Download effect of electric field treatment on avocado oil

Nov. 2013. Vol. 1, No.1
ISSN 2133-2476
International Journal of Research In Agriculture and Food Sciences
© 2013 IJRAFS & K.A.J. All rights reserved
http://www.ijsk.org/ijrafs.html
EFFECT OF ELECTRIC FIELD TREATMENT ON AVOCADO OIL
JOSÉ ALBERTO ARIZA ORTEGA1, María Reyna Robles López2,
Raúl René Robles de la Torre2,
1
Universidad Autónoma del Estado de Hidalgo. Instituto de Ciencias de la Salud. Área Académica de Nutrición. Carretera
Actopan-Tilcuautla, ex-hacienda la Concepción, san Agustín Tlaxiaca, Pachuca. CP.
2
Centro de Investigación en Biotecnología Aplicada-Instituto Politécnico Nacional.
Carr. est. Sta. Inés Tecuexcomac, Km 1.5. Tepetitla, Tlaxcala, México.
E-mail:*[email protected]
ABSTRACT
We propose an experimental proposal to evaluate the temporal effects of electric field (EF)
application on avocado oil samples, based on the idea of inactivation of Polyphenol-Oxidase Enzyme (POE)
in avocado pulp. In the present work, EF treatments (9 kVcm-1, frequency 720 Hz and time of 3 min) and two
strategies were utilized: EF on avocado oil (oil 1) and EF on avocado pulp, then the oil was extracted (oil 2)
were evaluated to assess their effect on the fatty acid profile in avocado pulp. The effect of EF treatment on
chemical values of the oils: acidity, peroxide and iodine were also determined. After EF treatment, nonsignificant changes in the contents of saturated fatty acids, monounsaturated and polyunsaturated fatty
acids were observed, with the chemical values determined in avocado oil crude presented deterioration, but
changes were statistically not significant.
Keywords: Avocado, electric field, fatty acids, gas chromatography, oil.
et al., 2000); among the emerging technologies are: high
hydrostatic pressure, modified atmospheres, ultrasound,
irradiation,
freeze
drying,
microwave,
pulsed
electromagnetic field or pulsed electric field and electric
field (Raso and Barbosa-Cánovas, 2003).
1. Introduction
Avocado is mainly consumed as a fresh fruit,
however, to increase commercialization on a large scale and
to give an added value to avocado pulp, it is important to
develop food products derived from this fruit with an
extended shelf life. One the problems for preserving
avocado pulp products is the enzymatic browning, catalyzed
by the action of polyphenol oxidase and other oxidantreducing enzymes (Dorantes et al., 2004).
Pulsed
electric
field
(PEF)
inactivates
microorganisms and enzymes, is a non-thermal of
conservation method that uses a high voltage (kV cm-1) and
the time of application is short µs or ms (Qin et al., 1996).
Researchers have suggested that the effect of the
electric field on enzymes resides in the modification of its
conformational structure. Yeom et al. (1999) studied the
effect of PEF (50 kV cm-1, 2000 µs, 35 °C) on papaya, and
they determined that the decrease of the enzyme papain
(90%) is by the loss of α-helix structure. On the other hand,
Giner et al. (2002) reported that PEF treatment (22.3 kV cm1
, 6000 µs, 15 °C) on the pear affects the enzyme polyphenol
oxidase (70%), due to the PEF modifies its molecular
structure.
To avoid this deterioration in the avocado pulp,
traditional and emerging methods are used. Traditional
methods usually consist of thermal processes. However, the
application of heat is not suitable for most fruits and
vegetables (Jacxsens et al., 2001). Emerging technologies
may have a solution to the mentioned problem, because
these inactivate enzymes and produce microbiologically safe
foods with fresh-like flavour and taste without significant
loss of nutrients (Espachs-Barroso et al., 2003), moreover,
they avoid the negative effects of thermal treatments (Giner
13
Nov. 2013. Vol. 1, No.1
ISSN 2133-2476
International Journal of Research In Agriculture and Food Sciences
© 2013 IJRAFS & K.A.J. All rights reserved
http://www.ijsk.org/ijrafs.html
On the other side, among the nutritional composition
of avocado pulp, the lipids are second in concentration with
values of 21% and are a potential source of oil (OrtizMoreno et al., 2003). Avocado oil contains fatty acids
similar to the virgin olive oil (Ratovohery et al., 1988). The
main monounsaturated and polyunsaturated fatty acids, are
oleic acid (C18:1 or ω-9) and linoleic acid (C18:2 or ω-6),
found in a relative concentrations of 60.28 and 13.66% in
avocado oil and in virgin olive oil a value of 73 and 7%
respectively (Andrikopoulos et al., 2002).
2.3 Gas chromatography
The gas chromatography (GC) system consisted of a
GC HP-5890 (Hewlett-Packard Company, Palo Alto,
California, USA) equipped with a Flame Ionization Detector
(FID). The especifications of column were RT®-2560 fused
silica capillary column (biscyanopropyl polysiloxane), 100
m long, 0.25 mm ID, 0.2 μm film thickness (Restek
Corporation, Bellefonte, Pennsylvania, USA). To calibrate
the GC system for analysis, a FAMEs mixture of 37component Food Industry FAME Mix (Restek Corporation,
USA) were used. The injection was realized with 2 µL (split
ratio 20:2). In where the best conditions were the follows:
the injector and detector were maintained at 230 and 250 °C
respectively. The carrier gas was N2 at a flow rate of 1.2 mL
min-1. For avocado oil samples, the oil was saponified and
derivatized at methyl esters, using KOH 1 N (IUPAC, 1979).
The extraction of methyl esters was performed using
10 mL of hexane and 10 mL of distilled water, two phases
were separated. Residue was solubilized in hexane. The
samples were injected and were analyzed with the
specifications that were indicated previously. The fatty acids
content was calculated as the percentage total of fatty acids
methyl esters (FAMEs).
Omega fatty acids (ω-9 and ω-6) are associated the
linolenic acid (C18:3), which is the precursor of fatty acids
ω-3 (stearidonic acid C18:4, arachidonic acid C20:4 and
eicosapentaenoic acid C20:5). Eicosapentaenoic acid is the
precursor of the docosahexaenoic acid (C22:6),
prostaglandins, thromboxanes and leukotrienes, these
compounds are related with important biological functions,
such as the activation of platelets and leukocytes, stimulate
the coagulation process, are extremely potent constrictors of
the smooth musculature and increases vascular permeability
(Teitelbaum and Walker, 2001).
Avocado oils can provide renewable sources of highvalue fatty acids for both the chemical and health-related
industries. The idea of this study was concerning the
treatment of electric field in avocado oil and its effect on
fatty acids that are required in these food guacamole, pulp
and oil.
2.4 Electric field treatment
In a previous study for the inactivation of polyphenol
oxidase enzyme in avocado pulp with electric field (EF),
was demostrated that the activity of the enzyme decreased a
70% upon EF treatment with 720 Hz, 9 kV cm-1 and 3 min.
However, is not known the effect of the EF on fatty acids,
for this reason two series of experiments were carried:
2. Materials and methods
Avocado (Persea americana Mill var. Hass) in the
stage of commercial ripeness was used. For the work, a
sample of 3 undamaged fruits free of defects were selected,
subsequently they were washed and was removed manually
epicarp and seed. Avocado pulp was characterized for the
following analysis of moisture, protein, lipids, crude fiber,
ash and carbohydrates by difference (Matissek et al., 1998).
Each analysis was performed in triplicate.
1.- Avocado oil was extracted with solvent and
treated directly with the electric field (oil 1).
2.- Avocado pulp was first exposed to the electric
field and after oil was extracted with solvent (oil 2).
The samples were deposited between two electrodes
at 20 kV and 2 cm away (10 kV cm-1), the waveform was
square and the electrical power was 5 mA. The experiments
were performed in triplicate.
2.5 Statistical analysis
2.1 Oil extraction
For oil extraction, avocado pulp was homogenized in
a blender (Braun Food Processor MultiPractic) for 20 s. 100
g of pulp were placed into a porous cartridge and was
extracted using hexane by soxlhet method at 69 ± 1 °C for 4
h (Ortiz-Moreno et al., 2003).
The data were expressed as mean ± SE. Statistical
analysis were performed using analysis of variance
(ANOVA). A value of α = 0.05 was considered statically
significant, with the Statistical Analysis System, version 6.1
(SAS Institute Inc., Cary, NC, USA).
2.2 Chemical values
Determinations of acidity (NM, 1987a), peroxide,
(NM, 1987b) and iodine values (NM 1981) were carried out
using mexican norms. Each analysis was performed in
triplicate.
3. Results and discussion
3.1 Characterization of pulp and avocado oil
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Nov. 2013. Vol. 1, No.1
ISSN 2133-2476
International Journal of Research In Agriculture and Food Sciences
© 2013 IJRAFS & K.A.J. All rights reserved
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Oil content in avocado pulp of hass variety using
Soxlhet method extraction (69 ± 1 °C for 4 h) was of 90% of
yield. Bizimana et al. (1993) extracted avocado oil of the
same variety by slurries and centrifugation, with the
followings conditions 5:1 water to avocado ratio, pH 5.5, 5%
CaCO3 or CaSO4, heating temperature 75-98°C, gravity
settling for four days at 37°C and 12.300 x g of centrifugal
force and its recoveries a 70-80% avocado oil. Solvent
employed for obtained the oil in this work increased the oil
extraction, due to the solvent polarity (hexane) which has
structural and chemical characteristics that is similar to the
oil, facilitating its solubility and obtaining. The nature of
solvents selected is an important factor as well as the applied
temperature to the extraction treatment, since it may damage
some containing structures oil, as reported Ortiz-Moreno et
al. (2003), these investigators studied the effect of different
extraction methods on the cells containing the oil, mainly
idioblasts (which are round and have a smooth surface), and
they concluded that at a temperature >100 °C the cells are
transformed into an irregular form and a rough surface,
which it affects oil extraction and the yield.
On the other hand, in relation to compositional
analysis of the avocado pulp (wet basis) are shown in the
first column of Table 1 and compared with reported values
in the literature by Bora et al. (2001) and Ortiz-Moreno et al.
(2003).
Table 1. Characterization and comparison of avocado pulp with other varieties.
Varieties
Component (%)
Hass
Fuerte
(Bora et al., 2001)
Hass
(Ortiz-Moreno et al., 2003)
73.8 ± 3.1
78.24
77.3
Protein
1.4 ± 0.2
1.01
1.6
Lipids
15.3 ± 2.2
15.39
15.8
Fiber
0.51 ± 0.01
0.53
0.4
Ash
1.5 ± 0.3
0.66
1.3
7.49 ± 1.2
4.17
5.6
Moisture
Carbohidrates
Sample of 3 replicates ± SD.
Table 1 shows values different analysis of avocado
pulp, first, moisture content in our result was similar to
reported by Bora et al. (2001) and Ortiz-Moreno et al.
(2003) for avocado fuerte and hass varieties. Sanchez-Perez
(2001) indicated that when present avocado pulp a moisture
content approximately 80%, the fruit is in its physiological
ripening or harvest point, moreover, increase its respiration
rate and releases carbon dioxide and ethylene, if it not
carefully collected and transported affects its post-harvest
life and its quality, caused by mechanical damage that
accelerates its deterioration by the enzymes and microbial
growth due to moisture content and nutrient.
persimmon, and about six times as much as the two other
common fruits listed, apricot and apple. Polansky and
Murphy (1966) compared the protein content of 26 more
common fruits and vegetables (41 entries counting separate
cultivars and years). The avocado was in first place with
about two to ten times the protein content of the others.
FAO/WHO (1973) reported the recommend value the
eight essential amino-acids concentration that contain the
food, valyne 50 mg, lysine 55 mg, phenylalanine 60 mg,
isoleucyne 40 mg, leucyne 70 mg, treonyne 40 mg,
metionyne 35 mg and tryptophan 10 mg. By taking previous
data, the avocado pulp is a complete food in terms of
protein, since it contains seven of eight essential aminoacids reported by FAO/WHO, in 100 g of avocado pulp
amino acids are found valyne 63 mg, lysine 59 mg,
phenylalanine 48 mg, isoleucyne 47 mg, leucyne 46 mg,
treonyne 40 mg and metionyne 29 mg. Tryptophan is the
limiting amino-acid in avocado pulp (Ortega, 2003). The
fact that the avocado pulp is an excellent source of essential
amino-acid, can be an option in the diet it could already be
In relation with protein value avocado pulp contains a
low level (Table 1). Proteins contents in avocado species are
lower than the corresponding values for conventional fruit.
Slater et al. (1975) reported that avocado hass variety
contain 2.4% protein on a fresh weight basis, this is
unusually high for a fruit. Hall et al. (1980) compared the
essential amino acid content of 15 fruits, the avocado was
second only to the rare tucuma from Brazil which had about
three times as much as mango, orange, peach and
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Nov. 2013. Vol. 1, No.1
ISSN 2133-2476
International Journal of Research In Agriculture and Food Sciences
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of significant benefit in where protein consumption is
insufficient (Hall et al., 1980).
avocado pulp contain a high percentage of potassium and
sodium minimal and indicated that the nutritional value of
minerals in 100 g of avocado pulp are potassium 340 mg,
phosphorus 38 mg, calcium 10 mg, iron 0.6 mg and sodium
3 mg, comparing these values with the recommended
amounts 340 mg, 42 mg, 10 mg, 3 and 1 mg respectively, it
is observed that the avocado pulp contains minerals similar
to the reported by Center Experimental and Applied
Endocrinology (CENEXA, 1991).
Table 1 are showed that the lipids in avocado pulp are
second in concentration. The lipids content in avocado pulp
are important from the nutritional point, due its low content
saturated fatty acids and high concentration of unsaturated
fatty acids, are useful in the prevention and treatment of
coronary artery disease, hypertension and type 2 diabetes
(Simopoulos, 1999) and various benefits to consumer health
(Rosamond, 2008). When Carranza et al. (1997) made
clinical studies in patients with high cholesterol levels, they
found that an avocado enriched diet produced a significant
reduction in low-density lipoproteins (bad cholesterol) and
total cholesterol, while diets enriched with soy and
sunflower did not change the total cholesterol
concentrations. Lerman et al. (1994) concluded that in noninsulin dependent diabetic patients it was beneficial to
replace carbohydrates for lipids, such as the ones found in
avocado. This will favor the reduction of triglycerides in the
blood plasma.
Moreover, vegetables high in potassium which
include the common potato and winter squash, are
commonly eaten cooked. Boiling can remove up to 30% of
potassium originally present, giving the avocado an
additional advantage (Smith et al. 1983).
Some nutraceutical ingredients that have been found
in avocado pulp are antioxidants, such as vitamin E or
tocopherols (4.31 UI 100 g-1) and glutathion (17.7 mg 100g1
). They both work as antioxidants, neutralizing free radicals
that may damage aging cells, the heart, and contribute to the
development of some types of cancer, such as mouth and
pharynx (Heber, 2001). It has also been reported that
avocado is a source of lutein (248 mg 100g-1, considered a
high content), a carotenoid that helps to protect the eye from
diseases such as cataracts. The amount of β-sitosterol in this
fruit is similar to the one found in soy and olives. Animal
studies have demonstrated that this compound is related to
the inhibition of cancerous tumors (Heber, 2001). For all of
the above, it can be concluded that the inclusion of avocado
in the everyday diet can bring health benefits to the health of
human beings, bearing in mind that no food is 100%
complete, and a single food will not provide all required
nutrients and nutraceuticals. The diet shall include several
food items from all the different groups in order to deliver a
good nutrition.
Fiber content in avocado pulp is low. However, there
are studies that indicated its health benefits, Smith et al.
(1983) compared the fiber content of sixteen fruits and
eighteen vegetables, of the thirty-four food sources, only the
avocado had large amounts of both soluble and insoluble
fiber (2.1 % and 2.7% by fresh weight, respectively).
Therefore, avocado would be a very pleasant means toward
that end. Anderson (1990) reported that fiber intake lowers
the risk for cardiovascular disease, some cancers,
hypertension (high blood pressure), diabetes, obesity and
with the addition of gastrointestinal diseases. For some
disorders, a mixture of both soluble and insoluble fiber
appears to be most beneficial.
It can be observed in Table 1 that the ash content is
similar for hass variety. Batista et al. (1993) reported that
Table 2 shows the results of the chemical values determined in the avocado oil extracted from pulp with solvent (hexane)
and treatment with electric field.
Table 2. Characterization of avocado oil treatment with electric field.
Chemical analysis
Avocado oil
Acidity (% oleic acid)
1.29 ± 0.8
Peroxide (mEq O2 kg-1 of oil)
3.79 ± 1.4
Iodine by reagent of Wijs (cg I2 g-1)
85.65 ± 1.9
Means of 3 replicates ± SE.
Acidity value is defined as the quantity in mg of
KOH necessary to neutralize the free fatty acids in 1.0 g of
oil or fat (Allen et al., 1982; NM, 1987a; Matissek et al.,
1998), is a direct measure of the quality of the oil, and
reflects the care taken right from blossoming and fruit set to
the eventual sale and consumption of the oil (Tous, and
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Nov. 2013. Vol. 1, No.1
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Ferguson, 1996). Avocado oil samples studied increase in
free fatty acid content was found, in comparison with the
values obtained by Ortiz-Moreno et al. (2003) of 0.65%
oleic acid indicated for crude avocado oil and for virgin
olive oil with 0.49 % of oleic acid (Andrikopoulos et al.,
2002), but, if it are within the specified maximum for
Mexican Standard NMX-F-052-SCFI-2008 for crude
avocado oil with 1.5% oleic acid (NM, 2008) and with
maximum value (% m/m) reported by CODEX STAN
(1989) for virgin olive oil of 3.3 % of oleic acid. Therefore
the avocado oil had a minimum formation of free fatty acids.
The quantity varies of according to the extraction method,
with high acidity by Soxhlet method (4% of oleic acid) due
to a beginning of oxidation, this low acidity value
characteristics a parameter stable oil at the temperature
(CODEX Alimentairus, 1993).
abstracts hydrogen and originates allyl hydroperoxide
(Schweitzer and Schmidt, 2003). An alternative to reduce
the oxidation of fatty acids would employ a bleaching
refining method, however, studies of avocado oil
acceptability by consumers (Ortiz-Moreno et al., 2003),
indicated that the green color in oil is desirable similar to
extra-virgin olive oil. Therefore, it is suggested to minimize
contact of the light exposure during handling of the oil and
have to be bottled in glass bottles dark color (CeballosMoyano et al., 2003; Psomiadou and Tsimidou, 2002).
Iodine value is the measure of the unsaturated fatty
acids in fats and oils and it is expressed in terms of the
number of cg of I2 absorbed per g of sample, absorbable
iodine percent (NM, 1981). The treatments are within the
interval specified in the Mexican Norm of 85-90 cg I2 g-1
(NM, 2008), these values are similar the reported by the
virgin olive oil of 75-94 cg I2 g-1 (CODEX STAN, 1989) and
the values were greater than the determined by OrtizMoreno et al. (2003) of 81.1 cg I2 g-1 for crude avocado oil
of the hass variety. With the results of the chemical
characterization of the crude avocado oil, overall there was
no a significant increase in the deterioration of the oil, this
may have been due to decreased enzyme activity of the
lipase enzyme and the oil storage. In other related work,
Grahl and Märkl (1996) observed a significant reduction
(about 60%) of lipase content in milk, with batch mode
HIPEF treatment at 21.5 kV cm-1, up to 20 pulses. On the
other hand, Xin-an et al. (2010) studied high-intensity pulsed
electric field (HIPEF) with a intensity of 50 kV cm-1 on
peanut oil samples with storage periods, and concluded that
HIPEF treatment, reduces the oxidation rate and therefore,
the unsaturated fatty acids and nutritional value of peanut oil
can be preserved. Probably to the decrease enzyme activity
of lipase enzyme that degrades the unsaturated fatty acids of
oils.
Peroxide value, it indicates the mEq of O2 in the form
of peroxide per kg of fat or oil (NMb, 1987). As can be seen,
there is an increase of peroxide in the treatments, major
value the reported for virgin olive oil with 2.89 mEq O2 kg-1
of oil (Andrikopoulos et al., 2002). However, the oxidation
of unsaturated fatty acids contents were lower in comparison
to the value published by Ortiz-Moreno et al. (2003) of
10.68 mEq O2 kg-1 of oil for the same variety and extracted
with hexane (70 °C for 4 h). Moreover, Mexican Norm
NMX-F-052-SCFI-2008 for avocado oil establishes a
maximum value of 10 mEq O2 kg-1 of oil so that the value is
lower than the specification and for the virgin olive oil ≤20
mEq O2 kg-1 of oil (CODEX STAN, 1989). Chlorophyll
levels avocado oil may be a factor that generated the autooxidation of unsaturated fatty acids by singlet oxygen, since
it contains a concentration of 40-60 ppm of chlorophyll
(Werman and Neeman, 1986). Karp (2005) indicated that the
singlet oxygen can be produced at four sites within the
chloroplast, site where it find the chlorophyll. The normally
photoactivated chlorophyll transfers its excitation energy to
the reaction centers of photosystems under conditions that
prevent the capture of light energy is used the electron
transport system, and this energy can excite and bring
oxygen to singlet, and to reaction whit the double bonds of
the unsaturated fatty acids, due to the proton abstraction
allylic position, and forms an exciplex (oxide epoxide) that
3.2 Gas chromatography
Results of GC analysis of the FAMEs of the avocado
oil samples. Below in the Figure 1 and 2 shows the
chromatograms of the oils untreated and treated with electric
field.
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Figure 1. Avocado oil treated directly with electric field (oil 1) and the FAMEs identified in the control and in oil samples were A:
methyl palmitate (C16:0), B: methyl palmitoleate (C16:1, cis-9), C: methyl stereate (C18:0), D: methyl oleate (C18:1, cis-9) E:
methyl vaccenate (C18:1, cis-11), F: methyl linoleate (C18:2, cis-9,12) and G: methyl linolenate (C18:3, cis-6,9,12).
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Figure 2. Avocado pulp treated with electric field and oil was extracted by maceration (oil 2). FAMEs identified in the control and
in oil 2 were A: methyl palmitate (C16:0), B: methyl palmitoleate (C16:1, cis-9), C: methyl stearate (C18:0), D: methyl oleate
(C18:1, cis-9) E: methyl vaccenate (C18:1, cis-11), F: methyl linoleate (C18:2, cis-9,12) and G: methyl linolenate (C18:3, cis6,9,12).
Tables 3and 4 are shown the results of the analysis of FAMEs of the avocado oil samples.
Table 3. Results percentages of saturated FAMEs in the avocado oil samples.
Oil 1
1
E
2
F
3
t
C16:0
C18:0
0
0
0
19.14 ± 1.0a
0.45 ± 0.01b
9
720
180
19.12 ± 1.0a
0.42 ± 0.01b
Oil 2
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1
E
2
F
3
t
C16:0
C18:0
0
0
0
19.8± 1.0a
0.45 ± 0.01b
9
720
180
19.28 ± 1.0a
0.43 ± 0.01b
1
E, electric field strength (kV cm-1), 2F, frequency (Hz), 3t, time (s).
Means of 3 replicates ± SE.
Different letters in superscripts between untreated and
respectively, with six different treatment times (40 to 180
treated samples indicate significant difference (p < 0.05).
µs), however, these investigators reported that none of these
changes were statistically significant. In another study about
Table 3 can see that not were observed significant
pasteurization of grape juice with electric field pulsed
changes (p > 0.05) in the contents of saturated FAMEs
bipolar (35 kV cm-1, 1000 Hz, 1 ms), the saturated fatty
between untreated and treated samples of the oils 1 and 2.
acids (C12:0, C14:0, C16:0 and C18:0), not showed
Zulueta et al. (2007) studied the conservation of a drink of
significant differences in concentration, only C12:0 of
orange juice-milk treated with pulsed electric field of high
0.32% to 0.19% (Garde-Cerdán et al., 2007). In avocado oil
intensity, and determined that the profile of saturated fatty
the C12:0 was not identified, therefore it could not be
acids (lauric C12:0, myristic C14:0, palmitic C16:0 and
confirmed, in general the concentration of saturated FAMEs
stearic C18:0) not showed any changes at all in their
not showed significant changes as reported by earlier
concentrations, except the C12:0 from 0.129 and 0.136% to
researchers.
0.126% after the treatment at 35 kV cm-1 and 40 kV cm-1
Table 4 are showed the results of FAMEs composition of avocado oils.
Table 4. Results percentages of unsaturated FAMEs in the avocado oil samples untreated and treated with electric field.
Oil 1
1
E
2
F
3
t
C16:1
C18:1
C18:1
C18:2
C18:3
Total
0
0
0
8.42 ± 0.9a
48.7 ± 1.0b
4.7 ± 0.7d
16.1 ± 1.1e
1.5 ± 0.2f
79.42
9
720
180
8.48 ± 0.91a
48.6 ± 1.0b
4.71 ± 0.7d
16.2 ± 1.2e
1.5 ± 0.2f
79.49
Oil 2
1
E
2
F
3
t
C16:1
C18:1
C18:1
C18:2
C18:3
Total
0
0
0
8.11 ± 0.91a
49.5 ± 1.0c
4.6 ± 0.71d
16.0 ± 1.0e
1.5 ± 0.21f
79.71
9
720
180
8.6 ± 0.9a
49.64 ± 0.98c
4.35 ± 0.7d
16.2 ± 1.0e
1.5 ± 0.22f
80.29
1
-1
2
3
E, electric field strength (kV cm ), F, frequency (Hz), t, time (s).
Means of 3 replicates ± SE.
Different letters in superscripts between untreated and
intensity, reported that the concentration of unsaturated fatty
treated samples indicate significant difference (p < 0.05).
acids palmitoleic (C16:1) and oleic (C18:1) there were no
significant changes in their concentrations in any of the
treatments (0.913 % to 0.938 %, and 65.5 % to 66.0 %
respectively). Another study on the non-thermal
FAMEs of unsaturated fatty acids that were
pasteurization of grape juice using bipolar pulsed electric
quantified in the oils were methyl palmitoleate (C16:1 cisfield, it was observed that there were not changes in the
9), methyl oleate (C18:1 cis-9), methyl linoleate (C18:2 cisconcentration of unsaturated fatty acids C18:1 of 2.29 % to
9, 12), methyl eicosenoate (C20:1 cis-11), methyl linolenate
2.3 %, C18:2 of 25.38 % to 24.2 % and C18:3 of 10.07 % to
(C18:3 cis-9, 12, 15), and methyl eicosadienoate (C20:2 cis9.4 % (39), which is similar to that obtained in this work.
11, 14). The concentration of FAMEs of the oils 1 and 2
(treated and untreated) samples was similar (p>0.05).
4. Conclusions
Zulueta et al. (38) in their investigation on a beverage of
orange juice-milk treated with pulsed electric field of high
20
Nov. 2013. Vol. 1, No.1
ISSN 2133-2476
International Journal of Research In Agriculture and Food Sciences
© 2013 IJRAFS & K.A.J. All rights reserved
http://www.ijsk.org/ijrafs.html
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