Introduction: Richard
nutritional
aspects
of palm oil1’2
C Cottrell
ABSTRACT The production, composition, and food uses ofpalm oil are outlined in this introduction to a detailed appraisal ofthe nutritional and health implications ofthe use of palm oil in the food supply. The putative role of dietary fats and oils in general, and ofpalm oil in particular, in the etiology of coronary heart disease and cancer is critically assessed. It is concluded that the evidence available is difficult to interpret unambiguously. Some evidence to suggest that the minor components of palm oil might have useful biological effects is also discussed. Am J C/in Nuir 199 1;53:9895- 10095. KEY
WORDS
heart
disease,
vitamin
Palm
oil, triglyceride,
arteriosclerosis,
cancer,
carotene,
tocotrienol,
thrombosis,
cholesterol,
E
coronary heart disease (CHD) and cancer. The evidence in these areas and its strengths and weaknesses are, therefore, outlined. Apart from the major components ofthe oil, there is evidence to suggest important effects from some minor constituents, notably the tocotrienols. Data from this emerging field of investigation are also examined. The review concludes by drawing together the threads of the various lines ofevidence covered and offering some suggestions about the reliance that should be placed on the available data and the conclusions that can be drawn from them. As in most aspects of nutritional science, concrete conclusions are, in general, premature, and commentators offering spurious certainty should be treated with suspicion. Nonetheless, some clear statements are merited and these are noteworthy.
Preface The use of palm oil in food products has recently been called into question on health grounds, particularly in the United States. Because palm oil contains somewhat higher concentrations of saturated
fatty
acids
(saturates)
than
do
many
other
vegetable
oils in their natural state (which may not reflect their composition after hydrogenation for food use), it has been claimed that palm oil should be avoided along with animal fats as part ofthe “pmdent diet” for the control of heart disease. These claims are, at best, a gross oversimplification of the available evidence regarding the role ofdiet in influencing some disease processes ofthe heart and major arteries. At worst, much of the public comment could be seen to arise merely from the scaremongering
tactics
of certain
competing
commercial
inter-
ests. This review is written to provide a dispassionate appraisal of the current state of knowledge in a highly complex and controversial field of science, with particular emphasis on the relevance of a broad range of evidence to a specific question: “What are the nutritional effects of palm oil?” The answer to this question turns on an appreciation of the relevant aspects of nutrition and toxicology, because too much of anything, even air and water, constitutes a hazard to health. To gauge the current level of consumption as well as to provide necessary background information on the reasons for its use, this review examines the uses to which palm oil is put. This review also deals with the basic biological processing of oils and fats, of which palm oil is a typical example. This leads naturally to an account of the evidence for any adverse effects from excessive consumption of any of the components of the oil. This discussion of possible adverse effects presumes an understanding of the role of diet, especially fats, in, for example, Am J C/in Nuir
199 l;53:989S-1009S.
Printed
in USA.
© 1991 American
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
Introduction Palm oil is produced from the fruit of the Elaeis guineensis tree and has been used for food for some 5000 y (1). This tree originated in West Guinea and was introduced to other parts of Africa, Southeast Asia, and Latin America along the Equator belt after the introduction ofthe slave trade in the 15th century. It was not until the end of the 18th and the beginning of the 19th centuries that palm oil entered world trade. As far as Malaysia is concerned, the oil palm was first introduced in 1870 as an ornamental plant and it was not until 19 17 that the first commercial planting was seriously undertaken. Malaysia was not recognized as a major oil producer for another 50 y. By contrast, in 1988 Malaysia produced 4.5 Tg of crude palm oil and accounted for 58% of the world production of this cornmodity (2). Palm oil is now widely used, with a world production of 7.8 Tg in 1987- 1988. This compares with 15.26 Tg of soya oil and a total world production of 52.06 Tg of major vegetable and marine oils (3). Total world production of all oils and fats (including animal fats and industrial oils) was 72.47 Tg (4). Consumption varies throughout the world but tropical oils (palm, palm kernel, and coconut) account for 2-3% of the average American’s intake of edible fats and oils whereas soya oil accounts for 30% and animal fats account for 56% of the intake (5).
‘From 2
Address
Association,
the Leatherhead reprint
Randall’s
Society for Clinical
Food Research
requests
to RC Cottrell,
Road, Leatherhead,
Nutrition
Association,
Surrey, UK.
Leatherhead
Food Research
Surrey KT22 7RY, UK.
989S
9905
COTTRELL
TABLE
1
Fractional
fatty acid composition
Fatty acid
of major
Palm
6:0
-
8:0
-
10:0
-
16: 1 I 8:0 18:1
0.001 0.0 10 0.438 0.001 0.048 0.389
18:2
0.106
18:3 20:0
0.003 0.003
12:0
14:0 16:0
20: 1
Palm kernel
Coconut
0.002 0.033 0.035 0.478 0. 163 0.085
Soybean
0.004 0.073 0.066 0.478 0. 18 1 0.089
Bunches
of fruit
-
-
-
-
-
-
-
-
-
-
-
-
Tr
0.001
0.033 0.453
0.008 0.237 0.008 0.026 0.184
0.001 0.121 0.002 0.024 0.321
0.024
0.016
0.538
0.325
0.530
0.509
Tr 0.014
0.001 0.003 0.001
0.009 0.005 0.003
-
-
-
-
-
-
-
-
-
-
-
-
0.002
-
-
0.033 0.001
0.001
-
0.005 0.001
-
-
-
-
-
-
-
-
-
-
-
-
0.002
-
0.002
-
-
-
-
-
-
-
0.00 1 0.001
0.001
are
cut from mill.
the oil palms Following
when
sterilization,
ripe
and
to arrest
fatty
acid
composition,
palm
oil triglycerides
can be fractionally crystallized to produce a high-melting steam and a low-melting olein fraction, thus extending the range of food products in which they can be used (10). Further fractionation yields a product ofintermediate characteristics, palm midfraction, and other specialty oils such as a very-low-meltingpoint olein for use in salad oils. Some minor components of the oil separate unequally among the fractions. For example, the olein is enriched in tocopherols and tocotrienols. Nowadays, palm olein is the major exported product of the Malaysian industry.
of palm
oil
0.01 1 -
containing
oil falls differences
higher
Fractionation
0.01 1
high
Palm
within
a relatively
acids
The fatty acid composition ofpalm oil as compared with other major oils and fats in their natural state (ie, unhydrogenated) is given in Table 1. The range for fish oils (unprocessed) includes
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
of polyunsaturated
narrow
due to geographical higher
palmitic oil can
stearic
acid
acid content
fatty
acids
(PU-
range.
There
region-Ivory content
and
are only
minor
Coast
samples
Sumatran
oils
have have
a
(1 1).
be fractionated
to palm
olein
and
palm
stearin.
The
fatty acid composition of these compared with palm oil is given in Table 3. Palm olein and palm stearin share the same major fatty acids, namely palmitic acid, oleic acid, and linoleic acid. However, palm olein has relatively more oleic acid and linoleic acid and less palmitic acid than does palm steam. One point that should be taken into account when comparing palm oil with other vegetable oils is the content of trans fatty acids. Palm oil has a semisolid texture at room temperature, so hydrogenation is not necessary. Other oils, such as soybean or rapeseed, are hydrogenated during the manufacture of margarines and shortenings. Hydrogenated fats often contain appreciable proportions of trans fatty acids and the effect of excessive intakes ofthese on health is uncertain (14). The concentration
Fatty
levels
FAs)-menhaden, sardine, and pilchard oils-and those with high levels of monounsaturated fatty acids (MUFAs)-capelin, pout, sprat, and herring oils. Table 1 shows the fatty acid composition of the common edible oils and fats used in foods. Table 2 summarizes the fatty acid types of these fats and oils. Fish oils contain long-chain, highly unsaturated acids such as eicosapentaenoic and docosahexaenoic acids, which are not found in animal fats or vegetable oils. The major difference between palm oil and other oils and fats is its higher proportion of palmitic acid in the constituent fatty acids. The fatty acid composition ofsamples ofgenuine whole palm
a slightly
Composition
Tr
0.075 0.004 0.002
-
to the
oftheir
Tr 0.114
-
0.027 0.064
the action ofspoilage enzymes (6), the fruit is stripped from the bunch (7) and digested (7) and the oil extracted, usually with a screw press (8). The crude oil is allowed to settle and then is centrifuged, dried, and filtered. The product at this stage is a clear, stable oil of a deep orange-red color that is used directly for cooking in many parts of the world. But for the majority of uses the oil is refined and fractionated to produce products of low color value (6). Two methods of refining are in widespread use; the more common is the physical process and the more flexible, the alkali method (9). Both methods yield an oil ofbland color and flavor and good shelf stability.
Because
Corn
0.024 0.154
oils
transported
Cottonseed
-
0.00 1
Oil production rapidly
Groundnut
0.112 0.001 0.004 0.220
-
-
20:2 22:0 22:1 22:2 24:0 24:1
fats and oils*
ofa
fat also has dietary
of fatty acids consequences.
at the triglyceride Palm
oil has more
2-position palmitic
acid at the 2-position than does any other common vegetable oil and it was shown that infants thrive on feeds with an enriched content of palmitic acid at the triglyceride 2-position (1 5, 16).
PALM
OIL
991S
IN NUTRITION
Rapeseed
Fatty acid
Safflower
Sunflower
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.001
-
6:0
8:0 10:0 12:0 14:0 14:1
Beef fat
Pork
0.046
0.092
0.045
0.003 0.015
0.001 0.058
0. 125
0.2 1 1
0.594
0.382
0.304-0.480
0.768 0.001 0.003 0.002
0.662
0.207 0.101 0.006 0.0 15
0.450 0.006 0.005 0.006
0.006-0.018 0.003-0.007 Tr-0.009 0.003-0.01 7 0.0-0.001
-
-
0.068
0.065
18:0
0.001 0.024
18: 1 18:2 18:3 20:0 20: 1 20:2 20:5 22:0 22:1 22:2 22:6 24:0 24:1 *
Sesame
0.0-0.00 1 0.001 0.027-0.048 0.008-0.025 0.209-0.289 0.023-0.091 0.070-0.265
0.001 0.001
16:0 16:1
(low erucic acid)
-
-
0.003 0.00 1
-
-
-
-
-
-
-
-
-
0.003 0.002
0.003 0.007
-
0.008 0.001 0.002
-
-
0.001 0.001
0.001
Fish oil
0.00 1 0.001 0.014-0.017 0.0-0.001 0.231-0.283 0.018-0.033 0.1 17-0.240 0.297-0.453 0.081-0.126 0.007-0.012 0.002-0.003 0.008-0.01 3 0.003-0.005
-
-
0.0-0.102 -
0.100-0.240 0.046-0.130 0.007-0.078 0.083-0.188 -
Tr-0.002 0.013-0.177 -
0.060-0.176
-
Tr
0.0-0.001
0.0-0.004
-
0.0-Tr
Tr-0.OOl
-
-
0.0-Tr
0.0-0.005
-
-
-
-
-
-
-
0.00 1 0.002
-
fat
-
0.002-0.215 -
0.028-0.162
-
0.0-0.006
-
-
-
From refs 1 1-13. Tr, trace.
Triglyceride
carbon
number
With regard to triglycerides, palm oil is distinguished from other oils by its high levels of48-, 50-, and 52-C glycerides. The 50- and 52-C glyceride groups are present at almost equal levels. Ranges
of carbon-number
are given
fractions
Minor
compositions
for
palm
oil
and
its
4.
in Table
constituents
Carotenoids Carotenoids,
Tocols Palm
although
copherols and tocotrienols but is unusual in that it is especially rich in ‘y-tocotrienol (Table 5) (17-20; AB Gapor, unpublished observations). Tocols are physiologically active as vitamin E and are useful natural antioxidants, so their loss during refining should be minimized. Steam deodorization, distillation, and fractionation, however, all cause some losses(2l) but the majority of the tocols remain in the refined oil (Table 5).
oil and its fractions generally there is some variation.
contain high levels of tocols, Palm oil contains both to-
ofcrude
oils, animal
MUFA
SFA
0.109 0.024 0.016
0.390 0. 155 0.064
0.500
Palm-kernel oil Coconut oil Soybean
0.613
0.224
0.164
Palm
oil
oil
by most
0.819 0.919
TABLE
oil. Unrefined
for the characteristic
at concentrations
palm
ofcarotenoids.
components, ent in smaller ural state but cesses, which
fats, and crude
PUFA
source
are responsible
oil, are present
L in the crude food
TABLE 2 Fraction of fatty acid types in vegetable fish oils (from Table 1)
which
palm
Alpha-
oil thus represents and
fl-carotenes
color
ofSOO-700
mg/
the richest are the
major
with ‘y-carotene, lycopene, and xanthophylls presamounts. Some populations use the oil in its natall carotene is destroyed by current refining protraditionally produce the light-colored oils preferred
consumers.
3
Fractional
fatty acid composition
of palm
oil and its fractions
Groundnut
oil
0.325
0.465
0.205
Cottonseed
oil
0.531
0.193
Cornoil
0.518
0.326
0.275 0.156
Safflower oil Sunflower oil
0.769 0.664
0. 132 0.2 13
0.100 0.122
Rapeseed
0.308
0.62 1
0.072
16:1
Tr-0.003
Tr-0.002
Tr-0.002
0.456
0.389
0.155
18:0
0.040-0.055
0.039-0.044
0.044-0.055
oil
Sesame oil Beef fat Porkfat Fish oils S
acid;
PUFA,
0.009-0.026
0.091-0.148 0.088-0.338 polyunsaturated
SFA, saturated
Fatty
acid
Palm
oil
12:0 14:0
0.0-0.002 0.008-0.01
16:0
0.431-0.463
Palm
3
olein
Palm
stearin
0.00 1-0.002 0.009-0.010
0.001-0.002 0.010-0.013
0.395-0.408
0.465-0.689
0.338-0.6 13 0.323-0.501
0.307-0.614 0.366-0.555
18:1
0.367-0.408
0.427-0.439
0.199-0.384
18:2
0.094-0.119
0.106-0.114
0.041-0.093
0.144-0.710
0.107-0.422
18:3 20:0
0.001-0.004 0.001-0.004
0.0-0.004 0.001-0.003
0.001-0.002 0.001-0.003
fatty acid; MUFA,
monounsaturated
fatty
fatty acid.
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
S
From reference
1.
992S
COTTRELL
TABLE4
TABLE
Ranges
o f carbon-number
fract ional
Palm
oil
Palm
46-C
0.0-0.01
48-C 50-C 52-C 54-C 56.C
0.068-0.097 0.383-0.440 0.375-0.412 0.085-0. 1 19 0.0-0.007
*
From
reference
compositions*
8
olein
Palm
0.003 0.026-0.03 1 0.377-0.393 0.443-0.457 0. 123-0. 128 0.006-0.008
in crude
0.009-0.030 0.102-0.427 0.394-0.422 0.119-0.379 0.025-0.103 0.002-0.006
Cholesterolt Brassicasterolt Campesterolt Stigmasterolt $-Sitosterolt 6-5-Avenasterolt #{244}-7-Stigmasterolt #{244}-7-Avenasterolt
11.
*
in Table 6, (22) the major sterols in palm oil and its fractions are $-sitosterol, campesterol, and stigmasterol. Sterols and esters do not seem to serve any really useful function
rimental
Polar
it has
been
may give antioxidant effect
suggested
effects)
that
some,
like
nor do they have
process
in palm oil is phosphatidylcholine is monogalactosyldiglyceride. The wetmost of the phospholipids in the palm
leaves palm
oil
contains
relatively
low
levels It has been
Free acids
of phosreported
and tocotrienols
Oils and fats*
when
Total phenol palm oil (23).
concentration
446
is usually
it reaches
the
refinery
but
badly
handled
oils
may
up to 10% (24).
Impurities Small amounts ofiron and copper may be present in the crude oil, which are pro-oxidants in catalytic amounts. Iron impurities are derived from wear and tear of oil-mill machinery and may be minimized by using stainless steel at strategic points in the milling
process
usually
contains
or by magnetic 5 gJL
nutritional
aspects
of palm oil1’2
C Cottrell
ABSTRACT The production, composition, and food uses ofpalm oil are outlined in this introduction to a detailed appraisal ofthe nutritional and health implications ofthe use of palm oil in the food supply. The putative role of dietary fats and oils in general, and ofpalm oil in particular, in the etiology of coronary heart disease and cancer is critically assessed. It is concluded that the evidence available is difficult to interpret unambiguously. Some evidence to suggest that the minor components of palm oil might have useful biological effects is also discussed. Am J C/in Nuir 199 1;53:9895- 10095. KEY
WORDS
heart
disease,
vitamin
Palm
oil, triglyceride,
arteriosclerosis,
cancer,
carotene,
tocotrienol,
thrombosis,
cholesterol,
E
coronary heart disease (CHD) and cancer. The evidence in these areas and its strengths and weaknesses are, therefore, outlined. Apart from the major components ofthe oil, there is evidence to suggest important effects from some minor constituents, notably the tocotrienols. Data from this emerging field of investigation are also examined. The review concludes by drawing together the threads of the various lines ofevidence covered and offering some suggestions about the reliance that should be placed on the available data and the conclusions that can be drawn from them. As in most aspects of nutritional science, concrete conclusions are, in general, premature, and commentators offering spurious certainty should be treated with suspicion. Nonetheless, some clear statements are merited and these are noteworthy.
Preface The use of palm oil in food products has recently been called into question on health grounds, particularly in the United States. Because palm oil contains somewhat higher concentrations of saturated
fatty
acids
(saturates)
than
do
many
other
vegetable
oils in their natural state (which may not reflect their composition after hydrogenation for food use), it has been claimed that palm oil should be avoided along with animal fats as part ofthe “pmdent diet” for the control of heart disease. These claims are, at best, a gross oversimplification of the available evidence regarding the role ofdiet in influencing some disease processes ofthe heart and major arteries. At worst, much of the public comment could be seen to arise merely from the scaremongering
tactics
of certain
competing
commercial
inter-
ests. This review is written to provide a dispassionate appraisal of the current state of knowledge in a highly complex and controversial field of science, with particular emphasis on the relevance of a broad range of evidence to a specific question: “What are the nutritional effects of palm oil?” The answer to this question turns on an appreciation of the relevant aspects of nutrition and toxicology, because too much of anything, even air and water, constitutes a hazard to health. To gauge the current level of consumption as well as to provide necessary background information on the reasons for its use, this review examines the uses to which palm oil is put. This review also deals with the basic biological processing of oils and fats, of which palm oil is a typical example. This leads naturally to an account of the evidence for any adverse effects from excessive consumption of any of the components of the oil. This discussion of possible adverse effects presumes an understanding of the role of diet, especially fats, in, for example, Am J C/in Nuir
199 l;53:989S-1009S.
Printed
in USA.
© 1991 American
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
Introduction Palm oil is produced from the fruit of the Elaeis guineensis tree and has been used for food for some 5000 y (1). This tree originated in West Guinea and was introduced to other parts of Africa, Southeast Asia, and Latin America along the Equator belt after the introduction ofthe slave trade in the 15th century. It was not until the end of the 18th and the beginning of the 19th centuries that palm oil entered world trade. As far as Malaysia is concerned, the oil palm was first introduced in 1870 as an ornamental plant and it was not until 19 17 that the first commercial planting was seriously undertaken. Malaysia was not recognized as a major oil producer for another 50 y. By contrast, in 1988 Malaysia produced 4.5 Tg of crude palm oil and accounted for 58% of the world production of this cornmodity (2). Palm oil is now widely used, with a world production of 7.8 Tg in 1987- 1988. This compares with 15.26 Tg of soya oil and a total world production of 52.06 Tg of major vegetable and marine oils (3). Total world production of all oils and fats (including animal fats and industrial oils) was 72.47 Tg (4). Consumption varies throughout the world but tropical oils (palm, palm kernel, and coconut) account for 2-3% of the average American’s intake of edible fats and oils whereas soya oil accounts for 30% and animal fats account for 56% of the intake (5).
‘From 2
Address
Association,
the Leatherhead reprint
Randall’s
Society for Clinical
Food Research
requests
to RC Cottrell,
Road, Leatherhead,
Nutrition
Association,
Surrey, UK.
Leatherhead
Food Research
Surrey KT22 7RY, UK.
989S
9905
COTTRELL
TABLE
1
Fractional
fatty acid composition
Fatty acid
of major
Palm
6:0
-
8:0
-
10:0
-
16: 1 I 8:0 18:1
0.001 0.0 10 0.438 0.001 0.048 0.389
18:2
0.106
18:3 20:0
0.003 0.003
12:0
14:0 16:0
20: 1
Palm kernel
Coconut
0.002 0.033 0.035 0.478 0. 163 0.085
Soybean
0.004 0.073 0.066 0.478 0. 18 1 0.089
Bunches
of fruit
-
-
-
-
-
-
-
-
-
-
-
-
Tr
0.001
0.033 0.453
0.008 0.237 0.008 0.026 0.184
0.001 0.121 0.002 0.024 0.321
0.024
0.016
0.538
0.325
0.530
0.509
Tr 0.014
0.001 0.003 0.001
0.009 0.005 0.003
-
-
-
-
-
-
-
-
-
-
-
-
0.002
-
-
0.033 0.001
0.001
-
0.005 0.001
-
-
-
-
-
-
-
-
-
-
-
-
0.002
-
0.002
-
-
-
-
-
-
-
0.00 1 0.001
0.001
are
cut from mill.
the oil palms Following
when
sterilization,
ripe
and
to arrest
fatty
acid
composition,
palm
oil triglycerides
can be fractionally crystallized to produce a high-melting steam and a low-melting olein fraction, thus extending the range of food products in which they can be used (10). Further fractionation yields a product ofintermediate characteristics, palm midfraction, and other specialty oils such as a very-low-meltingpoint olein for use in salad oils. Some minor components of the oil separate unequally among the fractions. For example, the olein is enriched in tocopherols and tocotrienols. Nowadays, palm olein is the major exported product of the Malaysian industry.
of palm
oil
0.01 1 -
containing
oil falls differences
higher
Fractionation
0.01 1
high
Palm
within
a relatively
acids
The fatty acid composition ofpalm oil as compared with other major oils and fats in their natural state (ie, unhydrogenated) is given in Table 1. The range for fish oils (unprocessed) includes
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
of polyunsaturated
narrow
due to geographical higher
palmitic oil can
stearic
acid
acid content
fatty
acids
(PU-
range.
There
region-Ivory content
and
are only
minor
Coast
samples
Sumatran
oils
have have
a
(1 1).
be fractionated
to palm
olein
and
palm
stearin.
The
fatty acid composition of these compared with palm oil is given in Table 3. Palm olein and palm stearin share the same major fatty acids, namely palmitic acid, oleic acid, and linoleic acid. However, palm olein has relatively more oleic acid and linoleic acid and less palmitic acid than does palm steam. One point that should be taken into account when comparing palm oil with other vegetable oils is the content of trans fatty acids. Palm oil has a semisolid texture at room temperature, so hydrogenation is not necessary. Other oils, such as soybean or rapeseed, are hydrogenated during the manufacture of margarines and shortenings. Hydrogenated fats often contain appreciable proportions of trans fatty acids and the effect of excessive intakes ofthese on health is uncertain (14). The concentration
Fatty
levels
FAs)-menhaden, sardine, and pilchard oils-and those with high levels of monounsaturated fatty acids (MUFAs)-capelin, pout, sprat, and herring oils. Table 1 shows the fatty acid composition of the common edible oils and fats used in foods. Table 2 summarizes the fatty acid types of these fats and oils. Fish oils contain long-chain, highly unsaturated acids such as eicosapentaenoic and docosahexaenoic acids, which are not found in animal fats or vegetable oils. The major difference between palm oil and other oils and fats is its higher proportion of palmitic acid in the constituent fatty acids. The fatty acid composition ofsamples ofgenuine whole palm
a slightly
Composition
Tr
0.075 0.004 0.002
-
to the
oftheir
Tr 0.114
-
0.027 0.064
the action ofspoilage enzymes (6), the fruit is stripped from the bunch (7) and digested (7) and the oil extracted, usually with a screw press (8). The crude oil is allowed to settle and then is centrifuged, dried, and filtered. The product at this stage is a clear, stable oil of a deep orange-red color that is used directly for cooking in many parts of the world. But for the majority of uses the oil is refined and fractionated to produce products of low color value (6). Two methods of refining are in widespread use; the more common is the physical process and the more flexible, the alkali method (9). Both methods yield an oil ofbland color and flavor and good shelf stability.
Because
Corn
0.024 0.154
oils
transported
Cottonseed
-
0.00 1
Oil production rapidly
Groundnut
0.112 0.001 0.004 0.220
-
-
20:2 22:0 22:1 22:2 24:0 24:1
fats and oils*
ofa
fat also has dietary
of fatty acids consequences.
at the triglyceride Palm
oil has more
2-position palmitic
acid at the 2-position than does any other common vegetable oil and it was shown that infants thrive on feeds with an enriched content of palmitic acid at the triglyceride 2-position (1 5, 16).
PALM
OIL
991S
IN NUTRITION
Rapeseed
Fatty acid
Safflower
Sunflower
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.001
-
6:0
8:0 10:0 12:0 14:0 14:1
Beef fat
Pork
0.046
0.092
0.045
0.003 0.015
0.001 0.058
0. 125
0.2 1 1
0.594
0.382
0.304-0.480
0.768 0.001 0.003 0.002
0.662
0.207 0.101 0.006 0.0 15
0.450 0.006 0.005 0.006
0.006-0.018 0.003-0.007 Tr-0.009 0.003-0.01 7 0.0-0.001
-
-
0.068
0.065
18:0
0.001 0.024
18: 1 18:2 18:3 20:0 20: 1 20:2 20:5 22:0 22:1 22:2 22:6 24:0 24:1 *
Sesame
0.0-0.00 1 0.001 0.027-0.048 0.008-0.025 0.209-0.289 0.023-0.091 0.070-0.265
0.001 0.001
16:0 16:1
(low erucic acid)
-
-
0.003 0.00 1
-
-
-
-
-
-
-
-
-
0.003 0.002
0.003 0.007
-
0.008 0.001 0.002
-
-
0.001 0.001
0.001
Fish oil
0.00 1 0.001 0.014-0.017 0.0-0.001 0.231-0.283 0.018-0.033 0.1 17-0.240 0.297-0.453 0.081-0.126 0.007-0.012 0.002-0.003 0.008-0.01 3 0.003-0.005
-
-
0.0-0.102 -
0.100-0.240 0.046-0.130 0.007-0.078 0.083-0.188 -
Tr-0.002 0.013-0.177 -
0.060-0.176
-
Tr
0.0-0.001
0.0-0.004
-
0.0-Tr
Tr-0.OOl
-
-
0.0-Tr
0.0-0.005
-
-
-
-
-
-
-
0.00 1 0.002
-
fat
-
0.002-0.215 -
0.028-0.162
-
0.0-0.006
-
-
-
From refs 1 1-13. Tr, trace.
Triglyceride
carbon
number
With regard to triglycerides, palm oil is distinguished from other oils by its high levels of48-, 50-, and 52-C glycerides. The 50- and 52-C glyceride groups are present at almost equal levels. Ranges
of carbon-number
are given
fractions
Minor
compositions
for
palm
oil
and
its
4.
in Table
constituents
Carotenoids Carotenoids,
Tocols Palm
although
copherols and tocotrienols but is unusual in that it is especially rich in ‘y-tocotrienol (Table 5) (17-20; AB Gapor, unpublished observations). Tocols are physiologically active as vitamin E and are useful natural antioxidants, so their loss during refining should be minimized. Steam deodorization, distillation, and fractionation, however, all cause some losses(2l) but the majority of the tocols remain in the refined oil (Table 5).
oil and its fractions generally there is some variation.
contain high levels of tocols, Palm oil contains both to-
ofcrude
oils, animal
MUFA
SFA
0.109 0.024 0.016
0.390 0. 155 0.064
0.500
Palm-kernel oil Coconut oil Soybean
0.613
0.224
0.164
Palm
oil
oil
by most
0.819 0.919
TABLE
oil. Unrefined
for the characteristic
at concentrations
palm
ofcarotenoids.
components, ent in smaller ural state but cesses, which
fats, and crude
PUFA
source
are responsible
oil, are present
L in the crude food
TABLE 2 Fraction of fatty acid types in vegetable fish oils (from Table 1)
which
palm
Alpha-
oil thus represents and
fl-carotenes
color
ofSOO-700
mg/
the richest are the
major
with ‘y-carotene, lycopene, and xanthophylls presamounts. Some populations use the oil in its natall carotene is destroyed by current refining protraditionally produce the light-colored oils preferred
consumers.
3
Fractional
fatty acid composition
of palm
oil and its fractions
Groundnut
oil
0.325
0.465
0.205
Cottonseed
oil
0.531
0.193
Cornoil
0.518
0.326
0.275 0.156
Safflower oil Sunflower oil
0.769 0.664
0. 132 0.2 13
0.100 0.122
Rapeseed
0.308
0.62 1
0.072
16:1
Tr-0.003
Tr-0.002
Tr-0.002
0.456
0.389
0.155
18:0
0.040-0.055
0.039-0.044
0.044-0.055
oil
Sesame oil Beef fat Porkfat Fish oils S
acid;
PUFA,
0.009-0.026
0.091-0.148 0.088-0.338 polyunsaturated
SFA, saturated
Fatty
acid
Palm
oil
12:0 14:0
0.0-0.002 0.008-0.01
16:0
0.431-0.463
Palm
3
olein
Palm
stearin
0.00 1-0.002 0.009-0.010
0.001-0.002 0.010-0.013
0.395-0.408
0.465-0.689
0.338-0.6 13 0.323-0.501
0.307-0.614 0.366-0.555
18:1
0.367-0.408
0.427-0.439
0.199-0.384
18:2
0.094-0.119
0.106-0.114
0.041-0.093
0.144-0.710
0.107-0.422
18:3 20:0
0.001-0.004 0.001-0.004
0.0-0.004 0.001-0.003
0.001-0.002 0.001-0.003
fatty acid; MUFA,
monounsaturated
fatty
fatty acid.
Downloaded from https://academic.oup.com/ajcn/article-abstract/53/4/989S/4715161 by guest on 19 January 2018
S
From reference
1.
992S
COTTRELL
TABLE4
TABLE
Ranges
o f carbon-number
fract ional
Palm
oil
Palm
46-C
0.0-0.01
48-C 50-C 52-C 54-C 56.C
0.068-0.097 0.383-0.440 0.375-0.412 0.085-0. 1 19 0.0-0.007
*
From
reference
compositions*
8
olein
Palm
0.003 0.026-0.03 1 0.377-0.393 0.443-0.457 0. 123-0. 128 0.006-0.008
in crude
0.009-0.030 0.102-0.427 0.394-0.422 0.119-0.379 0.025-0.103 0.002-0.006
Cholesterolt Brassicasterolt Campesterolt Stigmasterolt $-Sitosterolt 6-5-Avenasterolt #{244}-7-Stigmasterolt #{244}-7-Avenasterolt
11.
*
in Table 6, (22) the major sterols in palm oil and its fractions are $-sitosterol, campesterol, and stigmasterol. Sterols and esters do not seem to serve any really useful function
rimental
Polar
it has
been
may give antioxidant effect
suggested
effects)
that
some,
like
nor do they have
process
in palm oil is phosphatidylcholine is monogalactosyldiglyceride. The wetmost of the phospholipids in the palm
leaves palm
oil
contains
relatively
low
levels It has been
Free acids
of phosreported
and tocotrienols
Oils and fats*
when
Total phenol palm oil (23).
concentration
446
is usually
it reaches
the
refinery
but
badly
handled
oils
may
up to 10% (24).
Impurities Small amounts ofiron and copper may be present in the crude oil, which are pro-oxidants in catalytic amounts. Iron impurities are derived from wear and tear of oil-mill machinery and may be minimized by using stainless steel at strategic points in the milling
process
usually
contains
or by magnetic 5 gJL
