FHT – Flour HeatTreatment.

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Flour Heat Treatment.Modification of grain product properties.

Definition of FHTFlour Heat Treatment is a process designed to modify the properties of flour, germ, and bran. FHT can be divided into two basic processes: hydrothermal treatment and thermal treatment.

ApplicationsFHT products can be applied in a large number of different ways in the food industry:

– Coatings Hydrothermally treated flour is excellently suited for

preparing batters for coating fish, meat, and vegetables. Thankstoitsoptimizedcoldviscosity, •battersorbreadingsadhereperfectlytothefood •drippingofthebatterisreduced.

– Bakery products Thermallytreatedfloursareusedforcakeswithhigh

sugarandfatcontents.Thesefloursarecharacterized by their

•strengthenedglutenproperties •finegranulation. In order to achieve a long shelf life of fresh dough, raw

materials with low microbiological contamination are required.Heattreatmentsanitizestheflourbyinactivatinga large proportion of the microorganisms.

– Binders FHTflourisapplied,amongotherthings,asathickener

for soups and sauces. Heat treatment • increasesthehotviscosityoftheseflours •driestheproducttopreventmoisturefrommigrating

to the other substance components • inactivatesmicroorganismsandenzymes.

– Other applications The FHT process allows bran, germ (e.g. of wheat)

aswellasricebrantobestabilized,enablingthem to be preserved by

•essentiallyinactivatingfat-splittingenzymes •reducingalargeproportionofthemicroorganisms

by heat •optimizingtheproductmoisture. These grain byproducts can, for example, be used in

muesli mixes or in cereal bars.

Stabilized bran and germ.Soup and sauce flours.

Cakes.

Coatings.

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Hydrothermal processThe term “hydrothermal process” refers to the treatment of flour by heat and moisture in the form of water and steam. The goal of this process is to modify the flour substance components such as starch and gluten. In addition,enzymesandmicroorganismsareinactivated.

PrincipleFHT is a continuous process with a throughput capacity upto2500kg/h.Hydrothermalflourtreatmentcanbedivided into three steps:• hydrothermaltreatment:injectionofsteamandwater

into the flour, followed by a retention time in the heat retention screws

• gentledryingbyhotairinthermopneumaticconveyors• removalofagglomeratedparticlesbysieving,whichare

then ground

Product propertiesThe goal of hydrothermal treatment is to • increasethehotandcoldviscositybygelatinizingthe

starch• improvethewatersolubilitybydenaturingthegluten• inactivateenzymesingrainbyproductssuchasgerm

and bran to improve the shelf life

Hydrothermal flour treatment.Moisture and heat.

Water content

Wet gluten content

Cold viscosity

Hot viscosity (amylogram)

Water absorption index

Degreeofgelatinization

Base flourBatter flour

Aspiration system

Scale

Magnet

Steam Water

Heat retention screws

Thermopneumatic conveyorHeat exchanger

Sievingmachine

Impact mill

Hammer mill

Plansifter

Magnet

Magnet

Impact mill

Pneumaticconveyor/ aspiration filter

(B4-Cup)

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Thermal processThe term “thermal process” refers to the treatment of flour by heat, followed by an appropriate retention time. This process is less intensive than the hydrothermal process. Thefloursthusretaintheirbakingcharacteristics.Theheatacts particularly upon the gluten and the microorganisms.

PrincipleThe thermal process allows a throughput capacity up to 2000kg/hofproduct.Theprocesscanbedividedintothefollowing discrete steps:• gentleheatinginacurrentofhotairinthermopneumatic

conveyors• temperatureretentioninheatretentionscrews• moistureadditiontoadjustthewatercontent• screeningandgrindingtoadjusttheparticlesize

Product propertiesUnlikehydrothermallytreatedflours,thermallytreatedfloursretaintheirbakingcharacteristics.Suchfloursareapplied as• cakeflourwithstrengthenedglutenframework,for

cakeswithveryhighsugarandfatcontents• soupflourswithincreasedhotviscosityandalow

moisture content

Thermal flour treatment.Heat and retention time.

Water content

Wet gluten contentCold viscosity

(B4-Cup)

Hot viscosity (amylogram)

Energy (extensigram)

Resistance to extension (extensigram)

Extensibility (extensigram)

Water absorption (farinogram)

Base flourCakeflour

Pneumaticconveyor/aspiration filter

Aspiration system

Scale

Magnet

Thermopneumatic conveyor

Heat exchanger

Heat retention screws

Sievingmachine

Impact mill

Magnet

Impact mill

Hammer mill

Plansifter

Magnet

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Overall process. Tailor-made customer solutions.

System typesThe core components of all FHT systems (heat retention screws and thermopneumatic conveyors) for the hydro-thermal and thermal processes are identical. The two processes can be combined in one single system. This produces maximum production flexibility, since it is possible to produce• flourswithgelatinizedstarch• bakingflourswithstrengthenedgluten• driedflours• stabilizedgermandbranon a single system. A system may also be designed to meet specific process requirements.

The system capacities are related to the specific product and may vary according to • theprocess(thermal/hydrothermal)• theheatretentiontimeintheretentionscrews• theintensityoftreatment.Theprocessandthesystemsizearematchedtothecustomer’s specific needs.

Control systemA PLC control system controls and monitors the entire process. Operation, data gathering, and recipe management are performed by the Buhler WinCoS process control system.

The recipe-oriented control system is based on • theroutingrecipe,whichdefinestheprocesssequence• recipe(productformula)withtheactualprocess

parameters• theproductionjobwiththedatarelevanttoproduction.Theadministrationauthorizationsforthevariousrecipelevels can be defined on a user-specific basis.

Product traceability is ensured by • permanentrecordingoftheparametersrelevant

to the process• ajob-orientedoperatingmodeofthecontrolsystem.

MU

160

77 e

n 09

09

1500

DF

Bühler AG

CH-9240 Uzwil , Switzerland

T +41 71 955 11 11

F +41 71 955 66 11

www.buhlergroup.com