International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
Optimization and Performance Evaluation of Electrically
Operated Popcorn Making Machine
Ugwu K. C., Osuoha J. C. And Omoruyi A.
Department of Agricultural and Bioresource Engineering
Department of Agricultural Engineering Technology
Enugu State University of Science and Technology, Enugu, Nigeria
National Business and Technical Examination Board, Enugu, Nigeria
Edo State College of Agriculture, Iguoriakhi, Edo, Nigeria
ABSTRACT
An electrically operated popcorn making machine was optimized and its performance was evaluated. The machine
consists of three chambers (electrical unit, heating/popping unit and discharging unit) vertically assembled together
as a single machine. The whole unit is mounted on an adjustable stand to take care of differences in height of the
operator. The machine works on the principle of mechanically agitated and electrically heated. An electric motor of
0.5hp supply power via electric motor spindle through gear to the stirring shaft which stirs the corn on popping.
Also, electricity supply power to the heating element for heat generation on the popping pot. The performance
evaluation was done using three different moisture contents which include 12.66%, 13.66% and 14.66% at six
different feed rates of corn. The average popping efficiency of the machine was 77.71%. The results showed that
popping efficiency of the machine increases as the moisture content of the corn decreases. Also, the increase in the
feed rate decreases the efficiency of the machine. The Analysis of Variance (ANOVA) for the effect of moisture
content and feed rates confirmed that these factors are significant parameters that affect the efficiency of the
machine.
Keywords: Optimization, Performance, Evaluation, popcorn, Machine .
1.0 INTRODUCTION
Maize (also known as corn) and botanically called
Zeamays is a family name of this cereal grain, of
which about 50 species exist. There are now about 50
species of maize grown around the world, wherever
suitable growing conditions allow for its cultivation.
Maize species are differentiated by kernel shape,
number, colour and size [4].
Maize requires a lot of light and low but long night
temperature higher than 100C, maize requires a fairly
high temperature in order to germinate. It also
requires enough water and humid air in order to
flower and fertilize. The effect on yield of water is
most critical during the period of flowering (from
male flowering to female flowering.) And the
requirements for water are closely related to climate
and also to the length of the growth circle. Maize is
particularly sensitive to wind damage because of the
size of the plant and the width of its leaves. Like all
other plants, maize requires minerals for its growth
[6].
Depending on need, the ears may be harvested when
they are still green, i.e. before they are mature or
when they are fully mature. Harvesting of maize can
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either be done manually or mechanically, that is
either by hand and hand tools or by machines, which
depending on the type may harvest just the ears, or
harvest the grains directly. Once the ears have been
harvested they are dehusked and dried, either
naturally (by using the heat from the sun or solar
energy) or artificially in ovens or hot air blowers.
Drying may also take place in traditional granaries or
in special open sheds known as cribs. After drying,
the ears are shelled; the dried maize grain is stored in
bulk in sacks or silos. The grains are dried to safe
storage moisture content of between 13.5 and 14%
ww [3]
Popcorn is a zeamays variety known as everta. It has
a kernel type that pops and turns into puffs when it is
exposed to heat. It pops because its kernels have a
hard moisture-seal hull and a dense starchy interior.
This allows pressure to build inside the kernel until
an explosive pop result. A damage to the exterior of
the kernels will allow steam to escape causing the
popcorn not to pop. There must be a concentration of
approximately 13.5% moisture in the kernel. With
too much water the kernel will pop as denser pop
corn. Prior to popping, they are processed by
removing them from the cob, drying them to safe
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
storage moisture content – the stage at which they are
popped. Popcorn growers and distributors dry the
kernel until they reach the moisture level at which
they expand the most. This differs by varieties and
conditions but is generally in the range of 14.15%
moisture by weight [7].
Popcorn can be made by using dry or wet corn. Dry
popping also known as hot air popping does not make
use of oil during the popping process. The unpopped
grain is put in a basket or wire cage and agitated over
a heat source like camp fire or coal stove and
allowing the corn to pop and seasoning it with butter
or salt. Another form of dry popping is the hot air
popping which transfers convective heat to the cooler
kernels and when enough hot air heats the kernels
they pop. The blown hot air also serves as the
agitator. In the wet popping method, corn is placed in
a container with a solid base. Oil is added (either
before the corn or poured on top) and the oil helps to
distribute the heat and cause more even and complete
popping. Commercial popping machines use wetpop method and coconut oil (or other vegetable oils)
for its aroma and lightness. Microwave popcorn also
uses the wet pop method, although the moisture is
present in a solidified form of oil, flavouring and salt
that melts when microwaving process begins [7].
Popcorn is a popular snack especially among students
and other youths and even among some of the elderly
group of people in the society. As a result of this
emerging popularity of popcorn, its preparation is
now generating a lot of interest among some
graduates and other school leavers who are
unemployed and want to take up the job as a means
of livelihood [1].
On the other side of the emerging trend, it is not too
popular and user friendly in its preparation
techniques which employ manually operated and gasfired machines, that is, where kerosene stoves and
firewood for popping is not used. In the case of gasfired technique there is risk of gas explosion and the
heat received by the operator in the process of turning
the kernel during popping. In the case of kerosene
stove and firewood, the cleanliness of the operating
environment is always a serious issue considering the
smoke and sooth coming from the heat sources. All
these factors put together brought to the fore the need
to develop an electrically operated machine that uses
electricity for heat generation. It is intended for use
by small to medium scale businesses, and can be
further developed for industrial/large scale
productions.
The main objective of the research work is to
optimize and construct a popcorn making machine
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that can reduce the arduous task involved in making
popcorn by local means [1].
2.0 MATERIALS AND METHODS
The popcorn making machine was developed by
using the following materials which include clinch
device, hack saw, tape, welding machine and
electrodes, an electric filling machine and Lathe
machine. An electrically popcorn making machine,
efficient and economically viable was optimized and
fabricated with readily available and cheap materials
(suitable engineering materials that could give
optimum performance in service). Materials for
fabricating the machine were chosen on the basis of
their availability, suitability, economic consideration,
viability in service etc.
2.1 Methods and Optimization of popcorn making
Machine
The shaft was designed on the basis of strength; and
was subjected to axial loads in addition to combine
torsion and bending loads. . Consideration was given
to the axial load (F) which comprises the spike that
stirs the corn and the weight of the corn to be popped.
To determine the shaft diameter, we adopt the
formula;
d3 =
..[5].....................1
Where;
d = diameter of shaft (mm)
Kb = combined shock and fatigue factor for
bending moment.
Kt = combined shock and fatigue factor for
torsional moment.
Mb = Resultant bending moment (Nm)
Mt = Resultant torsional moment (Nm)
δsy = Allowable shear stress (MN/m2)
π = constant, 3.142
The optimization of the already existing machine
which is kerosene stoves, fire wood and gas fired to
adjustable electrically operated popcorn making
machine that have an easy mechanical assistance that
will enhance the hazardous and arduous way of
producing popcorn at reduced energy and time. The
optimization include reducing the boredom to the
operator, time wasted, energy and
increasing
neatness of the popcorn produced and as well to free
the operator from the smoke and sooth coming out
from the heat source of the former. It will save the
operator from the risk of gas explosion and the heat
received in the process of turning the kernel during
popping.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
2.2 Principle of Operation of the Machine
The popcorn making machine comprises of the
electrical, the heating/popping, and the discharge
units. The electrical unit houses all the electrical
accessories and supplies the electrical energy which
is utilized by the machine in generating heat. The
heating/popping unit comprises the heater-pot
arrangement which heats and pops the corn which is
received by the discharge unit and from where the
popped corn is collected for consumption. The three
units are mounted on an adjustable stand to take care
of differences in height of the operator of the
machine. The machine works on the principle of
mechanically agitated and electrically heated. This
means that the machine operates on the principle of
conversion of energy from electrical to heat by the
use of a high resistant heat generating element which
converts electrical energy to heat energy. An electric
motor of 0.5hp supply power via electric motor
spindle through gear to the stirring shaft which stirs
the corn on popping. The heat generated by the
heating element is transferred to the content of the
pot (oil and popcorn) by heat conduction process
through the bottom of the pot.
It was shown in table 2 that the machine performed
highest (90%) at 50g, 100g, and 150g feed rates and
lowest (66.7%) at 300g feed rate using 13.66%
moisture content. The average percentages of the
corn popped at that moisture content was 83.62% and
the un-popped was 16.38% respectively.
The results obtained using 14.66% moisture content
at six different feed rates were shown in table 3.The
highest percentage of popped corn at that moisture
content was 67.5%, which was obtained at 50g feed
rate of corn. The lowest percentage of popped corn
was obtained at 300g feed rate which was 60%. The
average percentage of recovered popped corn was
65.02% and the average percentage of un-popped
corn recovered was 34.98%. These results showed
that the higher the moisture content and the feed rates
the lower the percentage of corn popped.
Table 4 showed the analysis of variance (ANOVA)
of the results obtained which signified that the
moisture contents and feed rates are important
parameters that affect the efficiency and the
performance of the optimized popcorn making
machine.
2.3 Evaluation of the electrically operated popcorn
making machine.
The machine was tested with three difference
moisture contents at six difference feed rates. The
effect of these difference moisture contents on
machine parameters such as popping efficiency,
duration of popping, neatness of the popcorn after
popping and the un-popped corn were determined.
The weight of popped corn, weight of un-popped
corn, percentages of un-popped corn and percentages
of popped corn were taken during the test. The
performance test was conducted for each moisture
content at six different feed rates using those
parameters for the fabricated machine. The results
obtained were analyzed using analysis of variance
(ANOVA).
4 CONCLUSIONS AND RECOMMENDATION
3 RESULTS AND DISCUSSION
The performance of the electrically operated popcorn
making machine was determined using three different
moisture contents and six different feed rates. The
efficiency of the machine was also obtained using
these moisture contents and the feed rates. It was
observed in table 1 that the highest percentage
performance of the machine was 90% at 50g and
100g feed rates and the lowest percentage
performance of the machine was 75% at 300g feed
rates using 12.66% moisture content. The average
percentages of the corn popped was 84.5% and the
un-popped corn was 15.5% respectively.
ISSN: 2231-5381
The electrically operated popcorn making machine
was optimized and its performance evaluated. The
results obtained showed that the highest average
percentage of corn popped was 84.5% which was at
12.66% moisture content. The results deduced that
the higher the moisture content and feed rate, the
lower the percentage of corn popped by the
optimized machine. The machine reduces the
drudgery and improves neatness as a result of
mechanized nature of agitating (stirring) the corn and
a better source of heat, that is electricity. The
machine was incorporated with adjustable stand to
take care of differences in height of operators, which
the former did not consider. The machine is
recommended to the commercial popcorn makers,
because of its time limitation, ease of operation and
hygienic way of popping corn.
REFERENCE
[1] Jesc C.S., Davin S. R., Xiaodong J., Richard A. W., and David
S. J., (2014): Effect of flake shape on packing characteristics of
popped popcorn, Journal of Food Engineering, Volume 127, Pp 75
-79
[2] Miller, I. and Freund, J.E. (1985) Probability and Statistics for
Engineers. 3rd Edition pg 332 - 354
[3] Rouanet, G. (1987) Maize. The Tropical Agriculturist Series.
(Rene Coste, Editor):Macmillan Education Publication Ltd.
London and Oxford, Pp 201 – 344
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
[4] Russel, S.P. (1970) Peanuts, Popcorn, Ice Cream, Candy and
Soda Pop and How They Began. Abingdon Press, New York, Pp
29 - 67
[5] Shigley, J.E. (2011) Mechanical Engineering Design (9 th
Edition) (pp 58 – 59, 504 -511)
[6] Woodside, D. (1980) : What makes Popcorn Pop? New York
Atheneum Pp 78 -100.
[7] www.popcorn.org/forTeachers;(en.www.wikipedia.org/popcorn)
Table 1: Machine performance at 12.66% moisture content on six different feed rates of corn
Feed
Quantity
Popping
Wt. of popped
Percentage of
Wt of un-
Percentage of
Diff in wt
Time lag
rate (g)
of oil (ml)
Time
corn (g)
popped corn
popped
un-popped corn
before and after
(mins)
(mins)
corn(g)
popping
50
8
2.75
45
90%
5
10%
Nil
2
100
16
3.00
90
90%
10
10%
Nil
-
150
24
3.25
130.5
87%
19.5
13%
Nil
-
200
32
4.0
170
85%
30
15%
Nil
-
250
40
4.5
200
80%
50
20%
Nil
-
300
48
5.0
225
75%
75
25%
Nil
-
1050
168
22.5
860.5
507
189.5
93
Total
175
28
3.75
143.42
84.5
31.58
15.5
Average
Table 2: Machine performance at 13.66% moisture content on six different feed rates of corn
Feed rate
Quantity
Popping
Wt. of
Percentage of
Wt of un-
Percentage of
Diff in wt
Time lag
(g)
of oil (ml)
Time
popped corn
popped corn
popped
un-popped corn
before and
(mins)
(mins)
(g)
corn(g)
after popping
50
8
2.3
45
90%
5
10%
Nil
2
100
16
2.5
90
90%
10
10%
Nil
-
150
24
2.75
135
90%
15
10%
Nil
-
200
32
3.66
170
85%
30
15%
Nil
-
250
40
5.3
200
80%
50
20%
Nil
-
300
48
5.5
200
66.7
100
33.3%
Nil
-
1050
168
22.01
840
501.72
210
98.28
Total
175
28
3.67
140
83.62
35
16.38
Average
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
Table 3: Machine performance at 14.66% moisture content on six different feed rates of corn
Feed
Quantity
Popping
Wt. of popped
Percentage of
Wt of un-
Percentage of
Diff in wt
Time lag
rate (g)
of oil (ml)
Time
corn (g)
popped corn
popped
un-popped corn
before and
(mins)
(mins)
corn(g)
after
popping
50
8
3.0
27
67.5%
13
32.5%
10
2
100
16
5.0
50
66.7%
25
33.3%
25
-
150
24
5.5
80
66.7%
40
33.3%
30
-
200
32
6.0
100
66.7%
50
33.3%
50
-
250
40
6.3
125
62.5%
75
37.5%
50
-
300
48
8.0
150
60%
100
40%
50
-
1050
168
33.8
532
390.12
303
209.88
215
Total
175
28
5.63
88.67
65.02
50.50
34.98
35.83
Average
Table 4: Analysis of Variance (ANOVA) for The Effect of Moisture Content (Mc) and Feed rate on the Popping Efficiency of Popcorn
making machine.
Source of variation
Degrees
of
Sum of squares
Mean square
Computed F
freedom
Moisture
(A)
2
11288.70
5644.35
31.50
Feedrate (B)
5
51711.07
10342.21
57.70
Error
10
1792.47
179.25
Total
17
64792.24
Content
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 9 - October 2015
Fig 1: Isometric View of Labeled Electrically Operated Popcorn Making Machine
Fig 2: Isometric View of Electrically Operated Popcorn Making Machine with Dimensions
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