Senior Design Expo 2019

InstaSorg
Quincy Delp, Yifei Tian, Jason Fan, Chengke Fan,
Victoria Wang
Advisor: Arvind Narayanaswamy
Sorghum is a cereal grain, like oats, rice
and wheat, which is grown around the world. For
several reasons, it is a promising candidate for
increased production over the next decade. It is
gluten free. It contains a different (and arguably
superior) nutrient profile than other commonly
consumed grains 1 . Most importantly, it is resistant
to water logging and drought. If we are trending
towards precipitation being less consistent, this is an
essential trait. It is consumed by people regularly in
Sub-Saharan Africa and by livestock in the US but
not by the growing global middle class in the US,
China, or India. We believe this is because of its
long cooking time – on a stove, sorghum takes 60 to
90 minutes to cook. If meal preparation occurs after
coming home from work, this time frame simply
isn’t feasible. Our aim is to make a device which
prepares quick-cooking sorghum that can be cooked
on the stove or in the microwave in 10 minutes or
less.
To outline the specifications of our device
we performed a series of tests and calculations.
Specifically, we needed to isolate a pre-cooking
temperature, pressure and duration, the amount of
torque required to actuate the flaking device, and
the heat, wind speed and duration of our drying
device. We are using an InstaPot to pre­cook the
sorghum, which we operate at a temperature of 100
C and pressure of 70-80 kPa for a duration of 5
minutes to achieve a sufficiently high moisture
content. We required 0.8 Nm of Torque and 5.024
W of Power from the driving motor of the mill. The
NEMA-23 motor we ordered is capable of 3.0 Nm
and operates at up to 50.4 W. Finally, for a target
batch-size of 50 grams and based on a calculated
mass transfer coefficient of 0.00717 kg/m^2s, we
require our fan and heating element to be powered
for 6 minutes and 20 seconds to achieve a moisture
ratio of 0.13, the safe limit for grain storage.
Our design builds on existing models for
quick-cooking cereal. 2 It differs in a few key ways.
First, we use knurled aluminum rather than a flatfaced
cylinder to perform flaking. This creates a
tighter grip with the grain and is able to create a
larger surface area, reducing the rehydration time
required. Second, rather than cooking the grain after
flaking, we immediately move to dry 3 . While we
risk uneven starch gelatinization, we save
tremendous amounts of energy from the second
cooking step and believe that starch is fully
gelatinized by the pressure cooking.
The device is manufactured in a few
modules. The flaking module (detachable) contains
an aluminum base plate, on which is mounted the
stepper motor and driver, knurled rollers, and
microcontroller. The main housing was made using
aluminum t-slotted bars and food safe acrylic
stenciled in a laser cutter. The basket (detachable)
is made using stainless steel screen and hangs on
two steel dowels. The drying elements are made
using a nichrome resistor and DC high-speed motor.
Finally, there is a screen which replaces the flaking
module during drying to prevent grains from flying
out of the device.
We hope that by decreasing the cooking
time of this nutrient rich, gluten free, resilient crop,
Sorghum will gain prominence in and beyond the
sustainable agriculture community.
References
1
Sorghum:https://ndb.nal.usda.gov/ndb/foods/show
/20067 Oats:
https://ndb.nal.usda.gov/ndb/foods/show/45342702
Rice:
https://ndb.nal.usda.gov/ndb/foods/show/45260158
2
Miller, F. J. (1957). US Patent No. US2930697A.
Retrieved from
https://patents.google.com/patent/US2930293A
3
Glenn, Gregory M. and Johnston, Ruth K. (1992)
"Mechanical Properties of Starch, Protein and
Endosperm and Their Relationship to Hardness in
Wheat," Food Structure: Vol. 11: No. 3, Article 1.
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