810J.Wangetal./FoodChemistry106(2008)804–810

testwheatvarietiesextractedwithtraditionalmethods,suchasSoxhletextractionandmix-stirringextraction(Adom,Sorrellls,&Liu,2003),andwheatgrainanditsfractions,suchasaleurone,bran,andmicronisedaleurone,maysigni cantlydi erintheirtotalphenoliccontents(Zhou,Laux,&Yu,2004).Thetotalphenoliccontentsofthebranextractsfromahardredwinterwheatgrownatfourdi erentlocationswere2.29–3.24mgGAE/gbran,usingSoxhletextractionwithabsoluteethanolfor15h(Yu,Perret,Harris,Wilson,&Haley,2003).Thetotalphe-noliccontentsofthebranextractsfromahardwhitewinterwheatgrownat vedi erentlocationswere2.29–3.05mgGAE/gbran,usingSoxhletextractionwithabsoluteetha-nolfor15h(Zhou&Yu,2004).Thisindicatedthattheapplicationofultrasonicationfortheextractionofpheno-liccompoundsfromwheatbranwasase ectiveasSoxhletextraction,andtheultrasound-assistedextractioncouldgreatlyshortentheextractiontime.Thee ciencyofultra-sonicationcouldbeexplainedbythefactthatsonicationsimultaneouslyenhancedthehydrationandfragmentationprocesswhilefacilitatingmasstransferofsolutestotheextractionsolvent,withoutsigni cantdecompositionofthesolvent(Toma,Vinatoru,Paniwnyk,&Masom,2001).4.Conclusions

Thispresentstudyindicatesthatwheatbrancanbecon-sideredagoodsourceofphenoliccompounds.Theextrac-tiontimestronglya ectsthephenoliccontentoftheextracts.TheoptimalconditionsobtainedbyRSMfortheextractionofphenoliccompoundsfromwheatbranunderultrasonicationincludethefollowingparameters:ethanolconcentration,64%;extractiontemperature,60°C;andextractiontime,25min.References

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