- Zachte tarwe - Harde tarwe
- Wisselende eigenschappen - Hoog EW-gehalte &
per soort glutenkwaliteit
- Vooral broodbakkerij, … - Hoog β-caroteengehalte
- Melig uitzicht - Vooral pasta, …
- Glazig uitzicht
Volkorenbloem = 100% extractie, vermaling waarbij bloem, zemelen en kriel niet gescheiden worden
Integraalmeel = <78%, vermaling met hamermolen, deeltjesgrootte afhankelijk van grootte zeef
Patentbloem = <55%, enkel het binnenste van endosperm vermalen (hoogkwalitatief!)
1.2.3 Chemische samenstelling
% Korrel Bloem
Vocht 9-18 13-15
EW 8-15 9-14
Vet 1,5-2 1-1,6
As (mineralen) 1,5-2 0,6-0,8
ZM 60-68 64-69
Vezels 2-2,5 0,2-0,35
KH 2-3 1,5-2
=> op broodzak bv: 11,5/680 -> 11,5% EW en 0,68% mineralen
, ZETMEEL
- 25% amylose
- Lineair polymeer/helix
- a-1,4-glycosidische bindingen tussen glucose-eenheden
- Niet oplosbaar
- Neiging tot retrogradatie, gelvorming & syneresis
- 75% amylopectine
- Vertakte polymeer
- a-1,4- & a-1,6-glycosidische bindingen tussen glucose-eenheden
- Oplosbaar/hoog WBV
- Kleine neiging tot retrogradatie & stabiel
=> getest met jood -> verkleuring hangt af van # omwentelingen in helix (blauw = amylose, rood =
amylopectine)
Amylose & amylopectine zitten in de ZM-korrels
-> moleculen worden door H-bruggen in
radiale richting geassocieerd: kristallijne
bundels of micellen
Amorfe = sterk vertakte amylopectine-moleculen
Kristallijne = sterk geordende amylose-moleculen
=> sterke structuur -> onoplosbaar in water (neemt wel water op in amorfe delen -> 12-30%)
Verstijfselingsproces
- Nemen water op tot 30-50% van hun eigen gewicht
- Start bij 60°C
- H-bruggen worden verbroken
- Water in de korrel bindt met de vrijgekomen OH-groepen
- Membranen en cellen zwellen op
- OH-verbindingen tussen ZM-moleculen worden verbroken
- Korte lineaire ketens diffunderen uit de cellen (amylose!)
- Korrels barsten en ZM komt vrij en is omgeven door geadsorbeerd water (verstijfseling)
- Bij temperatuursdaling: herstel H-bruggen, gelvorming & retrogradatie
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