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glass, but pure sucrose will not form a glass. Com-

mercial sugar glasses are always made from sucrose

and some other sugar. Initially, invert sugar was used

but has now been largely replaced by glucose syrup.

Glucose syrup is a much better stabilizer of sugar

glasses than invert sugar. In practice, boiled sweets

become unstable by absorbing water. Initially, the

product becomes sticky then soft, followed ultimately

by crystallization. The rate at which high boilings can

absorb water is diffusion-limited. The high-molecular-

weight fraction in glucose syrup inhibits the migration

of water into the sweet. This gives a markedly more

stable product than invert sugar does. Glucose syrup

also gives the boiled mass a plastic consistency when

warm, which makes it much easier to handle.

Formulation of Boiled Sweets

0021 The manufacture of stable boiled sweets depends on

obtaining a product with a low moisture content. The

higher the glass transition temperature, the more

stable the product is. As water can be regarded as a

plasticizer, it reduces the viscosity of the system and

thus reduces the glass transition temperature. The

water content of the finished product depends on

the cooking temperature. The important parameter

at the formulation stage is the ratio of sugar to glu-

cose syrup. The situation to avoid is ending up with a

product that is excessively hygroscopic, which will

reduce the shelf-life by making the product sticky.

Increasing the proportion of glucose syrup increases

the proportion of dextrose and the high-molecular-

weight dextrose oligomers. Increasing the proportion

of dextrose makes the product more hygroscopic,

which increases the tendency of the product to

become sticky. As the proportion of high-molecular-

weight material is increased, the viscosity of the liquid

mass increases. These viscosity and hygroscopicity

problems restrict the proportion of glucose syrup

that can be used. If a conventional acid converted

syrup is used, using a different DE only makes one

problem or the other worse. Boiled sweets are made

with ratios of sucrose to glucose of from 70:30 to

45:55. The common proportions are 60:40 and 50:50.

0022The high-maltose syrups break away from these

restrictions, as the spectrum of carbohydrates present

is modified to increase the maltose while reducing

the dextrose and the high-molecular-weight fraction.

Using these syrups, a high boiling can be made with

approximately sucrose to glucose 35:75 with the

properties of a product of a 55:45 product.

Science of Gums, Jellies, and Licorice

0023In these products, a colloid is incorporated to obtain

the desired texture. Most of these colloids are gelling

agents, e.g., gelatine, but some such as gum acacia

and certain modified starches do not gel. The sub-

stances used (see Table 1) are chemically quite dis-

parate, but they all have the ability to self-associate.

An important difference is between those like gel-

atine, which gel thermoreversibly, and other gelling

agents, which gel irreversibly, e.g., pectin. Licorice is

slightly different from the other sweets in that it is

made from wheat flour directly rather than with a

purified starch. The important science is the texture

of the product, which can be studied as rheology. If a

sample is placed between the two plates (Figure 6),

and one plate is oscillated, the structure of the sample

will not be destroyed, but a transducer on the other

element will produce an output wave form. This wave

form can be analyzed in terms of an elastic and a

viscous component.

Grained Products

0024In some products, the sucrose is intended to grain or

crystallize. Examples are fondant, fudge, and monte-

limar. In these products, there is a high proportion of

sucrose, as opposed to other sugars.

Fondant

0025Confectionery fondants are normally made by boiling

a mixed sucrose and glucose syrup to concentrate it.

CHCOOH

−CO

Amino acid Dicarbonyl

Aldehyde α-Amino carbonyl

fig0005 Figure 5 Strecker degradation.

SWEETS AND CANDIES/Sugar Confectionery 5707

The mixture is then cooled with beating to produce

fine sucrose crystals. It is possible to make a fondant

using dextrose instead of sucrose. Crystalline dex-

trose has a positive heat of solution, i.e., heat is

absorbed. This produces a marked cooling effect,

which goes well with a peppermint flavor, but it is

not appreciated in other flavors. After a fondant has

been made, the crystals undergo Ostwald ripening.

Fudge

0026 A fudge-like product can be made by adding either a

fondant or milled sugar to a toffee; alternatively, a

sugar-rich caramel can be induced to grain.

Panned Products

0027 In these products, one or more layers of sugars have

been laid down. There are two different processes

used, hard panning and soft panning. These processes

involve building up a coating of sugar and sometimes

other things layer by layer. This is one of those

processes that the confectionery and pharmaceutical

industries have in common. The normal modern

small-scale method is to use a rotating dragee pan

(Figure 7). These pans are traditionally made of

copper but now more commonly stainless steel. The

pan is equipped to be rotated, and usually, there will

be a system for supplying and extracting air and

possibly with a system for spraying in sugar syrup.

Hard panning

0028Hard-panned coatings are purely sucrose, whereas

soft pan coatings are a mixture of sucrose and glucose

syrup. Sugared almonds, mint imperials, nonpareils

(hundreds and thousands), as well as sugar-coated

chocolate lentils or eggs are normally hard panned.

It is possible to soft pan some of these products, e.g.,

almonds. In hard panning, the centers are tumbled

in the pan, and a sugar syrup is applied. The rotation

tbl0001 Table 1 Properties, chemistry, and sources for gums and gelling agents

Agent Properties Chemistry Source

Gelatine Thermoreversible gelling agent Protein Bovine or porcine hides or bones

Starch Irreversible gelling agent Carbohydrate Maize or wheat or potatoes

High-amylopectin starch Nongelling starch Carbohydrate Waxy maize

Gum acacia Gum Polysaccharide Trees of the species Acacia senegal

Agar agar Thermoreversible gelling agent Polysaccharide Red seaweeds

Alginate Irreversible gelling agent Polysaccharide Brown seaweed

Carrageenan Thermoreversible gelling agent Sulfated polysaccharide Red seaweeds

Gellan gum Thermoreversible or irreversible

gelling agent

Polysaccharide Pseudomonas elodea

Guar gum Thickener exhibits synergy with

some gelling agents

Galactomannan Seeds of cyamopsis tetragonolobus

Pectin – high methoxyl Irreversible gelling agent Polygalacturonic acid Citrus peel or cider apple pomace

Pectin – low methoxyl Thermoreversible gelling agent Demethoxylated pectin Citrus peel or cider apple pomace

Gum tragacanth Gum or mucilage Polysaccharide Astragalus shrub

Locust bean or carob gum Thickener exhibits synergy with

some gelling agents

Galactomannan Endosperm of locust beans from

Ceratonia siliqua

Xanthan gum Thickener exhibits synergy with

locust bean gum

Polysaccharide Aerobic fermentation of Xanthomonas

campestris

Egg albumen Whipping agent and irreversible

gelling agent

Protein Egg white

Enzyme-modified soy protein Whipping agent Protein Soy beans

Truncated cone

Plate

fig0006 Figure 6 Cone and plate geometry.

Rotation

system

fig0007Figure 7 Dragee pan.

5708 SWEETS AND CANDIES/Sugar Confectionery

of the pan and the tumbling of the centers spread the

syrup out into a thin layer. The water is evaporated,

which causes the sugar to crystallize. The process is

inevitably slow. The water can evaporate only at a

certain rate, and the rate of crystallization of the

sugar cannot be accelerated. The rate of evaporation

can be increased by increasing the temperature and

the air flow as well as reducing the humidity of the air.

Increasing the temperature will reduce the rate of

crystallization. The layers applied are only 10–

14 mm thick. As the layers are so thin, they follow

the contours of the product. If the center can be

damaged by heat, heating the pan may not be pos-

sible. An air supply and extraction speed up the

panning process considerably. In an unventilated

pan, the process would slow down as the air became

saturated with water vapor. In general, hard panning

is done in large pans, whereas soft panning is done in

small pans. Small products such as nonpareils tend to

be made in small pans, whereas large items are pro-

duced in larger pans.

Soft panning

0029 Soft panning involves applying a syrup to the centers,

as does hard panning, but the soft panning syrup is

intended not to crystallize. Instead of evaporating the

water, as in hard panning, milled sugar is added,

which dissolves in the water in the syrup. The syrup

used in soft panning would be either all glucose syrup

or a 50:50 mixture of sucrose and glucose syrup. This

process is carried out in the cold and without using

drying air. Dust extraction is needed for reasons of

health and safety. Soft panning is a much more rapid

process than hard panning. It can be applied to soft

centers that would be unsuitable for hard panning. As

the coating is thick, the shape of the center tends to be

lost. Typical soft panned products are jelly beans and

dolly mixture components.

Process Control Systems

0030 Attempts to automate panning initially concentrated

on the time and temperature. A more modern ap-

proach is to measure the absolute humidity to control

the drying cycle. This is claimed to be an improve-

ment on systems that rely on temperature and the

elapsed time. In particular, because the actual humid-

ity is measured, process parameters can be optimized

to maximize throughput. In a time–temperature

system, in order to avoid under-drying, the time set

would have to be the maximum necessary.

Toffees and Caramels

0031 In these products, the Maillard browning reaction

between reducing sugars and proteins is essential to

the taste and color of the finished product. The pro-

teins used are from skim milk solids. Inefficient

cooking pans promote this reaction at the heating

surface to give a good product. If the same ingredients

are cooked in an efficient continuous system, the

reaction is suppressed to such an extent that the

product is unacceptable. In practice, holding vessels

known as caramelizers are used to promote the

Maillard reaction.

0032In addition to skimmed milk solids and sugars,

toffees contain fat. Originally, toffees were made

from full cream milk solids, and the fat was milk fat.

Now, a total or partial replacement with vegetable

fat is possible. If sufficient milk protein is present, the

fat disperses easily in the toffee, leaving a fatty layer

on the surface that facilitates cutting. If insufficient

milk protein is present, other emulsifiers will have to

be added.

Chewing Gum

0033Chewing gum is a flavored and sweetened rubber,

originally natural, but now usually synthetic. It is a

product where confectionery becomes involved with

polymer chemistry. The gum base in chewing gum is

technically a rubber. The original ingredients were

the natural products chicle and jelutong-pontianak,

which were used alone or in a mixed gum base.

The synthetic polymers used are mainly vinyl esters

in particular polyvinyl acetate. Butadiene styrene

rubber, isobutylene–isoprene copolymer, and poly-

isobutylene can be used. As in other fields of polymer

chemistry, plasticizers such as glycerine esters of

hydrogenated or polymerized resin, lanolin, and po-

tassium, and sodium stearates are used. Different

gum bases are used for chewing gum and bubble

gum. Bubble gum base will contain either higher

levels of polymers or polymers with a higher molecu-

lar weight. The higher level or molecular weight of

the polymer makes the gum base more extensible and

hence able to form bubbles.

Sugars

0034In order for a product not to have a gritty feel in the

mouth, the sugar has to have a very fine particle size.

Individuals differ in their response to particle size, but

particles above 20–40 mm are normally found to be

gritty.

Dextrose

0035Dextrose monohydrate is sometimes used as an alter-

native to sucrose in chewing gum. The endothermic

heat of solution of dextrose gives a cooling sensation

in the mouth that goes well with mint flavors but not

with others.

SWEETS AND CANDIES/Sugar Confectionery 5709

Aerated Products

0036 Technically, the problems in producing aerated prod-

ucts are in making and stabilizing a foam. Typically,

aerated confectionery products involve making a

foam and then causing it to set. A popular ingredient

is egg albumen, which is a whipping agent and can be

set irreversibly by heat. Some products are made with

the combination of egg albumen and a gelling agent,

e.g., gelatine. The only aerated confectionery prod-

ucts that work differently are those that are a high

boiling that is chemically aerated and relies on the

product passing through the glass transition before

the bubbles collapse. These products sometimes

contain material like gelatine to enhance foaming.

Examples are bonfire toffee, honeycomb crunch,

and peanut brittle.

Tabletting

0037 Tablets are made by compressing a powder in a die.

Under the pressure in the die, the powder fuses and is

ejected as tablet. Tabletting requires a free-flowing

powder that will flow freely when poured into the

die but bonds satisfactorily when compressed.

Lozenges

0038 Lozenges are one of the oldest forms of sugar confec-

tionery. Lozenges are cut from a sheet of dough and

then dried. Lozenge manufacture is one of the areas in

which sugar confectionery is related to pharma-

ceutical products.

Lozenge manufacture

0039 Lozenges are made by taking a milled sugar and

making it into a dough. The best textures are achieved

by using the smallest possible sizes of sugar. Lozenges

are normally made with a binder. The traditional

binder is gum tragacanth, which is probably the best

material. Other materials that are used are gum

acacia, gelatine, and xanthan gum. A mixture of

gum acacia and gum tragacanth is sometimes used.

Gum arabic used alone gives very brittle sweets that

break easily.

0040Drying The stamped pieces are then spread on to

trays where a slight crust of dry sugar forms on the

surface. The lozenges are then dried at 35–40



C until

the moisture content is around 1.5%. If the lozenges

are dried too rapidly, the lozenges shrink and crack.

Extended drying times lead to loss of flavor and

yellowing. A trace of blue color is often added to

give a blue–gray color rather than a yellow–gray

color. Flavor is a problem in lozenges, as the flavor

must be volatile to be perceived in the finished

product, but volatile flavors are often lost during

drying. The reason why drying cannot be accelerated

is that the moisture has to migrate from the center

of the sweet to the surface.

Conclusion

0041Sugar confectionery is an area where the product

came first and the science arrived afterwards. The

science, however, is challenging.

See also: Amino Acids: Properties and Occurrence;

Browning: Nonenzymatic; Toxicology of Nonenzymatic

Browning; Glucose: Properties and Analysis; Gums:

Properties of Individual Gums; Food Uses; Dietary

Importance; Jams and Preserves: Methods of

Manufacture; Chemistry of Manufacture; Sucrose:

Properties and Determination

Further Reading

Edwards WP (2000) The Science of Sugar Confectionery.

Cambridge: The Royal Society of Chemistry.

Hill S and Easa AM (1998) The Maillard Reaction in Foods

and Medicine, pp. 113–138. Cambridge: The Royal

Society of Chemistry.

Fisher C and Scott TR (1997) Food Flavours: Biology and

Chemistry. Cambridge: The Royal Society of Chemistry.

Jackson EB (ed.) (1995) Sugar Confectionery Manufacture,

2nd edn. London: Chapman & Hall.

Lees R and Jackson B (1973) Sugar Confectionery and

Chocolate Manufacture. Glasgow: Blackie Academic &

Professional.

5710 SWEETS AND CANDIES/Sugar Confectionery

SYRUPS

M A Clarke, Sugar Processing Research Institute

Incorporated, New Orleans, LA, USA

This article is reproduced from Encyclopaedia of Food Science,

Introduction

0001 Syrups, which are sweeteners in liquid form, usually

of high viscosity, have been used as food sweeteners

since the early days of humanity, e.g., honey. This

article includes information on the source and pro-

duction, composition and properties, and use of

cane and golden syrups, molasses, sorghum syrups,

corn-, glucose-, fructose- and starch-derived syrups,

fruit-based syrups, and maple syrups. (See Honey.)

Cane Syrups, Golden Syrups, and

Molasses

0002 Cane syrups are usually made from sugarcane juice,

concentrated by evaporation, after clarification,

before any sugar is crystallized out or otherwise

removed. (See Sugar: Sugarcane.)

Cane Syrup

0003 The term ‘cane syrup’ as applied to consumer prod-

ucts has a regional orientation to southern USA and

other sugarcane-processing areas, where cane syrups

and blends are sold for use on pancakes, biscuits, and

cereals and in cooking. For food industry use, cane

syrups are produced at sugarcane factories in Louisi-

ana and Hawaii, or at refineries, where a blend of

brown and golden-colored streams are combined to

produce syrup. Cane syrups are dark golden brown in

color, with medium flavor intensity (caramel, butter-

scotch, cane and green flavors; no heavy molasses

flavor), and are partially inverted. (Inversion is the

process in which sucrose is converted by hydrolysis to

an equimolar mixture of glucose and fructose.) A

factory evaporator syrup is often completely inverted,

and mixed with uninverted syrup, to give a product of

approximately 85



Brix, 25–30% sucrose and 50–

52% invert. This is a relatively clear and low-ash

material. (See Carbohydrates: Classification and

Properties; Fructose; Sucrose: Properties and Deter-

mination.)

0004 Cane sugar refineries make liquid sucrose, a

watery, colorless solution of 67–70



Brix (percentage

on a solids basis) sucrose, generally prepared by

redissolving granulated sugar, but in some special

refineries, e.g., in Brazil and Canada, by extensive

ion exchange resin decolorization and carbon treat-

ments. This product is often sold to beverage com-

panies and canners because the high quality of color

and clarity are immediately apparent.

0005Liquid invert sugar, which includes a range of

liquid products of sucrose, glucose, and fructose of

75–77



Brix, was, until the late 1970s, a major prod-

uct (15% of market) in the USA. It has been replaced

by the cheaper starch-based syrups, most notably

high-fructose corn syrup. Liquid products are still

made in the UK, other parts of Europe, South

America, and other areas.

Golden Syrup

0006Golden syrup is most popular in the UK, Canada,

South Africa, and Australia (countries in which it is

manufactured). It is a high-Brix (77–82



), partially

inverted syrup, filtered several times over bone char-

coal to give it a special golden color, very mild flavor,

and high clarity. The syrup is generally inverted with

sulfuric acid and neutralized with calcium carbonate,

so that no soluble salt will remain as a reaction prod-

uct to affect the special flavor. Typical analysis (cour-

tesy of Tate and Lyle Sugars) is as follows: invert,

50%; sucrose, 32%; ash, 1.4%, and solids, 82.6%.

The syrup is used directly on cereals, breads, and

baked goods, and in home baking, e.g., in syrup

pudding or tart. Golden syrup tends to crystallize on

storage and is therefore usually sold in cans.

0007The obvious advantages, in many applications, of

handling sugar in dissolved form have led to the

extensive distribution and use in bakery products of

sucrose and invert sugar syrups. Liquid sugars can be

roughly classified into sucrose types, invert (or

mixed) types, and refinery syrups or liquid brown

sugars. Sucrose is available at 66.5–68% solids

content. This is the limit of solubility of sucrose

at ordinary temperatures. Two or three grades, vary-

ing for the main part only in color, are usually

available.

0008If part of the sugar is inverted, the resulting syrup

will retain higher concentrations of solids in solution.

Common commercial types are syrups of 73% or

76% solids with 30% or 60% invert. Totally inverted

syrups contain 72–73% solids, of which perhaps 5%

is sucrose.

0009Because of the low water content, all of these

syrups are quite resistant to microbiological spoilage.

The invert syrups are probably somewhat superior in

this regard because of their lower water activity. (See

Water Activity: Effect on Food Stability.)

SYRUPS 5711

Molasses

0010 Molasses (or treacle in the UK consumer market) is a

general term for concentrated juice from sugarcane or

sugarbeet, or raw cane sugar in concentrated solution

after varying amounts of sucrose have been removed.

Sugarcane molasses is the major food molasses. Both

sugarbeet and sugarcane molasses are used for animal

feed and as fermentation sources for ethyl alcohol and

other chemicals. These uses are amply described in

the literature and are not discussed here. Recent de-

velopments in technology have made possible some

sugarbeet molasses food products; these are at present

available in limited quantity. (See Sugar: Refining of

Sugarbeet and Sugarcane.)

0011 Several common terms for molasses are defined as

follows. Blackstrap molasses is the byproduct from a

sugarcane factory or raw sugar refinery; it is the

heavy, dark viscous liquid remaining after the final

stage of sugar crystallization from which no further

sugar can be crystallized economically by the usual

methods. Types of blackstrap are further defined by

the US Department of Agriculture (USDA) as super-

ior, normal, or utility, but these are ready definitions

for feed-grade material.

0012 High-test molasses is the product obtained by con-

centrating clarified cane juice to approximately 85



Brix; it is partially inverted with either acid or invert-

ase enzyme. High-test molasses is produced from

cane juice instead of sugar, not as a byproduct of

sugar production. High-test molasses, also known as

fancy molasses, cane invert syrup, or cane juice mo-

lasses, is a premium product, higher in sugars content

and of a more aromatic flavor than blackstrap. It has

been subjected to less heat than blackstrap, and so

contains relatively fewer sugar decomposition

products, which can add bitter flavor.

0013 Sulfured molasses is the byproduct of raw sugar

manufacture in which sulfur dioxide has been added

to the molasses to bleach color. Sulfured molasses

may be lighter in color, but it is higher in ash of the

insoluble sulfate type. The term ‘unsulfured’ is more

common. The approximate composition of cane mo-

lasses (blackstrap) is given in Table 1.(See Preserva-

tion of Food; individual constituents.)

0014 Most commercially available molasses, for con-

sumer purchase or food industry use, is made by

blending various cane factory and refinery molasses

and syrups for desirable – and constant – flavor and

quality.

0015 Physical properties of molasses vary with compos-

ition. Viscosity can vary over several orders of magni-

tude depending on inorganic and polysaccharide

composition and temperature. Cane molasses has an

acid pH, usually between 5 and 7. The salts content

(2–8%) can contribute buffering capacity, to stabilize

flavors and prevent hydrolysis, and can also provide

flavor for feed use.

0016Color and flavor are the major properties besides

nutrition that molasses contribute to food processing.

Molasses always contributes some sweetness, to a

degree which usually decreases as color darkens.

The range of flavors is broad, ranging from caramel,

cane flavor in light high-test molasses, to heavy, bitter

notes, sometimes with licorice characteristics. Exten-

sive research has shown that molasses flavor is a

complex mixture. Because of this wide range of

flavors, molasses can be used to mask or disguise

other, less pleasant flavors, e.g., bitterness of bran in

wholewheat (wholemeal) products; as an enhancer in

sauces and licorice products. Molasses can also be

used as a coloring agent, for golden to dark brown

colors, especially in baked goods, and as a color

enhancer, or masking agent, to disguise gray or

gray-brown tones. Molasses displays humectancy,

colligative, and water absorption (lowering of water

activity) properties that would be expected of a

sucrose syrup of similar solids composition; these

properties lead to wide application in intermediate-

moisture foods and in baked goods with extended

shelf-life. However, nonsugars in molasses appar-

ently have some effect on humectancy: molasses

has been shown to be more effective in retaining a

high moisture content than either sucrose or corn

syrups. Molasses nonsugars also exhibit an antioxi-

dant effect, significant when this fraction is used at

some 3% of the fat level in the food product, and

important for health foods. Inclusion in whole-grain

products is one potential role for this fraction. (See

Antioxidants: Natural Antioxidants; Colorants (Col-

ourants): Properties and Determination of Natural

Pigments.)

0017Molasses is a food product that has often been

claimed to be a secret of youthful behavior and ap-

pearance (e.g., to inhibit hair graying). Technological

investigations, such as the isolation and characteriza-

tion of the antioxidant fraction, may provide a scien-

tific basis for what formerly appeared to be myths.

0018A dried molasses product, usually mixed with corn

syrup solids to absorb water, is also available for use

in dry mixes.

0019Syrups and molasses products sold to the food

industry represent the result of blending various mo-

lasses and syrups to produce products of consistent

color, flavor, and functional properties. Table 2 lists

several typical blends, their composition, flavor char-

acteristics, and potential applications. These blends

are typical of material sold directly to the consumer as

molasses in the USA, and as treacles, syrups, or blends

in, other countries.

5712 SYRUPS

Sorghum Syrup

0020 Sweet sorghum (Sorghum bicolor) is a giant grass,

somewhat similar in appearance to sugarcane, but

able to withstand cooler climates. In the Midwest

and parts of the southern states of the USA, the juice

of sweet sorghum is heated, clarified by skimming,

and concentrated into a syrup. Sorghum juice tends to

be higher in invert sugars than cane juice; it is there-

fore difficult to crystallize sweet sorghum sugar, and

syrup is the product of choice. Sorghum syrup is

produced by small plants in Tennessee, and northern

Mississippi and Alabama (further information is

available from the National Sweet Sorghum Pro-

ducers Association, PO Box 1071, Knoxville, TN

37901-1071, USA). (See Sorghum.)

0021 The light-brown-colored syrup has a distinctive,

pungent odor and flavor, in addition to its sweetness

and molasses-like flavor. It is often blended with other

(sugar- or starch-based) syrups, but is seldom sold

industrially. Production is a cottage industry at

present.

Starch-Based Sweeteners and Syrups

0022Starch is a polymer of glucose and, upon hydrolysis

by acid or by amylase enzyme, it yields glucose and a

variety of maltooligosaccharides. The process has

been employed in the USA to produce sweetener

syrups since the 1840s, at first on potato starch and

some 20 years later on corn, or maize, starch. Crys-

talline glucose, more often called dextrose in the corn

refinery industry, and glucose syrup remained the

major starch-based sweetener products until the

1960s. Enzyme-catalyzed isomerization of glucose

to fructose, a sweeter sugar, then made possible

tbl0001 Table 1 Approximate composition of cane molasses

Main constituents Components Normalrange

Water 17–25%

Sugars Sucrose 30–40%

Glucose (dextrose) 4–9%

Fructose (levulose) 5–12%

Other reducing substances (as invert) 1–4%

Total reducing substances (as invert) 10–25%

Other carbohydrates Gums, starch, pentosans, also

traces of hexitols; myoinositol,

D-mannitol, and

uronic acids

2–5%

Ash As carbonates

7–15%

Bases:

Potassium oxide (30–50%)

Calcium oxide (7–15%)

Magnesium oxide (2–14%)

Sodium oxide (0.3–9%)

Metal oxides (as ferric) (0.4–2.7%)

Acids:

Sulfur trioxide (7–27%)

Chloride (12–20%)

Phosphorus pentoxide (0.5–2.5%)

Silicates and insolubles (1–7%)

Nitrogenous compounds Crude protein (as N  6.25) 2.5–4.5%

True protein 0.5–1.5%

Amino acids, principally aspartic and glutamic acids,

including some pyrrolidine carboxylic acids

0.3–0.5%

Unidentified nitrogenous compounds 1.5–3.0%

Nonnitrogenous Aconitic acid (1–5%), citric, malic, oxalic, glycolic 1.5–6.0%

Mesaconic, succinic, fumaric, tartaric 0.5–1.5%

Wax, sterols, and phosphatides 0.1–1.0%

Vitamins Thiamin (B

) 2–10 p.p.m.

Riboflavin (B

) 1–6 p.p.m.

Pyridoxine (B

) 1–10 p.p.m.

Nicotinamide 1–25 p.p.m.

Pantothenic acid 2–25 p.p.m.

Folic acid 10–50 p.p.m.

Biotin 0.1–2 p.p.m.

Percentage of ash given in parentheses.

Source: United Molasses Company, London, UK. By courtesy of the Technology Division of Crompton and Knowles Corporation, Mahwah, NJ, USA.

SYRUPS 5713

high-fructose syrups, with ratio of sweetening power

to energy equivalent to that of sucrose. The corn-

refining industry in the USA now makes available a

wide range of sweeteners, with crystalline fructose as

the newest addition. Corn-based starch hydrolysis

products are also manufactured in Argentina,

Canada, Japan, and eastern Europe. In the EC, the

starch base for these sweeteners is usually potato,

increasingly wheat, and, in at least one factory in

Finland, barley. Products are similar in composition,

properties, and use to those made from corn; thus

cornstarch-based products are used as examples

here. (See Dextrins; Starch: Structure, Properties,

and Determination; Sweeteners: Intensive.)

0023 In general, corn-based sweeteners are classified

into the following seven categories:

0024 Corn syrup (glucose syrup) is the purified, concen-

trated, aqueous solution of nutritive saccharides

obtained from edible starch and has a dextrose

equivalent of 20 or more.

0025 Dried corn syrup (dried glucose syrup) is a corn

syrup from which the water has been partially

removed.

0026 Dextrose monohydrate is purified and crystallized

d-glucose containing one molecule of water of

crystallization with each molecule of d-glucose.

0027 Dextrose anhydrous is purified and crystallized d-

glucose without water of crystallization.

0028 Maltodextrin is a purified concentrated aqueous

solution of nutritive saccharides obtained from

edible starch, or the dried product derived from

the solution and having a dextrose equivalent less

than 20.

0029High-fructose corn syrup is a purified, concen-

trated, aqueous solution of nutritive saccharides

obtained from edible starch in which a portion of

the dextrose has been isomerized to fructose.

0030Crystalline fructose is a purified and concentrated

d-fructose obtained from edible starch in either

dry crystal or remelted liquid form.

Products in 2, 6, and 7 are of direct interest as syrups;

the others are listed for explanation of the processes

involved.

0031Composition of the typical range of syrups is out-

lined in Table 3.

Starch-Based Syrups Manufacture

0032Common methods employed in the commercial pro-

duction of corn syrups are the acid process, the acid–

enzyme process, and multiple enzyme process. In the

acid conversion process, a starch slurry of the appro-

priate dry substance is acidified to pH of about 2 and

pumped to the converter. After neutralization, liquor

is clarified and concentrated by evaporation to an

intermediate density. The resulting syrup is further

clarified, decolorized, and finally concentrated in

evaporators to the final required density. Some syrups

are treated with ion exchange resins for further

refinement.

0033The acid–enzyme process is similar except that the

starch slurry is only partially converted by acid to a

given dextrose equivalent (DE), then treated with an

appropriate enzyme or contribution of enzymes to

complete the conversion.

0034In multiple enzyme processes, starch granules are

gelatinized and the preliminary starch-splitting or

tbl0002 Table 2 Molasses and syrup blends

Characteristic

description

(%)

Unsulfured

molasses

(%)

Bakerymolasses

(%)

Confectioneryand

all-purpose

molasses (%)

Condimentmolasses

(%)

Robust

molasses

Composition

Sucrose 35 32–36 33–37 30–36 33–37

Invert 37 36–40 28–32 21–27 16–20

Total sugars 72 70–74 63–67 54–60 51–55

Ash 2.5 1.2–2.5 4.5–5.5 6.5–8.5 8.0–9.0

Color Golden brown Light brown Medium brown Dark brown Dark brown

Flavor Sweet, mild aroma,

syrup flavor

Sweet mild,

distinctive

Moderate sweet,

strong aroma

Strong, pungent

flavor,good

background

Strong flavor

heat-resistant

Humectancy Some Good Good Some Some

Buffer effect Yes Yes Yes

Applications Table syrups,

toppings, peanut

butter, fruit

pure

es,

confectionery,

and alcohol

products

Fruit cakes,

brownies, muffins,

spiced baked

goods

Barbecue sauce,

extended products,

candies (hard

and caramel),

toasted foods,

gingerbread

Fermented products,

condiments,

and sauces

Leavened and

fermented

goods,

soy sauce,

tobacco, licorice,

baked beans,

caramel, snacks

5714 SYRUPS

depolymerization is brought about by an a-amylase

enzyme, rather than by means of acid.

0035 Various intermediate syrups of differing composi-

tion may be further converted with enzymes having

specific modes of action or providing particular types

of end product, such as high-maltose syrups, high-

fermentable syrups, and others.

High-Fructose Corn Syrup

0036 Dextrose or glucose solutions or high-DE substrates

produced from starch by acid–enzyme or dual

enzyme processes are refined by carbon and ion

exchange systems and treated enzymatically with

isomerase in an immobilized enzyme system. Isomer-

ization is usually carried to a point where the sub-

strate contains 42% fructose. Following this step, the

product is refined again through carbon and ion ex-

change systems and is evaporated to a dry solids level

of 71%. (See Enzymes: Uses in Food Processing.)

0037 In the production of syrups with a fructose level

above 50%, the original 42% fructose feedstock is

passed through separation columns of cationic ion

exchange resins which retain fructose and dextrose.

Fructose is removed; dextrose is recirculated for fur-

ther isomerization. In a standard moving-bed system,

the fructose fraction is generally recovered at an 80–

90% concentration, and blended with 42% fructose

feedstock to produce 55% fructose content, at a dry

solids level of 77%. The high-level feedstock may

also be refined and evaporated to produce 90%

high-fructose syrup.

High-Maltose Syrups

0038Enzyme technology has been developed to produce

syrups that are higher in maltose than an acid-

converted syrup of similar DE. These syrups are

used for fermentation (brewing) and for applications

in icecream and confectionery where physical proper-

ties are more important than sweetness. The low

dextrose concentration allows control of color devel-

opment in a heated product. The 65% maltose syrup

is a fine material for catalytic reduction.

Chemical and Physical Properties of Corn Syrups

0039Corn syrups all have pH values on the acid side,

minimum 3.5–5.5, to minimize color and flavor de-

velopment. Ash (mainly sodium chloride) levels in

corn syrups are low. Although sulfur dioxide is used

extensively in the preparation of starch from corn,

processing, especially those processes using ion ex-

change resins, can remove residual sulfur dioxide so

that products contain acceptably low levels of sulfite

and its oxidation product, sulfate. Fermentability of

corn syrups is another useful chemical property;

fermentable extract is defined as the percentage of

carbohydrates, on a dry-weight basis, fermented by

bakers’ yeast under controlled conditions. The higher

the DE, the higher the fermentability.

0040The reducing sugars characteristics of glucose,

fructose, and maltose allow participation in Maillard,

or browning, reactions, for brown crust formation

in baking and production of caramel color. (See

Browning: Nonenzymatic; Caramel: Methods of

Manufacture.)

0041Density of corn syrups is usually measured in

degrees Baume

instead of Brix. Syrups content (e.g.,

55% high-fructose corn syrup) is always expressed on

a solids basis.

0042Corn syrups, because of their solids content, have

colligative properties similar to those of sucrose

invert syrups as regards boiling point elevation and

freezing point depression: the latter is an important

factor in icecream hardness and melting. Osmotic

pressure increase is a measure of control against spoil-

age in jams and preserves. The syrups’ very high

viscosities are an important property in food process-

ing, controlling handling characteristics, and air

retention.

0043The humectant, or hygroscopic, properties of corn

syrups vary with their carbohydrate composition.

Lower-DE syrups are less hygroscopic, while malto-

triose and maltotetraose may be the most hygro-

scopic sugars. Variation in this property may be

tbl0003 Table 3 Composition of corn syrups

Designation Ash Saccharides,

carbohydrate basis

28 DE 0.3 8 8 11 73

36 DE 0.3 14 11 10 65

34 HM 0.3 9 34 24 33

43 HM 0.3 9 43 18 30

43 DE 0.3 19 14 12 55

43 DE (ion-

exchanged)

0.03 19 14 12 55

53 DE 0.3 28 18 13 41

63 DE 0.3 36 31 13 20

63 DE (ion-

exchanged)

0.03 36 31 13 20

66 DE 0.3 40 35 8 17

95 DE 0.3 95 3 0.5 1.5

95 DE (ion-

exchanged)

0.03 95 3 0.5 1.5

HFCS 42 0.03 95 3 0.7 1.3

HFCS 55 0.05 95.7 3 0.4 0.9

Crystalline fructose 0.05 100.0

DE, dextrose equivalent, or total reducing sugars reported as dextrose

percentage solids; HM, high-maltose; HFCS, high-fructose corn syrup; DP,

degree of polymerization; DP

dextrose (dextrose plus fructose for HFCS;

fructose for crystalline fructose); DP

, maltose; DP

, maltotriose; DP

,sum

of saccharides DP

and above.

Courtesy of the Corn Refiners Association, Washington, DC, USA.

SYRUPS 5715

used to control the texture and keeping quality

of baked goods, confectionery, and intermediate-

moisture foods, where corn syrups are employed as

moisture conditioners, food plasticizers, crystalliza-

tion inhibitors, and stabilizers.

0044 Applications and uses of starch-derived syrups in-

clude the following: baby and geriatric foods; bakery

products; beverages, brewed, alcoholic, carbonated,

and still; breakfast foods; cheese spreads and cheese-

based foods; coffee whiteners; condensed sweetened

milk; confectionery; eggs (frozen or dried); extracts

and flavors; frosting and icings; fruits and vegetables;

icecreams; industrial products (adhesives, chemicals,

dyes and inks, explosives, paper, textiles, tobacco);

jams, jellies, marmalades, and preserves; meat prod-

ucts (sausages, etc.); peanut butter; pharmaceutical

and medical; pickles and pickle products; pork and

beans; prepared mixes; seafood (frozen); syrups

(table, chocolate, cocoa, fruit, medicinal, soda foun-

tain, cordials, etc.); soups; toppings.

0045 High-fructose corn syrup is also widely used in

processed foods, bakery products, beverages (colas

and other carbonated soft drinks, and still drinks),

canned juices, canned fruits, condiments, confection-

ery products, frozen desserts, jams, jellies, and

preserves, pickles, and wine.

0046 Lycasin Lycasin, originally manufactured in

Sweden by the Lykeby Starch Co., is a hydroge-

nated glucose syrup, which does not crystallize out,

even at low temperatures, and has a viscosity similar

to that of high-fructose corn syrups. It is a mixture of

hydrogenated homologs of glucose and glucose poly-

mers, said to prevent dental cavities, although not

suitable for diabetics, and used in jams, preserves,

drinks, and hard-boiled candies.

Maple Syrup

0047 Maple sweetners, made by concentration of the sap of

the sugar maple tree (Acer saccharum), are produced

in eastern Canada and north-eastern USA. Heating of

the sap causes flavor and color development, as well

as concentration, and the characteristic maple flavor

of the syrup and sugar (sold in granulated or in block

form) is a major attraction. The pure product is more

expensive, by an order of magnitude, than sucrose or

starch-based sweetners, and, as a result, many blends

of maple syrup with other syrups, or of other syrups

with maple flavoring, are available, and nowadays

are generally labeled as such; false labeling of maple

products was common some years ago.

0048 The composition of maple syrup is shown in

Table 4. The carbohydrate make-up of fresh maple

syrup is almost entirely sucrose. This will invert with

time, but provides a means of detecting adulteration

or replacement of maple syrup with cheaper, starch-

based syrups: genuine maple product does not con-

tain maltose, while starch-based products do.

0049Physical properties of maple syrup are similar to

those of sucrose syrups, making the product suitable

for baking and confectionery, but, because of its cost,

most maple syrup is sold directly, and used as pancake

syrup or in home baking. Characteristic maple flavor

has been shown to be a complex mixture of plant

components (guiacyl acetone, vanillin) and products

of thermal degradation of carbohydrates (isomaltol,

acetol, a-furanone). (See Carbohydrates: Interactions

with Other Food Components.)

Fruit Syrups

0050A new product has entered the sweetener syrup field

in the USA, Europe, and South America: fruit syrup

or fruit juice concentrate. Excess fruit crops, or dam-

aged fruit unsuitable for its original destination as

fruit, fruit products, or wine, is prepared in juice

form. The juice is decolorized and the flavors re-

moved, through proprietary processes, and the

remaining material – usually a solution of invert

sugar, because fruit sucrose is hydrolyzed to invert

in the process – is concentrated to about 75



Brix at

pH 4, and sold as a natural fruit sweetener. The

product is designed for the natural foods market, so

that the terms ‘fruit sweetener’, ‘sweetened only with

fruit’ and ‘no sugar added’ can be displayed on the

label, although the last statement is questionable.

These fruit products, made in different places from

apple, peach, pear, citrus, and grape juices, sell, on

solids basis, at five to six times the price of sucrose.

See also: Antioxidants: Natural Antioxidants; Caramel:

Methods of Manufacture; Carbohydrates: Classification

and Properties; Interactions with Other Food

tbl0004Table 4 Composition of maple syrup

Component Amount (%)

Water 34.0

Sucrose 58.2–65.5

Hexoses 0.0–7.9

Malic acid 0.093

Citric acid 0.010

Succinic acid 0.008

Fumaric acid 0.004

Soluble ash 0.30–0.81

Insoluble ash 0.08–0.67

Calcium 0.07

Silica 0.02

Manganese 0.005

Sodium 0.003

5716 SYRUPS