Efficiency of sieving or classification for dry fractionation of aot mills and beta-glucans enrichment.

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Passage desDéportés 2, 5030Gembloux, Belgium; contact e-mail: atisa(â)fsagx.ac.be :http://www.fsagx.ac.be/ta 2Wal.Agri S.A.-R&D,Sombreffe, Belgium; contacte-mail: roiseux.o(âlwalagri.be; hUo://www.walagri.be

JAVEVE Group -Merksem, Belgium; contact e-mail: erik.vanderbekera.>aveve.be ;http://www.aveve.be

INTRODUCTION

Thereis an increasing interest for nutritional andhealthc1aimsin food products. Itis weilknown

thatoatand inparticular ~-glucans (Fig. 1)contribute to cholesterol lowering leading toan health

c1aim in countries like Finland, UK and USA. This potential is now in discussion into CE

(1924/2006). However, formulation of a product with such an heath c1aim isdifficult due to

modifications of hydration Iikewater holding of viscosity Iinkedwith increase levels of ~-glucans and thehighersolubility ofoat proteins (Table 1).

For testing to solvethis technical problem, fractions withan increased levelof ~-glucans can be

produced. Nevertheless, an increase in~-glucans islinked to an increase, which is not always

wished,ininsoluble fibretoobecause ofthepresence of ~-glucans inthe outer partof the grain.

Moreover,oat milling istechnically difficult duetothepresence ofhusks andhighIipidcontentof the grain(Table1).

Tllblc-1:G(,IlC'nlconlpo~itionor diffut'ntcommoncut'~~ Whut /IIIlUt' Ibrlt')' 0" l'rold," 9-16'" 10-12', 9-12', 12-IP, or••'hkhsoltlblt' 15 e, 7', 24', 65', F" 2·3', 4·10', 1-2', 6-8', Crudt'fibrt' 2-3', 2·3', 5-6', 3~', ~gh.A('II," 0,5-1,5', 0,1', 2.0-9.0', 2.5-6.6', DRY FRACTIONATION

With theaim toproduce cereal ingredients concentrated in ~-glucans, we investigated sieving and classification (Fig. 2) process on

common andnaked(without adherent husks)oat(Fig. 3) fleurs from different origins. Dry fractionation process permits to label oat

fractionsas naturalingredients.

Flg..3.Common (Il).ndn.kt'd (b)011IMrn('h tic.1.(.'ht'mk.1structure'0(~I.JH1."~JltJÇ.m

CHEMICAL COMPOSITION

We found increasing levels of ~-glucans incommon and naked oatfractions from

classifications (Tables 2) and sieving (Table 3). Composition in dietary fibres (AOAC 991.43), proteins, antioxidant activity (AA) and starch were also investigated.

Beta-glucans intakein rawmaterials ishigh forthetwonaked oatvarieties (4,0 % DM),butlower forcommon oatvarieties (from 2,0to 2,5 %DM)because oftaking account of husks. By classification on the two types of oats, we can double concentration of ~-glucans. Forcommon oatvarieties, itseems possibleto valorise thegrainandthehuskwithout peeling(Table 3).

T.bk-2 Composition(%or1)/11)of".kW o.t fractionsfrom dllS!lirlClIriotl

Fractions p.glucans Protelns AA' IOF2 SOF' TOF'

7,2% 16,8% 21,4% 7.5% 29,0% 5,0% 15,2% 16.7% 6,2% 22,9% 1,9% 11,2% 7.1% 3,5% 10.5% 1,5% 10,1% 7,5% 1,2% 8,6%

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--For naked oat varieties, therelationship between ~-glucans and insoluble dietary fibres are also original (Fig. 4). Indeed, in comparison with commercial whole-oat flour and oat bran (from common oatafter dehusking) which isa cJassicalsource of ~-glucans inthe agro-food industries,

theratio between insoluble dietary fibre and ~-glucans contents were lower. So, it can beof

interest forcertain food processes forwhichexcess ofinsoluble fractions isnotdesirable.

20 15 10 Nakedoat CommonOilt 6.0'" 5,1'" 6.2'" ".6% 5.9% ".1'" 4,9% 3,8% 2.3% 2,3% 1,5% 1.3% Fractions Ta"'"J:Ikta.puCllIU intauo(n:lkt'd andcommonoa'rractioM

fromNt"'inc

Corrrrercjal Corrrrercsaloat whole-oatüour bran

Fraction A Fraction B

lN CONCLUSION, thedevelopment of amore efficient process will lead totheproduction ofseveral fractions containing increasing levels of ~-glucans. Moreover, the enrichment in~-glucans lead to anincrease in proteins and OF intake, and alsoto an higher AA. PERSPECTIVES Investigatetheinfluence of rawmaterialdrymatter andparticle size ofoatflouron the classification Analysethedistribution oftheprotein solubility intothefractions Characterise the compounds responsibleof the AA