WO1994022330A1

WO1994022330A1 - Crumb composition and method of preparation

Info

Publication number: WO1994022330A1
Application number: PCT/EP1994/000570
Authority: WO
Inventors: Douglas James Barnes; Elsie Mary Clark; Alan Phillip Davies; Simon Jon Ingman
Original assignee: Unilever Plc; Unilever N.V.
Priority date: 1993-03-26
Filing date: 1994-02-28
Publication date: 1994-10-13
Also published as: AU6207694A

Abstract

A crumb composition and method for its preparation is disclosed, the crumb comprising: (a) protein wherein the protein is not substantially denatured and forms a continuous phase within the crumb structure; and (b) starch, wherein the starch is not gelatinised and forms a dispersed phase within the protein continuous phase. Such crumbs are able to retain crispness at 15 % moisture content. The crumbs have the desired crispness properties following microwave heating after storage in a freezer.

Description

CRUMB COMPOSITION AND METHOD OF PREPARATION

FIELD OF THE INVENTION

The invention relates to a crumb and a method for its preparation. The crumb being resistant to substantially high relative humidity without degradation of quality.

BACKGROUND ART

There is a continuing need for coated food products, such as coated meat, poultry, vegetables or fish. In particular coated products which may be stored frozen and then subsequently conveniently prepared for consumption by the consumer using a microwave oven are desirable.

US 4 568 550 (General Foods Corporation) discloses a method for preparation of a fully cooked flour-based product, particularly breadcrumbs, by extruding a dough at 60°C to 120°C while under pressures and effective shear conditions for a period of time effective to set the protein and partially gelatinise the starch in the flour while maintaining the starch granule integrity. By partially gelatinised, it is meant that all the starch granules have begun to gelatinise and swell, but without necessarily being fully gelatinised.

However, crumbs prepared using this methodology do not have the required crisp properties when stored frozen and then heated for consumption using a microwave oven. Furthermore other well known crumb coating materials also become soggy on storage and conventional microwave heating does not re¬ establish the pre-storage crispness properties.

We have now solved this problem and are thus able to provide a crumb for which crispness can be regained even after prolonged storage in a freezer and heating with a microwave oven. In order to solve this problem we have discovered that it is essential for the wheat-flour based crumb to have a wheat protein continuous phase. Also the starch present within the crumb must not be gelatinised and is therefore present as a discontinuous or dispersed phase located within the wheat protein continuous phase.

Furthermore the level of denaturation of the wheat protein is critical . Excessive wheat protein denaturation causes extensive cross-linking of the wheat protein providing a material which will absorb water more readily and produce a soggy, non-crisp crumb.

DISCLOSURE OF THE INVENTION

Accordingly the present invention provides a crumb comprising wheat protein, wherein the wheat protein is not substantially denatured and forms a continuous phase within the crumb structure; and starch, wherein the starch is not gelatinised and forms a dispersed phase within the wheat protein continuous phase.

Furthermore, the crumb composition preferably comprises up to 25% wheat protein, and more preferably from 10 to 25% by weight wheat protein, and most preferably comprises from 11.5% to 25% by weight wheat protein. Protein contents are defined as percentage total nitrogen multiplied by 5.7 and expressed on a dry weight basis.

It is essential that any starch present is not gelatinised. This enables the formation of a dispersed starch phase within the wheat protein continuous phase. By "not gelatinised" we mean that the starch granules have retained their crystalline structure, as measured by light microscopy using polarised light.

One suitable method of preparation of crumbs having the desired properties aforementioned is vacuum baking.

Vacuum baking may be conducted either in a conventional conduction or radiant heat oven or by using alternative forms of baking, for example a microwave oven.

Initially a dough is mixed having a total water content of from 35-65%, preferably 40-46%. The dough composition includes wheat flour. Preferably the dough composition comprises high quality, high protein wheat flours having a protein content of from 10.5%. Examples of suitable flours include N American wheat flours such as Canadian Western Red Spring wheats.

If desired, such flours can be made to have a higher protein content by air classification to separate the starch. A concentrate is particularly desirable when a dough composition including added waxy maize starch is required, without diluting the final wheat protein content.

The dough may either be subjected to vacuum baking alone in order to reduce the water content to the desired level for the final crumb (normally 2 to 12%) , or vacuum baking may be used initially until a water content of approximately 20% is achieved, after which a more rapid heating method may be employed to achieve the required final water content .

Suitable rapid heating methods are hot air drying, a fluidised bed, conventional oven baking, and microwave oven heating.

In the vacuum oven, the temperature rise of the dough is delayed due to the latent heat vaporisation of water. Therefore a large rise in temperature of the dough does not occur until most of the water has been removed. This is critical to ensure only partial cross-linking of the wheat protein network and non-gelatinisation of starch. It has been demonstrated that wheat starch gelatinisation occurs at temperatures as low as 60°C at 40% water content, but at less than 33% water content, the wheat starch gelatinisation temperature is higher than 100°C. Therefore in the vacuum oven baked dough, the dough temperature is kept low until most of the water has been removed, preventing starch gelatinisation.

Once most of the water has been removed from the dough, a more rapid drying method may be employed to achieve the final required water content without problems of starch gelatinisation.

USE OF THE CRUMB

Crumbs according to the invention may be used to provide food products such as coated meat, poultry, vegetables or fish.

The crumb is preferably applied to a food substance which has first been wetted by deglazing or dipping into, or spraying with, a fluid substance such as water or batter. The total coating may be pre-set, for instance by pre- frying. The pre-frying temperature is suitably selected from 100-195°C for the required time to set the structure.

Food products coated with the crumb according to the invention on heating for consumption have a desirable crisp crumb, superior to previously known crumbs. This is particularly true when the product is prepared for consumption via microwave heating following frozen storage.

The desirable crisp crumb is achieved without the need for elaborate packaging designed to improve crispness on cooking in a microwave. Examples

The invention will be illustrated by the following examples :

Example 1 : Comparative Examples A-D

Canadian Western Red Spring wheat flour (60g) was mixed into a dough with water (40ml) in a Brabender Do-Corder bowl at a constant speed (60rpm) unti.1 peak torque. The dough was then placed on a shelf inside a vacuum oven

(0.06m³ capacity) set at 70°C and a pressure of 60 mmHg.

After 24 hours in the oven, the expanded, dry dough was removed and gently broken into crumbs (2.4-2.8mm) .

The product was tested for moisture resistance by equilibrating in environments of different relative humidity. After equilibration the moisture content of the product was determined and also the brittleness properties by determining the acoustic emission using a Locan^R analyzer when fracturing the product and expressing this as a percentage of the acoustic emission when fracturing the freshly prepared products.

Crumbs hydrate in a freezer to approximately 15% moisture content . The precise moisture content is dependent on the crumb composition. The object of the crumbs of the invention is therefore to achieve a crumb which retains crispness at 15% moisture content.

Results are shown in Table 1.

Results were compared with four commercially available crumbs as follows:

Comparative Example A - RHM Pandora F1004 Comparative Example B - RHM Fresco Comparative Example C Lucas 7036 Comparative Example D Witwood WTM 15

Results are shown in Table 1

Comparative Example E

Results were compared with crumbs manufactured such that the starch granules have begun to gelatinise and swell and therefore no longer retain their crystalline structure as measured by light microscopy using polarised light.

A dough was prepared in a Brabender Do-Corder bowl at a constant speed of 60 rpm until peak torque was reached, having the following ingredients:

Canadian Western Red Spring wheat flour 306.8g

Water 180.7g

Yeast 6.lg

Salt 6.1g

The dough was allowed a bulk fermentation period of 30 minutes (covered with plastic to prevent surface drying) following mixing. The dough was then weighed and moulded into baking tins and placed in a prover set at 38°C, 75°C relative humidity for 30 minutes. After proving the dough was then baked at 230°C, until an internal loaf temperature of 85-90°C was reached.

The bread was sliced into 1 cm slices and then dried at 37°C in an oven. Crusts were removed from the dry slices and the remaining material milled into crumbs (2.4-2.8 mm) .

The product was tested for moisture resistance as described above for Example 1.

Results are shown in Table 1 Examples 2 -4

The method described for Example 1 was repeated except that the vacuum oven was set at the following temperatures :

Example 2 - 80°C Example 3 - 90°C Example 4 - 100°C

The products were tested as in Example 1. Results are given in Table 2.

Table 1

AE Moisture

Example

0% RH 57% RH 72% RH 75% RH 0% RH 57% RH 72% RH 75% RH

1 100 - 94 60 1.1 - 14.1 14.5

A 100 141 - <1 1.7 10.5 - 14.7

B 100 90 - <1 1.8 10.9 - 15.2

C 100 52 - <1 1.4 10.4 - 14.4

D 100 85 - 0 1.5 11.0 - 15.6

10 E 100 128 - 2 2.0 11.8 - 14.8

Table 2

15 Example AE Moisture

0% RH 69% RH 72% RH 75% RH 0% RH 69% RH 72% RH 75% RH

2 100 70 31 11 1.7 12.0 13.1 13.9

3 100 71 45 16 1.4 11.9 13.1 14.0

4 100 85 45 22 1.4 11.9 13.1 13.9

Claims

1. A crumb comprising wheat protein, wherein the wheat protein is not substantially denatured and forms a continuous phase within the crumb structure; and starch, wherein the starch is not gelatinised and forms a dispersed phase within the wheat protein continuous phase.

2. A crumb according to claim 1 comprising upto 25% wheat protein.

3. A crumb according to claim 1 or 2 comprising from 10 to 25% by weight protein.

4. A crumb according to any preceding claim comprising from 11.5% to 25% by weight wheat protein.

5. A method of preparing a crumb coating according to any preceding claim comprising vacuum baking a dough.

6. A method according to claim 5 wherein the dough has an initial water content of from 35 to 65% by weight.

7. A method according to claim 5 or 6 wherein the dough has an initial water content of from 40-46% by weight.

8. A method according to any one of claims 5 to 7 comprising:

(i) vacuum baking a dough to a moisture content of approximately 20%; and then

(ii) heating the dough more rapidly by any suitable means to the required moisture content.

9. A method according to claim 8 wherein the means for more rapidly heating the dough is selected from a fluidised bed, hot air drying, conventional oven baking, and microwave oven heating.