Content uploaded by Stefan Cenkowski
Author content
All content in this area was uploaded by Stefan Cenkowski
Content may be subject to copyright.
Volume 48 2006 CANADIAN BIOSYSTEMS ENGINEERING 3.9
Quality of extracted sea buckthorn seed
and pulp oil
S. Cenkowski1*, R. Yakimishen1, R. Przybylski2 and W.E. Muir1
1Department of Biosystems Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada; and 2Department of
Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada. *Email:
stefan_cenkowski@umanitoba.ca
Cenkowski, S., Yakimishen, R., Przybylski, R. and Muir, W.E. 2006.
Quality of extracted sea buckthorn seed and pulp oil. Canadian
Biosystems Engineering/Le génie des biosystèmes au Canada 48: 3.9-
3.16. The effects of four oil-extraction techniques (solvent extraction
using petroleum-ether, supercritical fluid extraction using carbon
dioxide (SCFE CO2), screw pressing, and aqueous extraction) on the
nutritional quality of sea buckthorn seed and pulp oil were evaluated
by quantifying fatty acids, tocopherols and tocotrienols, total
carotenoids, and sterols. The extracted quantities were compared
against solvent extraction using chloroform/methanol as reference.
Seeds and pulp-flakes were obtained by pilot-scale processing and
separation. Juice was first extracted from berries on a bladder press and
then wet pulp cake was dried at 50ºC for 24 h in a forced-convection
drying oven. The dried seeds and pulp-flakes were separated using an
industrial mixer and a vibratory screen separator. Processed seeds and
pulp-flakes were then subjected to the four oil-extraction techniques.
The concentration of fatty acids in oil extracted from seeds and pulp-
flakes was similar in all tested extraction techniques. The predominant
fatty acids were linoleic (35.3-36.3%) and linolenic (35.9-38.5%) acids
in seed oil, and palmitic (34.4-35.5%) and palmitoleic (34.4-38.5%)
acids in pulp oil. Alpha-tocopherol (vitamin E) was the major
tocopherol identified in the seed oil (43 to 53% of total tocopherols)
and pulp oil (74 to 85% of total tocopherols) and the extracted quantity
depended on the extraction technique used. Petroleum-ether extraction
gave the highest total carotenoid concentration of 22 mg/100 g in seed
oil and 527.8 mg/100 g in pulp oil. The lowest carotenoid
concentrations were obtained with 3h-SCFE CO2 (6.2 and 122.3
mg/100g of oil from seed and pulp, respectively). Beta-sitosterol
(prostate treatment natural compound) was the predominant sterol
identified in the seed oil (97% range of total sterols for all extraction
techniques) and pulp oil (96-98% of total sterols for extraction
techniques tested). Petroleum-ether extraction consistently recovered
oils having higher amounts of all analyzed nutritional components.
Aqueous extraction and screw pressing methods were limited by the
type of material which could be processed. No oil was recovered from
sea buckthorn seeds by aqueous extraction and no oil was recovered
from pulp-flakes by screw pressing. The SCFE CO2 method was
flexible in extracting both seed and pulp oils having relatively high
concentrations of all identified nutritional compounds. Keywords: sea
buckthorn, oil, quality, supercritical fluid extraction, screw pressing,
solvent extraction, aqueous extraction, pulp, pulp-flakes, seeds,
nutraceutical compounds.
Les effets de quatre techniques d’extraction d’huiles (extraction
par solvant utilisant l’éther de pétrole, extraction par fluide
supercritique utilisant le dioxide de carbone (EFSC CO2), extraction
avec une presse à vis, extraction aqueuse) sur la qualité nutritionnelle
des graines et de l’huile de pulpe de l’argousier ont été évalués en
quantifiant les acides gras, les tocophérols et les tocotriénols, les
caroténoïdes totaux et les stérols. Les quantités extraites ont été
comparées à celles obtenues lors de l’extraction par solvant utilisant du
chloroforme/méthanol, celle-ci étant utilisée comme méthode de
référence. Les graines et les flocons de pulpe ont été obtenus par
transformation et séparation à l’échelle du laboratoire. Premièrement,
le jus était extrait des baies à l’aide d’un pressoir pneumatique et
ensuite la pulpe humide était séchée à 50ºC pour 24 h dans un four à
convection forcée. Les graines séchées et les flocons de pulpe ont été
séparés en utilisant un mélangeur industriel et un crible vibrant. Les
graines et les flocons de pulpe ainsi traités ont été alors soumis aux
quatre techniques d’extraction d’huile. La concentration en acides gras
dans l’huile extraite des graines et des flocons de pulpe était
comparable pour chacune des techniques d’extraction testées. Les
acides gras prédominants étaient les acides linoléïques (35,3-36,3%)
et linoléniques (35,9-38,5%) dans les graines et les acides palmitiques
(34,4-35,5%) et palmitoléïques (34,4-38,5%) dans l’huile provenant
de la pulpe. L’alpha-tocophérol (vitamine E) était le principal
tacophérol identifié dans l’huile des graines (43 à 53% du total des
tocophérols) et dans l’huile provenant de la pulpe (74 à 85% du total
des tocophérols) et la quantité extraite était dépendante de la technique
d’extraction utilisée. L’extraction à l’éther de pétrole a procuré la plus
grande concentration de caroténoïdes totaux avec 22 mg/100 g dans
l’huile des graines et 527,8 mg/100 g dans l’huile de la pulpe. Les plus
petites concentrations de caroténoïdes ont été obtenues avec EFSC
CO2 -3h (6,2 et 122,3 mg/100g d’huile provenant respectivement des
graines et de la pulpe). Le bêta-sitostérol (composé naturel pour le
traitement de la prostate) était le principal stérol identifié dans l’huile
de graines (environ 97% des stérols totaux pour chacune des
techniques d’extraction) et dans l’huile de pulpe (96-98% des stérols
totaux pour les techniques d’extraction testées). L’extraction par
l’éther de pétrole a, de manière constante, extrait des huiles possédant
les quantités les plus grandes de tous les composés nutritifs analysés.
Les méthodes d’extraction aqueuse et utilisant une presse à vis étaient
restreintes quant au type de produit qu’elles pouvaient transformer.
Aucune huile n’a été extraite des graines d’argousier par l’extraction
aqueuse, situation similaire avec les flocons de pulpe en utilisant la
presse à vis. La méthode EFSC CO2 était flexible en extrayant des
huiles des graines et de la pulpe qui avaient des concentrations élevées
de tous les composés nutritifs identifiés. Mots clés: argousier, huile,
qualité, extraction par fluide supercritique, pulpe, flocons de pulpe,
graines, composés nutraceutiques.
INTRODUCTION
The functional food and nutraceutical markets, collectively
estimated as a multi-billion dollar global industry (up to $86
billion, 5 to 7.5% annual increase), has been gaining popularity
(Oomah and Mazza 1999; Hardy 2000; Menrad 2003).
However, there is major concern that these unprecedented
growth rates are likely to- and have already attracted
LE GÉNIE DES BIOSYSTÈMES AU CANADA CENKOWSKI et al.3.10
irresponsible market entrants distributing products that do not
deliver on quality (Hardy 2000; Datamonitor 2005). Berries
from sea buckthorn (Hippophae rhamnoides L.), a shrub still
virtually unknown in North America are currently being
incorporated as a functional food and into nutraceutical products
in Europe and Asia. (Li and Schroeder 1999). Traditional
products from the berries include juices, liqueurs, wine, jams,
candy, and ice-cream. However, the berry’s unique chemical
and nutritional composition has offered economic potential as
a health food in North America (Oomah and Mazza 1999;
Storey 2000).
Sea buckthorn seed and pulp oils are considered the most
valuable components of the berries comprising a unique fatty
acid composition, fat-soluble vitamins, and plant sterols (Yang
and Kallio 2002). The seed oil, defined as being highly
unsaturated, comprises two essential fatty acids, "-linolenic
(C18:3n-3) (the parent substance of omega-3 fatty acid which
helps to prevent chronic diseases such as heart disease and
arthritis) and linoleic (C18:2n-6) acids (omega-6 fatty acid;
unsaturated fatty acid considered essential to the human diet).
The contributions of "-linolenic and linoleic acids are
commonly at the 20 to 35 and 30 to 40% range, respectively
(Yang and Kallio 2002). Oil from the pulp contains more
saturated fatty acids than from the seeds and comprises
primarily palmitic acid (C16:0; most common saturated fatty
acid), palmitoleic acid (C16:1n-7, unsaturated fatty acid), and
lower concentrations of polyunsaturated acids (Kallio et al.
2002). Seed oil contains "-, $-, (-, and *-tocopherol isomers
which comprise 93 to 98% (84 to 318 mg/kg of berries) of the
total tocopherols (fat soluble alcohols that behave similar to
vitamin E, an important antioxidant that neutralizes free radicals
in the body). Alpha-tocopherol (vitamin E) constitutes 76 to
89% of tocopherols in whole berries (Kallio et al. 2002).
Among pigments, $-carotene (important anti-oxidant in the food
industry) is the most abundant in the pulp oil and constitutes 15
to 55% of total amount of carotenoids (Yang and Kallio 2002).
Important sterols include cholesterol, phytosterols and steroid
hormones, and their contents in seeds, pulp, and fresh whole
berries (ssp. Rhamnoides and sinensis) are 1200-1800, 240-400,
and 340-520 mg/kg of berries, respectively (Yang et al. 2001).
The process used to separate oil from oil-bearing materials
has a direct effect on the extractability and quality of oil
(Bargale et al. 1999). Oil quality is also affected by the
contamination of other oils and foreign material, colour fixation
from increased processing temperatures, increases in free fatty
acids, and oxidation (Burkhalter 1976). Four extraction
techniques (solvent extraction using petroleum-ether,
supercritical fluid extraction using carbon dioxide - SCFE,
screw pressing, and an aqueous extraction) were evaluated by
Yakimishen et al. (2005) for their extraction efficiencies
(percentage of oil recovery). Seed oil recoveries were 65.1 and
41.2% for SCFE CO2 (45ºC and 35 MPa) and screw pressing,
respectively. No oil was recovered from seeds by aqueous
extraction. Pulp-flake oil recovery was 86.3% for SCFE CO2.
The aqueous extraction yielded only 6% of pulp oil. No oil was
recovered from pulp flakes by screw pressing. Aqueous
extraction produced pulp oil characterized as being visually
attractive (dark red and clear), having a pleasant fruity smell,
and remaining as a liquid at room temperature for over a year.
Unfiltered seed oil after screw pressing was yellowish-brown
and cloudy due to seed particulates in the oil. Extracted pulp-
flake oil in SCFE CO2 was red and existed as a semi-solid at
room temperature. Temperatures above 30ºC returned the
semisolid oil to liquid. Seed oil was a clear, yellow-brown liquid
at room temperature. Seed oil from petroleum ether extraction
was bright yellow and existed as a clear liquid at room
temperature, while the pulp oil was clear, bright-red, and
solidified when cooled to room temperature. Each extraction
technique affected the oil, but the effects of extraction technique
on specific compounds in the extracted oil were not reported.
The cosmetic, nutraceutical, functional food, and
pharmaceutical industries are very demanding and require
products that meet stringent criteria of performance and
composition (Kalustian 1985). Thus, processing to isolate oils
should not affect the endogenous nutritional components
originally present in plant oils (Puupponen-Pimiä et al. 2002).
Increasing processing temperatures can improve oil yield but at
the same time can negatively affect oil quality (Carr 1997). Oils
expelled at temperatures below 60ºC are classified as “cold
pressed”, and have a positive market connotation (cold press
means that oils are extracted at temperatures below 60ºC
(Bockisch 1998).
The objective of this research was to determine the effects
of four extraction techniques: solvent extraction using
petroleum-ether, supercritical fluid extraction using CO2, screw
pressing, and aqueous extraction on the nutritional components
in sea-buckthorn seed and pulp oils.
METHODOLOGY
Preparation of experimental material
Sea buckthorn berries (Hippophae rhamnoides L. ssp.
rhamnoides, cv. Indian-Summer) were collected from a 15-year
old orchard at Pearl Creek Farms in Melville, Saskatchewan.
Berries were manually harvested in November 2002. Berries
were hand cleaned to remove dry leaves, branches, and berries
damaged by harvesting and then wind screened. Cleaned berries
were double bagged in 50-kg portions, placed in cardboard
boxes, frozen to approximately -15ºC, and shipped to the
University of Manitoba via bus (approximately 10 h in
transport). Upon arrival, the berries were stored in a walk-in
freezer at -25ºC for approximately 2 to 3 months.
Oil was extracted from sea buckthorn seeds and pulp-flakes
obtained by pilot-scale processing and separation. The pilot
scale processing was conducted at the Food Development
Centre (FDC) in Portage la Prairie, Manitoba. Juice was
extracted from berries on a bladder press using 0.8 MPa
maximum pressure for a 5-min extraction time. The wet pulp-
cake was then dried at 50ºC for 24 h in a forced-convection
drying oven. The dried seeds and pulp-flakes were separated
using an industrial mixer (Hobart Cutter Mixer, Troy, OH)
operated for short time intervals (approximately 3 s) repeatedly
for 10 to 15 cycles to minimize seed damage, and a vibratory
screen separator (SWECO, Toronto, ON) operated at 1200 rpm
(Yakimishen et al. 2005). The seeds and pulp flakes were then
stored at -5ºC until they were used in the oil extraction
experiments, approximately 1 to 4 months later.
Oil extraction
Oils were isolated from sea buckthorn seeds and pulp-flakes by:
(i) solvent extraction using petroleum-ether, (ii) supercritical
Volume 48 2006 CANADIAN BIOSYSTEMS ENGINEERING 3.11
fluid extraction with carbon dioxide (SCFE CO2 at 45ºC and
35 MPa), (iii) expelling with a screw press, and (iv) aqueous
extraction.
Solvent extraction using petroleum-ether (boiling range 35-
60ºC) was done in a Goldfisch laboratory oil extraction
apparatus (Model 35001, Labconco Corporation, Kansas City,
MO) following a standard method (AACC 2000). Prior to
extraction, seeds were prepared by grinding them in two 15-s
cycles in a rotary mill (Stein Mill, Model M-2, Stain labs Inc.,
Atchison, KS). During petroleum ether extraction, the oil
temperature was maintained at 45 ±1ºC and measured using a T-
type thermocouple connected to an Omega microprocessor
thermometer (model HH23, Omega Engineering, Stamford,
CT).
Supercritical fluid extraction was conducted using a
supercritical fluid extraction screening system (Newport
Scientific Inc., Jessup, MD). The major component of the SCFE
system included a carbon dioxide source (compressed cylinder
of liquefied CO2 gas, 99% pure), a continuous compressor, a
cylindrical stainless steel extraction vessel (300-mL capacity),
a temperature controlled heating pad (silicone-rubber type,
180 W) external to the extraction vessel, a stainless steel
cylindrical oil collection vessel (125-mL capacity), and a flow-
rate indicator with a flow totalizer. Seeds were prepared by
grinding following the method used in petroleum-ether
extraction. A 140-g sample of ground seeds or a 70-g sample of
pulp-flakes was loaded into a high-pressure extraction vessel of
381 mm inside diameter and 267 mm inside depth. Steel wool
(grade #2, medium course) was placed at the bottom and top of
the extraction vessel to prevent the sample particles from
entering and clogging the supercritical CO2 inlet and outlet. To
prevent channeling of the supercritical CO2 through a sample,
steel wool was also inserted at a midway point between two
equal layers of the sample. All samples (ground seeds or pulp-
flakes) were gently compacted inside the extraction vessel to
0.6 kPa. Oil extraction from seeds and pulp-flakes was
conducted at 45ºC and 35 MPa. Flow rate of CO2 through the
sample in the extraction vessel was maintained at approximately
4.5 L/min.
Oil pressing was conducted using a Täby oil screw press
with a 6-mm die (model Type-20, Skeppsta Maskin AB, Örebro,
Sweden). A method adopted from Singh et al. (2002) was used
for oil pressing trials. Prior to pressing, the screw was first
allowed to heat for 20 min via a 120-W electrical resistance
heating ring attached around the press head to raise its
temperature to 95ºC. After heating, the whole seeds and pulp-
flakes were pressed for 4 min to achieve steady flow of press
cake and oil and then 300 g of seeds or pulp-flakes were fed into
the screw press (Yakimishen et al. 2005). During screw
pressing, a computer and data acquisition system (Omega
MultiScan 1200, Omega Engineering, Stamford, CT) was used
to monitor and record the temperature of the extracted oil
stream. Extracted oil was collected in 25-mL vials which were
wrapped with aluminum foil for protection from light (Kiritsakis
et al. 1984). The oil samples in vials were flashed with nitrogen
prior to storage at -25ºC and were analyzed 2 to 4 months later.
In aqueous extraction, seeds were prepared by grinding
following the method used in petroleum-ether extraction.
Ground seeds were added to 40% ethanol in the ratio of 1:2.5
per volume and heated for 2 h at 70ºC in a water bath stirred
periodically. The mixture was centrifuged in 500-mL bottles for
10 min at 8275 × g (7000 rpm, Sorall RC-5C plus, rotor GS-3,
Sorvall, Newton, CT) and at 20ºC. The liquid fraction was
decanted and centrifuged again at room temperature for 10 min
at 17200 × g (10000 rpm, rotor SS-34) to recover seed oil. To
extract oil from the pulp, approximately 2 kg of berries were
macerated using a blender (Osterizer, model LR47897,
Sunbeam Corp, Delray Beach, FL) in approximately 100-g
batches. The blades of the blender were covered with surgical
tubing to prevent seed damage. The blender was operated in
‘stir’ mode for short time intervals (5 to 10 s) repeatedly for 10
cycles. The slurry was heated in a water bath for 1 h at 45ºC and
then centrifuged in 250-mL bottles for 5 min at 7425 × g
(7000 rpm, Sorvall RC Superspeed, model SV728211, rotor
SLA-1500, Sorvall, Newton, CT). Centrifugation produced
three layers: a top cream layer (an emulsion of pulp oil and
suspended solids), a middle juice layer, and a solids layer (seeds
and pulp fibre). The two first layers were decanted and mixed
with 95% ethanol in the volume ratio of 2:1. The mixture was
heated in a water bath for 2 h at 80ºC stirring periodically. The
mixture was then centrifuged in 50-mL vials for 10 min at 7425
× g (7000 rpm) and 45ºC. The resulting oil layer was drawn
from each vial using a Pasteur pipette, flashed with nitrogen,
and used as the starting material for oil analysis.
Oil analysis
To evaluate the levels of extracted compounds in the oil by each
of the four tested extraction techniques, chloroform/methanol
extraction was conducted. This technique can extract all lipids
from a sample and, therefore, served here as reference (Christie
1992).
Fatty acid analysis Composition of fatty acid was established
by analysis of methyl esters prepared according to AOCS
(2000) method Ce 1-62. The fatty acid methyl esters were
analyzed using a Hewlett Packard gas chromatograph (GC)
(Model 5890, Hewlett Packard, Palo Alto, CA) equipped with
split/splitless injector and flame ionization detector. A fused
silica capillary column DB-23 (30 m x 0.25 mm, with film
thickness of 0.25 :m, J&W Scientific, Folsom, CA) was used.
The linear velocity of the hydrogen carrier gas was 0.5 m/s. For
injection, 1 µL of sample was used with a split ratio 1:80.
Column temperature was programmed as follows: 155ºC held
for 2 min, increased at a rate of 2ºC/min to 215ºC, and final
temperature held for 1 min. The injector and detector
temperatures were set at 250ºC. The fatty acid esters were
identified by comparing retention data with a standard mixture
(#461, NuChek Prep, Elysian, MN). The fatty acid composition
was expressed as a mass percentage of the total amount of fatty
acids.
Tocopherol and tocotrienol analysis Tocopherols and
tocotrienols were analyzed following ISO (2004) procedure
9936. These components were separated using normal-phase
High Performance Liquid Chromatography (HPLC) on
Shimadzu 10AD apparatus with a Shimadzu SIL-10A
autoinjector, and RF-10AXL flourescence detector (Shimadzu
Corporation, Kyoto, Japan). The fluorescence detector
excitation and emission wavelengths were set at 290 and
LE GÉNIE DES BIOSYSTÈMES AU CANADA CENKOWSKI et al.3.12
Table 1. Major fatty acid compositions in sea buckthorn seed and pulp oil, as mass percentage of total amount of fatty
acid, extracted with different extraction techniques.
Fatty acid
(common name)
Reference Extraction technique (seeds and pulp)
Chloroform/
methanol
Petroleum-
ether
SCFE CO2
3 h or 6 h Screw press Aqueous**
Seeds*
16:0 (Palmitic)
18:0 (Stearic)
18:1n-9 (Oleic)
18:1n-11 (11-Octadecanoic)
18:2n-6 (Linoleic)
18:3n-3 (Linolenic)
7.5 ± 0.1
2.8 ± 0.01
13.4 ± 0.03
2.3 ± 0.02
36.3 ± 0.2
35.9 ± 0.2
7.0 ± 0.1
2.6 ± 0.04
13.6 ± 0.02
2.1 ± 0.1
35.5 ± 0.2
37.4 ± 0.1
7.2 ± 0.3
2.4 ± 0.1
13.0 ± 0.3
1.9 ± 0.01
35.9 ± 0.1
37.9 ± 0.1
6.7 ± 0.2
2.5 ± 0.01
13.6 ± 0.04
1.9 ± 0.05
35.3 ± 0.1
38.5 ± 0.2
n/a
Pulp*
16:0 (Palmitic)
16:1 (Palmitoeic)
18:0 (Stearic)
18:1n-9 (Oleic)
18:1n-7 (11-Octadecanoic)
18:2n-6 (Linoleic)
18:3n-3 (Linolenic)
24:1 (Nervonic)
34.8 ± 0.3
34.4 ± 0.01
1.2 ± 0.01
3.4 ± 0.03
7.1 ± 0.03
13.5 ± 0.1
2.0 ± 0.2
1.1 ± 0.01
35.2 ± 0.1
35.0 ± 0.03
1.2 ± 0.01
3.3 ± 0.1
6.9 ± 0.01
12.8 ± 0.01
1.5 ± 0.01
1.3 ± 0.1
35.5 ± 0.01
36.3 ± 0.1
1.1 ± 0.0
3.5 ± 0.03
6.9 ± 0.05
12.4 ± 0.1
1.2 ± 0.01
0.9 ± 0.02
n/a
34.3 ± 0.01
38.5 ± 0.01
1.1 ± 0.0
3.2 ± 0.01
7.3 ± 0.02
13.0 ± 0.1
1.1 ± 0.01
0.05 ± 0.01
* Standard deviations (n = 2)
** Non-processed pulp used
n/a = technology not applicable
335 nm, respectively. A Prodigy 5-:m silica column (250 mm
x 3.20 mm; Phenomenex, Torrance, CA) was used for
separation with 5% tert-butylmethyl ether in hexane as the
mobile phase. The 10 :L sample (solution of oil in hexane) was
injected for analysis. The identification of individual
tocopherols was done by comparing retention data with
standards (MJSBioLynx, Brockville, ON; Cat# MT1072,
MT1071, MT1073, and MT1790 for calibration of each
tocopherol and diluted accordingly in hexane). Quantification
is based on external calibration for all isomers of tocopherol and
tocotrienol. Amounts of tocopherols and tocotrienols are
expressed as a percentage of the total amounts of tocopherol and
tocotrienol and in mg/100 g of oil.
Determination of carotenoids Total amounts of carotenoids
were determined following the modified method by Gao et al.
(2000). Solutions of oil in hexane (0.1 g/10 mL) were measured
at 460 nm in the spectrophotometer (Spectronic, model 3000
ARRAY, Milton Roy, Ivyland, PA). Quantification of the
amounts of carotenoids were based on calibration with $-
carotene standard (type II: synthetic) and amounts of
carotenoids were expressed in mg/100 g of oil.
Analysis of sterols Sterols were analyzed by GC following a
method adapted from Yang et al. (2001). Oil samples were
saponified at room temperature with 2M potassium hydroxide
in ethanol for 24 h. After saponification, water was added to the
sample and unsaponified matter was extracted three times with
diethyl ether. Extracts were washed with water until neutral and
the solvent was removed using a rotary evaporator under
vacuum. Residue was dissolved in isooctane and analyzed for
composition. Sterols were analyzed using Shimadzu GC model
17A (Shimadzu Corporation, Kyoto, Japan) on a DB-5 capillary
column (30 m x 0.25 mm; phase thickness 0.25 :m, Restek,
Bellefonte, PA). The column temperature was programmed as
follows: held at 60ºC for 1 min, programmed at 40ºC/min to
240ºC, held for 1 min, and finally programmed to 300ºC at
2ºC/min, final temperature was held for 2 min. Hydrogen
(2.2 mL/min) was used as a carrier gas. The injector and
detector temperatures were set at 275 and 320ºC, respectively.
Sterols were identified by comparison of retention data with
standards and quantified using internal standard 5"-cholestane.
Sterol amounts were expressed as a mass percentage of the total
amount of sterols and in mg/100 g of oil.
Oil samples obtained from seeds, pulp (in aqueous
extraction), and pulp-flakes using different extraction techniques
were analyzed in duplicate.
RESULTS and DISCUSSION
Fatty acids
Three major fatty acids namely oleic, linoleic, and linolenic acid
were in the seed control sample extracted with
chloroform/methanol. These fatty acids comprised more than
85% of all fatty acids (Table 1). The latter two acids were the
predominant fatty acids with contributions of 36.5 and 35.9%,
respectively. Similar values were reported for European (ssp.
rhamnoides) sea buckthorn seeds (Yang and Kallio 2002). Seed
oil for subspecies sinensis and rhamnoides has been
characterized as being high in unsaturated fatty acids (40%
linoleic, 20% linolenic, and 17% oleic acids) and lower in
Volume 48 2006 CANADIAN BIOSYSTEMS ENGINEERING 3.13
Table 2. Major tocopherol and tocotrienol concentrations (mg/100 g oil) in sea buckthorn seed and pulp oil obtained
with different extraction techniques.
Compound
Reference Extraction technique (seeds and pulp)
Chloroform/
methanol
Petroleum-
ether
SCFE CO2Screw press Aqueous**
3 h 6 h
Seeds*
"-tocopherol
$-tocopherol
(-tocopherol
*-tocopherol
$-tocotrienol
Plastochromanol-8
121 0 ± 6.2
9.5 ± 0.6
130.0 ± 5.4
6.4 ± 0.9
6.7 ± 0.3
2.9
223.4 ± 11.8
11.8 ± 0.1
177.4 ± 4.5
8.0 ± 0.1
9.7 ± 0.3
n/d
170.5 ± 36.9
11.2 ± 0.3
154.2 ± 18.4
8.8 ± 0.3
7.6 ± 1.5
n/d
196.7 ± 18.3
12.1 ± 0.3
176 ± 10.2
8.6 ± 0.2
9.2 ± 0.6
n/d
147.8 ± 4.4
8.1 ± 0.02
127.0 ± 4.1
5.3 ± 0.1
7.2 ± 0.4
n/d
n/a
Pulp*
"-tocopherol
$-tocopherol
(-tocopherol
*-tocopherol
(-tocotrienol
Plastochromanol-8
220.8 ± 0.0
21.1 ± 0.2
11.1 ± 0.3
6.5 ± 0.3
1.7 ± 1.2
13.2 ± 0.2
143.7 ± 7.9
14.5 ± 0.1
7.2 ± 0.4
5.3 ± 1.2
2.3 ± 0.6
8.1 ± 0.2
101.1 ± 16.2
11.3 ± 0.01
6.7 ± 0.1
6.0 ± 0.03
2.3 ± 0.01
1.6 ± 0.4
113.0 ± 12.1
12.6 ± 0.5
7.0 ± 0.2
6.2 ± 0.2
2.5 ± 1.0
1.9 ± 1.1
n/a
138.4 ± 11.4
9.4 ± 1.5
3.0 ± 0.2
n/d
2.9 ± 0.2
8.3 ± 1.0
* Standard deviations (n = 2)
** Non-processed pulp used
n/a = technology not applicable
n/d = not detected
saturated fatty acids (13% palmitic and 8% steric acids) (Li and
Beveridge 2003). Seed oil from these subspecies has a high
concentration of two essential fatty acids, namely linoleic (42%)
and linolenic (39%) acid. Higher concentrations of linolenic
acid (37.4 – 38.5%) were found when solvent SCFE CO2 or
screw press were used in comparison to chloroform/methanol
extraction as control (35.9% for seeds). The variation in the
concentration of fatty acids in the four tested techniques was
negligible.
There was no difference in fatty acid composition in seed or
pulp-flake oil extracted by SCFE CO2 conducted for 3 h versus
6 h. Therefore, Table 1 does not distinguish the extraction
duration for SCFE CO2.
Palmitic and palmitoleic acid were the predominant fatty
acids in the sea buckthorn pulp-flake oil. Contributions of both
acids to the pulp-flakes in the reference sample were 34.4 and
34.8%, respectively (Table 1). Lipids from the pulp of
subspecies sinensis and rhamnoides have been characterized
(Yang and Kallio 2002) as having high concentrations (up to
47%) of saturated fatty acids comprised primarily of palmitic
acid and lower concentrations of unsaturated fatty acids such as
palmitoleic (28%), oleic (18%), linoleic (4%), and linolenic
(2%). Palmitoleic acid concentration in oil extracted from pulp
by aqueous extraction was the highest (38.5%) among the four
techniques tested. This could be attributed to the fact that in
aqueous extraction unprocessed pulp was used. In all other
extraction techniques pulp-flakes were produced by drying at
50ºC for 24 h, which may have reduced the concentration of
palmitoleic acid in the oil.
Tocopherols and tocotrienols
Control sample concentrations (chloroform/methanol extracted)
comprising 273.6 mg/100 g of oil of tocopherols and
tocotrienols in seed and 261.2 mg/100 g of oil in the pulp oil are
shown in Table 2. Seed oil was comprised primarily of "-
tocopherol (vitamin E) and (-tocopherol, which were more than
90% of the total amount of analyzed chromanols.
Concentrations of "-tocopherol, the predominant tocopherol
in the seed oil, fluctuated with extraction method (Table 2). The
concentration of "-tocopherol was highest in the petroleum-
ether extracted oil (223.4 mg/100 g oil), followed by SCFE CO2
(170.5 to 196.7 mg/100 g oil), and then screw pressing
(147.8 mg/100 g oil). Concentrations of "-, $- and (-
tocopherols tended to increase with the SCFE CO2 duration (3
versus 6 h extraction time). Screw pressed oil contained the
lowest concentration of tocopherols and tocotrienols.
Generation of friction during screw pressing, resulting in
temperatures exceeding 60ºC, may have caused thermal
degradation of tocopherol and tocotrienols (Bockisch 1998).
Predominant tocopherols in the pulp oil were "-tocopherol
and $-tocopherol, with "-tocopherol constituting 85% of the
total tocopherols and tocotrienols identified (Table 2).
Processing of pulp which included, thawing berries, macerating,
extracting juice, pressing cake, drying, threshing, and sieving
had a deleterious effect, decreasing "-tocopherol concentrations
in pulp-flake oil. Pulp oil extracted by petroleum-ether
contained the highest concentration of "-tocopherol
(143.7 mg/100 g oil), followed by aqueous (138.4 mg/100 g
oil), and SCFE CO2 (101.1 mg/100 g for 3 h extraction; to
113.0 mg/100 g oil for 6 h extraction).
LE GÉNIE DES BIOSYSTÈMES AU CANADA CENKOWSKI et al.3.14
Table 4. Sterol concentrations (mg/100 g oil) in sea buckthorn seed and pulp oil obtained with different extraction
techniques.
Compound
Reference Extraction technique (processed seeds and pulp-flakes)
Chloroform/
methanol
Petroleum-
ether
SCFE CO2Screw press Aqueous**
3 h 6 h
Seeds*
Cholesterol
Campesterol
Stigmasterol
$-sistosterol
n/d
17.2 ± 0.5
n/d
598.9 ± 6.3
3.7 ± 1.0
22.4 ± 0.5
n/d
746.3 ± 22.8
n/d
19.9 ± 0.1
n/d
667.8 ± 20.8
n/d
22.5 ± 0.7
n/d
748.1 ± 5.1
n/d
18 ± 10.7
2.7a
635 ± 43.9
n/a
Pulp*
Cholesterol
Campesterol
Stigmasterol
$-sistosterol
4.6 ± 0
9.7 ± 0.1
n/d
522.06.8
4.5 ± 1.4
12.4 ± 0.6
6.6 ± 2.5
576.9 ± 32.3
n/d
10.9 ± 0.04
n/d
525.0 ± 13.5
n/d
10.9 ± 0.2
10.8 ± 3.4
525.7 ± 5.2
n/a
n/d
6.6 ± 0.6
n/d
288.6 ± 8.6
* Standard deviations (n = 2)
** Non-processed pulp used
a n = 1
n/a = technology not applicable
n/d = not detected
Table 3. Total carotenoids sea buckthorn seeds and pulp oil obtained with different oil extraction techniques. Total
carotenoids are expressed in mg/100g of expressed oil.
Material
Reference Extraction technique*
Chloroform/
methanol
Petroleum-
ether
SCFE CO2Screw press Aqueous**
3 h 6 h
Seeds
Pulp
17.2 ± 0.2
347.1 ± 48.2
22.2 ± 0.7
527.8 ± 14.9
6.2 ± 2.6
122.3 ± 3.7
11.7 ± 0.1
148.4 ± 11.7
15.3 ± 0.1
n/a
n/a
292.4 ± 16.1
* Standard deviations (n = 2)
** Non-processed pulp used
n/a = technology not applicable
Total carotenoids
Total carotenoid concentration in oil obtained from seeds from
the reference sample was 17.2 mg/100 g oil (Table 3).
Beveridge et al. (1999) reported trace amounts of total
carotenoids in seed oil of some sea buckthorn varieties ranging
between 50 and 85 mg/100 g oil. Beveridge (2003) reported a
total carotenoid concentration of 41.1 mg/100 g in seed oil of
cv. Indian-Summer, however, the method of oil extraction was
not mentioned. It seems that in our experiments separation of
seeds from pulp involving thawing berries, macerating,
extracting juice, pressing cake, drying, threshing, and sieving
negatively affected the total concentration of carotenoids. A
comparison of total carotenoids in seed oil showed substantial
variation in the carotenoid content between solvent extraction
(22.2 mg/100 g oil), SCFE CO2 (6.2 to 11.7 mg/100 g oil), and
screw press (15.3 mg/100 g oil). Concentration of total
carotenoids increased with extraction time (3 to 6 h). Screw
pressed oil contained higher amounts of total carotenoids
compared to the SCFE CO2 technique.
Total carotenoids in chloroform/methanol extracted oil from
pulp-flakes were 347.1 mg/100 g oil. Beveridge (2003) reported
a wide range of total carotenoids from 330 to 1000 mg/100 g
oil, depending on plant subspecies or cultivar. Petroleum-ether
extracted pulp oil (Table 3) had the highest concentration of
total amounts of carotenoids (527.8 mg/100 g oil) followed by,
aqueous extraction (292.4 mg/100 g oil), and SCFE CO2
extracted oil (148.4 mg/100 g oil, 6 h extraction). The
concentration of total carotenoids from SCFE CO2
pulp-flake oil
increased with extraction duration from 122.3 mg/100 g oil after
3 h to 148.4 mg/100 g oil after 6 h extraction.
Sterols
Presence of cholesterol, campesterol, stigmasterol, and $-
sitosterol in seed oil extracted with chloroform/methanol as
reference and the four tested techniques are shown in Table 4.
Seed oil was comprised primarily of $-sitosterol (97%) with
trace amounts of campesterol (2%). Yang et al. (2001) reported
Volume 48 2006 CANADIAN BIOSYSTEMS ENGINEERING 3.15
Table 5. Effect of extraction methods employed on changes of nutritional components in oils (order of increasing
concentration: low < high < highest).
Oil components
Extraction method
Petroleum-
ether SCFE CO2Screw press Aqueous
Seed oil
Major fatty acids Similar concentrations for most fatty acids
Major tocopherols and tocotrienols
Total carotenoids
Major sterols
high
high
high
highest
highest
highest
low
low
high
n/a
n/a
n/a
Pulp oil
Major fatty acids Similar concentrations for most fatty acids
Major tocopherols and tocotrienols
Total carotenoids
Major sterols
high
highest
highest
low
low
high
n/a
n/a
n/a
high
high
low
n/a = not applicable, no oil extracted
that $-sitosterol is the major sterol in seeds of ssp. sinensis.
Cholesterol and stigmasterol were not detected in seed oil
samples.
The concentration of $-sitosterol in seed oil changed with
extraction method, namely solvent extraction (746.3 mg/100 g
oil), SCFE CO2 (667.8 to 748.1 mg/100 g oil), and screw
pressing (635.0 mg/100 g oil) (Table 4). A similar trend was
evident with campesterol concentrations. The amount of $-
sitosterol and campesterol increased by more than 10% when
extraction time was increased from 3 to 6 h. Beta-sitosterol and
campesterol concentrations in the seed oil were lower for screw
pressed oil compared to solvent extraction and SCFE CO2
extracted oils. The highest oil temperatures were evident in the
screw pressing ranging from 63.0 to 69.6ºC. Frictional heat
generated during screw pressing resulted in temperatures greater
than 60ºC that may have caused thermal degradation of these
compounds. Analysis of the screw press residues would be
needed to verify the above statement. Cholesterol was found
only in the solvent extracted seed oil at a concentration of
3.7 mg/100 g oil.
Campesterol, stigmasterol, and $-sitosterol were present in
the pulp oil with the latter having the highest contribution
(97%). The petroleum-ether technique extracted similar
quantities of cholesterol (4.5 mg/100 g oil) as was extracted by
the chloroform/methanol method. This technique also extracted
the highest amount of $-sitosterol (576.9 mg/100 g oil) as
compared to SCFE CO2 (525.0 mL/100 g oil) and aqueous
extraction methods (288.6 mg/100 g oil). The duration of SCFE
CO2 extraction had no effect on concentrations of sterols.
However, after a 6 h extraction, stigmasterol (10.8 mg/100 g oil)
was detected in the pulp oil.
Nutritional quality summary
The information gathered in this research on nutritional
components such as fatty acids, tocopherols and tocotrienols,
carotenoids, and sterols in sea buckthorn seed and pulp oils
showed the effects of processing and extraction on final product
quality. Table 5 qualitatively summarizes relative concentrations
of fatty acids, tocopherols and tocotrienols, total carotenoids,
and sterols associated with the extraction technologies studied.
Petroleum-ether extraction consistently recovered oils having
higher amounts of all analyzed nutritional components. Yang
and Kallio (2002) suggested that solvent extraction is not
suitable for sea buckthorn oil extraction because harmful solvent
residues can be left behind in extracted oil and adds to
environmental pollution. Aqueous extraction and screw pressing
methods are limited by the type of material (seeds vs pulp)
which can be processed (Yakimishen et al. 2005). The SCFE
CO2 method was flexible in extracting both seed and pulp oils
having relatively high concentrations of all identified nutritional
compounds. The addition of co-solvents with CO2 may enhance
selectivity for extracting additional nutritional components. Data
presented on the concentrations of nutritional components
associated with a Canadian sea buckthorn cultivar may be used
as a guideline for processing and extracting to achieve oils
having high nutritional value.
CONCLUSIONS
The nutritional qualities of seed and pulp oils from sea
buckthorn berries were evaluated after oil extraction was
conducted using four oil isolation techniques. These were:
solvent extraction using petroleum-ether, supercritical fluid
extraction using carbon dioxide (SCFE CO2), screw pressing,
and aqueous extraction. The extracted nutritional quantities
were compared against solvent extraction using
chloroform/methanol as reference. In general, aqueous
extraction was unsuccessful in extracting oil from sea buckthorn
seeds and screw pressing was unsuccessful in extracting oil from
pulp-flakes.
The concentration of fatty acids in oil extracted from seeds
and pulp-flakes was similar in all tested extraction techniques.
Petroleum-ether extraction recovered oils having the highest
concentrations of tocopherols (420.6 mg/100 g seed oil and
170.7 mg/100 g pulp oil) and tocotrienols (9.7 mg/100 g seed
oil and 7.6 mg/100 g pulp oil), carotenoids (22.2 mg/100 g seed
oil and 527.8 mg/100 g pulp oil), and sterols (772.4 mg/100 g
seed oil and 600.4 mg/100 g pulp oil), followed by SCFE CO2.
Screw pressed and aqueous extracted oils contained the lowest
amounts of nutritionally important components.
Concentrations of "-, $-, (-tocopherols, and total
carotenoids extracted with oil from seeds and pulp-flakes, and
LE GÉNIE DES BIOSYSTÈMES AU CANADA CENKOWSKI et al.3.16
$-sitosterol and campesterol extracted with oil from seeds
increased with the SCFE CO2 duration (3 versus 6 h extraction
time); but the duration of SCFE CO2 extraction had no effect on
concentrations of sterols extracted from pulp-flake oil.
ACKNOWLEDGEMENTS
The authors thank the Natural Sciences and Engineering
Research Council (NSERC), Manitoba Hydro, and the Manitoba
Rural Adaptation Council (MRAC).
REFERENCES
AACC. 2000. 02-01A. Fat acidity – General method. In 2000
Approved Methods of the American Association of Cereal
Chemists, 10th edition, 1-2. St. Paul, MN: American
Association of Cereal Chemists.
AOCS. 2000. Ce 1-62. In Official and Tentative Methods of the
American Oil Chemists Society. Champaign, IL: AOCS.
Bargale, P.C., R.J. Ford, F.W. Sosulski, D. Wulfsohn and J.
Irudayaraj. 1999. Mechanical oil expression from extruded
soybean samples. Journal of the American Oil Chemists
Society 76(2):223-229.
Beveridge, T. 2003. Chemical composition and some physical
properties. In Sea Buckthorn (Hippophaë rhamnoides L.):
Production and Utilization, eds. T.S.C. Li and T. Beveridge,
79-88. Ottawa, ON: NRC Research Press.
Beveridge, T., T.S.C. Li, B.D. Oomah and A. Smith. 1999. Sea
buckthorn products: Manufacture and composition. Journal
of Agriculture and Food Chemistry 47(9):3480-3488.
Bockisch, M. 1998. Fats and Oils Handbook. Champaign, IL:
AOCS Press.
Burkhalter, J.P. 1976. Crude oil handling and storage. Journal
of the American Oil Chemists Society 53(6): 332-333.
Carr, R. 1997. Oilseed processing. In Technology and Solvents
for Extracting Oil Seeds and Nonpetroleum Oils, eds. P.
Wan and P. Wakelyn, 101-120. Champaign, IL: AOCS
Press.
Christie, W.W. 1992. Gas Chromatography and Lipids - A
Practical Guide. Ayr, Scotland: The Oily Press.
Datamonitor. 2005. Insights into tomorrows nutraceutical
consumers. http://www.researchandmarkets.com/reports/
c29794/ (2005/12/20)
Gao, X., M. Ohlander, N. Jeppsson, L. Björk and V. Trajkovski.
2000. Changes in antioxidant effects and their relationship
to phytonutrients in fruits of sea buckthorn (Hippophaë
rhamnoides L.) during maturation. Journal of Agricultural
and Food Chemistry 48(5):1485-1490.
Hardy, Gil. 2000. Nutraceuticals and functional foods:
introduction and meaning. Nutrition 16(7-8):688-697.
ISO. 2004. Procedure 9936. Determination of Tocopherols and
Tocotrienols Content - Method by High Performance Liquid
Chromatography. Geneva, Switzerland: International
Standards Organization.
Kallio, H., B. Yang, P. Peippo, R. Tahvonen and R. Pan. 2002.
Triacylglycerols, glycerophospholipids, tocopherols,
tocotrienols in berries and seeds of two sspecies (ssp.
sinensis and mongolica) of sea buckthorn (Hippophaë
rhamnoides). Journal of Agriculture and Food Chemistry
50(10):3004-3009.
Kalustian, P. 1985. Pharmaceutical and cosmetic uses of palm
and lauric products. Journal of the American Oil Chemists
Society 62(2):431-435.
Kiritsakis, A.K. 1984. Effect of selected storage conditions and
packaging materials on olive oil quality. Journal of the
American Oil Chemists Society 61(12):1868-1870.
Li, T.S.C. and T. Beveridge. 2003. Sea Buckthorn (Hippophae
Rhamnoides L.): Production and Utilization. Ottawa, ON:
NRC Research Press.
Li, T.S.C. and W.R. Schroeder. 1999. A Grower’s Guide to Sea
Buckthorn. Pacific Agri-Food Research Centre, Agriculture
and Agri-Food Canada, Research Branch, Summerland, BC.
Menrad, K. 2003. Market and marketing of functional food in
Europe. Journal of Food Engineering 56(2-3):181-188.
Oomah, B.D. and G. Mazza. 1999. Health benefits of
phytochemicals from selected Canadian crops. Trends in
Food Science and Technology 10(6-7):193-198.
Puupponen-Pimiä, R., A.-M. Aura, K.-M. Oksman-Caldentey,
P. Myllärinen, M. Saarela, T. Mattila-Sandholm and K.
Poutanen. 2002. Development of functional ingredients for
gut health. Trends in Food Science and Technology 13(1):3-
11.
Singh, K.K., D. Wiesenborn, N. Kangas and K. Tostenson.
2002. Characterization of preparation parameters for
improved screw pressing of crambe seed. Transactions of
the ASAE 45(4):1029-1035.
Storey, G. 2000. Competitive market analysis of sea buckthorn
in Saskatchewan. Publication AFIF 19970307. Department
of Agricultural Economics, University of Saskatchewan,
Saskatoon, SK.
Yakimishen, R., S. Cenkowski and W.E. Muir. 2005. Oil
recoveries from sea buckthorn seeds and pulp. Applied
Engineering in Agriculture 21(6):1047-1055.
Yang, B. and H. Kallio. 2002. Composition and physiological
effects of sea buckthorn (Hippophaë) lipids. Trends in Food
Science and Technology 13(5):160-167.
Yang, B., R.M. Karlsson, P.H. Oksman and H.P. Kallio. 2001.
Phytosterols in sea buckthorn (Hippophaë rhamnoides L.)
berries: Identification and effects of different origins and
harvesting times. Journal of Agricultural and Food
Chemistry 49(11):5620-5629.
