WO2015086740A1

WO2015086740A1 - Method and arrangement for obtaining an extruded/expanded cereal-based biscuit coated with fat and a savory dough

Info

Publication number: WO2015086740A1
Application number: PCT/EP2014/077367
Authority: WO
Inventors: Luciano LOPEZ JAUREGUI
Original assignee: Molinos Rio De La Plata S.A.; Molinos Ip S.A.
Priority date: 2013-12-12
Filing date: 2014-12-11
Publication date: 2015-06-18
Also published as: UY35839A; BR102014008582A2; PE20150977A1; AR093961A1

Abstract

A method for obtaining an extruded/expanded cereal-based biscuit with a fat and savory dough coating, comprising the steps of: mixing in a mixer the raw materials used for the base biscuit comprising mainly an ingredient having a high content of starch such as starch from corn, potato, cassava, sorghum or rice or wheat flour, with the addition of ingredients providing to the final aspect of the base biscuit protein sources such as powder milk, cheese whey powder or simple sugars such as sucrose or glucose, salt, and dyes, as well as other expansion- modifying ingredients such as calcium carbonate, baking powder (sodium bicarbonate and an acidic agent such as calcium monohydrogen phosphate) or a dietary fibre; making the biscuits forming the substrate on which the invention is put into practice, in an extruder using a head with dies forming strips of expanded material. adjusting the thickness of the strips of expanded material in a roller and then cutting them to form biscuits; placing the biscuit, using a vibrating distributor, on a single plane without overlaps and then delivering them onto a conveyor belt, characterized in that the biscuits are coated with a fat spray to seal the biscuits and allow for a subsequent application of a highly moisturized and fluid dough (batter), and then baking and cooling them on a conveyor before packing.

Description

METHOD AND ARRANGEMENT FOR OBTAINING AN EXTRUDED/EXPANDED CEREAL-BASED BISCUIT COATED WITH FAT AND A SAVORY DOUGH

Field of the Invention

The present invention relates to a method for applying dough onto the surface of extruded and/or puffed cereal biscuits or a mixture thereof, having a low moisture content, to obtain a savory flavored biscuit with improved organoleptic acceptability of the product, in terms of flavor, crispiness and appearance.

Background of the invention

Rice is used for manufacturing biscuits mainly by two methods: puffing and extrusion. In the first method, previously moistened rice grains are placed in a heated matrix. Pressure is applied on said matrix heating the counterpart for a few seconds. As they rapidly expand, in addition to gellation of starch granules, the water contained therein evaporates, thus causing expansion of the structure to yield a light, edible product, although organoleptically unattractive. When using extrusion, low density expanded biscuits are produced from rice flour and ingredients such as salt, sugar, powder milk, etc. The use of other ingredients or higher proportions of the above- mentioned ingredients affects puffing and thereby the final texture of the product. Flavoring of the biscuits is carried out by spraying with an adherent liquid such as oil or any hydrocolloid solution, and subsequent application of powder essences followed by drying if an aqueous liquid has been employed. The appearance of the product is unattractive when compared to local product standards.

Summary of the Invention

A mixture of ingredients having a high proportion of amylaceous products such as rice flour and the like is expanded in a single or twin-screw extruder using linear inserts to form a fine strip which is cut to the desired size, and arranged on a flat surface. Such formulation is shown in table I:

Ingredients %

Rice flour 90 - 95

Skimmed Milk Powder 6 - 4 Salt 2 - 0.5

Sugar 2 - 0.5

TABLE I

Subsequently, fat matter is sprayed onto the extruded formulation and thereafter a highly fluid and moisturized dough (hereinafter referred to as "batter") is applied to provide solids which are immediately submitted to a baking and cooling process thereby imparting the characteristic appearance, crispiness and flavor.

Before applying the batter, the extruded biscuit must be sealed, since it has a high water absorption capability due to its high porosity and chemical composition. In the present invention, this is achieved by spraying a fine layer of molten fat thereon. The molten fat used in the present invention may be of plant or animal origin, and it is applied at a temperature from 45 to 70^Q C, preferably from 50 to 60^Q C.

The application of the batter as a topping to improve appearance and texture requires the use of carbohydrate-based ingredients such as starches from various cereals (wheat, rice, corn) with the addition of other ingredients. The present invention incorporates emulsifiers as wetting agents, such as polysorbate, polyglycerol esters, lecithin, monoglycerids and diglycerids, to lower surface tension of the suspension (batter) and thus achieving the required coating on the biscuit.

The batter may contain different additional ingredients such as flavorings, dyes, sugars, salt, vitamins, and minerals.

The arrangement for producing the savory biscuits may include powder weighing and mixing systems, single and twin-screw extruders, rollers, and biscuit cutters. The biscuit cutter lowers the linear speed of the extruded material down to speeds which are more suitable for the subsequent operations. A vibrating distributor allows distributing the product over a width which is much larger than the original (80 cm - 100 cm). Application of fat is carried out by spraying. The batter is applied by means of a curtain coating machine. The process ends in an oven in which the biscuits are subjected to evaporation and cooking steps, mainly of the upper part and drying and browning of the lower part and the subsequent cooling of the biscuit exiting the oven.

Description of the Drawings Figure 1 shows the different steps of the process.

Detailed description of the invention

The raw materials used for manufacturing the biscuits are previously mixed in a high performance horizontal mixer 1 fed by a pneumatic conveyor. The raw materials used for the base biscuit consist mainly of ingredients having a high starch content such as starch from corn, potato, cassava, sorghum or rice or wheat flour, with the addition of ingredients providing protein sources such as powder milk, cheese whey powder or simple sugars such as sucrose or glucose, salt, and dyes, to the final aspect of the base biscuit. It may also include other ingredients for modifying expansion such as calcium carbonate, baking powder (sodium bicarbonate and an acidic agent such as calcium monohydrogen phosphate) or a dietary fibre.

The biscuits forming the substrate on which the invention is put into practice, are made in an extruder 2 (twin-screw or single screw) using a head with dies that form strips of expanded material. The strips of expanded material exit the extruder with a linear speed of from 10 to 30 m/min, preferably from 15 to 25 m/min. The strips of expanded material have a width of from 20 to 60 mm, preferably from 25 to 35 mm, and a thickness of from 3 to 10 mm, preferably from 6 to 8 mm. The bulk density of the extruded material is in the range of 0.08 to 0.13 g/cm³, preferably 0.10 - 0.1 1 g/cm³, which is achieved with process temperatures above 140^Q C in the extruder.

The thickness of the strips of expanded material obtained from extruder 2 is adjusted using a roller/cutter 3, which in addition results in a more uniform and flat surface for the subsequent application of a topping. When the strips of expanded material are cut, the product has a moisture of for example from 5% to 15 %, preferably from 8 to 12 % and a temperature of, for example, from 50 to 95^Q C, preferably from 70 to 85^Q C, which imparts flexibility for cutting without generating fine powders.

The width of the biscuits obtained with the roller/cutter 3 is from 2 to 4 cm, with length from 2 to 8 cm, preferably from 2.5 to 3.5 cm wide and from 2.5 to 3.5 cm length. The cut biscuits are placed on a vibrating distributor 4 which consists, for example, of 1 to 6 vibrating trays, preferably from 2 to 4 vibrating trays, which place all the biscuits in a single plane without overlaps. The biscuits are then derived to a belt or screen where the surface area covered by the biscuits during conveyance comprises from 20 to 50 % of the total surface. The speed of the conveyor is related to the output of the extruder and therefore linear speed varies.

The biscuits are delivered onto a conveyor belt operating at a speed from 5 to 20 m/min, preferably from 18 to 14 m/min, which delivers them to a spraying system 5 for the application of fat. In the present invention fat is used for sealing the biscuits and thus allowing for applying the batter. Hydrogenated or intersterified molten fat of animal or plant origin is used, having a melting point from 30 to 45^Q C, preferably from 32 to 40^Q C, which is sprayed in small droplets covering the surface of the biscuits. Spray is generated by means of a high-pressure metering pump which forces the molten fat through nozzles for its pulverization. Dosing of fats may be regulated by adjusting the speed of the pump. Doses vary from 0.005 g/cm² to 0.02 g/cm². Exceeding fats falling onto the conveyor belt is recovered with a scraper which drains into a heated trough flowing into a feeding tank by means of a pump and to a spraying pump after passing through a filter. The feeding tank is replenished from an external tank.

The next step involves application of the liquid batter. The batter consists of a mixture of carbohydrates such as starches or flours, salt, color generating agents such as powder milk or cheese whey, glucose, emulsifiers, fats, flavorings and dyes, at the ratios shown in table II.

TABLE II

The batter is prepared in a high shear solid-liquid mixer rotating at a speed of 3000 rpm. Solids are added gradually in order to prevent lump formation. Cold water at a temperature of 5 - 10^Q C should be used to avoid an increase of batter temperature caused by the mechanical work of the mixer. The concentration of the final batter is from 30 to 65 % solids, preferably from 45 to 60% solids, with a viscosity from 100 to 800 cps which is critical for its application.

Once prepared, the batter is stored in tanks with a cooling jacket to keep its temperature from 10 to 15^Q C and thus prevent bacteriological growth. Application of batter is carried out with a commercial coating machine 6. This equipment generates a curtain of batter through which the previously fat-treated biscuits are transported by means of a conveyor belt. The applied fat has no organoleptic function but only that of sealing the highly porous biscuit to avoid collapsing of its structure.

To assist this process, the present invention contemplates the inclusion, among the components of the batter, of an emulsifier to reduce surface tension of the batter and thus achieve a suitable coating of the biscuit. Batter dosage on the biscuit is from 0.03 g/cm² to 0.06 g/cm², preferably from 0.04 g/cm² to 0.05 g/cm², which in terms of applied solids represent from 0.015 to 0.035 g/cm² of batter solids. The application means comprise operative elements to adjust the curtain parameters for application of the batter (height, output rate, tilting), as well as conveyor belt speed, blower position and power, and vibrator for removing excess batter. Conveyor belt speed ranges from 8 to 20 m/min, preferably from 10 to 14 m/min.

The formulation corresponding to this product is described in detail in table III:

Ingredients %

Extruded biscuit 70 - 80

Refined fat 10 - 5

Savory dough 20 - 15

TABLE II

Baking 7 is the next operation after applying the batter. Given that high moisture in the batter layer is critical for the structure of the biscuit as it has a great tendency to deform or collapse, baking must take place for a very short period of time immediately following the preceding steps. This operation must be performed in a direct flame oven so that a high thermal transference capacity onto the product may be achieved. Residence time in the oven is from 2 to 5 minutes, with a conveyor belt speed from 8 to 20 m/min, more preferably from 10 to 14 m/min. At the output of the oven there is a cooling conveyor 8 on which biscuits are cooled to a temperature close to room temperature. The residence time is from 10 to 20 minutes, preferably from 12 to 15 minutes, and thereafter they pass on to packaging 9. The final moisture of the biscuit, prior to packaging 9, is from 2 to 6 %, preferably from 3 to 4 %.

Example 1 :

An extruded biscuit was manufactured based on rice flour (93 %), powder milk (3 %), salt (2 %), and sugar (2 %) under the following process conditions of the extruder:

• Flow rate of dry ingredients: 300 kg/h

· Water added to the extruder: 20 kg/h

• Screw speed: 200 rpm

Working temperatures: 160; 130; 130; 100; 70; 30 °C

The strips exited the extruder at a speed of 22 m/min, having a width of 32 mm, a thickness of 7 mm, a bulk density of 0.1 1 g/cm³, and 9.5 % moisture. Thickness was reduced to 6 mm by means of a roller.

Strips were cut into biscuits that were 3 cm long , 3.2 cm wide and 0.6 cm thick using a roller cutter and they were arranged employing a distributor to prevent overlapping of units.

The biscuits was delivered by means of a conveyor belt at a speed of 12 m/min to a spraying system for applying fat of animal origin having a melting point of 35 °C, previously molten and kept at 55 °C. Pump pressure was set to 2 bar to achieve a dosage of 0.01 g/cm², equivalent to 0.096 g/biscuit, an amount which is sufficient to completely cover the surface of the biscuit's upper face.

This was followed by application of the liquid batter, which had been previously made by mixing the powder ingredients detailed below in 50 % w/w water.

Dry ingredients of batter %

Rice flour 43

Corn Starch 43

Skimmed Milk Powder 5

Salt 8.95 Caramel color powder 0.05

Total 100

The viscosity of this preparation was of 200 cp at 15 °C. Conditions of the coating machine were adjusted so as to obtain a dosage of 0.04 g/cm² of liquid batter, equivalent to 0.384 g batter/biscuit.

• Height of curtain: 10 cm

• Metering pump: 70%

• Tilting position of the curtain: 4

• Blower height: 4 cm

• Blower capacity: 90%

• Conveyor speed: 12 m/min

After application of the liquid batter, the biscuits were introduced in a direct flame oven at a temperature of 180 °C, at a speed of 12 m/min and 3 minutes of residence time, whereby the initial 15.5% moisture content wet basis is reduced to 4% moisture content wet basis.

Under these process conditions, deformation and/or collapse of the biscuit was observed and further a rigid texture associated with the contact of water from the liquid batter with the porous structure of the rice biscuit.

Example 2:

The steps of extrusion, lamination, cutting and fat application were the same as in example 1 .

In the step of liquid batter, incorporation of polyglycerol ester as an emulsifier in the powder mixture, maintaining the dilution percent of 50 % w/w, was evaluated.

Dry ingredients of batter %

Rice flour 43

Corn Starch 41 .5 Skimmed Milk Powder 5

Salt 8.95

Caramel color powder 0.05

PGE emulsifier 1.5

Total 100

The incorporation of an emulsifier into the preparation leads to an increase in viscosity from 200 cp to 400 cp at 15 °C.

Conditions of the coating machine were adjusted so as to obtain a dosage of 0.04 g/cm² of liquid batter, equivalent to 0.384 g batter/biscuit.

• Height of curtain: 10 cm

• Metering pump: 70%

• Tilting position of the curtain: 4

• Blower height: 3 cm

· Blower capacity: 100%

• Belt speed: 13 m/min

After the liquid batter was applied, the biscuits were introduced in a direct flame oven at a temperature of 180 °C, at a speed of 12 m/minute and 3 minutes of residence time, whereby the initial 15.5% moisture content wet basis is reduced to 4% moisture content wet basis.

Under these process conditions, no deformation and/or collapse of biscuits occurred, and they had a crispy texture.

EXAMPLE 3:

Extruded biscuits were manufactured, based on rice flour (50 %), corn starch (30 %), wheat flour (13 %), powder milk (3%), salt (2 %) and sugar (2 %) under the following extrusion process conditions:

• Flow rate of dry ingredients: 300 kg/h • Water added to the extruder: 19 kg/h

• Screw speed: 220 rpm

Working temperatures: 160; 130; 130; 100; 70; 30 °C

The strips exited the extruder at a speed of 22 m/min, having a width of 32 mm, a thickness of 7 mm, a bulk density of 0.10g/cm³, and 9.0% moisture. Thickness was reduced to 6 mm by means of a roller.

Strips were cut into biscuits that were 3 cm long, 3.2 cm wide and 0.6 cm thick using a roller cutter and they were arranged with the distributor to prevent overlapping of units.

Biscuits were delivered by means of a conveyor belt at a speed of 12 m/min to a spraying system for applying intersterified vegetable oil molten at 50 °C. Pump pressure was set to 2 bar to achieve a dosage of 0.01 g/cm², equivalent to 0.096 g/biscuit, an amount which is sufficient to completely cover the surface of the biscuit's upper face.

Subsequently, application of the liquid batter was performed, which was previously made by mixing the powder ingredients detailed as follows in 50% w/w water.

The viscosity of this preparation was of 300 cp at 15 °C. Conditions of the coating machine were adjusted so as to obtain a dosage of 0.04 g/cm² of liquid batter, equivalent to 0.384 g batter/biscuit.

• Height of curtain: 12 cm

• Metering pump: 70%

• Tilting position of the curtain: 4

• Blower height: 4 cm

• Blower capacity: 100%

• Belt speed: 12 m/min

After application of the liquid batter, the biscuits were introduced into a direct flame oven at a temperature of 200°C, at a speed of 12 m/min and 3 minutes of residence time, whereby the initial 15.5% moisture content wet basis was reduced to 4% moisture content wet basis.

Claims

CLAIMS:

1 . A method for obtaining an extruded/expanded cereal-based biscuit with a fat and savory dough coating, comprising the steps of:

mixing in a mixer the raw materials used for the base biscuit comprising mainly an ingredient having a high content of starch such as starch from corn, potato, cassava, sorghum or rice or wheat flour, with the addition of ingredients providing to the final aspect of the base biscuit protein sources such as powder milk, cheese whey powder or simple sugars such as sucrose or glucose, salt, and dyes, as well as other expansion- modifying ingredients such as calcium carbonate, baking powder (sodium bicarbonate and an acidic agent such as calcium monohydrogen phosphate) or a dietary fibre;

making the biscuits forming the substrate on which the invention is put into practice, in an extruder using a head with dies forming strips of expanded material.

adjusting the thickness of the strips of expanded material in a roller and then cutting them to form biscuits;

placing the biscuit, using a vibrating distributor, on a single plane without overlaps and then delivering them onto a conveyor belt, characterized in that the biscuits are coated with a fat spray to seal the biscuits and allow for a subsequent application of a highly moisturized and fluid dough (batter), and then baking and cooling them on a conveyor before packing.

2. The method of claim 1 , characterized in that said sprayed fat is a molten hydrogenated or intersterified fat of animal or plant origin with a melting point from 30 to 45^Q C, preferably from 32 to 40^Q C.

3. The method of claim 2, characterized in that said molten fat is sprayed using a high-pressure metering pump which forces it through nozzles for its pulverization, where said pump regulates fat to a dosage of from 0.005 g/cm² to 0.02 g/cm².

4. The method of claim 1 , characterized in that the highly moisturized fluid dough comprises a mixture of carbohydrates such as starches or flours, salt, color generating agents such as powder milk or cheese whey, glucose, emulsifiers, fats, flavorings and dyes, with a final concentration of from 30 to 65 % solids, preferably from 45 to 60% solids, and a viscosity of from 100 to 800 cps.

5. The method of claim 4, characterized in that said high moisture fluid dough is applied at a rate from 0.03 g/cm² to 0.06 g/cm², preferably from 0.04 g/cm² to 0.05 g/cm², which in terms of applied solids represent from 0.015 to 0.035 g/cm² of batter solids.

6. The method of claim 1 , characterized in that baking is carried out in a direct flame oven so that a high thermal transference capacity onto the product may be achieved.

7. The method of claim 6, characterized in that residence time in the oven is from 2 to 5 minutes, with a conveyor belt speed from 8 to 20 m/min., preferably from 10 to 14 m/min.

8. The method of claim 1 , characterized in that the final moisture of the biscuit, prior to packaging, is from 2 to 6 %, preferably from 3 to 4 %.

9. An arrangement for use with the method of claim 1 , characterized by comprising:

a mixer for mixing the raw materials used for the base biscuit;

an extruder ;

a roller/cutter;

a vibrating distributor;

a sprayer;

a fluid dough coating machine

an oven; and

a cooling conveyor.

P/a de Molinos de la Plata Rio de la Plata S.A.