Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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PALM OIL

K G Berger, Chiswick, London, UK

Introduction

0001 Palm oil is obtained from the fruit flesh of the oil

palm (Elaeis guineensis Jacqu.), a native of the equa-

torial region of West Africa. Unrefined oil obtained

from wild palms has been a traditional food source

for the indigenous population for thousands of years.

However, its use for edible purposes elsewhere had to

await the development of suitable refining processes

to produce a bland pale-colored oil. Today, palm oil is

the second most abundant edible oil after soya bean

oil and is in universal use.

The Oil Palm

0002 The oil palm flourishes best in lowland regions of

high rainfall and close to the equator. Optimum con-

ditions are a rainfall of 1700 mm or more per annum,

evenly distributed through the year and a position

within 10



N and S of the equator, but it also grows

in isolated locations outside these limits, i.e., between



N and 20



S. The plant can be grown in a variety

of tropical soils, regular and sufficient water being

apparently more important than soil, provided that

the plant nutrient requirements are supplied.

Unfavorable soil factors are poor drainage and high

laterite or sand content. Special techniques have been

developed to enable peat soils to be used.

0003 The oil palm is a single-stemmed plant bearing

a number of fronds in a simple head. A mature palm

may have up to 50 fully opened fronds. One inflores-

cence arises from the axil of each leaf; male and

female inflorescences occur on the same palm. Both

consist of a central stem carrying about 200 flower

bearing spikelets. Each spikelet on the male inflores-

cences carries about 1000 flowers, and on the female

inflorescence 15–30 flowers. Pollination is by insects,

the most effective being the weevil, Elaeidobius

kamerunicus, native to West Africa. Ripe fruit

develops in about 155 days after fertilization, but

the bulk of the oil is synthesized in the final 2–4

weeks. The fruit bunch, containing 1500–2000 indi-

vidual fruits weighs 20–30 kg.

0004Considerable variation occurs in the wild palms,

and three types have been classified according to fruit

type. The most common wild type is the dura, char-

acterized by a relatively thin layer of flesh covering

the seed, which consists of a hard thick shell within

which lies the kernel. A small proportion of plants,

called pisifera, bear fruit with a thick layer of flesh

and a small kernel with a very thin or no shell.

Another small proportion of plants in the wild, the

tenera, has relatively thick flesh with a shell and

kernel of intermediate size.

0005The tenera type was found to be a natural cross

(DP) of dura and pisifera palms. When plantations

were first being developed in West Africa (in Belgian

Congo, now Zaire), the superior economic perform-

ance of the tenera was recognized, and the heritability

of shell thickness was discovered. Subsequent devel-

opment of improved planting material therefore

centered on selecting the best dura and pisifera plants

for crossing. The continuing efforts of plant breeders

have resulted in progressive increases in yield, as

shown in Table 1.

0006A slow development of oil palm plantations

occurred in Indonesia after World War I, soon to

be followed by Malaya. By 1938, Indonesia had

90 000 ha and Malaya 30 000 ha under oil palm.

After 1960, the area under oil palm increased rapidly

in Malaysia, reaching 3.2 million ha by 2001. Devel-

opments in Indonesia were slower, with 2.4 million ha

in 2001. These two countries are by far the largest

producers of palm oil and the main suppliers to the

world market. Plantation developments in Central

and South America have reached about 500 000 ha

in all, with Colombia, Ecuador, and Brazil having the

largest areas.

0007A unique feature of the oil palm is that the fruit

yields two distinct types of oil. Palm oil from the flesh

is the major product, whereas palm kernel oil is

tbl0001 Table 1 Progress through breeding and selection in South-east Asia

Material Bunches (tonnes ha

1

) Mesocarp to fruit (%) Oil to bunch (%) Oil (tonnes ha

1

)

Bogor 1878 16.5 58.7 17.6 2.8

Elmina 1933 20.1 58.2 17.0 3.4

OPRS 1969 24.8 64.1 18.3 4.5

Commercial DXP 1978 26.0 80.1 22.0 5.7

Adapted from the Palm Oil Research Institute of Malaysia Bulletin, November 1984 with permission.

PALM OIL 4325

obtained from the seed. Its chemical and physical

characteristics are quite distinct from palm oil, and

it has different applications. (See Palm Kernel Oil.)

Commercial Importance

0008 The importance of palm oil in the world’s oils and fats

economy is shown in Table 2, giving the total produc-

tion of 17 major oils and fats, and individual figures

for soya, palm, palm kernel, and rapeseed oils.

The figures given are 5-year averages and include

production forecasts to the year 2002. Figures in

brackets are the percentage of total. Production fig-

ures for sunflower oil (not shown in Table 2) are

similar to those of rapeseed oil, and that the other

oils among the 17 included in the total show little or

no growth trend.

0009 Table 2 shows that palm and palm kernel oils

together have increased their share of edible oil

supplies regularly for more than 20 years, and

are forecast to continue to do so. World produc-

tion of palm oil in 2001 was 23.6 million tonnes

of which 17.6 million tonnes were exported to

world-wide destinations. Eighty-eight percent of

the exports were of Malaysian and Indonesian

origin.

0010 In those African countries where the oil palm

grows, it continues to hold its position as the major

traditional food oil with an annual production of

about 1.5 million tonnes in the region. While much

of it is still eaten in the crude form, the consumer is

also increasingly demanding processed products.

0011 In a number of Latin American countries, palm

oil is seen as an efficient means of reaching self-

sufficiency, and current production of about 1.4

million tonnes is mainly for local consumption. In

contrast, domestic consumption in Malaysia is less

than 10% of production. The crop is mainly grown

for export, as a successful diversification from rubber.

Indonesia, the second largest producer, requires a

higher proportion of its production for internal con-

sumption, but is increasing production and exports

rapidly.

0012The importance of palm oil in the world market is

based on several factors.

0013It is comparatively cheap, often with an appre-

ciable discount to soya bean oil, the market leader.

0014It has technical attributes, useful in food manufac-

ture, especially its good stability to oxidation, and

its natural solid fat content.

0015It is a perennial crop, planted for an economic life

of 25–30 years. It mainly grows in equable cli-

mates in regions little affected by earthquakes or

hurricanes, so that production fluctuates less from

year to year than does that of annual crops.

Harvesting and Processing of the Fruit

0016Various traditional primitive methods of oil recovery

are still widely used in West Africa. Typically, the fruit

bunch is cut off, and allowed to ferment a few days,

so that the fruit detaches easily. The fruit flesh is

softened by boiling or by further fermentation, then

mashed in a pestle and mortar or under foot. Hot

water is added, the oil skimmed, and the water is

then boiled off in a separate container. The oil is

used without any refining.

0017In contrast, the modern plantation is usually asso-

ciated with a mechanical oil mill with a processing

capacity of 5–60 tonnes of fresh fruit bunches (FFB)

per hour. The harvesting of FFB is still done manually,

using an ax, or a sickle-type blade fixed to a pole,

depending on the height of the palm. Ripeness is

judged by the number of detached fruit that have

fallen below the bunch. The frond and then the

bunch are cut off. The bunch and any loose fruit are

picked up and carried manually, by barrow, in a light

animal-drawn vehicle, or with a light mechanical

vehicle to the nearest estate road. It is important not

to compact the soil close to the palms. Transport is

then by lorry to the oil mill. Bunches are emptied into

a chute, and filled into sterilizer ‘cages’ mounted on

tbl0002 Table 2 World production of oils and fats (1000 tonnes)

1968^1972 1973^1977 1978^1982 1983^1987 1988^1992 1993^1997 1998^2002

Total of 17 oils and fats 40 314 45 883 56 848 67 614 80 663 92 314 105 266

Soya bean oil 6 036 8 477 12 639 14 147 16 997 19 508 23 317

(15) (18.4) (22.1) (20.8) (21.1) (21.1) (21.9)

Palm oil 1 725 2 763 4 482 6 745 10 101 13 878 17 498

(4.3) (6.0) (7.9) (10.0) (12.5) (14.9) (16.6)

Palm kernel oil 406 437 545 862 1 232 1 655 2 175

(1.0) (1.0) (1.0) (1.3) (1.5) (1.8) (2.1)

Rapeseed oil 2 039 2 572 3 732 6 009 8 329 9 534 10 829

(5.0) (5.6) (6.6) (8.9) (10.3) (10.3) (10.3)

Adapted from Oil World Annual. ISTA Mielke, Hanburg, with permission.

4326 PALM OIL

wheels, which are then moved into a horizontal cylin-

drical pressure vessel on rails. Typically, up to 7 2.5

tonnes of fruit are cooked in one load. Steam at

304 kPa (3 atm) is applied for about 1 h. The contents

of the cage are then fed to a ‘bunch stripper’ consist-

ing of a horizontal rotating drum with baffles.

Bunches are repeatedly lifted and dropped, so that

the fruit is shaken out. It is then transported to a

‘digester’, a vertical steam-jacketed cylinder fitted

with rotating beater arms. The fruit is thoroughly

mashed and passes directly to a single or a twin-

screw press. The press extrudes a liquid at one end,

consisting of about 53% oil, 7% finely divided solids,

and 40% water, and a press cake containing the fruit

fiber and the nuts at the other end. The liquid phase

passes through a vibrating screen to a settling tank.

After about 2 h, the upper layer is clarified in a sealed

centrifuge; the oil is then dried under vacuum and

pumped to storage. The lower layer is treated in a

sludge centrifuge, or in a three-phase decanter, the oil

phase being returned to the settling tank.

0018 The cake formed by the press fiber and nuts is

processed in a separate stream. The cake is broken

up by rotating arms on a conveyor, and the fiber is

removed in a ‘polishing’ drum. The nuts are partially

dried by a warm air stream in a silo, before being

cracked in a centrifugal cracker. Nuts drop on to a

rotor, which throws them against a peripheral ring of

hardened metal. Kernels are separated from shells in a

pneumatic column and/or a hydrocyclone, washed,

and dried with hot air to below 8% moisture.

0019 The production of palm kernel is usually carried

out in a separate factory.

Treatment of Wastes

0020 Three aqueous waste streams arise in the oil mill:

0021 condensate from the sterilizing process;

0022 aqueous effluent from the centrifuges;

0023 waste water from nut processing.

Typically, for every 1 tonne of oil produced, the com-

bined aqueous waste is 2.5 tonnes containing 0.6%

oil and 3.9% dissolved and suspended solids. After

removal of any supernatant oil, this effluent is treated

until the water is of a quality suitable for discharge or

reuse in the process. A number of processes have been

adopted. Typically, treatment involves:

0024 1–2 days in an open acidification pond;

0025 up to 20 days in a tank for anaerobic digestion;

0026 about 20 days in a lagoon with vigorous aeration

for anaerobic digestion.

The press fiber, after separation of the nuts, is used

as fuel in the mill boilers. Consequently, the mill is

usually self-sufficient in fuel for steam and electric

power. Some shell may be used in the boiler. Alternate

uses are as hard-core on estate roads or as raw mater-

ial for charcoal.

0027Recently, an alternative treatment process has been

developed. The waste stream is partly dewatered in a

decanter centrifuge, and then treated in a rotary drier,

using heat from the boiler flue, or produced by burn-

ing empty fruit bunches. The resulting solid is used as

a fertilizer in the plantation.

Refining of Palm Oil

0028Crude palm oil may be refined by the traditional

alkali refining process. In view of its natural strong

red color, a highly active bleaching earth may be

required. Table 3 gives a flow sheet for a typical

process.

0029Crude palm oil usually contains 3–5% of free fatty

acids, and so the process losses in alkali refining tend

to be rather high. This has led to the development of

physical or steam refining, where the use of a some-

what higher temperature in a modified deodorizer

enables the free fatty acids to be removed by distilla-

tion instead of neutralization. The process has proved

to be more economical and is now being adopted for

other oils. A flow sheet for physical refining is given

in Table 4.

Further Processing of Palm Oil

0030Palm oil is subjected to further processes in the

refinery in order to make it more widely useful in

food applications.

0031The following processes are carried out on a large

scale in order to modify the physical properties:

0032fractionation;

0033hydrogenation;

0034interesterification.

Brief descriptions of the processes will be given here,

and the properties of the products will be described in

a later section.

0035The major glyceride components of palm oil range

from triolein (melting point 5



C) to tripalmitin

(melting point 66



C) with a number of mixed glycer-

ides of intermediate melting point.

0036Crystallization from the melt of this mixture at

a controlled temperature, followed by separation of

the liquid and solid phases, results in palm olein

and palm stearin. The characteristics of these

products depend on the temperature chosen for

crystallization and the efficiency of the separation

process. This may be by centrifugation, filtration on

a rotating band filter, or in a plate and frame filter. A

PALM OIL 4327

modification of the latter has each frame fitted with

an inflatable diaphragm, which enables pressure to be

applied to the solids, and results in very efficient

separation of the olein. Fractionation from solution

in acetone or hexane is more costly and is only used

when a sophisticated midfraction is required (see later

sections).

Hydrogenation

0037 Hydrogenation is a standard process in the edible oil

industry. It involves treating the oil with an activated

nickel catalyst with hydrogen under pressure and at

an elevated temperature. Vigorous stirring is re-

quired, since the liquid and gas phases have to contact

at the surface of the catalyst. The oil is neutralized,

washed, and bleached before hydrogenation, to avoid

deactivation of the catalyst. (See Vegetable Oils: Oil

Production and Processing.)

Interesterification

0038When a glyceride oil is stirred with sodium methoxide

(or other alkali catalyst) at a temperature of about



C, the fatty acid radicals are detached from their

original positions, and new glycerides are formed

with a random distribution of fatty acids. Examples

of interesterified products will be given in later

sections. (See Vegetable Oils: Oil Production and

Processing.)

tbl0003 Table 3 Flow sheet for alkali refining

Processstep Typical conditions Mainimpurities removedor reduced

Pretreatment, 0.1% phosphoric acid Phospholipids

Gum conditioning 80



C – 20 min Trace metals

Pigments

Neutralization 4 N caustic soda Fatty acids

20% excess Phospholipids

Pigments

Washing Soap

Drying Water

Bleaching 1% active earth Pigments

80–100



C, vacuum Oxidation products

Trace metals

Soap residues

Filtration Spent bleaching earth

Deodorization 240



C at 133–667 Pa (1–5 torr) Fatty acids

90–110 min Partial glycerides

Oxidation products

Pigment

Decomposition products

Polishing filter Traces of oil

Insolubles

tbl0004 Table 4 Flow sheet for physical refining

Processstep Typical conditions Mainimpurities removedor reduced

Gum conditioning 0.1% phosphoric acid Phospholipids



C – 20 min Trace metals

Pigments

Bleaching 1–2% active earth Phospholipids



C – 20 min Trace metals

Vacuum Pigments

Oxidation products

Filtration Spent earth

Deacidification and deodorization 260–265



C at 133–667 Pa (1–5 torr) Free fatty acids

Partial glycerides

Oxidation products

Pigment decomposition products

Traces of oil

Polishing filter Insolubles

4328 PALM OIL

Chemical Composition of Palm Oil and

Fractions

0039 Average fatty acid composition data from refined

palm oil and standard palm olein and stearin, as

traded, are shown in Table 5. Tailor-made fractions

are also available for specific requirements. The last

column shows the composition of a midfraction

obtained from palm oil under special conditions,

which is suitable for use in confectionery fats. Tri-

acylglycerol compositions for the same products are

given in Table 6.

Physical Properties of Palm Oil

0040 Many food products require a consistent or semisolid

fat as an ingredient in order to achieve the required

structure. An important feature of palm oil is its

natural content of solids. The average solid fat

content of palm oil products is given in Table 7.

Palm stearins of a wide choice of composition and

solid fat contents are available, for example, with solid

fat contents at 20



C ranging from 35 to 72%.

Minor Components of Palm Oil

0041Data for the minor components of palm oil, collected

from published sources, are given in Table 8. The

main sterols present are b-sitosterol (58%), campes-

terol (22%) and stigmasterol (11%). The main caro-

tenoids are b-carotene (56%) and a-carotene (35%).

The carotenoids are removed in the normal refining

process. The tocol content is unusual in having a high

proportion of unsaturated tocotrienols. Details for

crude and refined products are given in Table 9. The

tocols are important as vitamin E and as potent nat-

ural antioxidants. (See Antioxidants: Natural Anti-

oxidants; Carotenoids: Occurrence, Properties, and

Determination.)

tbl0005 Table 5 Mean fatty acid composition (%)

Refined palm Palm midfraction

Oil Olein Stearin

12:0 0.24 0.27 0.18

14:0 1.11 1.09 1.27 0.7

16:0 44.14 40.93 56.79 60.9

16:1 0.1 0.1 0.1

18:0 4.44 4.16 4.93 4.6

18:1 39.04 41.51 29.0 31.0

18:2 10.57 11.64 7.23 2.6

18:3 0.2 0.2 0.2 0.1

20:0 0.2 0.1 0.2 0.3

Data from Britannica Food Ingredients with permission.

Adapted from Siew WL, Tang TS, Oh FCH, Chong CL and Tan YA (1993)

Identity characteristics of Malaysian palm oil products: fatty acid and

triglyceride composition and solid fat content. Elaeis 6(1): 38–46, with

permission.

tbl0006 Table 6 Mean triacylglycerol compositon of refined oils

(carbon numbers by GLC)

Carbon number Palm oil Palm olein Palm stearin Palm

midfraction

C44 0.07 0.09 0.13

C46 1.18 0.77 3.13

C48 8.08 3.28 23.72 2.2

C50 39.88 39.52 40.31 78.9

C52 38.77 42.74 25.28 15.1

C54 11.35 12.80 6.86 0.7

C56 0.59 0.67 0.45

Unidentified 3.1

Carbon numbers are the sum of the carbon atoms in three acyl groups.

Data from Britannica Food Ingredients with permission.

Adapted from Siew WL, Tang TS, Oh FCH, Chong CL and Tan YA (1993)

Identity characteristics of Malaysian palm oil products: fatty acid and

triglyceride composition and solid fat content. Elaeis 6(1): 38–46, with

permission.

tbl0007Table 7 Mean solid fat content of standard refined oils

Te m p e ra t ur e

(



Palm oil

(mean) %

Palm olein

(mean) %

Palm stearin

(mean) %

Palm

midfraction

10 53.6 38.27 76.04

15 39.13 19.89 68.91

20 26.10 5.67 60.71 89.9

25 16.28 2.05 50.55 82.6

30 10.54 40.39 50.2

35 7.85 34.30 50.2

40 4.64 28.13 0.0

45 22.38

50 12.45

55 0.60

Tempered at 26



C for 40 h.

Adapted with permission from Siew WL, Tang TS, Oh FCH, Chong CL and

Tan YA (1993) Identity characteristics of Malaysian palm oil products: fatty

acid and triglyceride composition and solid fat content. Elaeis 6(1): 38–46,

with permission.

Data from Britannica Food Ingredients with permission.

tbl0008Table 8 Minor components of crude palm oil typical figures

(p.p.m.)

Sterols 490

4-Methyl sterols 360

Triterpenic alcohols 550

Isoprenoid alcohols 80

Other alcohols 130

Tocols 830

Carotenoids 670

Squalene 350

Other hydrocarbons 40

Reproduced with permission from Palm Oil Research Institute of Malaysia.

PALM OIL 4329

Food Uses of Palm Oil

Frying

0042 Palm oil has a good stability at the high temperatures

used in frying (usually 175–185



C), because of its

content of natural antioxidants, the absence of highly

unsaturated fatty acids, and the moderate content of

linoleic acid. Consequently, palm oil or palm olein is

widely used domestically and in industry, especially

for deep fat frying whether in a batch process, as in

restaurants and fast food outlets such as British ‘fish

and chip’ shops, or in continuous fryers. Palm oil is

used for doughnut frying, because the solids content

assists the adhesion of the sugar coating. Palm oil is

also used for the frozen ‘French fry’ industry and for

instant noodle frying in Japan and China. For potato

crisps (American ‘chips’), palm olein is preferred, or a

blend of palm olein with a more unsaturated oil such

as sunflower or soya bean oil.

Bakery Fats

0043 Texturized palm oil is used as such in some types of

biscuits. For other biscuits and for cakes, a formu-

lated shortening is required to obtain good aerating

properties. Some formulae with a satisfactory per-

formance are given in Table 10.

Vanaspati

0044 Vanaspati may be defined as a cheaper alternative to

butterfat, having a melting point of about 37



Cand

a granular crystalline structure with little or no free

oil. It is generally based on vegetable oils suitably

hydrogenated or on a blend of oils. Vanaspati is the

customary domestic cooking fat in the Indian sub-

continent and the Middle East. When formulated

from liquid vegetable oils, the desired structure re-

quires a hydrogenation giving a high content of

trans fatty acid isomers (30–60%). This is regarded

as undesirable according to current nutritional

advice. A number of formulae based on palm oil

and having low or zero trans fatty acids are given

in Table 11.

Margarines

0045Margarines can be classified as being for table use in

blocks or in tubs, general bakery margarines, and

puff-pastry margarines.

0046The textual properties are the textual properties

appropriate for each application, and these can

be obtained by blending a variety of ingredients.

Table 12 shows some formulae based on palm oil.

Confectionery Fat

0047Palm oil midfraction (see Tables 5–7)isusedasa

major component of blends designed to have physical

properties like cocoa butter, and compatible with it in

mixtures. Palm olein, partly hydrogenated under con-

ditions giving a high content of trans fatty acids, is

tbl0009 Table 9 Tocol content of palm oil (p.p.m.)

a-tocopherol a-tocotrienol g-tocotrienol d-tocotrienol Total

Crude palm oil Mean (n¼9) 162 165 324 81 774

Range 136–241 90–205 273–439 67–94 635–890

Refined palm oil Mean (n¼3) 117 117 158 31 426

Range 85–180 99–147 67–239 5–62 256–630

Refined palm olein Mean (n¼8) 141 152 218 49 561

Range 107–163 131–177 113–293 28–68 478–673

Reproduced with permission from Palm Oil Research Institute of Malaysia.

tbl0011Table 11 Vanaspati formulae containing palm oil products

Hardened palm olein (melting point 41



C) 24

Palm oil 56 80 70 80

Liquid oil 20

Rice bran oil 20

Palm stearin 7

Hardened soya bean oil (melting point



C) 23 20

Tr a n s fatty acids (%) 2.7 Nil 7.5 4

The blend is interesterified.

Current formulae of this type in use in Pakistan.

Reproduced with permission from Palm Oil Research Institute of Malaysia.

tbl0010Table 10 Shortening formulae containing palm oil

1234

Palm oil 50

Hardened palm oil melting point (49–51



C) 15

Liquid oil 35

Palm stearin 35 42

Hardened rapeseed oil melting point 36



C30

Rapeseed oil 35 40

Hardened palm oil melting point 42



C18

Palm olein (interesterified) 100

Reproduced with permission from Palm Oil Research Institute of Malaysia.

4330 PALM OIL

useful as a confectionary fat with limited compatabil-

ity with cocoa butter, or for use in toffee, bakery

coatings, and confectionery centers.

Miscellaneous Uses

0048 Palm oil is used instead of butterfat in icecream and in

filled milk or coffee whiteners. Partly hydrogenated

palm oil is used in dried soups, where its stability

against oxidation is important.

Special Products

0049 Using a modified refining process, red palm oil and

palm olein, retaining about 80% of the carotenoid

content of the crude oil, have become commercially

available. Red olein has found uses in the manufac-

ture of attractively golden-colored potato crisps,

whereas red palm oil is being used in nutritional

intervention studies in South Africa and India. This

is potentially a very important use, in view of the high

incidence of xerophthalmia in developing countries.

0050 A commercial process is also in operation to obtain

a 99% pure concentrate of the tocopherols and

tocotrienols from the palm fatty acid distillate, the

byproduct of physical refining. The concentrate is

used in health supplements.

See also: Antioxidants: Natural Antioxidants;

Carotenoids: Occurrence, Properties, and

Determination; Palm Kernel Oil; Tocopherols:

Properties and Determination

Further Reading

Berger KG (1983) Palm Oil. In: Chan HT (ed.) Handbook

of Tropical Foods, pp. 433–468. New York: Marcel

Dekker.

Berger KG (1983) Production of palm oil from fruit.

Journal of American Oil Chemists’ Society 60:

158–162.

Hartley CWS (1988) The Oil Palm, 3rd edn. Harlow, UK:

Longman Scientific and Technical.

Kheiri SA (1987) Palm Oil. In: Gunstone FD (ed.) Critical

Reports on Applied Chemistry, vol. 15. London: Society

of Chemical Industry.

Siew WL, Tang TS, Oh FCH, Chong CL and Tan YA (1993)

Identity characteristics of Malaysian palm oil products:

fatty acid and triglyceride composition and solid fat

content. Elaeis 6(1): 38–46.

Tan BK and Oh FCH (1981) Malaysian Palm Oil Chem-

ical and Physical Characteristics, Porim Technology

No. 3. Kuala Lumpur: Palm Oil Research Institute of

Malaysia.

Palms See Coconut Palm; Date Palms; Sago Palm; Sugar: Sugarcane; Sugarbeet; Palms and Maples;

Refining of Sugarbeet and Sugarcane

Pancreatic Hormones See Hormones: Adrenal Hormones; Thyroid Hormones; Gut Hormones;

Pancreatic Hormones; Pituitary Hormones; Steroid Hormones

tbl0012 Table 12 Margarine formulae using palm oil products

Block

(temperate)

Block

(tropical)

Tub General bakery Danish pastry Puff pastry

Palm oil 50 80 50 65 40 50

Hydrogenated palm oil

(melting point 44



20 10 40 50

Liquid oil 30 50 10 20

Coconut oil 15

Palm stearin 20

Reproduced with permission from Palm Oil Research Institute of Malaysia.

PALM OIL 4331

PANTOTHENIC ACID

Contents

Properties and Determination

Physiology

Properties and Determination

G F M Ball, Wembley, London, UK

Background

0001 In 1933, a research team led by R. J. Williams isolated

from a variety of biological materials an acidic

substance that acted as a growth factor for yeast.

Williams’ team elucidated the chemical structure of

the purified substance and named it pantothenic acid

because of its apparently widespread occurrence

(Greek pantos, meaning everywhere). Pantothenic

acid was established as a vitamin in 1939, when it

was shown to be identical to a ‘filtrate factor’ re-

quired by rats for normal growth, and to a chick

antidermatitis factor. Sometimes referred to as vita-

min B

, pantothenic acid is a member of the water-

soluble B-group vitamins.

Structure and Physicochemical

Properties

0002 The biological activity of pantothenic acid is attribut-

able to its incorporation into the molecular structures

of coenzyme A and acyl carrier protein. The molecu-

lar structures of pantothenic acid and related com-

pounds are shown in Figure 1. Pantothenic acid

N; molecular weight ¼219.23) is com-

posed of pantoic acid linked by an amide bond to

b-alanine. The pantothenic acid molecule, having a

chiral carbon atom, exhibits optical isomerism as well

as being optically active. Only the d(þ) isomer occurs

in nature. Synthetic pantothenic acid is a racemic (dl)

mixture, and, since only the d isomer is biologically

active, this fact must be considered if the dl mixture

is to be used therapeutically. Pantothenic acid is

a pale yellow oil that is extremely hygroscopic and

so is unsuitable for commercial application. For

human food supplements, calcium d-pantothenate

[(C

Ca; molecular weight ¼476.53] is

used.

0003 The corresponding alcohol of pantothenic acid,

pantothenol (referred to commercially as panthenol),

is widely used as a source of pantothenate activity for

pharmaceutical vitamin products, because it is more

stable than the pantothenate salts, especially in liquid

multivitamin products that must be slightly acid to

preserve the thiamin content. Pantothenol does not

occur naturally and itself has no pantothenate activ-

ity, but it is converted quantitatively to pantothenic

acid in the body.

0004The stability of pantothenic acid and its calcium

salt in aqueous solution is highly dependent on the

pH. In contrast to other B-group vitamins, panto-

thenic acid becomes more stable as the pH of the

solution increases. Solutions of calcium pantothenate

are most stable between pH 5 and 7 but, even so, are

not stable to autoclaving, and therefore, sterilization

by ultrafiltration is necessary for pharmaceutical

preparations. Below and above these pH values,

solutions of calcium pantothenate are thermolabile.

Alkaline hydrolysis yields pantoic acid and b-alanine,

whereas acid hydrolysis yields the g-lactone of

pantoic acid. Pantothenic acid is unaffected by

atmospheric oxygen and light.

Dietary Sources

0005Pantothenic acid is widely distributed in foods of

both animal and plant origin. In concentration units

of mg per 100 g, the vitamin is particularly abundant

in liver (8), kidney (3), heart (2.5), egg yolk (4.6)

broad beans (4.9), and peanuts (2.7). Lesser amounts

are found in beef (0.6), chicken (1.2), potatoes (0.4),

broccoli (1.2), oatmeal (1.0), and milk (0.35), but

these will be important food sources if consumed in

sufficient quantity. Outstandingly high amounts are

found in the ovaries of tuna and cod (232) and in

royal jelly from the queen bee (50). In contrast, highly

refined foods such as sugar, fats and oils, and corn-

starch are totally devoid of the vitamin.

0006Coenzyme A is the major pantothenic acid-

containing compound present in foods of both animal

and plant origin, accompanied by small amounts

of other bound forms (phosphopantothenic acid, pan-

tetheine, and phosphopantetheine). Notable excep-

tions are human and bovine milk in which free

(unbound) pantothenic acid constitutes around 90%

of the total pantothenate content.

4332 PANTOTHENIC ACID/Properties and Determination

0007 Pantothenic acid has a good stability in most foods

during home cooking but is susceptible to leaching.

The roasting of meat causes degradation of less than

10%, but the meat drippings contain 20–25% of the

initial vitamin content.

0008 Estimates of dietary intakes of pantothenic acid

should be based not on the raw food values, but on

the cooked food values, otherwise falsely high esti-

mates of intake will be obtained. Table 1 presents

data taken from a study in which the pantothenic

acid content of 75 processed and/or cooked foods

was determined by radioimmunoassay. The foods

selected for analysis were those commonly consumed

in the USA. Samples were brought to a ready-to-eat

stage, following any package directions, and using

only the edible portion. Results indicated that the

canning of foods incurs large losses of pantothenic

acid, as does the conversion of grains to various cereal

products, and the processing of meats to produce fat-

and cereal-extended products such as frankfurters

and sausages.

0009 Little information is at hand regarding the nutri-

tional availability to humans of pantothenic acid in

food commodities. In one study, based on the urinary

excretion of pantothenic acid, the availability for

male human subjects ingesting ‘the average American

diet’ ranged from 40 to 61%, with a mean of 50%.

Analysis

0010Pantothenic acid in its various bound forms (mainly

coenzyme A) is routinely determined by microbio-

logical assay. Other published methods include radio-

immunoassay, enzyme-linked immunosorbent assay,

gas chromatography, and high-performance liquid

chromatography. For all of these techniques, it is

necessary to liberate pantothenic acid from its

bound forms by enzymatic hydrolysis, because only

the free vitamin can be measured. Hydrolysis is

not required, however, for calcium pantothenate-

supplemented foods or for milk in which the free

vitamin predominates.

Extraction from Food

0011Neither acid nor alkaline hydrolysis is applicable for

the liberation of bound pantothenic acid, since the

vitamin is degraded by such treatments. The only

practicable alternative is enzymatic hydrolysis, and

this was successfully accomplished through the sim-

ultaneous action of intestinal phosphatase and an

avian liver enzyme. This double enzyme combination

liberates practically all of the pantothenic acid from

coenzyme A, but it does not release the vitamin from

acyl carrier protein. The phosphatase splits the coen-

zyme A molecule between the phosphate-containing

OOH

HOOC CH

NH CO CHOH C

CO CH

NHNHCH

CO CHOH C

O OP

OPCH

CO CH

NHNHHS

β-Alanine

β-Mercaptoethylamine

Pantoic acid

Pantothenic acid

Pantetheine

4'-Phosphopantetheine

Pyrophosphate

(a) Pantothenic acid

(b) Coenzyme A (CoA)

Adenine

Ribose-3'-Phosphate

CO CHOH C

O OP

Serine ProteinCH

HO OP

fig0001 Figure 1 Structures of (a) pantothenic acid, (b) coenzyme A, and (c) acyl carrier protein.

PANTOTHENIC ACID/Properties and Determination 4333

moiety and pantetheine, while the liver enzyme

breaks the link in pantetheine between the panto-

thenic acid and b-mercaptoethylamine moieties.

Both enzymes are available commercially as powdered

extracts. Liver enzyme preparations contain a rela-

tively high amount of coenzyme A, which is converted

to pantothenate during the incubation period, thus

creating an unacceptably high blank value. Such

preparations can be purified quite simply by treat-

ment with Dowex 1-X4 anion exchange resin. Intes-

tinal phosphatase preparations contain negligible

amounts of coenzyme A and do not require purifi-

cation.

Microbiological Assays

0012 Microbiological methods, as applied to the determin-

ation of the B-group vitamins, are based on the abso-

lute requirement of a particular microorganism (the

assay organism) for the vitamin in question (in this

case, pantothenic acid); that is, the organism can

multiply only when the vitamin is present in the sur-

rounding medium. In a typical turbidimetric micro-

biological assay, aliquots of a standard solution of

pantothenic acid, or aliquots of the sample extract

containing pantothenic acid, are added to an initially

translucent basal nutrient medium, complete in all

respects except for pantothenic acid. Following

inoculation with the assay organism, the organism

multiplies in proportion to the pantothenic acid con-

tent of the standard or sample, and the extent of the

growth is ascertained by measuring the turbidity pro-

duced. Over a defined concentration range, the meas-

ured response will be directly proportional to the

amount of pantothenic acid present, and, within

this range, the sample solution and standard panto-

thenic acid solution can be compared accurately. The

usual assay organism is Lactobacillus plantarum

(ATTC (American Type Culture Collection) No.

8014), which can also be used for assaying nicotinic

acid and biotin. The basal nutrient medium can also

be used for assaying nicotinic acid and biotin, with

the exclusion of the relevant vitamin from the formu-

lation. Fatty acids are stimulatory in the presence of

suboptimal amounts of pantothenic acid, so a prelim-

inary ether extraction step may be necessary.

0013In the standard turbidimetric procedure, the basal

nutrient medium is prepared at twice its final concen-

tration. Multiple aliquots of a standard solution of

pantothenic acid and of enzyme-treated extracts of

the test food are added to a series of uniform assay

tubes in amounts suitable to produce gradations in

growth between no growth and maximum growth.

The contents of all tubes are diluted with water to

the same volume, and an equal volume of the basal

medium is added. The tubes are sterilized, cooled to a

uniform temperature, and then inoculated with an

actively growing culture of L. plantarum. The tubes

are incubated for 6–24 h at any selected temperature

between 30 and 40



C held constant to + 0.5



C until

growth has reached the maximum permitted by

the limiting vitamin present, pantothenic acid. The

growth response to standard and test extract is then

determined by measuring the turbidity produced. The

data obtained from the standards are used to con-

struct a standard curve from which the pantothenic

acid concentrations of the various sample aliquots are

derived. The use of multiple aliquots allows a validity

check to be carried out: the pantothenic acid concen-

tration found should be directly proportional to the

volume of aliquot taken. The amount of pantothenic

acid present in the original sample is then calculated

at the different test levels, and the results are averaged

to obtain the final result.

0014An alternative method, the radiometric micro-

biological assay, is based upon the measurement of

radioactive

generated from the metabolism of

C-labeled nutrient by the test organism. The

radioactivity is measured automatically by means of

a commercially available gas flow system incorpor-

ating an ionization chamber. Sample preparation for

this technique is simplified due to the fact that

tbl0001 Table 1 Pantothenic acid content of processed and/or cooked

foods purchased in Utah, USA

Food

Pantothenic acid content

(mgper100 g) (mean and

standard deviation)

Breads, cereals, and other grain products

Bran’ola bread (high-fiber) 0.458 + 0.044

Rolls, hamburger 0.471 + 0.075

Ready-to-eat cereals

Cheerios (oats) 1.341 + 0.198

Corn Flakes (corn) 0.284 + 0.032

Wheat Chex (wheat) 0.502 + 0.042

Rice, white 0.261 + 0.036

Meat, fish, poultry, and meat products

Beef, regular ground – pan broiled 0.671 + 0.048

Pork loin chops – pan broiled 0.650 + 0.051

Fish filet, frozen, breaded – baked 0.250 + 0.016

Chicken breast – baked with skin 1.188 + 0.049

Frankfurters 0.342 + 0.025

Salami 0.997 + 0.086

Fruits and vegetables

Orange juice, frozen, reconstituted 0.197 + 0.029

Potatoes – baked 0.318 + 0.045

Potatoes – boiled 0.291 + 0.018

Potatoes – canned 0.152 + 0.026

The use of brand names is for identification purposes only and does not

imply endorsement of a food product.

Data from Walsh JH, Wyse BW and Hansen RG (1981) Pantothenic acid

content of 75 processed and cooked foods. Journal of the American Dietetic

Association 78: 140–144.

4334 PANTOTHENIC ACID/Properties and Determination