Research Journal of Applied Sciences, Engineering and Technology 2(7): 669-672, 2010
ISSN: 2040-7467
© M axwell Scientific Organization, 2010
Submitted Date: September 18, 2010
Accepted Date: October 06, 2010
Published Date: October 25, 2010
Determination of Some Physical Properties of Nutmeg (Myristica fragrans) Seeds
1
M.H.R .O. A bdu llah, 2 P.E. Ch’ng and 3 T.H . Lim
1
Department of Applied Sciences,
2
Department of Com puter and M athematical Sciences,
3
Academy of Language Studies,
Universiti T eknolog i MAR A (U iTM ), 135 00 P ermatang Pauh, P enang, M alaysia
Abstract: Some physical properties of nutmeg (Myristica fragrans) seeds were determined at moisture content
of 81.85% wet basis. The mean length, width and thickness of the seeds were 23.09, 21.20 and 18.64 mm,
respectively. The average value for geometric mean diameter, sphericity, mass, surface area, volume, true
density, bulk density and porosity were 20.88 mm, 90.45%, 5.270 g, 1388.85 mm2 , 5860.00 mm 3 , 1199.18
kg/m 3 , 686.60 kg /m 3 and 41.83%, respectively. The coefficient of static friction on four types of structural
surface w as found to be ranging from 0.206 (galvanized steel sheet) to 0.376 (rub ber).
Key w ords: Myristica fragrans, nutmeg seed, physical properties
INTRODUCTION
Nutmeg (Myristica fragrans) is a nutlike fruit
popularly cultivated and harvested for its spice. A nutmeg
tree on average can grow up to 12 m and begins to bear
fruits after about six years of planting. Upon ripening, the
nutmeg fruit will turn yellow and split open to expose a
shining dark b rown seed that is surrounded by a reddish
mac e.
Nutmeg seed ha s many ap plication s particu larly in
culinary, pharmaceutical and cosmetic industries. The
nutmeg seed usually is processed to extract its oil. About
30-55% of the seed consists of oils an d 45-60% consists
of solid matter including cellulose materials. There are
two types of oils extracted from the nutm eg seed, namely
the "essential oil" which accounts for 5-15% of the seed
and the "fixed oil" or sometimes called the "nutmeg
butter" which accoun ts for 24-40% of the seed (Forrest
and Heacoc k, 197 2). Due to its arom a, the essential oil
extracted from the nutmeg seed has been used as a natural
flavouring and as a perfume in the cosmetic industries
(W inter, 1989). The oil has been used as a flavouring
agent to replace gro und nutm eg to avoid leaving particles
in foods and beverages. The oil has also been employed
as a flavour in dental creams in combination with
pepperm int, methyl salicylate and cloves (Poucher and
Jouhar, 1991). In the pharmaceutical industry, nutmeg has
been used as a form of medicine to treat man y illnesses
ranging from those affecting the nervous system to the
digestive system (W eil, 1965).
W orld production of nutm egs is estimated to average
between 10,000 and 12,000 tons per year with annual
world demand estimated at 9,700 tons (ITC, 2003) while
the production of mace is estimated at 1,500 to 2,000 tons.
The major producers of nutmeg are Indonesia and
Grenada which dom inate production and ex ports of both
products with a world market of 75 and 20%,
respectively. Other cou tries that supply nutmeg to the
world market include India, Malaysia, Papua New G uinea
and Sri Lanka, and other Carib bean coun tries. The main
importers are the European Community, the United
States, Japan and India.
Physical properties such as size, shape, mass, surface
area, volum e, density, ect. are essential information in the
design of equipment for handling, processing and storing
of the nutmeg seeds. In recent years, physical and
mechanical properties of seeds have been reported by
many researchers. The physical properties have been
studied for various types of se eds, such as locust bean
seed (Ogu njimi et al., 2002), quinoa seeds (Vilche
et al., 2003), amaranth seeds (Abalone et al., 2004), caper
seed (Dursun and D ursun, 2005), sweet corn seed
(Bulent et al., 2006), cucurbit seeds (Milani et al., 2007),
jatropha seed (Garnayak et al., 2008), roselle seeds
(Sánchez-Mendoza et al., 2008), chia seeds (Ixtaina
et al., 2008), fennel seed (Ahmadi and Mollazade, 2009)
and arigo se eds (Da vies, 2010).
Currently the harvesting and processing of nutmeg
seeds in Malaysia are done m anually. The operations are
slow and labou r intensive. The aim of this wo rk was to
determine some physical properties of nutmeg seeds
which could be useful in facilitating the design of
machines to handle and process the seeds.
MATERIALS AND METHODS
Fresh nutm eg fruits were procured from a wet market
in Bukit Mertajam town located in Penang state, M alaysia
Corresponding Author: M.H.R.O. Abdullah, Department of Applied Sciences, Universiti Teknologi MARA (UiTM), 13500
Permatang Pauh, Penang, Malaysia
669
Res. J. Appl. Sci. Eng. Technol., 2(7): 669-672, 2010
where m = mass of individual seed (kg) and V = volume
of individual seed (m 3 ).
The bulk density (D B ) was determined using the
method described by F raser et al. (1978) by filling an
emp ty 250 mL cylindrical container with nutmeg seeds.
The seeds were poured from a constant height, striking off
the top level and weighing. Bulk density was calculated
as:
on 21st July, 2010. Upo n arrival, the fruits were processed
man ually to detach the seeds from their shells and mace.
Foreign materials, broken and immature seeds w ere
removed from the sample. The physical properties of the
seeds were determined at the temperature and relative
hum idity of 24ºC and 6 3% , respectively.
Moisture content of the seeds was determined using
ASAE standard m ethod (A SAE , 1993). The seeds w ere
dried in an air ventilated oven at 90ºC for 48 h. Mo isture
content (wet basis) was calculated as:
(6)
(1)
where,m B = mass of seeds (kg) and V B = volume of
container (m 3 ).
Porosity (P) of the seed was determined as
(Thom pson an d Isaac, 196 7):
whe re MC(%) is the m oisture content, m i is the
initial mass and m d is the final mass of the se ed.
The length (L), width (W) and thickness (T) of 100
seeds were m easured using a digital vernier calliper
(Model CD-6BS-M itutoyo Corporation, Jap an) w ith
resolution of 0.01 mm. The measurements for each
dimension were replicated 100 times.
Geometric mean diameter (D) was found using the
following equation (M ohsenin, 1970):
(7)
The coefficient of static friction (: s ) was tested on
plywood, galvanized steel sheet, rubber and glass
surfaces. Seed was placed on the surface and raised
gradually by screw until the seed b egin to slide. T he an gle
that the inclined surface makes with the horizontal when
sliding begins w as measured. The coefficient of static
friction was calculated using:
(2)
Sphericity (S) of the seed was calculated as (Mohsenin,
1970):
(8)
(3)
where, 2 = angle that the incline makes with the
horizontal when sliding begins
The mass of 100 individual seeds was measured
using an electronic balance (Model PS200/2000/C/2RADWAG, Poland) with accuracy of 0.001 g. The
measurements w ere replicated 100 times.
Surface area, (A) was calculated using the formula
given by McCabe et al. (1986):
RESULTS AND DISCUSSION
The results of some of the physical properties of the
nutmeg seeds measured in this study were shown in Tab le
1. The leng th, width and thickness of the se eds w ere
found to be in the range of 17.86-29.52, 16.45-27.51 and
13.86-23.81 mm, respectively. The calculated geom etric
mean diameter ranges from 16 .58 to 26.59 mm with mean
value of 20.88 m m. The mean sphericity of the nutmeg
seeds was 90.45% while the mean mass of the seeds was
5.270 g. The average surface area was found to be
1388.85 mm 2 . The mean volume determined for 10 seeds
was 5860.00 mm 3 . True density and bulk density of the
seeds were 119 9.18 and 6 86.60 kg/m 3 , respectively. The
avera ge po rosity of the nutmeg seeds wa s 41.83% .
The coefficient of static friction of nutmeg seeds
against four types of structural surface was determined.
The results were indicated in Table 2 . It was found that
the rubber surface had the highest coefficient of static
friction followed by plywood, glass and galvanized steel
(4)
Volume (V) for 10 individual seeds was determined
using water displacement method (Dutta et al., 1988). The
seeds were weighed and coated with table glue and
allowed to dry in order to prevent water absorption. The
seed was low ered into a measuring cylinder containing
water such that the seed did not float during immersion in
water. The weight of water displaced by the seed was
recorded. The ratio of mass to volume of the seed was
treated as true density (D T ):
(5)
670
Res. J. Appl. Sci. Eng. Technol., 2(7): 669-672, 2010
Table 1: Some physical properties of nutmeg seeds
Physical properties
Unit of
measurement
M ois ture co nte nt (w .b.)
Length
Width
Thickness
G e om e tr ic m ea n d ia m et er (G M D )
Sp heric ity
Ma ss
Surface area
Volume
Tru e de nsity
Bu lk de nsity
Po rosity
%
mm
mm
mm
mm
%
g
mm 2
mm 3
kg/m 3
kg/m 3
%
No. of
observation
Mean
value
Minimum
value
Maximum
value
S .D .
5
100
100
100
100
100
100
81.85
23.09
21.20
18.64
20.88
90.45
5.270
1388.85
5860.00
1199.18
686.60
41.83
77.11
17.86
16.45
13.86
16.58
77.09
2.623
863.38
3400.00
1058.33
622.99
35.10
85.10
29.52
27.51
23.81
26.59
98.80
10.421
2220.94
8000.00
1685.88
729.59
60.67
3.08
2.68
2.49
2.65
2.51
3.60
1.852
331.76
1735.38
178.77
37.65
7.50
Minimum
value
0.194
0.158
0.213
0.176
Maximum
value
0.404
0.287
0.488
0.344
S .D .
100
10
10
10
10
Table 2: Coefficient of static friction of nutmeg seeds on four types of structural surface
Unit of
No. of
Mean
Coefficient of static friction on
measurement
observation
value
Plywood
25
0.328
Galvanized steel sheet
25
0.206
Rubber
25
0.376
Glass
25
0.264
W
2
sheet. This property is of paramount importance in
determining the steepness of the storage container, hopper
or any other loading and unloading device (Davies, 2010).
DB
DT
:S
CONCLUSION
The average m oisture content (wet basis) of the
nutmeg seeds determ ined in this study was 81.85% . The
mean length, width and thickness of the seeds were 23.09,
21.20 and 18.64 mm, respectively. The average value for
geometric mean diameter, sphericity, mass, surface area,
volume, true density, bulk density an d porosity w ere
20.88 mm, 90.45%, 5.270 g, 1388.85 mm 2 , 5860.00 mm3 ,
1199.18 kg/m 3 , 686.6 0 kg/m 3 and 41.83%, respectively.
The coefficient of static friction on four types of structural
surface was found to be vary from 0.206 (galvanized steel
sheet) to 0.376 (rubber). The technica l data obtained in
this study may be useful in the design of machine for
handling and processing of the nutmeg seeds.
0.046
0.032
0.060
0.041
Width of seed, mm
Angle that the incline makes with the horizontal
when sliding begins
Bulk den sity, kg/m 3
True density, kg/m 3
Coefficient of static friction
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NOTATION
Surface area of seed, mm 2
Geometric mean diameter, mm
Length of seed, mm
Mass of individual seed, kg
Mass of seeds in the determ ination of bulk
density, kg
mi
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md
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VB
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