This presentation shows the different engineering as well as physical properties of pea seed (Pisum Sativum). All the properties are evaluated and how it has been carried out with the help of different formulae and instruments is clearly described.

1. PHYSICAL PROPERTIES OF PEA SEED (Pisum sativum)
PRESENTED BY
SIDHARTHA SHANKAR BARAL
REGD. NO – 04-3282-2017
M.TECH (FMPE) FIRST YEAR

2. CONTENTS
INTRODUCTION
OBJECTIVE
MATERIALS AND METHODS
RESULTS AND DISCUSSION
CONCLUSION

3. INTRODUCTION
Pea (Pisum sativum) is one of the most common food plants in
Turkey grown for fresh consumption and raw material of canned
food industry.
Green pea conatins 6.7% protein, 0.5% oil and 13.9%
carbohydrates (Sehirali, 1988).
Pea is grown on 1450 ha areas in Turkey with a production rate
of 4000 t (SIS, 2002).
The physical properties of pea seeds are essential for the design
of equipment and facilities for the harvesting, handling,
conveying, separation, drying, aeration, storing and processing.

4. OBJECTIVE
To investigate some moisture-dependent physical properties
of pea seed namely, linear dimensions, sphericity, thousand
seed mass, projected area, bulk density, true density,
porosity, terminal velocity and static coefficient of friction
against different surfaces.

5. MATERIALS AND METHODS
 Dry pea seeds were taken for experimental purpose and foreign
matters were removed manually.
 Initial moisture content of the seeds was determined by oven drying
at 105 ± 1°C for 24 hours (Suthar and Das, 1996).
 Initial moisture content of the seeds was 10.06% d.b.
 The samples of the desired moisture contents were prepared by
adding the amount of distilled water as calculated from the
following relation (Sacilik, Ozturk and Keskin, 2003).
Q=
𝑊𝑖
(𝑀𝑓−𝑀𝑖
)
(100 −𝑀 𝑓
)
 The samples were then poured into separate polyethylene bags and
the bags sealed tightly.

6.  The samples were kept at 5°C in a refrigerator for a week to enable
the moisture to distribute uniformly.
 Before performing a test, the required quantity of the seed was taken
out of the refrigerator and allowed to warm up to the room
temperature for about 2 hours.
 The moisture content of the pea seed should be in the range from
10% to 16% for long storage period.
 To determine the average size of the seed, 100 seeds were picked
randomly and their linear dimensions such as length L, width W and
thickness T were measured using a micrometer.

7.  The one thousand seed mass was determined by means of an
electronic balance.
 The projected area of a seed was measured by a scanner connected
to a special computer (Ozarslan, 2002).
 The bulk density of the pea seed was determined using the
standard test weight procedure (Singh and Gowsami, 1996).
 The true density of the seed was determined using the toluene
displacement method (Sacilik, Ozturk and Keskin, 2003).

8.  The porosity was calculated using the relationship given by
Mohsenin(1970):
𝑃𝑓 = (1 − 𝑝 𝑏
𝑝𝑡
) ×100
where: 𝑃 𝑓 is the porosity in %, 𝑝 𝑏 is the bulk density in kg/m3 &
𝑝𝑡 𝑖𝑠 𝑡ℎ𝑒 true density in kg/m3.
 The terminal velocity of seeds was measured using a cylindrical
air column (Joshi, Das and Mukherjee, 1993; Yalcin and Ozarslan,
2004). The air velocity was measured by a hot wire anemometer.
 The static coefficient of friction of pea seed against 4 different
structural materials, namely rubber, aluminium, stainless steel and
galvanized iron was determined. The coefficient of friction was
calculated from the equation (Singh & Gowsami, 1996; Surthar &
Das, 1996):
μ = tan α
where μ = coefficient of friction and α = angle of tilt in degrees.

9. RESULTS AND DISCUSSION
1. Seed dimensions and size distribution
The mean dimensions of 100 seeds measured at a moisture
content of 10.06% d.b : length 7.80±0.49 mm, width 6.41±0.44 mm
and thickness 5.55±0.42 mm.
2. One thousand seed mass
The one thousand seed mass m100 increased linearly from 177.77
to 214.10g as the moisture content increased from 10.06% to
35.08%. The linear equation for one thousand seed mass is
formulated to be:
𝑚100 = 162.78 + 1.484𝑀𝑐 (𝑅2= 0.9971)
3. Projected Area of seed
The projected area of pea seed increased from 30.84 to 44.08
mm2, while the moisture content of seed increased from 10.06% to
35.08% d.b. The variation in projected area Ap in mm2 with moisture
content of pea seed can be represented by the following equation:
𝐴 𝑝 = 24.92 + 0.527𝑀𝑐 (𝑅2 = 0.9841)

10. 4. Sphericity
The sphericity of pea seed increased from 0.836 to 0.851 with the
increase in moisture content. The relationship between sphericity and
moisture content Mc in % d.b. can be represented by the following
equation:
∅ = 0.8302 + 0.0006𝑀𝑐 (𝑅2
= 0.9967)
5. Bulk Density
The values of the bulk density for different moisture levels varied
from 712.1 to 647.5 kgm3. The bulk density of seed was found to bear
the following relationship with moisture content:
𝜌 𝑏 = 733.36 − 2.5823𝑀𝑐 (𝑅2
= 0.9962)
6. True Density
The true density varied from 1160.5 to 1085.0 kg/m3 when the
moisture level increased from 10.06% to 35.08% d.b. The true density
and the moisture content of seed can be correlated as follows:
𝜌𝑡 = 1184 − 2.9879𝑀𝑐 (𝑅2
= 0.9600)

11. 7. Porosity
The porosity of pea seed increased from 38.64% to 40.32% with
the increase in moisture content from 10.06% to 35.08% d.b. The
relationship between porosity and moisture content can be
represented by the following equation:
𝑃𝑓 = 37.997 + 0.069𝑀𝑐 (𝑅2
= 0.9801)
8. Terminal Velocity
The terminal velocity was found to increase linearly from 9.00
to 9.40 m s-1 as the moisture content increased from 10.06% to
35.08% d.b. The relationship between terminal velocity and
moisture content can be represented by the following equation:
𝑉𝑡 = 8.8771 + 0.0149𝑀𝑐 (𝑅2 = 0.9823)

12. 9. Static coefficient of friction
The static coefficient of friction of pea seed on four surfaces (rubber,
aluminium, stainless steel and galvanized iron) against moisture content
in the range 10.06% to 35.08% d.b.
It was observed that the static coefficient of friction increased with
an increase in moisture content for all the surfaces. This is due to the
increased adhesion between the seed and the material surfaces at higher
moisture values.
The relationships between static coefficients of friction and moisture
content on rubber 𝜇 𝑟𝑢 , aluminium 𝜇 𝑎𝑙 , stainless steel 𝜇 𝑠𝑠 and
galvanised iron 𝜇 𝑔𝑖, can be represented by the following equations:
𝜇 𝑟𝑢 = 0.3789 + 0.001𝑀𝑐 (𝑅2 = 0.9936)
𝜇 𝑎𝑙 = 0.2763 + 0.0023𝑀𝑐 (𝑅2
= 0.9190)
𝜇 𝑠𝑠 = 0.2543 + 0.0016𝑀𝑐 (𝑅2
= 0.9616)
𝜇 𝑔𝑖 = 0.3407 + 0.002𝑀𝑐 (𝑅2 = 0.9708)

13. Parameters Moisture Content (% d.b) Coefficient of
determination
10.06 12.40 19.03 24.77 R2
One thousand
seed mass
177.70904 181.1816 191.02052 199.53868 0.9971
Projected area 30.22162 31.4548 34.94881 37.97379 0.9841
Sphericity 0.836236 0.83764 0.841618 0.845062 0.9967
Bulk Density 707.382062 701.33948 684.218831 669.396429 0.9662
True Density 1153.941726 1146.95004 1127.140263 1109.989717 0.9600
Porosity 38.69114 38.8526 39.31007 39.70613 0.9801
Terminal
Velocity
9.026994 9.06186 9.160647 9.246173 0.9823
Static
coefficient of
friction
𝜇 𝑟𝑢 0.38896 0.3913 0.39793 0.40367 0.9936
𝜇 𝑎𝑙 0.299438 0.30482 0.320069 0.333271 0.9190
𝜇 𝑠𝑠 0.270396 0.27414 0.284748 0.293932 0.9616
𝜇 𝑔𝑖 0.36082 0.3655 0.37876 0.39024 0.9708

16. CONCLUSION
The physical properties of pea seed for the moisture content range of
10.06% - 35.08% was studied and following conclusions are drawn:-
1. The thousand seed mass increased from 177.77 to 214.10 g and
the sphericity increased from 0.836 to 0.851 with the increase in
moisture content from 10.06% to 35.08% d.b.
2. The projected area increased from 30.84 to 44.08 mm2 and the
porosity increased from 38.64% to 40.32%.
3. The bulk density decreased linearly from 712.1 to 647.5 kg/m3
and the true density decreased from 1160.5 to 1085.0 kg/m3.
4. The terminal velocity increased from 9.00 to 9.40 m/s.
5. The static coefficient of friction increased for all four surfaces,
namely, rubber (0.388–0.413), aluminium (0.292–0.351), stainless
steel (0.270–0.311) and galvanized iron (0.360–0.409).