereof. A composition according to any one of the preceding claims wherein the prolamine is present in an amount of 10-90 weight percent based on the weight of the composition. A composition according to any one of the preceding claims wherein the prolamine is a zein. A composition according to any of the preceding claims wherein the lipid is soybean oil, sunflower oil, peanut oil, rapeseed oil, olive oil, sesame oil, palm fat or soy fat or a combination thereof. A composition according to any one of the preceding claims wherein the salt of a fatty acid is present in an amount of 0.1-50% by weight calculated on the weight of the composition. A composition according to any of the preceding claims wherein the lipid is present in an amount of 0.1-50 weight percent based on the weight of the composition. A composition according to any one of the preceding claims wherein the emulsifying fatty acid is present in an amount of 0.01-10% by weight calculated on the weight of the composition. A method of preparing a composition according to any one of the preceding claims wherein a prolamine and a salt of a fatty acid are dry blended and dispersed in an alcohol to provide a dispersion which is optionally heated and to which a lipid is added. A method according to claim 13 wherein the alcohol is methanol, ethanol, propanol, isopropanol, butanol or pentanol or a combination thereof. A method for applying a moisture-resistant edible coating to a foodstuff wherein a composition according to claims 1-12 is applied to the foodstuff. A method according to claim 15 wherein the composition is applied by means of ironing, spraying, spraying, spraying, dipping, brushing and / or rolling. A method according to claim 15 or 16 wherein the coating layer is dried. A moisture-resistant edible coating for foods comprising a prolamine, a lipid, and a salt of a fatty acid. A foodstuff comprising a coating according to claim 18. A foodstuff according to claim 19 being a compound foodstuff.