Quimico en alimentos

Páginas: 7 (1506 palabras) Publicado: 19 de enero de 2012
Importance of the Damaged Starch measurement

Presentation map
• 1/ The damaged starch • 2/ The milling – Industrial – Laboratory

• 3/ Effects on final products
• 4/ Methods for its measurement

• 5/ Description of a new method
• 6/ Conclusions

The Starch

• 67-68% of the Grain • 78-82% of the Flour • Amylose / Amylopectin • Semi crystalline structure

Presentation map
• 1/The damaged starch • 2/ The milling – Industrial – Laboratory

• 3/ Effects on final products
• 4/ Methods for its measurement

• 5/ Description of a new method
• 6/ Conclusions

Where does it come from ?
• Damaged starch comes from the wheat itself (as a function of hardness) -genetic criteria-

• It also comes from milling, including wheat tempering
-mechanical criteria-

Wheredoes it comes from ? A/ genetic criteria
For the same milling process, a hard kernel :
• Needs a longer resting time • Produce more semolina during breaking • Produce a flour with more damaged starch “Wheat hardness can be described as a resistance to crushing”

HARD

SOFT

Where does it come from ? B/ Mechanical criteria
Damaged starch = f (Rolls pressure)
Damaged Starch (UCD)
25,5 20,515,5 10,5 5,5 2 2,5 3 Pressure (bar) 3,5 4

Where does it come from ? B/ Mechanical criteria
Damaged Starch = f (Rolls adjustments)
Damaged Starch (UCD)
30 25 20 15 10 0 0,02 0,04 0,06 0,08 0,1 Rolls gap (mm) 5,5 bars 2,5 bars

Where does it come from ? B/ Mechanical criteria
Diagram Study

16 14
% damaged starch or flour extraction

120
damaged starch X flour quantity

12 10 86 4 2
Bk1 Bk2 Bk3 Bk4 Red 1 Red 2 Red 3 Red 4 Red 5 Red 6 Red 7 Red 8 Red 9

100 80 60 40 20 0

Damaged starch Flour produced Damaged starch given by stream

0

Streams

Presentation map
• 1/ The damaged starch • 2/ The milling – Industrial – Laboratory

• 3/ Effects on final products
• 4/ Methods for its measurement

• 5/ Description of a new method
• 6/ Conclusions Absorption
• Protein absorbs 1.8 times its weight of water • Pentosans 10 times.. • Native starch 0.4 times... • Damaged starch 4 times…

Water Release
68 66 16 64
% absorption.

20 18

14
Stability

62 60 58 56

12 10 8 6 4 2

54 10,1 12,3 14,4 15,5 Starch damage (Audidier) Hydration Stability

0

Why to care about damaged starch?
What we look for
Kneading Molding Proofing BakingAfter  A High yield (Water absorption capacity)  Good tolerance  Good tolerance  Good behavior  Good volume  Taste development  Volume increase  A good color  A good taste  A good conservation

To be avoided
 Sticky dough  Low hydrating flour  Sticky dough  Dougth too tough or soft  break down of dough with little volume  Dough collapsing in oven  Breads too “red”  Too fastcrumb hardening

In yellow, damaged starch action spots

How does it act ?
• Alongside with the action already determined on hydration, starch damage has an action on :
• Dough plastic characteristics • Proofing • Bread crust color

How does it act ? Effects on proofing characteristics
• Amylases can’t attack a native starch granule. • More damage more attacks are possible. • Breakingthe granule molecules liberates water. • Simple sugar are present and create :
– Intense yeast activity (a lot of CO2) – Coloration possibility higher.

How does it act ? Effects on final product
• Higher input of water allows to keep the loaf fresh longer.
But : • Simple sugar release provokes a very red crust • If intense, damaged starch can be responsible for :
– Sticky crumb – No volumebread – Too red bread.

How does it act ? Effects on final product
• If I do not have enough starch damage, I can :
• • Set the process differently Choose a harder type of wheat... Both of them...

• If I have to many starch damage, I can :





• •

Take care of amylases content (falling number) Add gluten to increase rheological properties. Set the process differently Change...
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