Section 7 - Debranning and Peeling

Question 1

Label the peritec diagram

Answer 1

Page 35

Question 2

Advantages of debranning

Answer 2

Improved flour quality
Improved flour purity
Nutritional content improved due to inclusion of more aleurone
Reduced bran contamination
Flour produces larger volume loaves due to increased falling number value
Reduction in number of mill passages required
Ability to integrate with host mills
Longer interval between refluting of rollermills

Question 3

Disadvantages of debranning

Answer 3

Power consumption is increased
Moisture loss of flour due to friction process in debranning
Loss of germ due to abrasion of outer skin of the wheat
Noisy due to impact and abrasion from machines
High moisture in the peeled bran can cause problems with handling, storage and disposal
Higher ash content due to greater quantity of aleurone layer present
Maintenance

Question 4

What are the 4 basic elements of a peritec debranning

Answer 4

Pre-conditioning
Debranning
Autoweight system
Co-product handling

Question 5

What is the moisture addition rate in pre conditioning debranning

Answer 5

up to 1% of wheat feed rate

Question 6

Does debranning pre condition affect finished flour moisture?

Answer 6

No

Question 7

Label the satake debranning machine

Answer 7

Page 36 fig 18

Question 8

How does the Satake Debranning machine work

Answer 8

1) Wheat enters the top
2) A rotating abrasion distribution scroll distributes the wheat evenly around the top of the abrasion chamber
3) The wheat travels down between rotating abrasive wheels and a slotted screen
4) 4 adjustable resistance bars are mounted vertically inside the abrasion chamber, as the wheat spirals down in the chamber it must squeeze between the 5-6mm gap between the bars and wheels
5) The abrasion chamber has a suction exhaust and air is drawn down the hollow section of the main shaft
6) The shaft has holes in it so the air is drawn through the working zone and out the slotted screen carrying bran with it
7) There is a weighted flap on the outlet of the chamber which sets the degree of debranning action by holding the wheat inside the chamber
8) Operator adjusts weight to achieve correct degree of debranning
9) Can have an autoweight fitted
10) The wheat is then carried to the bottom of the friction chamber - same basics as abrasion chamber but with lighter action

Question 9

Should the wheat surface be smooth or rough after debranning?

Answer 9

Rough - obvious patches of endosperm and aleurone layer

Question 10

Where is the peeling process found

Answer 10

In the second cleaning section after dampening and tempering

Question 11

What is removed during peeling

Answer 11

The outmost layers - the pericarp

Question 12

How does peeling work

Answer 12

Alternating friction between the special rotor and the screen, and friction between individual grains

Question 13

Advantages of peeling

Answer 13

Improved flour colour
Less specks
Higher yield of low ash white flour
Tendency for improvement of the falling number
Tendency for improvement of the baking volume
Reduction of the total microbial count up to 90%

Question 14

Disadvantages of peeling

Answer 14

Equipment requires more overall power than a conventional mill
Loss of germ due to abrasion of outer skin of wheat
Noise
Maintenance

Question 15

How does the DC Peeler remove the outermost bran layer

Answer 15

In the form of strips which are removed through a screen

Question 16

How does a Buhler DC Peeler work

Answer 16

The peeler is preceded by a dampener where a small amount of water is added to allow the slight separation of bran layers
The outmost bran layers are removed through the action of the grain with each other, the rotor and the screen
The peelings are aspirated away through the screen with the finished wheat as overtails
Level of peeling is controlled by grain time in the body of machine

Question 17

How are the satake debranner and buhler peeler different

Answer 17

The debranner is more complete and severe due to abrasive discs
peeler is much lighter cleaning the outer bran skin

Question 18

What happens if non-debranned wheat enters 1bk

Answer 18

The fluting cuts into the wheat and drags it to the nip of the roll and shears it into pieces. If the fluting is worn the wheat is just flattened as the bran hold the kernel together

Question 19

What happens when debranned wheat enters 1bk

Answer 19

the wheat grain shatters into fragments

Question 20

Does debranned or non debranned wheat use less power

Answer 20

debranned

Question 21

Does debranned wheat produce more coarse semolina on 1bk than a conventional mill

Answer 21

Yes