World Grain - June 2013 - 66

FEATURE: Sorghum milling Study

Proximate analysis of sorghum flours produced
by three different milling procedures
Diagram

sample

F20105
Com.
F20107
F20106

148
144
200
210

% Crude fat
(d.b.)*
1.43 ± 0.03b
1.47 ± 0.02b
2.77 ± 0.04a
1.42 ± 0.02b

% Ash
(d.b.)*
0.74 ± 0.01b
0.69 ± 0.01c
1.21 ± 0.01a
0.76 ± 0.02b

% Crude fiber
(d.b.)*
0.51 ± 0.04c
0.51 ± 0.03c
0.75 ± 0.03a
0.60 ± 0.03b

Moisture
(w.b.)*
13.13 ± 0.04b
11.19 ± 0.05d
13.53 ± 0.02a
13.01 ± 0.07c

*Mean ± sdev
*Means within a column followed by different letters are significantly different (P < 0.05, REGWQ test).

Comparison of different sorghum
flours based on color parameters
Diagram
F20105
Com.
F20107
F20106

sample
148
144
200
210

l-value
89.28 ± 0.01b
85.65 ± 0.01d
87.31 ± 0.01c
90.6 ± 0.01a

Mean ± sE
a-value
b-value
-0.93 ± 0.01b
9.53 ± 0.01c
1.49 ± 0.03d
10.2 ± 0.01a
-0.72 ± 0.01c
11.89 ± 0.00b
-1.04 ± 0.01a
8.91 ± 0.01d

Agtron Color
44.33 ± 0.58b
6.33 ± 0.58d
22.33 ± 1.53c
50.00 ± 1.00a

*Means within a column followed by different letters are significantly different (P < 0.05, REGWQ test).

baking behavior. The highest amount of
water was added to sample 210, while
the lowest was added to sample 200.
Concomitantly with water addition, peak dough viscosity is higher
for sample 210 and lowest for sample
200 due to high and low, respectively,
starch damage.
ConClusion
The study found that a long reduction

system which included impact detaching techniques produced white sorghum
flour with a high extraction rate and
good quality flour (compared with existing flour on the market), baking and
bread properties.
An impact dehulling machine and a prebreak roller mill were effective in preparing the sorghum kernels before first break.
The shattering effect of the fragile sorghum
bran was avoided by implementing air

separation of bran from endosperm before
each break. A purification system effectively cleaned and sorted the sorghum grits
by size.
Sorghum flours with different protein
contents were evaluated for their baking
quality properties.
The protein content of sorghum flour
was found to have a strong positive correlation with the amount of water added
to the batter, cell wall thickness, cell diameter and cell volume, and was strongly
negatively correlated with the number of
cells per square centimeter and L-value
of the bread crust. It was also correlated with the a-value and b-value of the
bread crust. The flow diagrams F20105,
F20106, and F20107 can be used successfully in their current form or with
small adjustments to obtain flour from
different sorghum hybrids at the laboratory scale. These diagrams also fill a gap
in the currently available milling literature. Additionally, they can be scaled up
in the sorghum processing industry.
The study said a growing glutenfree food product market would potentially provide a rapid return on the
necessary investment.
We want to hear from you — Send comments and
inquiries to worldgrain@sosland.com. For reprints of
WG articles, e-mail reprints@sosland.com.

For more information, see Page 110.

June 2013 / World Grain / www.World-Grain.com

http://www.prive.fr http://www.World-Grain.com

World Grain - June 2013

Table of Contents for the Digital Edition of World Grain - June 2013