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Digital Re-print - July | August 2012 Generating added value by Extrusion

www.gfmt.co.uk

Extrusion applied in the food process-ing industry serves for upgrading carbohydrate- and protein-based

raw materials. In the field of carbohy-drate-based raw materials, starch by far accounts for the largest share.

Grain-based foods are staples throughout the world. Day in, day out, millions of tons of grain are processed in food production plants. In addition to baking flour, dark flour and bran are also obtained during grain processing, especially with wheat.

Extrusion technology is a possible way of further processing flour and the by-products obtained in the process. Extruders are used in a wide variety of flour processing applica-tions. The most important resulting products are breakfast cereals, baby food, bread-crumbs, croutons, plus modified flours and starches used, for example, as soup or sauce binders or in the bakery industry.

Modified and still a clean labelModified flours are also called swelling

flours. Swelling flours are characterised by their modified water absorption capacity and their solubility properties. The viscosity of flour-and-water suspensions can be adjusted to the specific applications by selection of the suitable extrusion parameters.

If the correct amount of thermal and mechanical energy is introduced into the product in the extrusion process, this will enable end products to be made which are soluble either in cold or hot water and have a certain bandwidth of viscosities.

Swelling flours are used as binders, fill-ers, or freshness extenders in baked goods. The extrusion process is particularly suited to the modification of flours because it does not require the use of any chemi-cals whatever. These flours are therefore suitable also as ingredients in products subject to a ‘clean label policy’. When using extruded swelling flours, it is enough to declare wheat flour on the ingredient list.

Extrusion as an alternativeAnother possible use is the production of

breadcrumbs. Extrusion technology enables breadcrumbs to be produced on the basis of a wide variety of raw materials. Whereas high-protein flours such as wheat or rye flours are needed for developing a gluten framework in the traditional production proc-ess, it is basically possible to apply all starch-containing products in the extrusion process. This also allows the use of lower-grade wheat flours or corn (maize), rice, or potato flours. In this case, the dough is caused to rise on the one hand due to its expansion at the die.

Bühler presents new twin-screw extruder

“The goal of our development efforts was to offer an extruder which would satisfy customers’ needs in the respec-tive segments they are engaged in while still being a much simpler solution than the comparable all-rounder PolyTwin,” explains the development engineer in charge.

The PrioTwin has been designed for continuous production with few prod-uct changes. Thanks to its new modules and its leaner design, it is particularly easy to operate. It combines proven processes using simplified modules, which reduces the capital investment cost. In developing this new design, careful attention was also paid to inte-grating the extrusion process optimally in the upstream and downstream proc-ess stages in order to offer integral solu-tions with a high customer value.

Generating added value by

EXTRUSIONby Christopher Rubin, Head of Product Management and Marketing,

Pasta and Extruded Products business unit, Bühler, Switzerland

Grain&feed millinG technoloGy16 | July - august 2012

FEATURE

On the other hand, dough rising can also be controlled through specific chemical or physical agents. Fluctuations in the raw material quality are easier to balance in the extrusion process. In addition, it is possible to accurately adjust the texture, colour, and particle size.

Moreover, extrusion is a highly energy-effi-cient process. The much lower water contents in the product formula in comparison to tra-ditional production, in conjunction with short retention times, ensures low energy costs, especially during subsequent drying. The energy costs per ton of finished product – based on

a capacity of two metric tons per hour – are twice as high in the traditional process as in the extrusion process. In addition, the extruder offers the flexibility required to produce related products such as baking peas and croutons or even bread chips on a given processing line by selecting an appropriate configuration.

Extrusion increases value generation

Even very dark flours (low-grade flours) and wheat bran are suitable as raw materials for processing by the extruder. Low-grade

flours as well as wheat bran are as a rule sold at low prices to the feed manufacturing industry. The extruder enables also such ‘by-products’ to be upgraded into high-grade foods. Both by-products can be processed into breakfast cereals, but are also used in a modified form as ingredients in other foods. Bran flakes are highly popular today. Extruded wheat bran, for instance, can fetch double the price of wheat bran in its native form. The opportunities that wheat bran presents as a high-grade food are significant. The high dietary fiber content of wheat bran gives the product an ‘aura of health’.

The basis for making all the products mentioned above is grain flour. This is what the extru-sion process has in common with conventional bakery proc-esses. The difference however lies in the dough texture. The dough framework of conven-tional bakery goods is based on proteins such as gluten and pen-tosans. The texture of extruded products is based on starch. The raw material must have a starch content of at least five to ten percent in order to ensure a stable end product texture. The protein content may be low, that is, below ten percent. Flours with such protein contents are typi-

cally unsuitable for baking. As the flour price is – among other factors – also influenced by the protein content, low-protein flours are less expensive than high-protein ones. The extruder therefore allows also inexpensive flours to be processed.

More InforMatIon:Christopher Rubin, Bühler AG

Tel: +41 71 9551111Fax: +41 71 9553851Email: christopher.rubin@buhlergroup.comWebsite: www.buhlergroup.com

Extruded Bran Sticks – a by-product transformed into valuable food

Grain&feed millinG technoloGy July - august 2012 | 17

FEATURE

Extrusion applied in the food process-ing industry serves for upgrading carbohydrate- and protein-based

raw materials. In the field of carbohy-drate-based raw materials, starch by far accounts for the largest share.

Grain-based foods are staples throughout the world. Day in, day out, millions of tons of grain are processed in food production plants. In addition to baking flour, dark flour and bran are also obtained during grain processing, especially with wheat.

Extrusion technology is a possible way of further processing flour and the by-products obtained in the process. Extruders are used in a wide variety of flour processing applica-tions. The most important resulting products are breakfast cereals, baby food, bread-crumbs, croutons, plus modified flours and starches used, for example, as soup or sauce binders or in the bakery industry.

Modified and still a clean labelModified flours are also called swelling

flours. Swelling flours are characterised by their modified water absorption capacity and their solubility properties. The viscosity of flour-and-water suspensions can be adjusted to the specific applications by selection of the suitable extrusion parameters.

If the correct amount of thermal and mechanical energy is introduced into the product in the extrusion process, this will enable end products to be made which are soluble either in cold or hot water and have a certain bandwidth of viscosities.

Swelling flours are used as binders, fill-ers, or freshness extenders in baked goods. The extrusion process is particularly suited to the modification of flours because it does not require the use of any chemi-cals whatever. These flours are therefore suitable also as ingredients in products subject to a ‘clean label policy’. When using extruded swelling flours, it is enough to declare wheat flour on the ingredient list.

Extrusion as an alternativeAnother possible use is the production of

breadcrumbs. Extrusion technology enables breadcrumbs to be produced on the basis of a wide variety of raw materials. Whereas high-protein flours such as wheat or rye flours are needed for developing a gluten framework in the traditional production proc-ess, it is basically possible to apply all starch-containing products in the extrusion process. This also allows the use of lower-grade wheat flours or corn (maize), rice, or potato flours. In this case, the dough is caused to rise on the one hand due to its expansion at the die.

Bühler presents new twin-screw extruder

“The goal of our development efforts was to offer an extruder which would satisfy customers’ needs in the respec-tive segments they are engaged in while still being a much simpler solution than the comparable all-rounder PolyTwin,” explains the development engineer in charge.

The PrioTwin has been designed for continuous production with few prod-uct changes. Thanks to its new modules and its leaner design, it is particularly easy to operate. It combines proven processes using simplified modules, which reduces the capital investment cost. In developing this new design, careful attention was also paid to inte-grating the extrusion process optimally in the upstream and downstream proc-ess stages in order to offer integral solu-tions with a high customer value.

Generating added value by

EXTRUSIONby Christopher Rubin, Head of Product Management and Marketing,

Pasta and Extruded Products business unit, Bühler, Switzerland

Grain&feed millinG technoloGy16 | July - august 2012

FEATURE

On the other hand, dough rising can also be controlled through specific chemical or physical agents. Fluctuations in the raw material quality are easier to balance in the extrusion process. In addition, it is possible to accurately adjust the texture, colour, and particle size.

Moreover, extrusion is a highly energy-effi-cient process. The much lower water contents in the product formula in comparison to tra-ditional production, in conjunction with short retention times, ensures low energy costs, especially during subsequent drying. The energy costs per ton of finished product – based on

a capacity of two metric tons per hour – are twice as high in the traditional process as in the extrusion process. In addition, the extruder offers the flexibility required to produce related products such as baking peas and croutons or even bread chips on a given processing line by selecting an appropriate configuration.

Extrusion increases value generation

Even very dark flours (low-grade flours) and wheat bran are suitable as raw materials for processing by the extruder. Low-grade

flours as well as wheat bran are as a rule sold at low prices to the feed manufacturing industry. The extruder enables also such ‘by-products’ to be upgraded into high-grade foods. Both by-products can be processed into breakfast cereals, but are also used in a modified form as ingredients in other foods. Bran flakes are highly popular today. Extruded wheat bran, for instance, can fetch double the price of wheat bran in its native form. The opportunities that wheat bran presents as a high-grade food are significant. The high dietary fiber content of wheat bran gives the product an ‘aura of health’.

The basis for making all the products mentioned above is grain flour. This is what the extru-sion process has in common with conventional bakery proc-esses. The difference however lies in the dough texture. The dough framework of conven-tional bakery goods is based on proteins such as gluten and pen-tosans. The texture of extruded products is based on starch. The raw material must have a starch content of at least five to ten percent in order to ensure a stable end product texture. The protein content may be low, that is, below ten percent. Flours with such protein contents are typi-

cally unsuitable for baking. As the flour price is – among other factors – also influenced by the protein content, low-protein flours are less expensive than high-protein ones. The extruder therefore allows also inexpensive flours to be processed.

More InforMatIon:Christopher Rubin, Bühler AG

Tel: +41 71 9551111Fax: +41 71 9553851Email: christopher.rubin@buhlergroup.comWebsite: www.buhlergroup.com

Extruded Bran Sticks – a by-product transformed into valuable food

Grain&feed millinG technoloGy July - august 2012 | 17

FEATURE

Innovations for a better world.

Innovative extrusion processes without limits. Bühler is the global technology

partner for companies producing breakfast cereals, snack foods, or food in-

gredients on a commercial scale. With its extensive extrusion know-how and

its passion for customized solutions, Bühler is always in a position to generate

added value and success for any product idea. Bühler offers an integral range of

products and services for all process stages – from correct raw material handling,

cooking and shaping through extrusion to drying of the extruded products. And

this for all market segments – from breakfast cereals and snack foods to modified

flours and starches, texturized proteins, or vitaminized rice. In short: extrusion

processes without limits.

extrusion@buhlergroup.com, www.buhlergroup.com/extrusion

Innovations for a better world.

Innovative extrusion processes without limits. Bühler is the global technology

partner for companies producing breakfast cereals, snack foods, or food in-

gredients on a commercial scale. With its extensive extrusion know-how and

its passion for customized solutions, Bühler is always in a position to generate

added value and success for any product idea. Bühler offers an integral range of

products and services for all process stages – from correct raw material handling,

cooking and shaping through extrusion to drying of the extruded products. And

this for all market segments – from breakfast cereals and snack foods to modified

flours and starches, texturized proteins, or vitaminized rice. In short: extrusion

processes without limits.

extrusion@buhlergroup.com, www.buhlergroup.com/extrusion

www.gfmt.co.uk

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In this issue:

• Generating added value by extrusion

• Health & safety in the working environment

• Powder Containment

July - August 2012

• Nutritional impact of pellet binders

• Technological expertise

Understandenzymerecoveryinpelletedfeed

• A fresh perspective on UK milling wheat

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