Effects of process parameters on the extraction efficiency and physicochemical characteristics of tea seed oil from “TRUNGDU” tea (Camellia sinensis O. Kuntze) variety

Vietnam Journal of Science and Technology 57 (3B) (2019) 75-86
doi:10.15625/2525-2518/57/3B/14390

EFFECTS OF PROCESS PARAMETERS ON THE EXTRACTION
EFFICIENCY AND PHYSICOCHEMICAL CHARACTERISTICS
OF TEA SEED OIL FROM
“TRUNGDU” TEA (Camellia sinensis O. Kuntze) VARIETY
Phan Thi Phuong Thao1, 2, *, Tran Thi Thu Hang2, Hoang Dinh Hoa1, Vu Hong Son1
1

Hanoi University of Science and Technology, No 1 Dai Co Viet, Hai Ba Trung, Ha Noi
2

Vietnam National University of Agriculture, Trau Quy, Gia Lam, Ha Noi
*

Email:

Received: 3 September 2019; Accepted for publication: 2 November 2019
Abstract. This research aimed at investigating the effects of extraction parameters on the
extraction efficiency and chemical characteristics of Trungdu tea (Camellia sinensis O. Kuntze)
seed oil, which is similar to olive oil with high portion of unsaturated fatty acids, especially
essential linoleic acid and low content of saturated fat. The study parameters were particle size
(0.25 - 2.00 mm), material/solvent ratio (1/12 - 1/6), temperature (25 - 55 oC), time (5 - 11 h),
speed of solvent movement (0 - 250 r/m) and extraction times (1 - 3 times). The responses such
as extraction efficiency, physicochemical characteristics (acid, peroxide, iodine and
saponification values) were determined. The results indicated that the extraction efficiency was
affected by all designed parameters. In addition, the temperature, particle size and extraction
time had the most significant effect on the iodine value and acid value. The extraction
temperature and the speed of solvent movement had pronounced effects on the acid, peroxide,
iodine and saponification values of tea seed oil. However, ratio of material/solvent and

extraction times did not appreciably affect on physicochemical characteristics of tea seed oil.
Furthermore, the optimal extraction efficiency with higher quality attributes was achieved in the
range of 35 to 45 oC, 7 to 9 hours, with a particle size of 0.5 mm, material/content ratio 1/8 to
1/12, movement speed of solvent 200 to 250 r/m and 2 times extraction. Therefore, the results
from this work will be useful for developing an optimal procedure for obtaining tea seed oil. In
addition, fatty acid composition of tea seed oil presented high content of oleic acid and linoleic
acid, which warrants the high quality oil in terms of fatty acid profile.
Keywords: tea seed oil, extraction parameters, efficiency, physicochemical characteristics.
Classification numbers: 1.3.1, 1.4.5
1. INTRODUCTION
Tea is native to East Asia and probably originated in the borderlands of north Burma and
southwestern China. Tea is an evergreen shrub around the year [1]. After water, it is the most
widely consumed drink in the world [2]. Today many countries in the world have used tea seeds


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

to produce cooking oil, herbal medicines such as Germany, China, Japan, India [3]. Tea and its
products have become increasingly popular recently. In China, over a million tons of tea seed
were produced each year [4]. The rapid increase for seed co-produced raised the challenge of
finding suitable commercial applications. That explains why there are many research groups
working on tea seed products for the development of this key industry. Like other genera of
Camellia (from Theaceae family), tea seeds are rich in oil (30–32 %) [5]. Tea seed oil is stable
and suitable in nutritional properties, has a shelf life value identical to that of the olive oil at a
temperature of 63 °C, has higher shelf life than that of sunflower oil, and is capable of increasing
the shelf life of sunflower oil when mixed [6]. Tea (C. sinensis) seed oil is highly edible and
equally important as a health-promoting food resource in the human diet due to its good
antioxidant activity [1]. Tea seed oil comprises of essential monoene and can be a suitable
feedstock for inedible applications, which may include surfactant production, biodiesel and
lubricants, biopolymers, etc., hence can serve as an alternative to petrochemicals, which are

limited in supply [7]. Moreover, tea seed oil contains high amount of unsaturated fatty acids [1],
especially linoleic acid, which is reported to lower blood cholesterol levels [8]. It also has a
minute amount of linolenic acid, which is an important factor in rancidity and off-flavor of oils
during storage [9]. Essential fatty acids are necessary for the human diet for the maintenance of
growth and reproduction [10]. Thus, using tea seeds as a source of edible oil has been suggested
as source of essential fatty acids, which would otherwise be a waste product.
Some variables have been reported to have effects on the extraction efficiency and
chemical characteristics of tea seed oil when extracted using solvent method such as: tea seed
clone type, solvent type, particle size, material/solvent ratio, extraction temperature, extraction
time, speed of solvent movement, extraction cycle. In this research using solvent extraction
method, the effects of some extraction parameters: particle size, ratio of material/solvent,
extraction temperature, extraction time, speed of solvent movement, extraction cycle on the
efficiency and chemical characteristics of “Trungdu” tea seed oil were investigated.
2. MATERIALS AND METHODS
2.1. Tea seeds
Tea seeds were harvested from mature tea plants of “Trungdu” tea variety (Camellia
sinensis O. Kuntze) in Phu Tho province, Vietnam in December 2017. The healthy tea seeds
were dried in ambient conditions to 8 - 10 % moisture and then manually de-husked. The desired
tea seed kernels were then milled using an electric blender (Philips HL7510/00, Netherlands) for
particle size reduction and test sample homogenization.
2.2. Experimental design
Parameters were particle size (0.25 - 2.00 mm), solid-solvent ratio (1/12 - 1/6), temperature
(25 - 55 oC), time (5 - 11 h), speed of solvent movement (0 - 250 r/m) and extraction times (1 - 3
times). The responses such as extraction efficiency, physicochemical characteristics (acid,
peroxide, iodine and saponification values) were determined.
2.3. Analytical methods
2.3.1. Oil content (OC)

76

Effects of process parameters on the extraction efficiency and physicochemical characteristics…

This was determined by expressing the mass of the oil extracted as a percentage by mass of
the oil-bearing material (milled seeds) minus the moisture content of the seed used in the
extraction [11].
2.3.2. Determination of extraction efficiency
Extraction efficiency is the percentage of oil extracted in relation to the amount of oil
present in the seed. Oil extraction efficiency was computed as the ratio of the weight of oil
recovered (Wor) to the product of the seed oil content (Soc) and weight of crushed seed sample
(Wcss) before extraction. It was mathematically stated as shown in the formula:
(

)

2.3.3. Determination of acid value (AV)
This was determined according to AOCS Official Method Cd 3d-63 [12]. The acid value is
defined as the number of milligrams of potassium hydroxide required to neutralize the free fatty
acids present in one gram of fat. Weigh, to the nearest mg, 5 - 10 g well-mixed sample into 250 300 ml Ether etylic. Add 50 - 100 ml alcohol-ether mixture and 0.1 mL phenolphthalein
solution. Titrate with 0.1 N alcoholic KOH until permanent faint pink appears and persists for
≥ 10 s.
AV =
where: V: ml alcoholic KOH solution, f: concentration adjustment coefficient KOH 0.1 N (f =
1), c: Weight of sample (g), 5.61: grams of KOH contained in 1 ml of KOH 0.1 M. Difference
between duplicate determinations should be ≤ 0.1 mg KOH/g fat.
2.3.4. Determination of iodine value (IV)
This was determined according to Wijs as indicated by AOCS Official Methods of Analysis
Cd 1-25 [13] using the formula:
(

IV =

)

and the results were expressed as g I2/100 g of oil, where; m is the weight (g) of oil, V is the
volume (ml) of Na2S2O3 used in the test, v is the volume (ml) of Na2S2O3 used in the blank and
T is the concentration of Na2S2O3 (mol/l) and 126.9 the atomic mass of iodine.
2.3.5. Determination of saponification value (SV)
This was determined according to AOCS method Cd 3-25 [14] with slight modifications.
About 5 g of oil was weighed into a 250 ml round bottom flask. Using a volumetric flask, 50 ml
of 0.5 M ethanol KOH was added to the sample. The mixture was boiled under reflux for 1 h.
The hot soap solution was then titrated with 0.5 M HCl using phenolphthalein indicator. A blank
was also run in the same manner. The saponification values were calculated using the formula:
SV =

(

)

and reported in mg KOH/g oil, where, 56.1 is the molecular weight of KOH, m is the weight (g)
of fat, V1 is the volume (ml) of HCl used in the sample, V2 is the volume (ml) of HCl used in
the blank and c is the concentration (mol/l) of HCl.

77


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

2.3.6

Determination of peroxide value (PV)

This was determined according to the IUPAC method 2.501 [11] with slight modifications.
Approximately 2 g of oil was weighed into a flask. Twenty milliliters (20 ml) of solvent (2:1 v/v,
glacial acetic acid: chloroform) was added to the sample followed by 1 ml of freshly prepared
saturated KI solution. A homogenous solution resulted. After a few minutes, 30 ml of water was
added and the mixture titrated with sodium thiosulphate solution (0.01 M) with starch solution as
the indicator. The peroxide values were calculated using the equation:
PV =

(

)

and reported in meq O2/kg oil, where: m is the weight (g) of oil, V1 is the volume (ml) of
Na2S2O3 used in the test, V2 is the volume (ml) of Na2S2O3 used in the blank and N is the
concentration of Na2S2O3 (mol/l), f: concentration correction factor.
2.3.7. Determination of fatty acid content
A gas chromatography-flame ionization detector (GC-FID) according to the Ce 1-62
Method of American Oil Chemists’ Society [15] determined the fatty acid composition of the tea
seed oil. Oil samples were converted to methyl esters by vigorous shaking of the oil solution in 1
ml n-hexane with 2 ml of methanol potassium hydroxide. The tube holding the solution was
placed in a water bath (60 °C) for 20 min and was shaken for 1 hour. After decanting during the
final 5 min, 1 μl of the upper layer was injected into the GC-FID (6890 N, Agilent, US)
equipped with a DB-225 capillary column (30 m × 0.25 mm x 0.25 μm) under the following
conditions: initial temperature = 35°C (1 minute)  180 oC (20 °C/min), final temperature =
220 °C (35 minutes), heating rate = 20 °C/min, detector temperature = 260 °C, injector
temperature = 250 °C, pressure of nitrogen (carrier gas) = 42.12 psi.
wx 

Ax 100  M
At  100

where: wx: relative mass fraction of component x (g/100 g); Ax: the area of the peak
corresponding to the component x (used area units); At: the total corrected area of all peaks,
excluding the solvent peak (used area units); M: the lipid content (g/100 g of seed).
2.4. Data analysis
Data obtained were subjected to analysis of variance (ANOVA) using Minitab
statistical package version 16 at p ≤ 0.05. The least significant difference (LSD) test was used
in mean separation where statistically significant differences were recorded. Data are tabulated
as means of triplicate determinations ± standard deviation (SD).
3. RESULTS AND DISCUSSION
3.1. Effect of particle size on extraction efficiency and physicochemical characteristics of
tea seed oil
It was observed that as the particle size increased (0.25 to 2 mm), extraction efficiency
decreased from 87.96 % to 71.86 % as shown in Table 1. The smaller particle size gave more
efficiency because of the higher surface area to volume ratio that in turn enhanced the contact
between the solvent molecules and tea seed particles during the extraction process [1]. When the
78


Effects of process parameters on the extraction efficiency and physicochemical characteristics…

size of the particle is small, it results in relatively large surface area, hence increasing the contact
area in between the solvent [16]. Size reduction also helps for easier accessibility of the soluble
substrates that are otherwise located deep inside the plant matrix [4].
Table 1. Effect of particle size on extraction efficiency and physicochemical characteristics of tea seed oil.

Particle
size (mm)

Extraction
efficiency (%)

AV
(mg KOH/g)

PV
(meq/kg)

IV
(gI2/100g)

SV
(mg KOH/g)

0.25

87.96a ± 0.03

2.61a ± 0.12

4.71a ± 0.39

89.60b ± 1.03

164.30c ± 4.45

0.50

87.79a ± 0.07

2.67a ± 0.23

4.54a ± 0.59

100.62a ±1.34

202.23a ± 5.95

1.00

81.36b ± 0.05

3.46b ± 0.06

4.67a ± 0.31

98.80a ± 0.89

204.56a ± 4.72

1.50

76.23c ± 0.24

3.51b ± 0.18

5.43ab ± 0.32

80.13c ± 3.14

209.46a ± 6.15

2.00

71.86d ± 0.01

5.42c ± 0.23

5.90b ± 0.12

69.23d ± 2.52

182.78b ± 7.45

Numbers followed by the different letter in the same column are significantly different at 0.05 levels.

The highest extraction efficiency (87.96 %) was obtained at the particle size of 0.25 mm,
but this had no statistically significant difference from that achieved at the particle size of 0.5
mm.
It was also shown that, the lowest acid value achieved at 0.25 mm, but there was no
significant difference from that at 0.50 mm, which were lower than the standard values of Codex
standard for vegetable oils (the maximum level of the acid value for pure oils is 4.0 mg KOH/g)
[17].
The number of peroxides present in edible fats and oils is an index of their primary
oxidative level. In fact, the lower the peroxide value, the better the fat or oil quality and its status
of preservation [18]. The peroxide value of tea seed oil was determined as 4.71 to 5.90 (meq/kg).
That means the particle size does not cause much change in the peroxide value, especially, there
was no significant difference in the PV between 0.25, 0.50, 0.10, 1.50 mm. In comparison with

the standard values of Codex Standard (the maximum PV for pure oil is 15 meq/kg), it can be
seen that the PV of all variables are lower than that. [17]
The iodine value was found to relatively decrease with increasing the particle size, the
highest IV (100.62 gI2/100 g) obtained at the size of 0.5 mm. Generally, the IV from this work is
higher than the one of C. sinensis seed oil reported by Yahaya (74.23 gI2/100 g) [7]. It is also
higher than the IV of palm oil (50 - 55 gI2/100 g), and equivalent to the one of peanut oil (86 107 gI2/100g) [17]. Several studies have shown that the concentration of oleic acid in tea seed oil
is higher than linoleic and linolenic [1,7]. Monounsaturated fatty acid in tea seed oil is more than
polyunsaturated fatty acid, hence probably a reason for its lower IV compared to other oil, which
is more polyunsaturated [19]. The fatty acid composition of the triacylglycerol greatly influences
this parameter.
Higher saponification values are indicative of the presence of lower molecular weight
compounds/ short chain fatty acids in the oil. Higher saponification values are more desirable
when considering oil for the soap industry. However, it is undesirable in the production of
biodiesel. The result presented in Table 1 shows no significant differences in SV between the
particle size of 0.5, 1.0, 1.5 mm. Some oils extracted from these solvents also concur with a
study that shows no significant differences in SV of tea seed oil (Indian), sunflower and olive
79


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

oils [20]. Thus, the difference of particle size only has a slight effect on the extraction efficiency
of tea seed oil. The average SV of tea seed oil from this work is equivalent to the value reported
by Yahaya (186.5 mgKOH/g of oil) [7].
When the size is small, observing the tea seed powder is too smooth, causing sticking much
on the grinding device, when filtering the filter speed lower, it causes more time. Thus, the
appropriate size was 0.5 mm.
3.2. Effect of the material/solvent ratio on extraction efficiency and physicochemical
characteristics of tea seed oil
Table 2. Effect of the material/solvent ratio on extraction efficiency and physicochemical

characteristics of tea seed oil.
Material/solve
nt ratio

Extraction
efficiency (%)

AV
(mg KOH/g)

PV
(meq/kg)

IV
(gI2/100g)

SV
(mg KOH/g)

1/6

70.06b ± 1.41

2.26a ± 0.14

5.98b ± 0.36

90.95a ± 3.84

187.12a ± 7.91

1/8

73.70b ± 3.14

2.51a ± 0.19

5.27ab ± 0.30

93.18a ± 6.79

189.1a ± 7.57

1/10

87.76a ± 0.51

2.67a ± 0.23

4.54a ± 0.59

91.86a ± 9.23

186.42a ± 9.43

1/12

89.77a ± 1.35

3.41b ± 0.1

4.57a ± 0.21

93.62a ± 9.55

188.84a ± 4.75

Numbers followed by the different letter in the same column are significantly different at 0.05 levels.

From Table 2, it can be seen that as the material/solvent ratio increased (1/6 to 1/12), the
extraction efficiency of tea seed oil increased from 70.06 % to 89.77 %. The larger the ratio of
material to solvent, the higher the extraction efficiency. However, there was no significant
difference in the extraction efficiency between the ratio of 1/10 and 1/12. As the ratio of material
to solvent increases, the amount of solvent used increases and the contact between oil and
solvent is more. The movement between them is more intense and the oil is more likely to
spread. However, the amount of tea seed is certain. Once the saturation state is reached, the
amount of oil extracted also reaches a certain level, and the extraction rate tends to be stable.
From the ANOVA result in Table 2, it can be seen that the material/solvent ratio did not
appreciably effect on chemical characteristics of tea seed oil, especially, there was no significant
difference in IV and SV in the operating condition ranges selected in the experiment. Material:
solvent ratio from 1/8 to 1/12 was suitable for the extraction of tea seed oil.
3.3. Effect of temperature on extraction efficiency and physicochemical characteristics of
tea seed oil
Table 3 indicates that the extraction efficiency was directly proportional to the extraction
temperature. The reason is the higher temperature accelerates the movement of particles and
solvent molecules, and then makes the dissolved oil more. However, from Table 3, it can be seen
that the average extraction efficiency remains the same at about 90 % as the temperature
increases from 40 to 55 oC (no statistically significant differences at 0.05 levels). Furthermore,
high temperature may promote epimerization, oxidation, and degradation reaction of
nutraceutical compounds. This result is in agreement with the values reported by Zarringhalami,

which stated that the extraction temperature using petroleum solvent is 40–60 oC [21]. It is also

80


Effects of process parameters on the extraction efficiency and physicochemical characteristics…

generally similar to the results from Yang-Lin and Aijun, with the optimum temperature for
extraction of tea seed oil is 40 oC [22, 23].
Table 3. Effect of temperature on extraction efficiency and physicochemical characteristics of tea seed oil.
Extraction
temperature
(0C)
25
30
35
40
45
50
55

Extraction
efficiency (%)

AV
(mg KOH/g)

PV
(meq/kg)

IV
(gI2/100g)

SV
(mg KOH/g)

76.03e ± 0.05

1.80a ± 0.01

4.30a ± 0.10

75.57c ± 0.93

151.14d ± 9.68

82.91d ± 0.05

2.11a ± 0.04

4.37a ± 0.16

85.88b ± 3.68

170.93c ± 2.83

87.79c ± 0.07
89.7b ± 0.53
90.15ab ± 0.1
90.38a ± 0.05

90.73a ± 0.05

2.67a ± 0.23
3.02a ± 0.09
5.27b ± 0.19
6.16b ± 0.40
7.53c ± 1.17

4.54a ± 0.59
5.07ab ± 0.12
5.78bc ± 0.29
6.29c ± 0.31
9.38d ± 0.20

100.62a ± 1.34
98.08a ± 1.05
86.84b ± 1.79
74.37c ± 2.29
66.98d ± 0.62

202.23a
211.82a
207.22a
186.45b
166.92c

± 5.95
± 2.41
± 2.04
± 4.65

± 2.44

Numbers followed by the different letter in the same column are significantly different at 0.05 levels.

The acid value was considered in the food industry as an indicator of the quality of the oil
and the degree of its degradation during heating. An increase in the acid value leads to the
development of unpleasant tastes and odors in oils. The increase in acid value attributed to the
hydrolysis of TAG (triacylglycerol) and/or cleavage and oxidation of fatty acid double bonds
[24]. Table 3 illustrates that the effect of extraction temperature on AV and PV followed the
same trend. Both the AV and PV were found to increase with increasing the extraction
temperature from 25 to 55 oC. This demonstrates that increased temperatures have caused an
increase in oxidation and decomposition of tea seed oil. This trend in acid value agrees with the
trend reported in Jatropha oil and seem oil extractions respectively [25]. However, there was not
significantly different in the ones as the temperature increased from 25 to 40 oC. These results
indicated that relatively lower temperatures are desirable to obtain lower acid values in tea seed
oil. Besides, both the IV and SV increased as the temperature increased from 25 to 40 oC where
they reached a plateau before decreasing from 45 to 55 oC. The highest values of IV and SV
were all recorded at 40 oC. From 35 to 45 oC was the temperature range for extraction efficiency
and high tea seed oil quaility.
3.4. Effect of time on extraction efficiency and physicochemical characteristics of tea seed oil
Table 4. Effect of time on extraction efficiency and physicochemical characteristics of tea seed oil.

5

72.00b ± 2.04

AV
(mg
KOH/g)
2.48a ± 0.32

7

87.76a ± 0.51

2.67a ± 0.23

4.54a ± 0.59

91.86a ± 9.23

186.42a ± 11.43

9

89.58a ± 1.03

3.37b ± 0.12

4.18a ± 0.64

92.64a ± 6.59

187.03a ± 5.50

Extraction time
(hours)

Extraction
efficiency (%)

PV
(meq/kg)

IV
(gI2/100g)

SV
(mg KOH/g)

5.09b ± 0.26

91.79a ± 5.62

184.5a ± 9.55

11

90.15a ± 0.78
3.49b ± 0.12
4.84ab ± 051
93.37a ± 4.90
188.37a ± 10.78
Numbers followed by the different letter in the same column are significantly different at 0.05 levels.

81


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

The results tabulated in Table 4 revealed that the extraction efficiency of tea seed oil
increased as the extraction time increased from 5 to 11 hours and reached the highest efficiency
(90.15 %) at 11 hours. However, from the ANOVA result, there were no statistically significant
differences in the extraction efficiency between the duration of 7, 9 and 11 hours. The extraction
efficiency of tea seed oil increased with the duration linearly because for longer duration the
particle and solvent will be in contact and thus the particles release more oil. However, after 7
hours the variance noted was not significant as shown in Table 4. It might be because diffusion
of oil was fast due to high initial oil content. This diffusion rate decreased significantly when the
oil content of sample decreased.
From the ANOVA result in Table 4, it was also shown that the extraction time had an
appreciable effect on AV, PV, but it did not significantly affect the IV and SV of tea seed oil.
Specifically, the AV increases from 2.48 to 3.49 mg KOH/g as the extraction time increase from
5 to 11 hours, but there are no significant differences in AV between the time of 5, 7 hours and
between 9, 11 hours. In addition, the PV does not significantly affect as the time increase from 7
to 11 hours. This indicates that extraction temperature tends to have more effects on the
chemical characteristics compared to time.
Besides, prolonged extraction time resulted in decomposition of oil, nutraceuticals and in
solvent loss through evaporation, thereby affecting mass transfer loss during extraction [26].
Therefore, taking into consideration that extraction time is crucial in economizing extraction
process cost, the optimal extraction time was selected to be 7 to 9 hours.
3.5. Effect of the speed of solvent movement on extraction efficiency and physicochemical
characteristics of tea seed oil
Table 5. Effect of speed of solvent movement on extraction efficiency and physicochemical
characteristics of tea seed oil.
Speed of
solvent
movement
(r/m)

Extraction

efficiency
(%)

AV
(mg KOH/g)

PV
(meq/kg)

0

62.76f ± 0.07

6.12d ± 0.13

50

70.95e ± 0.09

100

77.4d ± 0.09

IV
(gI2/100g)

SV
(mg KOH/g)

8.16d ± 0.20

59.88d ± 0.63

113.69c ± 3.18

5.35c ± 0.13

6.19c ± 0.20

61.80d ± 1.92

134.84c ± 4.64

5.02bc ± 0.53

5.33b ± 0.12

67.30c ± 0.68

175.45b ± 9.05

150
81.73c ± 0.01
4.33b ± 0.12
4.80ab ± 0.20
83.00b ± 0.67
193.82ab ±11.22
b
a
a

a
200
87.79 ± 0.07
2.67 ± 0.23
4.54 ± 0.59
100.62 ±1.34
202.23a ± 5.95
a
a
a
a
250
89.77 ± 0.60
2.40 ± 0.19
4.39 ± 0.07
100.30 ±2.28
202.62a ± 13.79
Numbers followed by the different letter in the same column are significantly different at 0.05 levels.

As illustrated in Table 5, the speed of solvent movement does affect the extraction
efficiency significantly (p < 0.05). As the speed of solvent movement increased, the extraction
efficiency of tea seed oil increased continuously. The highest efficiency obtained at the speed of
250 r/m. This was explained that the increasing in speed of solvent movement results in an
increment in solubility and diffusion due to increase in surface area available for mass transfer
between the particle and solvent, thereby enhancing the extraction efficiency.

82


Effects of process parameters on the extraction efficiency and physicochemical characteristics…

The result presented in Table 5 show that the speed of solvent movement had pronounced
effects on all the AV, PV, IV and SV of tea seed oil. Specifically, as the speed of solvent
movement increased from 0 to 250 r/m, both the AV and PV decreased gradually while the IV
and SV increased gradually. Moreover, the lowest AV and PV achieved at the speed of 200 and
250 r/m and the highest IV and SV also obtained at the speed of 200 and 250 r/m. Thus, 200 to
250 r/m was the approximate movement speed of solvent for tea seed oil extraction.
3.6. Effect of extraction times on the efficiency and physicochemical characteristics of tea
seed oil
Table 6. Effect of extraction times on the efficiency and physicochemical characteristics of tea seed oil.
Extraction
times
1

Extraction
efficiency (%)
87.76b ± 0.51

AV
(mg KOH/g)
2.67a ± 0.23

PV
(meq/kg)
4.54a ± 0.58

IV
(g I2/100 g)
91.86a ± 9.23

SV
(mg KOH/g)
186.42a ± 11.43

2

89.59ab ± 2.07

2.94a ± 0.19

5.27a ± 0.25

92.71a ± 5.69

185.77a ± 8.60

3

90.94a ± 0.66

3.8b ± 0.29

5.46a ± 0.14

93.98a ± 6.58

185.25a ± 4.88

Numbers followed by different letter in the same column are significantly different at 0.05 levels.

To assess the influence of multiple extraction times, all the above optimal extraction
parameters were used to determine the effect of a single, double, and triple extraction times on
the efficiency and chemical characteristics of tea seed oil. As can be seen from Table 6, there
was not difference in the extraction efficiency between the 2 times and 3 times; there was
difference in the extraction efficiency between 2, 3 times and 1 times extraction. Furthermore,
from the ANOVA result in Table 6, it was also shown that the extraction times did not
significantly affect all the AV, PV, IV and SV of tea seed oil. Therefore, for lower extraction
cost, 2 times extraction was selected to extract tea seed oil by solvent method.
3.7. Results of the composition of fatty acid
Analyses of fatty acid composition of extracted oil samples were at particle size 0.5 mm,
material-solvent ratio 1/10, temperature 40 oC, time 7 hours, speed of solvent movement 200 r/m
and 2 times extraction, whose the results are shown in the Table 7 and a chromatogram of fatty
acids in TSO sample is shown in Fig.1. Sengupta determined the composition of TAG in Indian
tea seed oil and found that oleic (C18:1), linoleic (C18:2), palmitic (C16:0), and stearic (C18:0)
acids were the major FA [27].
The ratio of saturated fatty acids to the unsaturated fatty acid content was 1:3 (24.8 % :
75.2 %). Thus, the content of UFA is high in total content, the UFA content indicated that C18:1
and C18:2 acids are the major UFAS in all tea seed oil obtained by the extraction method. Tea
seed oil has a high content of unsaturated fatty acids, especially essential linoleic acid (22.68),
which works to reduce blood cholesterol levels. It also has low linolenic acid (C18:3 content
(0.72 %), an important factor in rancidity and loss of flavor of oil during storage [28].
Moreover, the oleic acid seed oil is the highest of all fatty acids, accounting for 50.8 %. Tea
seed oil is an oil with a characteristic acid component of oleic acid and linoleic acid, so it is
considered a high quality oil.

83


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

Table 7. Composition fatty acid of tea seed oil.
Fatty acid
C12:0

SFA

MUFA

PUFA

Content (%)
0.01

C14:0
C16:0
C17:0
C18:0
C20:0
C24:0
Total
C16:1
C18:1
C20:1
Total
C18:2
C18:3
Total

0.12
17.2

0.16
6.95
0.21
0.15
24.8
0.21
50.8
0.79
51.8
22.68
0.72
23.4

Figure 1. A representative GC chromatogram of the fatty acids in crude TSO.

4. CONCLUSIONS
In the current research, single factor experiment approach was employed to determine the
optimal cost-effective condition of the extraction process of tea seed oil. Extraction parameters
were found to have varying effects on the extraction efficiency, AV, PV, IV and SV of tea seed
oil in the operating condition ranges selected in the experiment. The extraction efficiency was
significantly affected by parameters as particle size, material to solvent ratio, extraction
temperature, extraction time and speed of solvent movement while it was not affected by
84


Effects of process parameters on the extraction efficiency and physicochemical characteristics…

extraction cycle. In addition, the particle size and extraction time had the most significant effect
on the AV, IV and AV, respectively. The extraction temperature and the speed of solvent
movement had pronounced effects on all the AV, PV, IV and SV of tea seed oil. However, the

material/solvent ratio and extraction times did not appreciably affect on chemical characteristics
of tea seed oil. Furthermore, higher quality and performance characteristics were achieved in the
range of temperature, size, material/solvent ratio, time, speed of solvent movement and number
of extraction times: 35 to 45 oC, 0.5 mm, 1/8 to 1/12, 7 to 9 hours, 200 to 250 r/m, 2 times
extraction. This study underpins an in-depth investigation of the optimization of extraction
parameters of tea seed oil by surface reaction method, in other words, to develop a process of
extracting tea seed oil optimal. Further work should be done on the effect of extraction
parameters on the antioxidant properties of tea seed oil. Tea seed oil with oleic acid content with
the highest ratio of 50.80%, followed by linoleic acid with 22.4 %, are the two typical acids of
tea seed oil, so tea seed oil is considered a high quality oil.
Acknowledgements.
The
research
funding
from
Institutional
Cooperation
Program
between Vietnam National University of Agriculture and the Francophone Joint University Council,
Belgium (ARESS-CCD Project) was acknowledged.

REFERENCES
1.

Yamamoto T., Kim M., Juneja L. R. - Chemistry and Applications of Green Tea, CRC
Press 4 (1997) 8493-4006.

2.

Macfarlane A., Macfarlane I. - The Empire of Tea, The Overlook Press 32 (2004) 58567493.

3.

Yuefei W., Da S., Hao C., Lisheng Q. and Ping X. - Fatty acid composition and
antioxidant activity of tea seed oil extracted by optimized supercritical carbon dioxide, Int.
J. Mol. Sci. 12 (2011) 7708-7719.

4.

Takeuchi T. M., Pereira C. G., Braga M. E. M., Marostica M. R., Leal P. F., Meireles M.
A. A. - Extracting Bioactive Compounds for Food Products-Theory and Applications,
Boca Raton: CRC Press, 2009, pp. 464.

5.

Ravichandran R., Dhandapani M. - Composition characteristics and potential uses of
south Indian tea seeds, J. Food Sci. Technol. 29 (1992) 394–394.

6.

Ataii D., Sahari M. A., Hamedi M. - Some physico-chemical characteristics of tea seed
oil, J. Sci. Technol. Agric. Nat. Res. Water. Soil Sci. 7 (3) (2013) 173-183.

7.

Yahaya L. E., Adebowale K. O., Olu-Owalobi B. I., Menon A. R. R. - Compositional
analysis of tea (Camellia sinensis) seed oil and its application, Int. J. Res. Chem. Env. 1
(2) (2011) 153-158.

8.

Sahari M. A., Ataii D., Hamedi M. - Characteristics of tea seed oil in comparison with
sunflower and olive oils and its effect as a natural antioxidant, Am. Oil Chem. Soc. 81
(2004) 585–588.

9.

Gecgel U., Demirci M., Esendal E. and Tasan M. - Fatty Acid Composition of the Oil
from Developing Seeds of Different Varieties of Safflower (Carthamus tinctorius L.),
Journal of the American Oil Chemists’ Society 84 (2007) 47- 54.

85


Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son

10. Sari I., Baltaci Y., Bagci C., Davutoglu V., Erel O., Celik H., Ozer O., Aksoy N., Aksoy
M. - Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and
oxidative status - a prospective study, Nutrition 26 (2010) 399–404.
11. Paquot C. - Standard Methods for the Analysis of Oils, Fats and Derivatives 6th Edition.
Elsevier (1979)
12. AOCS Official Method Cd 3d-63. Acid Value of Fats and Oils.
13. AOCS Official Methods of Analysis Cd 1-25. Iodine Value of Fats and Oils.
14. AOCS method Cd 3-25. Saponification Acid Value of Fats and Oils.
15. AOCS Official Methods of Analysis Ce 1-62. Fatty acid composition.
16. Mokrani A., Madani K. - Effect of Solvent, Time and Temperature on the Extraction of
Phenolic Compounds and Antioxidant Capacity of Peach (Prunus Persica L.) Fruit,
Separation and Purification Technology 162 (2016) 68–76.
17. Codex Standard for Named Vegetable Oils cx-stan 210 – 1999.
18. Shahidi F., Zhong Y. - Lipid Oxidation: Measurement Methods, Bailey’s Industrial Oil

and Fat Products, 6th ed, edited by Shahidi F, John Wiley & Sons Inc, 2005, pp. 3616.
19. Eqbal M. A. D., Halimah A. S., Amina A, Zahfan M. K. - Fatty acid composition of four
different vegetable oils (Red palm olein, Palm olein, Corn oil and Coconut oil) by gas
chromatography, Sec. Int. Conf. Chem. Chemical Eng. 14 (2011) 31-34.
20. Sari I., Baltaci Y., Bagci C., Davutoglu V., Erel O., Celik H., Ozer O., Aksoy N., Aksoy
M. - Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and
oxidative status - prospective study, Nutrition 26 (2010) 399–404.
21. Soheila Z., Mohammad A. S., Mohsen B., Zohreh H. E. - Enzymatically modified tea seed
oil as cocoa butter replacer in dark chocolate, International Journal of Food Science &
Technology 45 (3) (2010) 540 – 545.
22. Yang-Lin O., Cheng-Jin M., Qun H., Chang-Song H. - Study on extraction of tea seed oil
by mix-solvents, Sichuan Food Fermentat (2007) P 6.
23. Aijun H., Qiqin F., Jie Z. - Solvent extraction of oil-tea camellia seed oil enhanced by
ultrasound, China Oils and Fats (2009).
24. Abdulkarim S. M., Long K., Lai O. M., Muhammad S. K. S., Ghazali H. M. - Frying
quality and stability of high-oleic Moringa oleifera seed oil in comparison with other
vegetable oils, Food Chem. 105 (4) (2007) 1382–1389.
25. Joseph O. A., Ahmad A., Francis K. - Influence of storage duration of Jatropha curcas
seed on oil yield and free fatty acid content, Journal of Agricultural and Biological
Science 7 (2012) 42-46.
26. Mokrani A., Madani K. - Effect of Solvent, Time and Temperature on the Extraction of
Phenolic Compounds and Antioxidant Capacity of Peach (Prunus Persica L.) Fruit,
Separation and Purification Technology 162 (2016) 68–76.
27. Sengupta C., Sengupta A., and Ghosh A. -Triglyceride Composition of Tea Seed Oil, J.
Sci. Food Agric 27 (1976) 1115–1122.
28. Kelvin O. G., Thomas K., John K. W., Kelvin O. M., Francis N. W. - Comparative
Assessment of the Fatty Acid Profiles of Crude Oils Extracted from Seeds of Selected Tea
(Camellia sinensis L.) Cultivars, Food and Nutrition Sciences 7 (2016) 1-7.

86