3rd meeting of young researchers at UP 1 - IJUP - Universidade do ...

Evaluation of Different Solvents for Oil Extraction from Grape seeds
A. Melo 1 , T.Mata 1,a , N.Caetano 2,a
a LEPAE – Laboratory for Process, Environmental and Energy Engineering
1 Department of Chemical Engineering, Faculty of Engineering, University of Porto (FEUP), R. Dr.
Roberto Frias S/N, 4200-465 Porto, Portugal
2 Department of Chemical Engineering, School of Engineering (ISEP), Polytechnic Institute of Porto
(IPP), R. Dr. António Bernardino de Almeida S/N, 4200-072 Porto, Portugal
The interest on biodiesel as a renewable fuel for transportation emerged as a response to the
current environmental concerns and also aiming to reduce our dependence on fossil fuels.
However the most common feedstocks for biodiesel production, such as soybean oil, rapeseed
oil, sunflower oil and palm oil, are also used in human food with the associated social and
environmental impacts. It is therefore necessary to find new sources of biodiesel feedstocks to
enable a sustainable future for the biodiesel industry. In this context arises the need to assess
the ability of extracting oil from the grape seeds using different solvents, so that this oil is
further considered for biodiesel production and as a potential substitute for the edible vegetable
oils mentioned above.
One started by gathering the bagasse from the wine production, containing mostly grape seeds,
grape peels and grape sticks. So, as a first step one separated the seeds from the remaining
components of bagasse, which was carried out manually and also using a sieve. For this
purpose sieves with two size screens where used: one for the finer contaminants (e.g. sand) and
one for the coarser contaminants (e.g. peels and sticks). The second step was the crushing of
the grape seeds in an industrial mill, until a thin and uniform particle size was obtained.
Thirdly, laboratorial tests were conducted for the grapeseeds oil extraction using different
solvents in a Sohxlet device. The solvents tested include n-hexane, n-heptane, n-octane,
cyclohexane, 1-propanol, 2-propanol, ethanol, methanol, and diethyl-ether. These solvents test
were designed not only to measure the ability of each solvent to perform the oil extraction but
also to compare possible differences in the oil content depending on the grape seed type, i.e. if
from white or red grape varieties. To recover the solvent from the oil extracted a simple
distillation was used.
Some properties of the oil extracted from the grape seeds were also determined, such as
kinematic viscosity, determined using a Cannon Fenske viscometer, density, determined by the
pycnometer method, the water content, determined using Karl Fischer coulometer, and the
iodine number, determined by titration.
References:
[1] Gandhi, A. P.; Joshi, K. C.; Jha, K.; Parihar, V. S.; Srivastav, D. C.; Raghunadh, P.; Kawalkar, J.;
Jain, S. K.; Tripathi, R. N. Studies on alternative solvents for the extraction of oil-I soybean.
International Journal of Food Science and Technology 38; 2003: 369-375.
[2] Maier, T.; Schieber, A.; Kammerer, D.R.; Carle, R., Residues of grape (Vitis vinifera L.) seed oil
production as a valuable source of phenolic antioxidants, Food Chemistry 112; 2009: 551-559.
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