Green solvent extraction and quality characteristics of passion fruit seed oil (Passiflora edulis Sims var. edulis)

VA) with Duncan’s 
test using the statistical software SAS 9.3. 
Results and Discussion 
Effects of the process variables on oil 
extraction from passion fruit seeds using a 
shaker 
Table 3 shows the results obtained from the 
shaker extraction of oil from Passiflora edulis 
var. edulis seeds. 
Solvent type had a strong effect on the oil 
extraction yield. The results showed that ethanol, 
hexane, and isopropanol gradually increased the 
oil extraction yield from 71.1 to 72.47% but they 
were not significantly different at a significance 
level of 5%. The remaining solvents, acetone and 
ethyl acetate, gave the highest oil extraction 
efficiencies and performed equally well as 
isopropanol and hexane. The only statistically 
significant difference in the extraction yield of 
passion fruit seeds was that ethanol was 
significantly lower than both ethyl acetate and 
acetone (P <0.05). 
With different polarities (hexane is a non-polar 
Table 3. Effects of the process variables on oil extraction yield from passion fruit seeds 
Solvent 
Yield 
(%) 
Material/ 
solvent ratio 
Yield 
(%) 
Extraction temperature 
Yield 
(%) 
Extraction 
time 
Yield 
(%) 
Acetone 72.98a 1/4 63.10c Room temperature 75.66b 1h 71.41c 
Ethanol 71.1b 1/6 72.88b 40oC 76.60ab 2h 71.62c 
Ethyl acetate 73.67a 1/8 74.51b 50oC 77.00ab 3h 75.26b 
Isopropanol 72.47ab 1/10 78.01a 60oC 77.46a 4h 78.52a 
Hexane 72.07ab 1/12 79.17a 70oC 77.74a 5h 79.49a 
Note: Values in the same column that do not share a common superscript are significantly different (P <0.05).
Green Solvent Extraction and Quality Characteristics of Passion Fruit Seed Oil (Passiflora edulis Sims var. edulis) 
472 Vietnam Journal of Agricultural Sciences 
solvent, ethanol and isopropanol are polar 
solvents, and ethyl acetate and acetone are 
aprotic polar solvents), different solvents 
resulted in different extraction efficiencies. The 
data indicated that the aprotic polar solvents were 
more suitable for the extraction of oil from purple 
passion fruit seeds since ethyl acetate and 
acetone had better oil extraction capacities than 
ethanol. Oliveira et al. (2014) also found the 
same result in that acetone was the best solvent 
compared to ethanol and isopropanol in 
extracting oil from passion fruit seeds. 
In accordance with Directive 2009/32/EC of 
the European Union on April 23, 2009, both ethyl 
acetate and acetone are allowed to be used as 
solvents in the food industry because they 
generate less waste than other solvents. Because 
the boiling point of ethyl acetate is 77oC, higher 
than that of acetone (56oC), ethyl acetate was 
selected for the next experiment due to less 
solvent loss during oil recovery. 
The oil content in the extracts strongly 
depended on the material to solvent ratio. There 
was an increase of the passion fruit seed oil yield 
with an increase of the material to solvent ratio 
(w/v). The material to solvent ratio of 1:12 (w/v) 
showed the highest amount of oil but was not 
significantly different from the ratio of 1:10 (w/v) 
(P >0.05). The opposite behavior is reported by 
Oliveira et al. (2014) who found that the ratio 1:4 
of passion fruit seeds to solvent was the best ratio 
to extract oil from these seeds. Maybe 
differences between yellow and purple passion 
fruit seeds led to the differences in findings 
between the results of Oliveira et al. (2014) and 
our study. 
A high material to solvent ratio could 
promote an increased concentration gradient, 
producing a higher chance of oil coming into 
contact with the extraction solvent, resulting in 
an increased diffusion rate that allows for greater 
extraction of materials by the solvent (Cacace & 
Mazza, 2003). These results were consistent with 
the mass transfer principle. However, the active 
component yields would not continue to increase 
once equilibrium had been reached (Herodež et 
al., 2003). An equilibrium constant trend was 
observed at the material to solvent ratio of 1:10 
(w/v) that indicated a sufficient amount of 
extracting solvent was used in the extraction of 
oil from passion fruit seeds and thus, this ratio 
was chosen for the determination of the 
extraction temperature and extraction time. 
Regarding the extraction temperature, the 
results indicated a significant increase in the oil 
extraction yield when the temperature increased 
from room temperature (28oC) to 60oC (P <0.05) 
but the oil extraction efficiency did not 
significantly differ between the temperatures of 
60 and 70oC (P >0.05). 
When performing extractions at low and 
mediate temperatures, from room temperature to 
50oC, the flexibility of the fatty constituents in 
the materials was not strongly promoted; hence, 
the extraction efficiency was around 76%. When 
the temperature was raised to 60oC, the thermal 
conductivity increased, which made the diffusion 
coefficient of the solutes increase, consequently 
increasing their solubility (Al-Farsi & Chang, 
2007) and thus, accelerating the whole extraction 
up to 78%. Although increasing the temperature 
to 60oC resulted in a 2% increase in the oil 
extraction yield, 60oC is not only closer to the 
boiling point of ethyl acetate (77oC), which 
might cause significant losses in the solvent, 
energy consumption, and economic efficiency, 
but small constituents of materials are also easily 
dissolved at this temperature, leading to 
difficulties in oil recovery. Therefore, room 
temperature (28oC) was selected for the 
extraction of oil from passion fruit seeds in the 
subsequent step. 
The evaluation of the extraction time 
showed that the extraction capacity of passion 
fruit seeds increased sharply when the 
extraction time was increased to 4h, but at 
longer extraction times, the efficiency did not 
increase significantly (P >0.05). This finding 
is in agreement with the report of Oliveira et 
al. (2014) who reported that the highest oil 
extraction capacity value from passion fruit 
seeds was obtained after 4h of extraction. 
These phenomena could be explained by Fick’s 
second law of diffusion, predicting that a final 
equilibrium between the solute concentration 
in the plant matrix and in the solvent might be 
reached after a certain time. 
Nguyen Thi Thu Nga et al. (2019) 
https://vjas.vnua.edu.vn/ 473 
Chemical and quality characteristics of 
Passiflora edulis var. edulis seed oil 
According to the chemical characteristics of 
passion fruit seed oil (Table 4), the oil content of 
Passiflora edulis var. edulis seeds was 27.28% on 
a dry basis indicating that these seeds were a good 
oil source when compared to soybean seeds, 
which contain about 25% on a dry basis (Hammad 
et al., 2012). The oil content reported in this study 
was higher than the values of 18.5% for P. edulis 
var. edulis seeds and 20.6% for P. edulis var. 
flavicarpa seeds in Uganda found by Nyanzi et al. 
(2005), and lower than the figures of 30.39% and 
30.22% for yellow passion fruit seeds in Brazil 
found by Malacrida & Jorge (2012) and Silva et 
al. (2015), respectively. Differences in the oil 
contents of P. edulis could be due to genetic, 
climate, and geographical attributes. 
The acidity index of the extracted oil 
provides important information on the condition 
of oil conservation. A high acidity index 
indicates that the oil was partly oxidized or 
degraded. The value found in this study (1.61 ± 
0.05 mg KOHg-1) was equal with the value found 
by Silva et al. (2015) and 1.5 times lower than 
the quality parameter of 4.0 mg KOHg-1 
according to The Codex Alimentarius 
Commission (2008). This result indicates that the 
studied oil can be used for food purposes as it 
meets the required standard. 
The determination of the peroxide value is 
used as an indicator of lipid oxidation. High 
peroxide values of extracted oil indicate that the 
oil was exposed to oxidative processes during the 
preparation of the raw material, extraction, or oil 
storage. In our study, the peroxide value of the 
seed oil from P. edulis var. edulis was 2.5 times 
lower than peroxide value of the seed oil from P. 
edulis var. flavicarpa found by Silva et al. (2015) 
of 1.54 ± 0.14 meqO2kg
-1 and far lower than the 
value that the Codex Alimentarius Commission 
established for refined and crude oils in 2008 at 
15 meqO2kg
-1. 
The GC analysis of the fatty acids of the P. 
edulis var. edulis seed oil showed a high content 
of unsaturated fatty acids such as linoleic and 
oleic (Table 5). Linoleic acid (C18:2n6), an 
essential polyunsaturated omega-6 fatty acid for 
humans, was the most dominant fatty acid 
making up 75.7% of the total fatty acids and was 
followed by oleic acid (C18:1n9) at 9%. These 
data were in agreement with the results reported 
by Nyanzi et al. (2005) in that linoleic and oleic 
acids made up the majority of the fatty acids 
found in the extracted oil of P. edulis var. edulis 
seeds with the values of 74.3% for linoleic acid 
and 13.6% for oleic acid. 
In comparison to the fatty acid compositions 
of soybean oil and sunflower oil, two popular 
vegetable oils used in the food, cosmetic, and 
pharmaceutical industries (Rabasco & Gonzalez, 
2000), the percentage of saturated fatty acids in 
Table 4. Chemical characteristics of P. edulis var. edulis seeds oil 
 Component Value* 
Oil content (%) 27.28 ± 0.54 
Acidity index (mg KOH g-1) 1.61 ± 0.05 
Peroxide value (meqO2 kg
-1) 0.62 ± 0.03 
Note: * Each value is the mean ± SD of triplicate extractions and determinations. 
Table 5. Fatty acid composition of P. edulis var. edulis seed oil 
 Fatty acids Composition (%) 
Oleic acid (C18:1n9c) 9 
Linoleic acid (C18:2n6) 75.7 
Docosahexaenoic acid (C22:6n3) 0.94 
Saturated fatty acid (SFA) 14 
Unsaturated fatty acid (UFA) 86 
Green Solvent Extraction and Quality Characteristics of Passion Fruit Seed Oil (Passiflora edulis Sims var. edulis) 
474 Vietnam Journal of Agricultural Sciences 
passion fruit seed oil amounted to 14%, while 
the value obtained for soybean oil was slightly 
higher (15.1%) and the value for sunflower oil 
was a little lower (12.36%). Among the 
monounsaturated fatty acids, oleic acid was the 
main representative and its content was the 
lowest in passion fruit seed oil (9%) and 
highest in soybean oil (21.73%), while the 
level of oleic in sunflower oil was 15.93% 
(Zambiazi et al., 2007). Linoleic was the 
dominant fatty acid among the polyunsaturated 
fatty acids (PUFAs) and the linoleic acid 
amount in passion fruit seed oil was higher than 
the vales determined in sunflower oil and 
soybean oil, which were 71% and 56%, 
respectively. It can also be noted that 
sunflower oil’s high PUFA content makes this 
oil a good salad oil source (Sullivan, 1980), 
and with the primary constituents of oleic, 
linoleic, and linolenic acids, soybean oil and 
sunflower oil can be employed in cosmetic 
products and pharmaceutical formulations 
(Rabasco & Gonzalez, 2000). Hence, the high 
content of PUFAs of the studied oil indicates 
this product is a good source of essential 
PUFAs for human use. 
Conclusions 
In this study, the effects of process variables 
on the solvent extraction of oil from passion fruit 
seeds were investigated using a shaker. The 
highest extraction yield was 78.52%, which was 
obtained using ethyl acetate at the ratio of 1:10 
material to solvent at room temperature (28oC) 
for 4h, and was similar to the results obtained 
with the conventional solvent hexane. Our results 
indicate that passion fruit seed oil extracted by 
ethyl acetate has a high content of PUFAs 
(around 77%) and thus, has good potential for use 
in the human food, cosmetic, and pharmaceutical 
industries. 
Acknowledgements 
The authors would like to acknowledge 
Vietnam National University of Agriculture 
for providing financial support under the 
Research Grant Scheme (Grant agreement 
T2017-08-55). 
References 
Al-Farsi M. A. & Chang Y. L. (2007). Optimization of 
phenolics and dietary fibre extraction from date seeds. 
Food Chemistry. 108(3): 977-985. 
Cacace J. E. & Mazza G. (2003). Mass transfer process 
during extraction of phenolic compounds from milled 
berries. Journal of Food Engineering. 59: 379-389. 
Codex Alimentarius. Fats, oils and related products 
(revised 2001). Second edition. 8. 
Cowan M. M. (1999). Plant products as antimicrobial agents. 
Clinical Microbiology Reviews. 12(4): 564-582. 
Directive 2009/32/EC (2009). The European Parliament 
and the Council of the European Union. on extraction 
solvents used in the production of foodstuffs and food 
ingredients. Official Journal of the European Union. 
141: 3-11. 
Hammad K. H. A., Zhmurko V. V. & Avksentyeva O. A. 
(2012). Seed Protein and Oil Content of the Soybean 
Cultivars under Different Climate Condition (Glycine 
max (L.) Merr.). American-Eurasian Journal of 
Agricultural and Enviromental Science. 12(5): 603-607. 
Herodež Š. S., Hadolin M., Škerget M. & Knez Ž. (2003). 
Solvent extraction study of antioxidants from Melissa 
officinalis L. leaves. Food Chemistry. 80: 275-282. 
Malacrida C. R. & Jorge N. (2012). Yellow passion fruit 
seed oil (Passiflora edulis f. flavicarpa): physical and 
chemical characteristics. Brazilian Archives of 
Biology and Technology. 55(1): 127-134. 
Nyanzi S. A., Carstensen B. & Schwack W. A. (2005). A 
Comparative Study of Fatty Acid Profiles of Passiflora 
Seed Oils from Uganda. Journal of American Oil 
Chemists’ Society. 82(1): 41-44. 
Oliveira R. C., Barros S. T. D. & Gimenes M. L. (2013). 
The extraction of passion fruit oil with green solvents. 
Journal of Food Engineering 117: 458-463. 
Oliveira R. C., Guedes T. A., Gimenes M. L. & Barros S. 
T. D. (2014). Effect of process variables on the oil 
extraction from passion fruit seeds by conventional 
and non-conventional techniques, Acta Scientiarum 
Technol. 36: 87-91. 
Rabasco A. A. M. & González R. M. L. (2000). Lipids in 
pharmaceutical and cosmetic preparations. Grasas 
Aceites. 51: 74-96. 
Rehm S. & Espig G. (1984). The Cultivated Plants of the 
Tropics and Subtropics, Eugen Ulhmer Publishers, 
Stuttgart, Germany. 185-186 (in German). 
Silva R. M., Placido G. R., Silva M. A. P., Castro C. F. S., 
Lima M. S. & Caliari M. (2015). Chemical 
characterization of passion fruit (Passiflora edulis f. 
flavicarpa) seeds, African Journal of Biotechnology. 
14: 1230-1233. 
Sullivan F. E. (1980). Sunflower oil processing from crude 
to salad oil, Journal of the American Oil Chemists' 
Society. 57: 845-847. 
Zambiazi R. C., Przybylski R., Zambiazi M. W. & 
Mendonça C. B. (2007). Fatty acid composition of 
vegetable oils and fats. Boletim Centro de Pesquisa de 
Processamento de Alimentos. 25: 111-120.