fht – flour heat treatment. - · pdf filemodification of grain product properties....
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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
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77 e
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1500
DF
Bühler AG
CH-9240 Uzwil , Switzerland
T +41 71 955 11 11
F +41 71 955 66 11
www.buhlergroup.com