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 American Journal of  
Food Science and Technology (AJFST)

Study on Some Engineering Properties of  Holeta Local Variety Garlic 
(Allium Sativum LAllium Sativum L.) .) Grown in Ethiopia

Abe Tullo1*

Volume 1 Issue 2, Year 2023
ISSN: 2834-0086 (Online)

DOI: https://doi.org/10.54536/ajfst.v1i2.1079
https://journals.e-palli.com/home/index.php/ajfst

Article Information ABSTRACT

Received: December 15, 2022

Accepted: December 29, 2022

Published: December 31, 2022

Garlic (Allium Sativum L.) is an important root vegetable that can be used as a spice in 
meals and has historically been used as a remedy for various ailments in Ethiopia. The 
physical properties of  the garlic bulbs and cloves were determined for use in the prototype 
design. The result showed that the equatorial diameter, polar diameter, thickness, geometric 
mean diameter, arithmetic mean diameter, sphericity, shape index, surface area, moisture 
content, hundred garlic bulb weight, bulk density, and angle of  repose of  the garlic bulbs 
were 45.89, 42.86, 30.43, 39.08 and 39.71 mm, 0.86, 1.34, 17.08 cm2, 66%, 2530 g, 596.70 
kg/m3, and 49.7o for garlic bulbs, respectively. Similarly, the result of  the width, length, thick-
ness, geometric mean diameter, arithmetic mean diameter, sphericity, shape index, surface 
area, hundred garlic cloves weight, bulk density, and angle of  repose of  the garlic bulbs were 
14.44, 31.02, 11.63, 17.15, and 20.07 mm, 0.57, 1.27, 4.06 cm2, 239.4 g, 468.4 kg/m3, and 
37.56o for garlic cloves, respectively. Therefore, these physical and mechanical properties of  
garlic bulbs and cloves were used in designing machine parts.

Keywords

Angle of  Repose, Bulk 
Density, Garlic, Physical 
Properties, Sphericity 

1 Oromia Agricultural Research Institute, Addis Ababa; Haramaya University, Haramaya, Ethiopia
* Corresponding author’s e-mail: abesokore@gmail.com

INTRODUCTION
Garlic (Allium sativum L.) belongs to the family Alliaceae 
and genus Allium and is a shallow root vegetable (Seifu 
et al., 2017). The Allium plant is the maximum essential 
vegetable plant used as a seasoning in maximum 
Ethiopian dishes. Among them, onion (Allium cepa 
L.) and garlic (Allium sativum L.) are acknowledged as 
“kitchen queens”, and are taken into consideration as one 
of  the maximum vital herbs for mass manufacturing in 
Ethiopia (Selvaraj et al., 2014). Garlic is the most used 
root vegetable after onions in Ethiopia. It has been used 
in many communities in Ethiopia as a flavoring agent 
in food and as a medicinal plant for various ailments 
(Addis and Abebaw, 2017), grown both during the main 
rainy season and under irrigated conditions (CSA, 2018). 
Garlic is processed into dehydrated products such as 
flakes, powders, pickles, canned goods, and bottles. 
Garlic products are sought after in the domestic market 
for catering and snack industries and are also exported 
to prominent markets to gain commercial value overseas 
(Channabasamma, 2014).
The physical properties of  garlic bulbs and cloves are 
essential for the design and development of  the separating 
device. The size and sphere of  the bulb determine the 
distance between the rubber rollers in the design of  the 
garlic clover. High bulk density affects structural loads 
(Channabasamma, 2014). Sajid et al. (2014) reported that 
the moisture content of  garlic (Allium sativum L.) was 
64.58%. Odebunmi et al. 2010 and Kimura et al. 2017 
also reported 65 and 58.6% moisture content in garlic, 
respectively. Masoumi et al. (2006) compared some 
physical properties of  two common types of  Iranian 
garlic cloves (white and pink), their study results showed 
that at different moisture levels ranging from 34.9% to 
56.7% w.b.

Channabasamma (2014) reported the dimensions of  the 
garlic bulb, such as the pole diameter; The diameter and 
thickness of  the equator are 61.25, 43.21, and 36.00 mm. 
Manjunatha et al. (2008) estimated the physical properties 
of  garlic with 40.50% moisture content on a wet basis 
namely shape compared with standard chart, diameter, 
length, width, and thickness in micrometers digital with 
0.01 mm accuracy. The length, width, and thickness 
of  shrimp are 1.92-2.91, 0.78-1.32, and 0.69-0.99 cm, 
respectively (Bahnasawy, 2007). Dress (2011) studied the 
physical properties of  garlic and cloves, for garlic bulbs: 
The length (L) ranged from 53.3 to 73.5 mm with an 
average value of  59.9 mm. The width (W) varies from 51.6 
to 67.2 mm with an average value of  58 mm. Thickness 
(T) varies from 39.6 to 51.5 mm with an average value of  
45.2 mm, for garlic cloves: Length (L) varies from 13.9 to 
36.6 mm with a price average value is 26.4 mm. The width 
(W) varies from 6 to 20 mm with an average value of  11.9 
mm. The thickness (T) varies from 4.1 to 13.5 mm with 
an average value of  8.5 mm. Bakhtiari and Ahmad (2015) 
found that the mean length, width, and thickness of  garlic 
cloves were 32.0, 21.8, and 20.9 mm, respectively.
The geometric and arithmetic mean diameters of  
garlic ranged from 2.53 to 4.93 and 2.53 to 5.02 cm, 
respectively, depending on the bulb size type (Bahnasawy, 
2007). Channabasamma (2014) and Rathinakumari et 
al. (2015) found that the geometric mean diameters of  
garlic bulbs and garlic cloves were 45.70 mm and 12.55 
mm, respectively. Dress (2011) studied some physical 
properties of  garlic bulbs and garlic cloves, for garlic 
bulbs: The diameter of  the arithmetic means ranged 
from 49.5 to 60.6 mm with an average value of  54 .4mm. 
The geometric mean diameter varies from 48.92 to 
59.31 mm with a mean of  53.85 mm, for garlic cloves: 
The arithmetic means diameter varies from 9.4 to 22.3 

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mm with an average value of  15.6 mm. The geometric 
mean diameter varies from 7.6 to 20.6 mm with a mean 
of  13.7 mm. Bakhtiari and Ahmad (2015) estimated the 
geometric and arithmetic mean diameters of  garlic cloves 
to be 24.4 mm and 24.9 mm, respectively.
The shape index is used to evaluate the shape of  garlic 
bulbs. It is very important in the design of  the sorting 
and grading machine, it is also used in the peeler. On 
the other hand, garlic bulbs are considered oval if  the 
shape index is ˃1.5; it is considered spherical if  the shape 
index is <1.5 (Bahnasawy, 2007 Channabasamma, 2014). 
The shape index ranged from 1.36 to 1.5 for garlic bulbs 
reported by Bahnasawy (2007) and 0.45 for garlic cloves 
by Channabasamma (2014). According to Rathinakumari 
et al. (2015), the bulb shape index of  garlic is 0.74. One 
hundred garlic bulbs and clove’s weight are important 
in the design of  sheds, seed containers, and the capacity 
of  transport tools (Bahnasawy, 2007). The mean weight 
of  cloves (g) was recorded as the mean weight of  ten 
randomly sampled cloves after drying (Tadesse, 2015). 
Channabasamma (2014) found that the weights of  one 
hundred garlic bulbs and garlic cloves ranged from 2270.7 
to 4849.0 and 260.0 and 392 g, respectively. Dress (2011) 
reported some physical properties of  garlic bulbs and 
garlic cloves, for garlic bulbs: weight from 45.3 to 87.6 g 
with a mean value of  62.5 g, and for cloves garlic: weight 
from 0.24 to 5.2 g with a mean value of  1.49 g. Bakhtiari 
and Ahmad (2015) estimated the average thousand-grain 
mass to be 6783.0–8159.3 g. Rathinakumari et al. (2015) 
estimated some physical, mechanical, and aerodynamic 
properties of  garlic at 60.92% moisture content on a dry 
basis, with a sphericity of  0.51. Dress (2011) has studied 
some physical properties of  garlic bulbs and garlic cloves, 
the mean spherical value for garlic bulbs is 0.9, and for 
garlic cloves, the mean spherical value is 0.53. According 
to Channabasamma (2014), the bulb sphere of  garlic 
is 0.74. Dress (2011) studied some physical properties 
of  garlic bulbs and garlic cloves. For garlic bulbs, the 
surface ranged from 75.2-110.5 cm2 with an average value 
of  91.4 cm2 while for garlic cloves, the surface ranged 
from 1.8 to 13.3 cm2 with an average value is 6.1 cm2. 
The surface of  garlic and clove bulbs ranges from 53.31 
to 136.4 cm2 (Bahnasawy, 2007). Bakhtiari and Ahmad 
(2015) estimated that the average surface area of  garlic 
cloves increased from 1718.3 to 2029.1 mm2 (17.18 to 
20.29 cm2).
Rathinakumari et al. (2015) found the garlic bulb and 
clove’s bulk densities were 453.5 kg/m3 and 424.94 
kg/m3, respectively. Dress (2011) studied the physical 
properties of  garlic bulbs and cloves. For garlic bulbs, 
bulk densities ranged from 0.4 to 0.55 g/cm3, with an 
average value of  0.45 g/cm3. On the other hand, the bulk 
density of  one garlic clove averaged 0.57 g/cm3, ranging 
from 0.45 to 0.61 g/cm3. Bakhtiari and Ahmad (2015) 
calculated that the average bulk density of  garlic cloves 
increased from 476.3 to 567.4 kg/m3. Masoumi et al. 
(2006) reported 468.8 to 612.8, and 510.2 to 672 kg/m3 

for white and pink garlic cloves, respectively. The angle 

of  repose of  garlic bulbs reported by Bahnasawy (2007) 
and Dress (2011) was 41.52 to 45.04o and 26 to 30.5o, 
respectively. Dress (2011) also reported that the angle 
of  repose of  garlic cloves was 39.5–41° (average 38.7°). 
Manjunatha et al. (2008) studied some of  the physical and 
mechanical properties of  garlic bulbs in the moisture 
content range of  23.05 to 40.50% (w.b.), where the angle 
of  repose increased from 25.53° to 37.50°, respectively. 
In a separate study, according to Channabasamma (2014), 
values for garlic bulbs and cloves ranged from 48.64-
57.99° and 37-40° respectively.
The farmers of  Arsi and West Arsi Zones of  Oromia 
Reginal State requested Asella Agricultural Engineering 
Research Center for a machine to separate cloves from 
garlic bulbs for planting due to the tedious and time-
consuming the traditional method of  garlic separation 
from a compound garlic bulb by hand, which results in 
hand injuries. There is a machine designed and developed 
for separating cloves from a garlic bulb in India and 
China. However, Those machines were very expensive 
and, designed and constructed for garlic varieties available 
in India and China. Therefore, Those machines need 
modification and additional costs due to big differences 
in the engineering properties of  Ethiopian garlic varieties 
from those countries’ garlic varieties. Considering the 
problems mentioned above, to design and construct a 
low-cost and effective garlic bulb separating machine 
from row material available in Ethiopia, studying the 
engineering properties of  the garlic bulb and clove is very 
important with the objective of  determining the physical 
and mechanical properties of  garlic grown in Ethiopia. 

MATERIALS AND METHODS
Experimental Location 
The study was conducted at the Asella Agricultural 
Engineering Research Center and the Kulumsa 
Agricultural Research Center. Determination of  some 
engineering properties of  the garlic bulbs and cloves 
was carried out at the Asella Agricultural Engineering 
Research Center (AAERC). The moisture content of  
garlic was analyzed at the Kulumsa Agricultural Research 
Center (KARC).

Experimental Materials 
A 50 kg garlic bulb of  Holeta local variety was obtained 
from Holeta local market. The study samples were packed 
in polyethylene plastic bags, transported to Kulumsa 
Agricultural Research Center (KARC), and stored at 
room temperature (25oC) for conduction of  moisture 
content and engineering properties of  garlic. 

Determination of  the Physical Properties of  Garlic 
Bulbs and Cloves
Moisture content of  garlic 
Fifteen kilograms of  garlic cloves were randomly obtained 
from the bulk samples, cleaned manually, and removed 
of  all foreign matter such as dust, dirt, stones, chaff, and 
damaged cloves.

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The moisture content of  garlic bulbs and cloves was 
determined by the convection method proposed by 
Madamba et al. (1994). Three samples of  15g each were 
weighed and placed in the oven. The sample was heated 
at 100±0.5 °C until a constant weight was reached, then 
the sample was removed and cooled in a desiccator for 
weighing on an electronic balance. Moisture content 
was calculated according to the following formula and 
expressed as a percentage (Channabasamma, 2014).

Where Mcdb = moisture content dry base, 
Wi = initial weight of  the sample, 
Wf  = final weight of  the sample.

Linear dimensions
100 garlic bulbs and cloves were randomly selected and 
their linear dimensions were measured to an accuracy of  
± 0.01 mm using a digital caliper (Model CD6BSMitutoyo 
Corporation, Japan). For garlic bulbs, equatorial diameter 
(De), pole diameter (Dp), and thickness (T) were 
measured. For garlic cloves, the main dimensions of  
length (l), width (b), and thickness (t) were measured 
(Bahnasawy, 2007; Channabasamma, 2014).

Geometric mean diameter
The geometric mean diameter (Dg) of  the garlic bulbs 
and cloves was calculated using equation 22 (Bahnasawy, 
2007; Channabasamma, 2014): 

Where; 
Dg = geometric mean diameter, mm, 
De = equatorial diameter, mm,
Dp = polar diameter, mm; 
T = thickness, mm.

Arithmetic mean diameter
The arithmetic means diameter (Dam) of  the garlic bulbs 
and cloves was calculated using equation 23 (Bahnasawy, 
2007; Channabasamma, 2014):

Where; 
Dam = arithmetic mean diameter, mm.
De = equatorial diameter, mm, 
Dp = polar diameter, mm; 
T = thickness, mm.

Shape index 
The shape was calculated using equation 24 (Bahnasawy, 
2007; Channabasamma, 2014): 

Where; 
De = equatorial diameter, mm,
Dp = polar diameter, mm,
T = thickness, mm.

Sphericity
The sphericity () of  the cloves was calculated using 
equation 25 (Bahnasawy, 2007; Channabasamma, 2014):
  
                                                                                                                      
Where; 
Dg = geometric mean diameter, mm
l = length, mm,
b = width, mm, 
t = thickness, mm.

Surface Area
The surface area of  the bulk sample was found by analogy 
with a sphere of  the same geometric mean diameter, 
using the following relationship (Dress, 2011):
              S =  × Dg 2         (6) 
Where; 
S = surface area in cm2, 
Dg = geometric mean diameter in cm.

Bulk density
Samples of  bulbs and garlic cloves were poured to the 
upper level into containers of  known volume. The excess 
sample was removed to keep the top surface perfectly flat 
and even. Make sure the bulbs and garlic cloves were not 
broken in any way. The sample inside the vessel was then 
weighed using an electronic balance. Bulk density was the 
ratio of  the mass of  the sample to the volume of  the 
container (Mohsenin, 1986). This procedure was repeated 
5 times (Channabasamma, 2014).
             ρb=Ms/Vc               (7) 
Where; 
ρb = bulk density, kg/m3, 
Ms = Weight of  sample in container, (kg), 
Vc = Volume of  the container, (m3).

One hundred garlic bulbs and cloves weight
100 garlic bulbs and 100 garlic cloves were randomly 
selected and weighed on an electronic scale (model 
PS200/2000/C/2 RADWAG, Poland) to an accuracy 
of  ±0.001 g and this procedure was repeated 5 times 
(Channabasamma, 2014).

Angle of  repose
The dynamic angle of  the repose of  bulbs and cloves 
was measured by the emptying method. A metal vessel 
125 mm long, 125 mm wide, and 200 mm high was used 
to determine the dynamic angle of  repose of  the bulb/
cloves. A detachable front panel 200mm high and 125 
mm wide was used to separate the material laterally. 
After filling and lining up the garlic sets in the container, 
I quickly pulled the front panel up and pushed it up so 
the garlic bulbs/garlic cloves poured out. Garlic bulbs/
cloves slide out of  the container through the open side, 
forming an inclined surface. After stabilizing the slope 
of  the material, the angle of  repose was calculated from 
the height and length of  the garlic sample remaining in 
the box. This procedure was repeated three times with 

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different samples and average values were calculated 
(Channabasamma, 2014). 

Where; 
0 =  angle of  repose in degree, 
H = height of  the sample in mm, 
L = length of  the sample in mm.

Table 1: Dimensional properties of  garlic bulbs and cloves at 66% m.c.d.b
Variables De(mm) Dp(mm) T(mm) Dg(mm) Dam(mm)
Bulb 45.89±7.97 42.86 ± 7.35 30.43 ± 5.62 39.08 ± 6.42 39.71 ± 6.44
Cloves 14.44 ± 3.06 31.02 ± 4.21 11.63 ± 3.31 17.15 ± 2.89 20.07 ± 6.48
Where; De = equatorial diameter, Dp = polar diameter, T = thickness, Dg = geometric mean diameter, Dam = arithmetic mean 
diameter; all values are means of  triplicates ± standard deviation

Figure 1: Determination of  an angle of  repose of  garlic bulbs/cloves

Data Analysis
All experiments were performed in triplicate. The 
collected data were analyzed by analysis of  variance 
(ANOVA) using statistical software R (version 3.4.3, 
2017). The results are presented using the mean value and 
standard deviation (mean ± standard deviation).

RESULTS AND DISCUSSIONS
The design of  garlic bulb processing unit operation 
is designed based on the physical properties of  garlic 
bulbs and cloves, such as pole and equatorial diameter, 
length, width, thickness, average diameter, geometric 
mean diameter, sphericity, weight, bulk density, and angle 
of  repose of  garlic bulbs and cloves (Channabasamma, 
2014). The engineering properties of  garlic bulbs 
and cloves, namely the dimensions, and physical and 
mechanical properties of  garlic bulbs and cloves, are 
discussed in the following sections. 

Dimensional properties of  garlic bulbs and cloves
Records of  dimensional characteristics of  the garlic 
bulb and clove samples such as equatorial diameter, 

polar diameter, thickness, geometric mean diameter, and 
average diameter are presented in Table.3.1. Accordingly, 
the values were 45.89, 42.86, and 30.43 mm for the first 
three of  the parameters, respectively. Similarly, the values 
for the remaining two parameters indicated in the list 
are 39.08 and 39.71 mm, respectively. Channabasamma 
(2014) reported garlic bulb size such as pole diameter, 
equatorial diameter, and thickness was 61.25, 43.21, and 
36.00 mm, respectively, which is higher than the values 
obtained in this study. The garlic clove sizes such as 
width, length, thickness, geometric mean diameter, and 
mean diameter were 14.44, 31.02, 11.63, 17.15, and 20.07 
mm, respectively. Other size records such as length, 
width, and thickness were shown as 27.30, 10.18, and 7.42 
mm as reported by Channabasamma (2014), which are 
lower than the results obtained from the present finding. 
Dress (2011) reported the dimensions of  garlic bulbs as 
59.90 mm in length, 58.00 mm in width, and 45.20 mm in 
thickness, which is higher than the result obtained in this 
work, and for the garlic cloves, values were 26.4 mm in 
length, 11.9 mm in width, and 8.5 mm in thickness, which 
again is lower than the results obtained in this work. 

Bakhtiari and Ahmad (2015) also found the mean length, 
width, and thickness of  garlic cloves were 32.0, 21.8, and 
20.9 mm, respectively, which are higher than the results 
of  the present work. However, values of  dimensions 
of  the hundred garlic cloves were comparable with the 
values of  1.92 to 2.91, 0.78 to 1.32, and 0.69 to 0.99 cm 

of  length, width, and thickness, respectively, of  fifteen 
cloves, which were reported by Bahnasawy (2007). The 
spacing between the rollers was selected based on these 
sizes (Channabasamma, 2014).
The geometric average diameters of  100 bulbs and garlic 
cloves were 39.08 mm and 17.15 mm, respectively. These 

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values are lower than the 45.70 mm geometric mean 
diameter of  garlic bulbs and higher than the 12.55 mm 
geometric mean diameter of  garlic cloves reported by 
Channabasamma (2014) and Rathinakumari et al. (2015). 
Bakhtiari and Ahmad (2015) also estimated the geometric 
average diameter of  garlic cloves to be 24.40 mm, which 
is higher than the current estimate. The geometric average 
diameters of  the garlic bulbs and cloves determined in 
this work showed lower values than the geometric mean 
diameter of  garlic bulbs which ranged from 48.92 to 
59.31 mm and of  the cloves, which ranged from 7.6 to 
20.60 mm as reported by Dress (2011). However, the 
geometric mean diameter of  values was comparable with 
those (2.53 to 4.93 cm) of  fifteen Egyptian garlic varieties 
reported by Bahnasawy (2007). 

The mean values of  the arithmetic average diameters of  
the one hundred garlic bulbs and cloves were 39.71 mm 
and 20.07 mm, respectively. These values were lower than 
the corresponding values of  bulbs, which ranged from 
49.5 to 60.6 mm (with a mean value of  54.4 mm) as 
reported by Dress (2011). However, the arithmetic means 
diameter (20.07 mm) of  the one hundred cloves was 
within the range of  9.4 to 22.30 mm (with the mean value 
of  15.6 mm) recorded by the same author. The arithmetic 
means diameter values recorded for the cloves in this 
work were less than the 24.90 mm for cloves reported by 
Bakhtiari and Ahmad (2015). On the other hand, these 
values of  the garlic cloves were comparable with the 2.53 
to 5.02 cm range reported for fifteen Egyptian garlic 
varieties (Bahnasawy, 2007). 

Figure 2: Dimensional measurement for garlic bulbs and 
cloves  

Figure 3: Moisture content test of  garlic

Physical characteristics of  garlic bulbs and cloves  
The surface area, sphericity, and shape index values for 
one hundred bulbs and cloves are shown in Table 2. The 
surface areas of  bulbs and garlic cloves were 17.08 cm2 and 
4.06 cm2, respectively. These values are less than 75.2 to 
110.5 cm2 (with a mean value of  91.4 cm2) and 53.31 to 

136.4 cm2 of  garlic bulbs reported by Dress (2011) and 
Bahnasawy (2007), respectively. However, the values for 
garlic cloves were in agreement with the values of  1.8 to 
13.3 cm2 reported by Dress (2011). The values for the cloves 
(17.08 cm2), were found to be close to the 17.18 to 20.29 cm2 

of  those reported by Bakhtiari and Ahmad (2015).

Table 2: Physical properties of  garlic bulbs and cloves at 66% m.c.d.b
Variables Wt of  100 Pieces (g) BD (kg/m3) AR(0) SA(cm2) Φ SI
Bulbs 2530 ± 77.13 596.7 ± 36.67 49.7 ± 2.06 17.08 ± 6.94 0.86  ± 0.03 1.34 ± 0.23
Cloves 239.4 ± 9.07 468.4 ± 20.94 37.56 ± 1.89 4.06 ± 1.17 0.57 ± 0.07 1.27 ± 0.12
Where; Wt = weight of  100 garlic bulb and clove, BD = bulk density, AR = angle of  repose, SA = surface area, ϕ = sphericity, 
SI = shape index; all values are means of  triplicates ± standard deviation

The sphericity of  garlic bulbs and cloves were 0.86 and 
0.57, respectively. These values are comparable with the 
0.9 and 0.53 of  the garlic bulbs and cloves, respectively, 
reported by Dress (2011) and with the 0.559 of  garlic 
cloves reported by Hacıseferoğulları (2005). These values 
were greater than 0.74 for garlic bulbs and 0.51 for 
the cloves, as reported by Channabasamma (2014) and 
Rathinakumari et al. (2015).
The shape index was 1.34 and 1.27 for bulbs and cloves, 
respectively. The bulb and clove shape index values 
were higher than 0.74 for garlic bulbs reported by 
Rathinakumari et al. (2015) and 0.45 for garlic cloves by 
Channabasamma (2014), but less than the 1.36 to 1.5 for 

garlic bulbs reported by Bahnasawy (2007). Garlic bulbs 
are considered spherical because the garlic bulb shape 
index is <1.5 (Channabasamma, 2014). Therefore, the 
current result showed the shapes of  both garlic bulbs and 
cloves of  the studied Holeta variety are spherical. The 
shapes of  garlic bulbs and cloves are very important in 
selecting the clearance between rollers.
Physical properties of  garlic bulbs and cloves such as 
weight of  one hundred pieces, moisture content, bulk 
density, and angle of  repose are presented in Table 3.2. 
The weights of  one hundred pieces were 2530 and 239.4 
g for garlic bulbs and cloves, respectively. These values 
were greater than the 45.3 to 87.6 g (with the mean value 

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of  62.5 g) of  garlic bulbs and 0.24 to 5.2 g (with the mean 
value of  1.49 g) of  the cloves reported by Dress (2011) 
and less than the 260 to 392 g of  the garlic cloves reported 
by Channabasamma (2014) and the 6783.0 to 8159.3g 
for one thousand pieces or 678.3 to 815.93 g for one 
hundred pieces of  garlic cloves by Bakhtiari and Ahmad 
(2015). The weight of  one hundred pieces determined in 
this work was comparable with the weight of  a similar 
number of  cloves reported by Channabasamma (2014), 
which ranged from 2270.7 to 4849g. These characteristics 
are used in the design of  the machine hopper capacity.  
The moisture contents of  garlic cloves in this work were 
66% db. Kimura et al. (2017) and Channabasamma (2014) 
reported the moisture contents of  garlic of  58.6% and 
59.36%, respectively, which are lower than the present 
finding. However, Odebunmi et al. (2010) and Sajid et 
al. (2014) reported moisture content of  65 and 64.58%, 
respectively, which are relatively close to the result 
obtained in this work.   
The bulk densities recorded in this study were 596.70 and 
468.40 kg/m3 for garlic bulbs and cloves, respectively. 
These values were greater than the 453.50 kg/m3 and 
424.94 kg/m3 reported for bulbs and cloves, respectively 
(Rathinakumari et al., 2015). The values were also 
greater than the 453.5 and 424.94 kg/m3 reported by 
Channabasamma (2014) for garlic bulbs and cloves, 
respectively. The values were in agreement with the 476.3 
to 567.4 kg/m3 reported by Bakhtiari and Ahmad (2015) 
for garlic cloves. The values were less than the 468.8 to 
612.8, and 510.2 to 672 kg/m3 reported by Masoumi et al. 
(2006) for white and pink cloves of  garlic, respectively.  
The angle of  repose of  bulb and cloves of  broken garlic 
were 49.7 and 37.56o, respectively. The results obtained 
in this work were greater than the values reported by 
Bahnasawy (2007) and Dress (2011), which ranged from 
41.52 to 45.04o and 26 to 30.5o (with a mean value 
of  28.5o) for garlic bulbs, respectively. Dress (2011) 
also reported 39.5 to 41o (with a mean value of  38.7o) 
for garlic cloves which are more close to the current 
finding. However, the findings for bulbs and cloves 
were comparable to the 48.64 – 57.99º and 37 – 40º, 
respectively, reported by Channabasamma (2014). These 
results were used to determine the inclination of  the feed 
hopper and the accommodation chute of  the garlic bulb 
separator. The feed hopper and collection chute were 
fixed at an angle of  77.27 and 45° respectively, which was 
greater than the angle of  repose of  the bulb and clove of  
broken garlic. This made the cloves easier to pour.

CONCLUSIONS AND RECOMMENDATIONS
Garlic (Allium sativum L.) is the most widely used root 
vegetable after onions and is mainly produced as a 
seasoning for food and has medicinal value for various 
diseases in Ethiopia. This research work has concluded 
that the engineering properties of  Holeta’s local variety 
of  garlic bulbs and cloves were determined to generate 
data that was used for designing the prototype machine. 
The dimensional properties of  garlic bulbs, based on 100 

pieces sample, were 45.89 mm equatorial diameter, 42.86 
mm polar diameter, and thickness of  30.43 mm. Similarly, 
the dimensional properties of  the cloves were 31.02 mm 
in length, 14.44 mm in width, and 11.63 mm in thickness.  
Other physical properties of  garlic bulbs indicated average 
values of  17.08 cm2 for surface area, 0.86 for sphericity, 
2530 g, as the weight of  hundred bulbs, moisture content 
of  66%, bulk density of  596.7 kg/m3, angle of  repose 
of  49.700, and shape index of  1.34. Likewise, the cloves 
exhibited an average surface area of  4.06 cm2, sphericity 
value of  0.57, 239.4 g weight of  hundred clove pieces, 
468.4 kg/m3 bulk density, 37.560 the angle of  repose, and 
1.27 shape index as physical and mechanical properties of  
garlic cloves. These physical and mechanical properties 
were used in designing machine parts. The studies of  
engineering properties of  other garlic varieties should be 
considered in the future.

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