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transported in the blood to be metabolized by the

liver into fat constituents. In total, about 50% of the

energy of the fermented polyols is available to the

human body.

0006 Based on the above metabolic behavior, the calor-

ific value of polyols can approximately be calculated

(Table 3). However, depending upon the methodolo-

gies used, values vary over a wide range. Therefore,

and because many polyols are used in combination

with each other, a European Union Directive has laid

down an average calorific value of 2,4 kcal g

4

for all

polyols.

0007 Because of the reduced digestibility of polyols,

their intake level is recommended to be restricted to

40–50 g day

1

(adults) and 30 g day

1

for children in

order to avoid gastrointestinal discomfort. Higher

doses may cause an osmotic diarrhea or increased

flatulence due to slow absorption and extensive fer-

mentation, respectively, but tolerance levels improve

upon adaptation. On the other hand polyols are very

suitable for diabetics, because rapid glycemic or

insulinemic response is avoided. For the same

reason sorbitol and xylitol are often applied in

parenteral nutrition to provide a more controllable

carbohydrate energy source compared to glucose or

fructose.

0008 Concerning dental health, polyols have long been

known to have no adverse effect on teeth. This is due

to the fact that mouth bacteria are unable to ferment

polyols, thereby avoiding the production of enamel-

solubilizing acids. With the intraplaque pH telemetry

test, it was shown that eating polyol-based sweets did

not decrease the plaque pH below the critical value of

5.7. Additionally, for xylitol, there is ample proof of a

cariostatic effect. In several studies, of which the

Turku study (Finland) is most famous, the incorpor-

ation of xylitol in a normal diet was proved to reduce

the occurrence of dental carics. Most probably,

xylitol selectively discriminates against the growth

of Streptococcus mulans, the major organism in-

volved in dental caries. (See Dental Disease: Role of

Diet.)

Occurrence and Methods of Production

0009Polyols like sorbitol, mannitol, and xylitol have been

well known over the last 30 years due to their occur-

rence in a number of fruits, vegetables, and cereals.

Although they occur in nature, their concentration in

plant material is too low for a simple, economic

commercial extraction, as practiced with sucrose. A

more complicated process is therefore needed for the

production of sugar alcohols.

0010Several techniques have been described to produce

polyols but only a few of them are of industrial im-

portance. These are mainly based on catalytic hydro-

genation of easily accessible carbohydrates, e.g.,

dextrose, glucose syrups, maltose syrups, invert

sugar, isomaltulose, xylose, and lactose. These carbo-

hydrates are obtained either by hydrolysis or isomer-

ization of natural raw materials like starch, sucrose,

milk (whey), and straw (Figure 2).

0011The carbohydrate raw material is hydrogenated in

an aqueous solution at elevated temperatures (120–

190



C) and hydrogen pressure (20–200 bar) using an

activated nickel catalyst. Hydrogenation can be per-

formed either in a batch or a continuous process, and

results in the addition of hydrogen to the carbohy-

drate precursor. Hydrogen pressure, temperature, pH

value, and type of catalyst are the most important

parameters influencing reaction time and selectivity.

They have to be well adjusted to obtain a high-purity

product in high yield. Purity of the raw material is

also of importance in this respect. The hydrogenated

carbohydrate (polyol-containing) solution is sub-

sequently refined by filtration, carbon, and/or ion

exchange resin treatment to remove salts as well as

colored byproducts formed during hydrogenation.

0012Sorbitol and maltitol are available as aqncous solu-

tions and also as crystalline material. Mannitol, xyli-

tol, lactitol, and isomalt are available as crystalline

material. All crystalline polyols are produced by

crystallization, solidification, or spray-drying of an

aqueous solution at an appropriate concentration.

tbl0002 Table 2 Sweetness values of sugar alcohols

Compound Relative sweetness

Polyol

Xylitol 80–100

Sorbitol 50–60

Mannitol 50–60

Maltitol 80–90

Lactitol 30–40

Isomalt 40–50

Erythritol 60–70

Sucrose

100

10% in H

O: 20



tbl0003 Table 3 Absorption characteristics of sugar alcohols

Polyol Absorbed from

the smallintestine

(%)

Excreted (%) Fermented

(%)

Calorific

value

(kcalg

1

)

Urine Feces

Xylitol 25–40 0 < 1 60–75 2.9

Sorbitol 15–20 0 < 1 80–85 2.6

Mannitol 15–20 15–20 < 1 80–85 1.9

Maltitol 45–60 0 < 1 40–55 3.2

Lactitol < 1 0 < 1 99 2.3

Isomalt 35–45 0 < 1 55–65 3.0

SUGAR ALCOHOLS 5667

Uses in Foods

0013 Substitution of sugars in food to achieve specific nu-

tritional objectives is not a new practice. Initially,

polyols like sorbitol and mannitol were used to

sweeten food for diabetics. To cope with sensorial

and technological requirements for noncariogenic

food, the range of polyols has been extended to

include products such as maltitol, xylitol, isomalt,

and lactitol.

0014 For the production of polyol-based foods, most

conventional types of food-manufacturing equipment

are used. However, manufacturing conditions (tem-

perature, vacuum, etc.) very often need to be adapted.

As some polyols are moderately hygroscopic, the

relative humidity of air during production and stor-

age conditions require careful control. It is also neces-

sary to assure good protection by careful wrapping

and/or packaging. When neccessary, sweetness of

polyol-based foods can be enhanced by adding the

neccessary amounts of intense sweetners like aspar-

tame, accsulphame K, cyclamate, and saccharin. (See

Sweeteners: Intensive.)

0015 In addition to the production of sugarless foods,

polyols, e.g., sorbitol, can also be used in convention-

ally sweetened food products in order to give specific

sensorial effects such as texture and reduced color.

There are also technological advantages such as

plasticity, workability, and shelf-life. In particular,

sorbitol is widely used for its humectancy power to

extend food products shelf-life.

0016The main uses of polyols in food products are

outlined below.

Sugar-Free Confectionery

0017This is the most important application field for

polyols.

Hard Confectionery

0018Hard confectionery is produced by boiling polyol

solutions or syrups to a very high dry-matter content

(98–99.4%) followed by cooling, molding, and wrap-

ping. The boiling temperature for such polyol confec-

tionery varies between 155 and 170



C depending

on the type of polyol. Severe vacuum conditions are

needed. With the exception of mannitol, all the

polyols can be used alone. However, for technical

and economical reasons very often combinations of

polyols are applied. It should be kept in mind that the

solubility of polyols strongly influences crystalliza-

tion and graining.

Soft and Chewable Confectionery

0019The main component in this application is a polyol

or a polyol blend (65–70% dry matter) which is

Maltitol syrupSorbitol syrup

Enzymatic hydrolysis Inversion Acidic hydrolysis Crystallization

Enzymatic

conversion

Invert sugarMaltose syrup

Dextrose/

glucose syrup

Xylose LactoseIsomaltulose

MaltitolSorbitol Mannitol Xylitol LactitolIsomalt

Hydrogenation/filtration/ion exchange/evaporation

Crystallization or solidification

Starch Sucrose Whey

Straw,

birch wood,

almond shells

etc.

fig0002 Figure 2 Commercial production of sugar alcohols. Reproduced from Sugar Alcohols, Encyclopaedia of Food Science, Food Technol-

ogy and Nutrition, Macrae R, Robinson RK and Sadler MJ (eds), 1993, Academic Press.

5668 SUGAR ALCOHOLS

presolubilized and cooked together with vegetable fat

(about 6%), emulsifier (about 0.8%), gelatin (about

1.4%), and other minor components, e.g., food-grade

acid, flavor, and color. After cooling, the mass is

formed and wrapped. Chewability of the sweets can

be obtained by acration of the cooked mass after

partial cooling using conventional acration tech-

niques such as pulling and continuous foaming.

Gums and Pastilles

0020 Maltitol syrups, alone or in combinations with either

lactitol or isomalt, are very suitable for the produc-

tion of gelatin gums. For some compositions it is

necessary to adapt the gelatin type and level as well

as the cooking conditions in order to obtain gum

properties equivalent to those obtained with conven-

tional sweetened gums.

0021 In pastilles a gum arabic/polyol ratio of 50/50 on a

dry-weight basis is advised. This composition is

cooked to 70–72% dry-matter content, molded in

starch, and dried to 90% dry matter. After demold-

ing, the gums are waxed. Maltitol syrups give good

pastilles with optimal shelf-life properties.

Tubletting

0022 Although all powdered polyols can be compressed on

rotary machines to give tablets, sorbitol is the most

common polyol used in this field.

0023 Powdered sorbitol has excellent flow properties for

tabletting. Good flowability is very important to pro-

vide a uniform tablet weight. Compared to other

directly compressible materials, powdered sorbitol

gives a high increase of tensile strength as a function

of compression force and is therefore very suitable for

direct compression. Due to their rather high hygro-

scopicity, sorbitol-based tablets should be protected

or stored under relatively dry conditions in order to

avoid softening due to moisture pick-up. The priabil-

ity of sorbitol tablets, even those compressed at low

pressure, is extremely low and is improved further by

storage at close to equilibrium relative humidity

(ERH). The overall performance of sorbitol powder

in tabletting depends upon different factors, such as

particle size and distribution, crystal morphology,

and compression conditions.

Chewing Gum

0024 The main components of sugar-free chewing gums

are gum base (25–30%), polyol powder as solid phase

(45–63%), and sorbitol or maltitol syrups as liquid

phase (10–30%). The solid phase can be sorbitol

powder, but more often a combination of sorbitol

and xylitol is used. The main advantages of xylitol

are its excellent cariostatic propertics, high sweetness,

and a pleasant cool taste due to its negative heat of

solution. Addition of a small quantity of glycerol

improves the plastifying properties; mannitol add-

ition prevents stickiness.

Chocolate

0025Total replacement of sucrose by polyol powder both

in bitter or milk chocolate is possible providing the

powder has an optimum purity, crystal morphology

and granulometry. A bitter chocolate consists of

40–50% cocoa mass, 40–50% polyol powder, and

5–10% cocoa butter.

0026Originally only sorbitol was used for sugar-free

chocolate. Recent trends are towards the use of

maltitol, isomalt, and lactitol.

Dragee Coating

0027Coating consists in covering cores, e.g., chewing

gum with a syrup which is close to its saturation

point, then inducing crystallization by evaporation.

Generally a lot of layers (40–50) are needed. The

temperature of polyol syrups, drying air, centers,

and core bed are very important processing param-

eters. Sorbitol is the most common sweetener for

sugarless coating, but maltitol, xylitol, isomalt, and

lactitol can also be used.

Bakery Products

0028Polyols can be used in bakery products due to their

specific properties which are lacking in many other

bulk sweeteners. The sugar alcohols contribute to

softness and storage capacity. They also regulate

moisture, taste, and sweetness. A combination of

polyols or a polyol combined with another sweetener

is preferred. If browning is too light, the baking tem-

perature can be raised or a small amount of fructose

can be added.

0029The baking industry uses crystalline sorbitol and

sorbitol solution in products for special dietary use. It

is also employed as a humectant to extend the shelf-

life of baked goods. The stability of baked products

can be improved by partial substitution of sucrose by

sorbitol, e.g., in cakes. Sorbitol is used in sponges and

cakes at between 5 and 8% of flour weight. In biscuits

and cream fillings it is used up to 10%. The freshness

of gingerbread is improved by adding only 5% sorb-

itol. It is also used to substitute sugar in classical

formulations for low-sugar products. (See Cakes:

Nature of Cakes.)

0030The use of the other polyols in bakery is rapidly

developing. The level of sugar replacement with these

sweeteners depends on the type of polyol and the

application objective. While, for some polyols, rather

SUGAR ALCOHOLS 5669

high usage levels can be achieved, e.g., for maltitol,

lactitol, and isomalt, for others, e.g., xylitol and man-

nitol, usage levels are generally low. These differences

are also related to the specific sensory and physico-

chemical properties of the polyols used. An important

contribution of the other polyols is, as for sorbitol,

the humectant properties which control the moisture

level in bakery products when stored for long periods.

In some cases, combinations of polyols can give inter-

esting complementary effects. The main applications

in the bakery field are cakes, biscuits, pastry, fillings,

and icings. In the last two products, xylitol and man-

nitol can be an asset due to their perceptible cooling

effect. (See Biscuits, Cookies, and Crackers: Nature of

the Products; Pastry Products: Types and Production.)

Other Areas of Application

0031 Polyols can also be used in sugarless jams and ice-

creams. Sorbitol-containing jams and preserves have

a clear taste and good texture. A sufficiently high

solids content can be obtained in order to inhibit

microbiological activity, thereby protecting the jams

against mold development. In order to avoid crystal-

lization during storage, the solubility of the polyol(s)

should be checked before formulating the food.

Erythritol

Chemical and Physical Properties

0032 Erythritol is a linear carbohydrate molecule of four

carbon atoms, each carrying one hydroxyl group. The

molecular structure is shown in Figure 3.

0033 Chemically, erythritol therefore belongs to the class

of monosaccharide polyols like sorbitol, mannitol,

xylitol, and glycerol. Erythritol is also a symmetrical

molecule and therefore it exists in only one form, the

mesoform. It forms anhydrous crystals with a moder-

ately sweet taste without off-taste or odors. The

powder has a transparent white brilliant appearance

and dissolves in water to give a colorless nonviscous

solution. Crystals melt at 122



C to form a colorless

and brilliant nonviscous melt.

0034Erythritol’s chemical properties are similar to those

of other polyols in that it has no reducing end groups

and thus has excellent heat- and acid-stability. It

differs in having a low solubility (37% ww at



C), a property which among these simple polyols

it shares with mannitol and isomalt. Heat of solution

is very low (181 J g

1

), a property shared with xyli-

tol. However, compared to the group of polyols pres-

ently used as sugar-replacers, erythritol has the lowest

molecular weight (122) which of course provides dif-

ferent properties, such as higher osmotic pressure and

lower water activity in solution. It has also a high

freezing-point depression and boiling-point elevation.

0035Compared to sucrose, erythritol has a sweetness

value of 60–70%. It has a clean, sweet taste, similar

to sucrose, a strong cooling effect, and shows many

synergies with intense sweeteners.

Occurrence and Methods of Production

0036Erythritol occurs in several foods at levels up to

0.13%. It is also present in human and animal tissue

and body fluids.

0037Briefly, erythritol is produced from wheat or corn

starch by enzymatic hydrolysis yielding glucose,

which is fermented by a safe and suitable yeast-like

fungi, Moniliella pollinis. Once erythritol is separated

from the sterilized fermentation broth, it is purified

by ion exchange resin, active carbon, ultrafiltration,

and crystallization. The final crystalline product,

which looks very similar to sugar, is more than

99.5% pure.

Uses in Foods

0038The main uses of erythritol in food products are

outlined below.

Tabletop Sweeteners

0039In tabletop applications, erythritol will be used at

levels up to 99.9% as a noncaloric, noncariogenic

carrier for intense sweeteners. In these applications,

the sensorial profile-modifying properties of erythri-

tol are of great importance, resulting in sweetness

synergy, improved mouth feel, and masking of off-

flavors. In addition, due to erythritol’s crystalline

structure and nonhygroscopic property, it offers

excellent flowability and stability as carrier.

Beverages

0040The synergies which erythritol shows when used in

combination with intense sweeteners are also very

useful in low-calorie beverages. Also, at use-levels of

3.5% or less, erythritol can mask certain off-flavors

in beverages like coffee, tea, and grapefruit juice.

HCOH

OHC

1,2,3,4-butanetetrol

fig0003 Figure 3 Molecular structure and chemical formula of erythritol.

5670 SUGAR ALCOHOLS

Chewing gum

0041 Good-quality noncaloric and noncariogenic chewing

gum can be formulated by using solely erythritol (use-

level up to 60%).

0042 Most of the sugar-free chewing gum produced

today has a tendency to become brittle and harder

during aging. This can be avoided and a sugar-free

chewing gum with softer texture, greater flexibility,

and improved shelf-life can be obtained by partial

replacement of the other sugar alcohol(s) using ery-

thritol.

Chocolate

0043 The use of erythritol in chocolate compositions

allows a dry conching process at high temperatures.

Due to the good heat-stability and low-moisture pick-

up of erythritol, it is even possible to work at higher

temperatures than traditionally used. This results in

enhanced flavor development.

0044 Erythritol-based chocolate is not only easy to

produce, it can also be considered a true ‘reduced-

calorie’ product.

Candies

0045 Sugar-free fudge with texture and shelf-life properties

equivalent to conventionally sweetened fudge can be

produced using erythritol (up to 40%) in combin-

ation with maltitol syrup (75% maltitol) to control

crystallization.

0046 Depending on the cooking temperature and

seeding level with erythritol, texture can be varied

from soft to hard. In hard candies, erythritol in its

crystalline form is used up to 50% for its cooling

effect as sherbet filling in die-formed hard candies,

or ‘sandwiched’ in between two layers in deposited

hard candies.

Fondant

0047 Using erythritol, it is possible to obtain sugar-free low-

calorie noncariogenic fondant with identical tech-

nical properties to classical products. Previously this

was impossible with the other low-calorie bulking

agents currently available. Pure erythritol induces

too high a crystallization, but 60% erythritol in com-

bination with maltitol syrup as a liquid phase helps to

control this phenomenon.

Lozenges

0048Research has shown that lactitol, crystalline malti-

tol, and erythritol are the only suitable materials to

produce a lozenge with a lower calorie content than

the conventional sugar-based lozenges, but which are

otherwise identical. In addition to the lower calorie

content and pronounced cooling effect, erythritol has

the added advantage over lactitol and crystalline mal-

titol of requiring a shorter drying time to obtain the

required texture at low residual moisture content.

Lozenges based on solely erythritol (up to 99%)

have excellent shelf-life properties, even when stored

under high humidity conditions.

Bakery (Pastry) Products

0049In fat cream, a very good texture is obtained with

erythritol at a use-level of 60% and a particle size

distribution below 300 mm. The manufacturing pro-

cess and shelf-life properties of the erythritol-based

fat cream are similar to those for conventional fat/

sucrose compositions. Erythritol has an effect of

masking the fatty mouth feel, giving a more refreshing

and attractive product. In addition, the calorie con-

tent of the composition is also reduced.

0050Reduction of calories in bakery products is particu-

larly difficult if only the sugar moiety is replaced.

Erythritol can reduce the caloric content by more

than 30% (dependent on the application) without

introducing undesirable side-effects. Additionally,

erythritol improves the shelf-life of bakery products.

Erythritol can be applied successfully in cookies, bis-

cuits, and cakes, where it improves baking stability

and shelf-life at an addition level of about 7%.

See also: Biscuits, Cookies, and Crackers: Nature of the

Products; Cakes: Nature of Cakes; Dental Disease: Role

of Diet; Isomalt; Pastry Products: Types and Production;

Sweeteners: Intensive

Further Reading

Tinfeld T and Mu

hlemann HR (1978) Cariogenicity and

acidogenicity of food, confectionery and beverages.

Pharmacology and Therupeutics in Dentistry 3: 53–68.

Sheimin A and Maekinen KK (1975) Turku sugar studies-

I–XXI. Acta Odontologica Scandinavica 33 (suppl. 70):

1350.

SUGAR ALCOHOLS 5671

SUNFLOWER OIL

FJSa

nchez-Muniz and C Cuesta, Universidad

Complutense de Madrid, Madrid, Spain

Origin and Systematics

0001 The cultivated sunflower (Helianthus annus L.) is a

plant of the family Asteraceae (Compositae). The

term Helianthus is derived from the Greek helios,

meaning sun, and anthos, meaning flower. The prop-

erty of this flower ‘turning with the sun’ is clearly

expressed by the Spanish and French languages

when naming this plant.

0002 Hypothesis suggests that the wild H. annus of the

western USA became a camp-following weed of North

American Indians. In time it was introduced into the

central part of the country where it was domesticated

for use primarily as food. Archeological evidence

indicates the occurrence of heads and achenes of

domesticated types of sunflower as early as the first

millennium bc, and it has been suggested that culti-

vation began as early as 3000 bc. During the early

sixteenth century European visitors to America intro-

duced the sunflower to Europe, principally to Spain,

from where it spread throughout the continent. It was

grown initially as an ornamental plant and later for

food and medical purposes. The sunflower was de-

veloped as an important source of oil during the early

1800s in Russia. More recently, wild species have

been used in breeding programs. They have been

found useful in improving disease and insect resist-

ance of cultivars. The success of breeders (most from

the Former Soviet Union) in improving the oil content

of seeds from less than 30% to over 50% was a major

factor in the development of the sunflower as a major

world oilseed crop.

0003 The plant is generally grown to obtain oil, but meal

and hulls are also used or present potential uses (see

below).

World Sunflower Crop

0004 Sunflower ranks among the most important annual

field crops grown in the world for production of

edible oil. During the last decade, the total produc-

tion of sunflower has increased. Thus, in 1989–91 it

was estimated at about 22.3 million metric tons. In

1998–99 world production was about 26.7 million

tons (Table 1).

0005 Sunflower grows well in most regions of the world,

with significant production occurring in each of the

six crop-producing areas (Figure 1). Europe and

America (North, Central, and South America) are

the leading producers of sunflower seed, accounting

for about 50% of the world’s total production. In

Figure 1 production efficiency (kg ha

1

) in the six

world crop-producing areas is also presented. Recent

data show that the ex-USSR and Argentina are the

largest producers (Table 1). Other leading producers

are also presented in Table 1. However, because pro-

duction depends on cultivars and in many countries

efficiency is determined by the weather, the leading

order can change. For example, in Spain, one of the

leading producers, a high percentage of sunflower

comes from dry-ground cultivars, thus sunflower

seed production may change dramatically from

a wet year to a dry year (by about half a million

tons).

0006Although sunflower is grown primarily for its oil,

there is limited production of certain cultivars grown

for nonoilseed or confection purposes.

World Sunflower Oil Production

0007World edible oil and fats production has increased in

the last years with a total seed production in the year

2001 of 306.9 million metric tons. The sunflower oil

production since 1998 is presented in Table 1. World

production of sunflowerseed in the season 2002/03 is

currently forecast at 23.8 million metric tons. World

tbl0001Table 1 World sunflower crop and sunflower oil production

(Million Tons)

Country 1998 1999 2000 2001 Estimated2002

(as available at

6thof Sep 2002)

Ex-USSR 5.76 7.39 7.88 5.4 6.97

Central Europe 2.8 3.3 1.9 1.9 2.4

Argentina 7.2 5.7 3.1 3.7 3.9

EU-15 3.4 3.1 3.3 2.9 2.6

South Africa 0.5 0.6 0.8 0.8 0.9

USA 2.4 2.0 1.6 1.6 1.5

China 1.5 1.8 2.0 1.8 1.9

India 0.9 0.8 0.8 0.95 1.0

Turkey 0.9 0.8 0.6 0.5 0.85

Others 1.5 1.7 1.6 1.7 1.7

Total world 26.9 27.2 23.6 21.2 23.8

Oil production

(42% yield)

11.3 11.4 9.9 8.9 10

Source: Anuario de Estadistica Agroalimentaria (2000) Madrid: Ministerio

de Agricultura, Pesca y Alimentacio

n; Unilever Food Espan

a (2002)

Statistics. Personal communication, Bilbao, Spain: Agra.

5672 SUNFLOWER OIL

production is thus seen recovering by about 2.6

million tons from last season but still this season’s

global sunseed crop is expected to remain approxi-

mately 3.4 million tons below the harvested amount

in 1998/99. Oil production is highly dependent on

the crop and thus is changeable from season to

season.

0008 Although sunflower oil is considered a premium

oil, with a correct equilibrium between linoleic acid

and tocopherols the benefits of monounsaturated

fatty acids to health has encouraged the production

of new oils with a high level of oleic acid, such as

high-oleic-acid sunflower oil, high-oleic-acid rape-

seed oil, high-oleic-sunflower oil (HOSO), etc. Thus,

recently several new variants of sunflower have

appeared with the aim of catering for the demand

for oils richer in oleic acid and with a lower price

than olive oil. Because they have greater oxidative

stability than conventional sunflower oil, high-oleic-

oil sunflower oils are expected significantly to expand

food and industrial uses of sunflower oil all over the

world.

Market and Prices

0009 Sunflower derives most of its economic value from

the oil extracted from the seeds; the remaining value

is from the meal. The oil is considered to be of very

high quality and generally sells for a premium in

world markets, over soybean, palm, and rapeseed

oils. In the period 1999–2001 sunflower oil price

range between US $400 and 600. The year 2002

estimate price for crude and refined sunflower oils

are 699 E/metric ton and 733 E/metric ton, re-

spectively. However, due to unfavorable weather

conditions further rise of prices for the sunflower oil

can be expected for the next 9–10 months.

0010Reduced crushing of sunflower seed, as crushing

margins remained inadequate, forced most crushers

to process rapeseed as an alternative. However, in-

creased arrivals of Argentina sunflower oil prevented

the oil price from rising sharply.

0011Sunflower oil initially maintained a high and justi-

fied premium over soybean and rapeseed oil but as

the lower Spanish crop was more or less compensated

by higher yields in Eastern Europe and France, the

market could not sustain the high premium. Cur-

rently the premium has eroded to US $80 from US

$100. Sunflower seed supplies from Russia and the

Ukraine have recently become uncertain as govern-

ments announced export taxes.

Oil Extraction

0012Before oil extraction, sunflower seed (c. 30% hulls) is

usually dehulled to 8–12% because of the high wax

content in the hulls. An outline of the extraction

process is shown in Figure 2. Before pressing, other

manipulations are necessary, such as delinting,

cracking, breaking, conditioning, and structuring.

Nowadays, the only presses used on an industrial

scale are screw presses or expellers. The pressure

applied in pressing can be as high as 300 000 kPa

but is commonly around 150 000 kPa. Capacities of

expellers used for prepressing are usually 100–200

tons per day, but equipment exists that can handle

up to 500 tons per day. The solvent extraction is

mainly carried out by percolation through the plate-

lets of prepared seeds using nontoxic solvents that

are powerful solvents for oils and nonsoluble in

1000

2000

3000

4000

5000

6000

7000

8000

9000

Surface Production Efficiency

Africa America Asia Europe Oceania Others

000 ha

000 tons

kg ha

−1

fig0001 Figure 1 World crop production of sunflower. Data from Anuario de EstadI

stica Agraria (1997) pp. 148–150. Madrid: Ministerio de

Agricultura, Pesca y Alimentacio

n; Unilever Food. Espan

a (2000) Statistics. Personal Communication. Bilbao, Spain: Agra.

SUNFLOWER OIL 5673

water, low in price, and also nonflammable and non-

explosive.

Treatment of Crude Oil

0013 In some countries the oil from the first pressing of

seed is used directly. However, to refine the oil to

change its color, odor, flavor, and physical properties,

it has become a common procedure to satisfy con-

sumer demands.

Refining

0014 Fats and oils contain minor compounds which must

be removed because they confer taste and smell that

can diminish consumer acceptance. Steps in the chem-

ical and physical refining of sunflower oil are similar

to the ones processed in other vegetable oils.

Degumming

0015The degumming process is necessary to eliminate

gums from the oils of some seeds. The oil is heated,

the phosphoric acid (85%) is added and, after a reac-

tion time, the gum-water sludge is filtered off or

separated by centrifugation.

Neutralization

0016After harvesting or during ripening, lipolytic enzymes

start to split the triacylglycerols contained in the oil

and the free fatty acids are originated; this increases

rapidly the acidity value. Because of this, it must be

removed. Neutralization of these fatty acids can be

performed by extraction, distillation, and chemical

processes. Another action is reesterification of the

free fatty acids with glycerol. Neutralization is carried

out by alkalis or ammonia.

Seed (dried)

Cleaning

Breaking

Conditioning

Flaking

Dirt, foreign material

Fuel

Hulls

80−90 ⬚C; 25−30 min

Added to meal

Waste

Prepressing

Pressing

Oil

Meal

(12−20%, rest oil)

Preparation of

expeller cake

Breaking

Flaking to 0.2−0.35 mm

Solvent extraction

Solvent removal

Steam 95 ⬚C 10−12 min

Drying/cooling

Meal

Solvent removal

Dehulling

Delinting

Cracking

to 0.2−0.35 mm

Meal

Oil

Meal Micella

Crude oil (degummed)

Degumming

Lecithin

fig0002 Figure 2 Sunflower oil extraction scheme. Modified from Dupont J (1999) Vegetable oils. In: Macrae R, Robinson RK and Sadler MJ

(eds) Encyclopedia of Food Science, Food Technology and Nutrition, pp. 4686–4714. London: Academic Press.

5674 SUNFLOWER OIL

Bleaching

0017 Among others, chlorophyll and carotenoids are

colored substances. They are removed in the bleaching

process by employing bleaching earth that adsorbs

and removes these particles.

Deodorization

0018 In this process odorous substances, mainly oxidation

products, are eliminated. Deodorization can be con-

sidered to be a water vapor distillation, and must be

carried out under vacuum, because the vapor pressure

of ketones and aldehydes at 200



C is of the order of

30 kPa, about 300 times higher than that of fatty

acids. The process is generally carried out for seed

oils at temperatures of about 240



C for deodoriza-

tion or 270



C if distillative neutralization includes

centrifugation.

0019 However, the deodorization temperature for sun-

flower seed oil is 220



C under *400 kPa. Neverthe-

less, depending on the application, it may be necessary

to modify the sunflower oil by means of hydrogen-

ation, interesterification, or fractionation and winter-

ization in order to change the melting point or

improve clarity.

Composition

Triacylglycerol Species and Fatty Acid Composition

0020 The chemistry and reactivity of natural fats and oils

are mainly dependent on their overall composition

and especially on the relative composition of the

fatty acid constituents. Furthermore, the structure of

the fats in terms of the relative proportions of differ-

ent molecular species or of the sterospecific distribu-

tion of fatty acids on the glycerol moieties have a

bearing on their properties. Table 2 presents the

fatty acid profile of these two sunflower oil variants.

The HOSO shows a fatty acid composition similar to

other monoenoic oils, such as olive oil. The triacyl-

glycerol composition of sunflower and HOSO is

shown in Table 3. The former is rich in trilinolein,

while the latter is rich in triolein.

0021 Table 4 shows the characteristics that sunflower oil

has to have in order to be an acceptable edible oil

according to European Community regulations. The

different fatty acid fraction contained in this oil may

be quite variable, as shown in Table 2. Nevertheless,

polyunsaturated fatty acids predominate. The per-

centage of oleic acid (C

:1, n-9) plus linoleic acid

:2, n-6) is rather constant (85–87%) because

both fatty acids originated in the same biosynthesis

chain. The linoleic acid is produced from oleic acid

by desaturation carried out by the D

desaturase

enzyme. The major n-6 fatty acid is linoleic acid,

ranking 50–72%. This edible oil also contains about

11–12% of saturated fatty acids (mainly palmitic and

stearic acids). Oleic acid represents about 16–25%

and only minor amounts of a-linolenic acid are

present (Table 4).

0022Sunflower oils from cold climates are poor in oleic

acidand veryrich in linoleicacid (about15% and 75%,

respectively) with an iodine value of 125–136, and do

not require winterization. Southern oils have been

found to contain over 50% of oleic acid and as little

as 35% of linoleic acid with an iodine value of *106.

tbl0002Table 2 Composition of sunflower oil and high-oleic-acid

sunflower oil

Sunflower (%) High-oleic-acid

sunfloweroil (%)

Trilinolein 26.1% 4.25%

Myristic acid 0.06% 0.05%

Palmitic acid 6.7% 4.29%

Palmitoleic acid 0.15% 0.13%

Margaric acid 0.07% 0.04%

Margaroleic acid 0.03% 0.05%

Stearic acid 4.9% 3.99%

Oleic acid 24.3% 75.7%

Linoleic acid 62.1% 13.7%

Linolenic acid 0.08% 0.06%

Arachidic acid 0.35% 0.35%

Gadoleic acid 0.14% 0.23%

Behenic acid 0.78% 0.97%

Lignoceric acid 0.14% 0.34%

Elaidic acid 0% 0.03%

Linoelaidic acid 0.14% 0.1%

Squalene 0.04% 0.05%

Total sterols 3618 p.p.m. 3100 p.p.m.

Cholesterol 0.09% 0.12%

Brasicasterol 0.07% 0.07%

24-metylencholesterol 0.14% 0.09%

Campesterol 8.5% 8.2%

Campestenol 0.24% 0.33%

Stigmasterol 8.0% 8.9%

D-7-campesterol 3.0% 3.2%

D-5-23-stigmastadienol 0.29% 0.38%

Clerosterol 0.87% 1.0%

b-Sitosterol 53.4% 53.8%

Sitostanol 0.36% 0.53%

D 5-avenasterol 2.7% 1.6%

D-5, 24-stigmastadienol 1.7% 2.0%

D-7-stigmasterol 15.6% 15.4%

D-7-avenasterol 5.0% 4.3%

Apparent b-sitosterol 59.3% 59.4%

Polyphenols 2 p.p.m. 2 p.p.m.

Alifatic alcohols 63 p.p.m. 59 p.p.m.

Polar content 3.7 % oil 3.6 % oil

Polymers of triacylglycerol 0.06 % oil 0.03 % oil

Dimers of triacylglycerol 0.62 % oil 0.18 % oil

Nonoxidized triacyglycerols 96.3 % oil 96.4 % oil

Oxidized triacylglycerols 1.57 % oil 1.13 % oil

Diacylglycerols 1.00 % oil 1.89 % oil

Monoacylglycerols 0.00 % oil 0.00 % oil

Free fatty acids 0.45 % oil 0.37 % oil

SUNFLOWER OIL 5675

Minor components

0023 In the last decade certain minor constituents of oils

have been extensively studied, because of their anti-

oxidant properties, and also because they can modu-

late the dietary cholesterol absorption, the fatty acid

metabolism and thus the serum cholesterol levels.

Table 2 shows a typical composition of sunflower

oil’s minor components. Large amounts of phytoster-

ols and tocopherols, and relatively high amounts of

squalene are present. Table 4 shows some admitted

limits for tocopherols and phytosterols in sunflower

oil.

Applications

Catering

0024 Contrasting with other vegetable oils, such as soy-

bean, corn, and cotton, the oil extracted from the

sunflower seed contributes about three-fourths of

the total value of the crop. Sunflower oil is appreci-

ated among vegetable oils because of its bland flavor,

light color, high smoke point, high level of linoleic

acid, and very poor linolenic acid content.

0025 Sunflower oil is primarily used as a salad dressing

and cooking oil. Furthermore, it is extensively used as

a major ingredient in some margarine and shortening

products. The use of sunflower oil in salad is less

frequent than olive oil in Mediterranean countries.

Nevertheless, sunflower oil is prominently used in

deep-fat frying throughout the world. At present,

Spaniards and others, particularly those who live

near to the Mediterranean coast, continue buying

and consuming a relatively large quantity of olive

oil, mainly for frying purposes. However, other oils,

mostly sunflower oil, have largely substituted the use

of olive oil. This situation is particularly acute in the

Spanish institutional sector (hospitals and welfare

centers, prisons, military bases, teaching institutions,

company dining facilities, government establish-

ments, etc.). Economic reasons have promoted the

production and consumption of sunflower oil.

tbl0003 Table 3 Triacylglycerol composition of sunflower oil and high-

oleic-acid sunflower oil

Sunflower oil High-oleic-acid sunflower oil

POP 0.3 0.6

POS 0.9

PLP 1.0

POO þ PLS 3.9 12.7

PLO 7.8 2.1

PLL 11

SOO 1.2 10.3

OOO þ SOL 10.6 60.2

OOL þ SLL 16.4 6.2

OLL 22.8 3.3

LLL 21 1.1

POP, palmitic, oleic, palmitic; POS, palmitic, oleic, stearic; PLP, palmitic,

linoleic, palmitic; POO, palmitic, oleic, oleic; PLS, palmitic, linoleic,

stearic; PLO, palmitic, linoleic, oleic; PLL, palmitic, linoleic, linoleic; SOO,

stearic, oleic, oleic; OOO, oleic, oleic, oleic; SOL, stearic, oleic, linoleic;

OOL, oleic, oleic, linoleic; SLL, stearic, linoleic, linoleic; OLL, oleic,

linoleic, linoleic; LLL, linoleic, linoleic, linoleic.

Source: Instituto de la Grasa (Sevilla, Spain), personal communication.

tbl0004Table 4 Sunflower oil characteristics

Minimum quality characteristics

Aspect Clear, transparent

after 24 h at 20+2



Odor and taste Normal

Color M 25 YU and 2.5 RU

Moisture and volatile compounds M 0.1%

Insoluble impurities in petroleum

ether

M 0.05%

Free acidity (% oleic acid) M 0.2%

Peroxide index (mmol l

1

active

Okg

1

oil)

M10

Soap residues Negative

Purity test

Vizern test Negative

Saponification index 188–194

Halphen reaction Negative

Iodine index (Hanus method) 80–145

Refraction index (at 25



C) 1.767–1.474

Nonglyceric esters Negative

Saturated fatty acids in triglyceride

b-position

M1%

Fatty acid composition

Lauric acid (12:0) M 0.1%

Myristic acid (14:0) M 0.1%

Palmitic acid (16:0) 3.5–8.0%

Palmitoleic acid (16:1) M 0.2%

Stearic acid (18:0) 3–7%

Oleic acid (18:1) 15–85%

Linoleic acid (18:2) 50–72%

Linolenic acid (18:3) M 0.2%

Arachidic acid (20:0) M 0.6%

Gadoleic acid (20:1) M 0.3%

Behenic acid (22:0) M 1%

Insaponificable 0.5–1.5%

Sterol composition

Cholesterol M 0.5%

Campesterol 6.5–10.5%

Stigmasterol

6.0–12.5%

b-Sitosterol 55.0–67.5%

D 7 stigmasterol 16.0–26.0%

Tocopherols

a-tocopherols 403–935 (p.p.m.)

b-tocopherols 0–45 (p.p.m.)

g-tocopherols 0–34 (p.p.m.)

d-tocopherols 0–7 p.p.m.)

D 5,23 stigmasterol þ clerosterol þ sitosterol þ D 5-avenasterol þ D5,24

stigmastadienol.

Alinorm 97/17. Conjoint program FAO/OMS.

Source: last modification to European Community Regulation CE no. 656/

95 to CE no. 2568/91.

UA and YA refer to Lovibond test.

YU, yellow units; RU, red units.

M, Maximum.

5676 SUNFLOWER OIL