- The document describes the design and testing of a maize grain roaster. It analyzes the roaster's components, including the cylinder and frame. - Experiments were conducted to evaluate how roasting method and time affect properties of the roasted maize like moisture content, color, phenol content, and functional qualities. Longer roasting times and the manufactured roaster led to greater changes. - Analysis found the manufactured roaster improved energy conservation compared to traditional open pan roasting, as it achieved higher internal temperatures and less heat loss to the environment.

1. RESULT AND DISCUSSION

2. Solid Work Design and Manufacturing of
Maize Grain Roaster
• The maize grain roaster was designed using solid work version
[30.1.0.0082/11.16.5.0] and manufactured from locally available materials.
The resultant manufactured roaster has composed of different components as it
is mentioned above at section ( 3.2.2 to 3.2.4).The main categories are the
cylinder, the shell that covers the cylinder, the frame, and the burning chamber.
The size of the roasting cylinder is 56 cm in diameter and 86 cm in length. The
cylinder also consists of internal and external parts. The internal part has
horizontal baffles, hollow shaft rod metal, and normal supports. The external
part of the cylinder consists of the hollow shaft that passes through the
cylinder, the inlet and outlet ports, the hopper, and the bearing support that
connects the frame and the main cylinder, which holds the grain. The design
and fabrication of each part of the grain roaster is described below.

3. Cylinder
• The cylinder shown in Figure 4.1 has a volume of 211818.74 cm3 (0.21181874
m3) and can hold 15 to 50 kg of grain. The cylinder has two main parts: the
horizontally attached four baffles with a 10 cm width and 85 cm length; and
the normal supporting thick metal that connects the cylinder wall and the
internal hollow rod metal shaft. The baffles are used to mix the grain very well
since it is a barrier cylinder surface there is grain sliding; the other importance
of the baffle is roasting the grain on the surface of the cylinder. The cylinder
has a small hole at the cap that is used to remove the vapor of the moisture
from the conditioned maize grain. In addition, this cylinder has an inlet and
outlet openings that are used to feed the grain in and out as well as ease the
cleaning. The main importance of vertical support is providing strength for the
cylinder and maintaining the load since it is fixed at the center of the cylinder
and equidistant from the center of the shaft.

4. Frame Design
• The frame of this equipment holds both shell and tube chamber and burning
chamber. The frame size was determined according to the clearance space
between the roasting cylinder and the shell jacket.
• Figure 4. frame components: (a) square rod metal frame, (b) frame cover,(c)
the bottom burning material holding .
• The above Figure ,Fig. 4.5, illustrates the structural components of the frame
that carry and connect the whole machine. The frame has two main aspects.
The first use is connecting and carrying the roaster cylinder, and the second is
used to welding jacket covers in both the lower burning chamber and the upper
chamber. The dimensions of the frame are 100 cm in length, 66 cm in height,
and 66 cm in width, which are selected according to the cylindrical roaster
dimension and expansion safety; hence, it was done with a 5-7 cm clearance
from the roaster cylinder.

5. Effect of Roasting Method and Roasting Time
on Physicochemical and functional properties
of Roasted Maize Grain (” Asharo Kolo”)

6. Proximate composition of roasted maize grain
(” Asharo kolo”)
• The overall experimental ANOVA p-value shows (RT, RM, and RT*RM)
result shows those the roasting methods and roasting times and the interactions
have significant differences on most proximate composition values. The
processing methods greatly affect the proximate composition of maize grain
products as studies quality protein maize more or less all proximate
composition increased from raw, boiling, and roasted respectively. The protein
content compared to the different roasting methods and raw maize shows
nearly less effect however the reality different processing affects the final
result, nearly this result to different processing, such as fermenting and un
fermenting as roasting and un roasting maize protein content. as studies show
the protein content increases with increased fermentation time and
corresponding roasting time
• Table 4. ANOVA p- values showing the significance of the main and
interaction effect of the roasting method and roasting time on proximate
composition

7. Effect of Roasting Time on Proximate
Composition of Roasted Maize Grain
• Proximate Composition of Roasted Asharo Kolo
• The according to Table 4.3 roasting time significantly affected most of the
proximate and nutritional components of roasted maize grain except the fiber
content. The moisture content and the ash content decrease with increasing
roasting time ,whereas the CHO & energy content and value increased. The
protein, fiber and fat contents are significant compared to the raw maize grain,
even though they have no significant effect on increments of roasting time.
• Table 4. .Effect of roasting time on proximate composition of roasted maize
grain
• RT Mc ash P Fi F CHO energy 30 9.36118a
1.36540a 8.32820a 2.23612b 4.69206a 74.0751c
371.842c 40 2.37638b 1.30734ab 8.41233a 2.07025b
4.87293a 81.0319b 402.340b 50 0.78438c 1.23622b
8.30160a 2.06789b 4.82368a 82.6771a 406.724a R
a c c a b c

8. Effect of Roasting Method on Proximate
Composition of Roasted Maize Grain
• According to the figure 4.8 the moisture content lower than the machine
roaster, but also fiber and ash also decreased ,whereas the fat and CHO content
increased. On the other hand, the protein content remains similar to that of
roasted in both methods.
• Figure 4. Effect of roasting method on proximate composition of maize grain
flour

9. Effect of Roasting Method and Time on
Colour, Bulk density and Phenol of Roasted
Maize Grain (” Asharo kolo”)
• The ANOVA result for effects of roasting method and time on color and
phenol of roasted maize grain is indicated in Table 4.4. In addition, values of
each color indicator, L,a,& b, and phenol of the roasted maize grain is
presented in Table 4.5.
• Table 4. ANOVA p- values showing the significance of physicochemical
changes of roasted Asharo kolo
• SV L a b BD phenol RM 0.019 0.004
0.011 0.099 0.000 RT 0.000 0.000 0.000 0.000 0.000
RM*RT 0.006s 0.051 0.007 0.209 0.000 SV: source of
variation, L, a, and b are color measurements
• Table 4. The effect of the roasting method and roasting time on the color
change and phenolic content of roasted maize grain
• RM RT L a b BD TPC(mg GAE/100g) MC
30 30.60±1.76bc -1.64±2.44b 6.23±9.74bc 468.0±17.6a

10. Effect of Roasting time on Colour Change,
bulk density and total phenol content of
Roasted Asharo Kolo
• The whiteness was 49.49-25.09, and the yellowness was 19.39- 7.91, and
37.20- 3.15 with higher and lower respectively with the corresponding roasting
time, temperature, and extraction time and temperature Roasting decreases
the lightness value from 80 up to 50, however, the colour change increases
from 15 up to 50 .
• Table 4. Effect of roasting time on physicochemical properties of Asharo Kolo
• RT L a b BD TPC 30 26.68±15.13b
7.49±5.37a 23.38±3.60a 469.05±20.95a 132.32±10.70c 40
22.38±6.31b 8.08±4.08a 8.91±3.55ab 453.5±43.0ab
148.06±7.32b 50 4.020±4.05c -1.79±2.68b -2.50±4.21b
398.1±62.9b 164.80±8.66a R 67.3375a 1.4950±0.1429ab
22.036±1.256a 762.32±8.47 65.066±0.028 The mean value with
different superscripts shows roasting time has a significant color difference (L,
a, and b), TPC is total phenolic content and R is raw maize grain flour.

11. Effect of Roasting Method on Colour Change
and phenol content of Roasted Asharo Kolo
• Table 4. Effect of roasting method on physicochemical properties of roasted
maize grain
• RM L a b BD TPC MC 16.08±7.72b
2.19±3.86a 3.98±6.46b 428.5±66.1a 144.73±16.66a MT
21.79±16.83b 6.99±7.15a 11.14±13.48ab 451.9±36.2a 152.07±15.51a R
67.34±2.93a 1.49±0.14a 22.03±1.25a 762.32±8.47 65.06±0.082b
CV 3.14 1.34 2.47 16.5 3.77 P 0.000 0.141 0.035
0.251 0.000 Note: The values expressed in mean ± standard deviation with
triplicate experiments; Means with different superscript letters (a-c) in
columns were significantly different at the level of p˂0.05; L, a, b, TPC and
BD represent the degree of lightness, red-green, and yellow-blue, total phenol
content and bulk density respectively.The roasting method according to the
table 4.7 illustrates did not affect the colour, the total phenol content and the
bulk density, but it has significant change with respect to the raw maize grain.

12. Effect of Roasting Method and Time on
Functional Properties of Asharo Kolo

13. Table 4. ANOVA P-values showing the
significance of the main and the interaction
effect of the roasting method and time on the
functional properties of roasted maize grain

14. Table 4. The Effect of the roasting method
and roasting time on functional properties of
roasted maize grain

15. and chemical reactions. Roasting can reduce
the water activity of maize grain by removing
moisture, resulting in a lower Aw compared
to raw grain. This decrease in water activity
can contribute to the preservation and
stability of the roasted maize grain.

16. Effect of Roasting Time on Functional
Properties of Roasted Maize Grain

17. Table 4. Effect of roasting time on functional
properties of roasted maize grain

18. Figure 4. Effect of roasting time on water
activity (aw) of roasted maize grain

19. Figure 4. Effect of roasting time on water
activity at different roasting methods

20. Effect of Roasting Method on Functional
Properties of Roasted Maize Grain

21. Table 4. Effect of roasting method on
functional properties of roasted maize grain

22. Performance Evaluation of the Manufactured
Roaster

23. Energy Conservation

24. Table 4. specific heat capacity of the roasted
maize grain

25. Table 4. the total amount of heat required in
two methods of roasting
• The energy absorbed by the maize grain in newly designed roaster is
greater than that of the open pan used in usual roaster, and this energy is
directly proportional to the average temperature change in the system. The
temperature in the newly designed machine is higher than the open pan roaster
due to the insulation and the shell cover, where as in the open pan roaster heat
source is exposed to environmental air which lower the temperature by
exchanging and increases the heat loss.

26. Moisture Removal/Rate of Roasting
• Performance Test
• The Performance determines by the determination of moisture content removal
from the maize grain. The samples were taken in moisture boxes from each lot
to determine the moisture content. The boxes are kept in a hot air oven at
1050C±3 for 24 hours and the weights are measured on an electronic digital
weighing machine having an accuracy of 0.01g. From the initial and final
moisture box weights, the moisture content of samples is determined and
expressed in percent (wb.) by using the following formula
•
• Where Mw, M1, and M2 are moisture loss, the mass of the sample before
roasting, and the mass of the sample after roasting respectively. The
performance parameters for all these are moisture content,
• Drying rate
• Calculation of drying rate

27. CONCLUSION AND
RECOMMENDATION

28. Conclusion
• Many grain food products are roasted for different purposes throughout the
world. According to the importance of roasting, there are many roasting
techniques and conditions, but in most developing countries roasting practice
is still traditional and has a bad impact on both labor workers and the food
product qualities. This study commonly compared two different roasting
methods, which are the one design and fabricated manual rotatable cylindrical
drum-like jacketed roaster and the usual traditional open pan roasters. This
research study aimed to harmonize traditional roasting practices as a
transitional for the transformation of traditional food processing to affordable,
better ergonomic effects and processing with the best uniform quality
products. The quality parameter assessment of roasted maize grain result
shows the interaction effect of roasting time and roasting method has a
significant effect on proximate composition, color, and phenol content but,
most of the functional properties are insignificant except WAC and water
activity. In a nutshell roasting method, roasting time, and their interaction of

29. Recommendation
• This research is broad and needs multidisciplinary knowledge and needs
collaboration of departments that can address technical skills and knowledge
since the research should address both the food product quality attributes and
the roaster machine evaluation and validation, so if this research is done with
Food engineering and Mechanical or other discipline’s like Electrical and
Industrial specialist experts it would solve the community roasting practice
problems, and able to scale up the product prototype for instant ingredient
production and commercialization, therefore future works for will be: Making
the power source electrical or solar system and uniform heat energy, instead of
manual rotation installing the gear or other pulley system to reduce torque
force, proper fan system installation, air entry and outlet for exhaust moisture
and smoke, proper insulation of the heated jacket and others are future works
for whom intended to work this thematic area.
• The other main concern is studying the effect of storage time and condition on
roasted maize grain, since shelf life is very important for instant ingredients’,