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The Composition of Oils in Pinus edulis
Michael Blair, Telletha Valenski, Andrew1 Sykes,
Russell Balda, and Gerald Caple
Abstract.-Pinon nut oil was reacted with sodium methoxide in methanol to
yield the free methyl esters. These methyl esters were analyzed by GCmass spectrometry. The pinon seeds are 60% by weight oil; of this oil 90%
were unsaturated fatty acids with 41 % being mono 9-octadecenoic acid and
59% being 9, 12-octadecadienoic acid. Small amounts of palmitic acid and
stearic acid, both saturated oils, were found, as were some C20 species.
Preliminary studies indicated the actual oil constituents varied in pinon
seeds from different areas. The highly unsaturated oil of Pinus edulis seeds
might be a useful dietary supplement, with the current health concerns
about the lowering of saturated fats in the diet.
INTRODUCTION
Foraging birds such as Pinon Jays, Scrub Jays,
and Clark's Nutcrackers, instinctively harvest
pinon nuts for the high supplement of fat. They
discriminate between good and bad seeds, cones
with a large nwnber of good seeds, and trees that
prod uced cones with a large number of good seeds
(Vander Wall and Balda, 1977). The pinon nut
provides the birds with good nourishment
throughout the cold winter months. This can also
be said for the Native peopl~ who also forage off
the nut.
Here we report on the composition of oils
found in the pmon nut. The percentage of oil
found 'in the pmon nut (Pinus edulis) is 58-62%
(C.W Bedkin, L.B. Shires). We have determined the
ratios of saturated and unsaturated fats in pmon
nuts by Gas chromotagraphylMass Spectroscopy
(CC/MS) and compared these ratios to other commercial oils. The seeds were found from different
areas of the southwest which gave variations in
percentage of oil. In addition, a one seed analysis
was done to make a comparison with larger quantities.
MATERIALS AND METHODS
After weighing the crushed nut, we separated
the oil from the pinon nut by using ,a nonpolar
1 Department of Chemistry and Biology, Northern Arizona University, Flagstaff, AZ.
225
solvent (hexane) to extract the oil, and then filtering the solution. The powder extraction was set
aside to do a protein and carbohydrate analysis.
After evaporating the solvent, the oil was
reweighed to give the percent oil in the seed,
which agreed with the range given in the introduction. For the preparation of methyl esters from
the oil extraction, triglycerides were reacted with
Sodium Methoxide (Olsson, Urban; Kaufmann,
Peter; Hersolof C. Bengt). Methyl esters were
separated from the nut and characterized by
GC/MS. Methyl linoleate, methyl oleate, methyl
stearate, and methyl palmitate were purchased
from Aldrich Chemical and used as standards.
GC-Mass Spectroscopy spectra were collected
on an HP 5890 Series II GC fitted with a 12m >I0.2mm >I- 0.33um HP-I crosslinked methyl silicone
gun1 column interfaced to an HP 5971A Mass Selective Detector.
RESULTS/CONCLUSION
The specific oils in Pinus edulis were characterized as the methyl esters by CC/MS. This could be
done on any quantity of pinon nuts, including a
single nut analysis. Figure 1 is a typical CC/MS
spectrum of a single nut analysis. We identified
four major oils present in Pinus edulis plus a small
percentage of higher C 20 oils. The molecular
weights and retention tilnes of these methyl esters
Composition
Table 1.-Retentlon Times ot Methyl Esters (minutes).
Palmitate
Mol.Wgt.
Shelled(Feb)
Shelled (June)
Freezer Nuts
Palmitate 270
Linolenate 292
Linoleate 294
Oleate 296
Stearate 298
270
15.97
17.42
17.1
17.19
L1nolenate
L1noleate
294
292
Shoulder
Shoulder
18.77
18.55
Oleate Stearate
296
18.31
19.22
18.85
298
18.34
19.38
19.05
of
Oil
7
7
i'r
7
/.I!
COITONSEED
/j!
L
1L
//A
•
Saturated
/,/1
•
Monounsaturated
•
Dlunsaluraled
/
f;)
O:her
OLIVE
V
V
/
..
.
PEANUT
18.82
'L
L
/
SAFFLOWER
18.92
V
18.96
/
/
/
SESAME
19.04
V
/
/
,.
/
SOYBEAN
are given in Table 1. The molecular weights and
the retention times of methyl esters purchased
from Aldrich closely match the methyl esters found
in the pinon nut. The shelled nuts (Feb) were run
under different GC conditions (higher Heliun1
column pressure) accounting for the faster in retention times. The freezer nut sample obtained
from a commercially available source and of unidentified history also contained an additional
unsa tura ted oil at 18.55 min (asterisk-Figure 2).
2GDOOOO
241)000::
2000COJ
161J')coa
/
V...
/
'PINON"
20
40
60
80
100
Figure 2.-Fat content of commercial oils Including plrion.
Figure 2 compares the fat content of Pinus edulis to
other common cODlffiercial oils (USDA Handbook
# 8). The graph shows the nut is high in unsaturated fat (90%), but has its own unique content of
mono and diunsaturated fats. The exact ratio of the
mono and diunsaturated esters were determined
by digital transformation of the linoleate and oleate
peaks and fitting the data to two Gaussian peaks
using a commercially available computer program
(Peak Fit). The relative amounts of linoleate to
oleate esters are 59% to 41 % by this technique.
Integration using the GC/MS software incorrectly
determined the relative percentages as 44/56% for
the linolea te/olea te ratio, almos t the opposite from
above, due to poor resolution of these peaks.
In the future we would like to develop a greater
separation of the methyl esters using COMS.
Preliminary evidence shows that a large nwnber of
isomers exist for n1ethyl linoleate and methyl
oleate. We would also like to know if seasonal
changes cause the pmon nuts to have different
percentage of oil.
1400COIJ
LITERATURE CITED
120DO(J\J
Bader, Alfred; Harvey, David; Nagarkatti, Jai. 1990.
Aldrich Chemical Company, Inc.
Bedkin, C. W; Shires, L. B. 1948. The Composition and
Value of pinon Nuts. Agricultural Experimental Station.
New Mexico of A &'M State College, New Mexico.
Christensen, Kerry M.; Whitham, Thomas C.; Balda, Russell
p. 1991. Discrimination among pinyon pine trees by
Clark's Nutcrackers: effect of cone crop size and cone
characters. Oecologia. 86: 402-407.
Olsson, Urban; Kaufmann, Peter; Herslof, Bengt C. 1990.
Multivariate optimization of a gas-liquid chromatOh'Taphk analysis of fatty acid methyl esters of black
currant seed oil. Journal of Chromatography. 505: 385-
100000')
Ii
I'
GODCO]
200QUO
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,
1'i:"e -)
17.(JO
1;.5J
1B.00
18.50
:9. co
394.
r
19.50
20.00
2G::O
Watt, Bernice K. 1963. Composition of Foods. Agriculture
Handbook No.8. Agricultural Research Service. United
States Department of Agriculture. 8: 135.
Figure 1.-Graph showing GC/MS characterization of methyl
esters.
226