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

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network and precipitation can occur. The optimum

pH for gelation is controlled by the degree of ester-

ification of the pectin as well as the soluble solids

content of the medium (Figure 6).

0035 Through their effect on the neutralization of the

pectin molecule, cations present in the system will

affect gelling. High ionic strength shifts the optimum

pH range towards higher values. This is particularly

visible with sodium ions. However, with ions such as

calcium or potassium that can bridge high-ester

pectin molecules in areas with a low density of ester,

there is a possible increase in junction zones. This

effect can become significant for high-ester pectin

with marked blockwise distribution of ester groups

(Figure 7).

0036 Water activity and sugar types Water activity and

sugar types will both affect the way hydrophobic

interactions can develop between the pectin mol-

ecules. As water activity is reduced, the hydrophobic

interactions are easier to form, causing faster gelling

to occur and the final gel strength to be increased.

0037 The commonest way of reducing water activity in a

food system is through the use of sugars. The effect of

sugars on hydrophobic interaction and so on gel

structure will be specifically linked to their molecular

conformation and their interaction with the neighbor-

ing water molecules (Figure 8).

0038 Influence of cooling rate and storage temperature

Cooling decreases molecular movement and allows

polymer molecules to interact at close distances. As

the cooling rate is increased, the gelation rate is also

increased. However, during rapid cooling and with a

low storage temperature, gelling can actually become

very slow, reflecting the difficult development of

hydrophobic interactions in these conditions. With

an intermediate cooling rate and temperature range,

hydrogen bonds and hydrophobic interactions

together can contribute to the build-up of a network

with the highest elasticity.

0039Properties of high-ester pectin gels Due to the nature

of the molecular interactions involved in high-ester

pectin gelation, gels made with these pectins will

typically not be thermo-reversible or shear-reversible.

When submitted to mechanical stress, the broken gel

will then show a high level of syneresis.

Gelling of Low-Ester Pectin

0040Low-ester pectin has traditionally been used for gel-

ling food products when the conditions required to

achieve a gel with high ester pectin were not met.

Recently however, low ester pectins have also found

applications in high sugar and low pH systems

because of their specific texture characteristics.

0041Though the same base mechanism applies, low

ester conventional and amidated pectin differ in

their gelling properties and offer a broad range of

functional properties.

0042Gelling mechanism The gelation of low-ester

pectins is the result of ionic linkage through calcium

bridges between carboxylic groups from two pectin

Marked block

structure

Rhamnose

Galacturonic acid

Methylated

galacturonic acid

Neutral sugar

Calcium

fig0007 Figure 7 Participation of calcium gelling in high-ester pectin gelation.

PECTIN/Properties and Determination 4445

chains with the participation of hydrogen bonding.

The linkage generally takes place upon cooling a

pectin and calcium system. The most commonly

accepted model of association is the eggbox model

(Figure 9). In this model, pectin chains could be

bridged by calcium ions, which incorporate in their

coordination shells two polyanion oxygen atoms

from one pectin molecule and three from another

chain. Even though a number of positive ions can

bridge pectin molecules, especially magnesium and

potassium, calcium is particularly effective in com-

plexing with carbohydrates, largely because its ionic

radius (0.1 nm) is big enough to coordinate with

many oxygen atoms and because of flexibility with

regard to the direction of its coordinate bonds.

0043The exact calcium requirements to obtain a gel

highly depend on the degree of esterification of the

pectin, the recipe, and process parameters such as the

rate of cooling. An increase in ionic strength, increase

in pH, or decrease in the degree of esterification

lowers the amount of calcium required to achieve

sol–gel transition. An optimum calcium level can be

defined for a given pectin in specific conditions.

Above this optimum level, pregelation will occur,

i.e., gelling will occur at too high temperatures to

obtain a coherent gel structure (Figure 10).

3.0 3.1 3.2 3.3 3.4 3.5 pH

High-fructose corn syrups

Sucrose

63 DE corn syrup

43 DE high-maltose corn syrup

42 DE corn syrup

Gel strength

fig0008 Figure 8 Effect of various sugars on high-ester pectin gel strength. DE, dextrose equivalent.

−

OOC

COO

−

COO

−

COO

−

OOC

COO

−

COO

−

COO

−

OOC

COO

−

COO

−

COO

−

fig0009 Figure 9 Eggbox model. Schematic overview of established low-ester pectin gel mechanism, showing calcium-induced junction

zones. Inset shows detail of the various types of possible hydrogen bonding that participate in the junction zone, together with the

calcium chelation (far left).

4446 PECTIN/Properties and Determination

0044 Gelling is dependent on the length of the junction

zones, that is, the number of galacturonic acid units

involved in electrostatic bonds with calcium. The

bonds are stable when at least seven consecutive

carboxyl groups from each chain are involved. If the

junction zones formed with calcium become too long,

a pectin precipitate may be formed. This may occur

with pectin with a very low degree of esterification

when large amounts of calcium are available.

0045 The presence of ester or amide groups prevents the

formation of junction zones in the interjunction seg-

ments of the molecules, making them more flexible.

Side chains also prevent aggregation of the pectin

molecules through steric hindrance.

0046 The typical high-ester pectin gelling mechanism

with hydrogen bonds and hydrophobic interactions

can also contribute to the final texture of low-ester

pectin gels, especially at low pH and with high soluble

solids concentration.

Parameters Influencing Gelling

0047 Although the availability of calcium is a critical factor

in the gelation of low-ester pectins, other parameters

in relation to the pectin molecule and media have a

significant influence on gelling and the final structure

obtained. The main parameters are the number and

distribution of ester and amide groups as well as the

molecular weight of the pectin molecule and the pH,

ionic strength, and water activity of the gelling

system.

0048 Influence of esterification Because calcium bonds

can only occur in esterification-free zones, gel

strength increases with a decreasing degree of esteri-

fication. For low-ester pectin with an average DE

above 30%, the distribution of the esters may be of

significant importance as it will control the length of

possible junction zones and influence the gelling

temperature, the final gel strength, and texture.

0049Influence of amidation The amidation of pectins

was developed in the 1940s as a means of modifying

the functional properties of low-ester pectins in order

to achieve better gelling control. The exact mechan-

ism by which the amide groups intervene in the

gelation remains to be fully explained. However, it

is generally accepted that amidation increases the

gelling power of low-ester pectins due to the possibil-

ity of hydrogen bonding involving amide groups. Gels

made with amidated pectins are firmer and require

less calcium; they are also more thermo-reversible

than ones made with low-ester conventional pectins.

0050Influence of molecular weight As for any polymer

gel, the length of the polymer governs the number of

junction zones required to achieve a coherent net-

work. Low-ester pectins with a high molecular weight

will exhibit a higher gelation rate, lower calcium

requirements for gelling, and an overall more cohe-

sive and elastic gel structure with a reduced tendency

towards syneresis.

0051Influence of pH At low sugar content, as the pH is

decreased, the pectin molecules are neutralized with

protons, decreasing the probability of junction zones

forming with calcium. This translates into higher

calcium requirements and a looser gel texture at a

low pH.

0052On the other hand, when the water activity of the

system is decreased by the addition of sugars, the

high-ester pectin gelling mechanism will start to play

a significant part in the gelling and the calcium

requirements will then be decreased when the pH is

lowered. In usual food systems, availability of natural

calcium will also be increased at a lower pH and thus

may reduce the need for extra calcium addition

(Figure 11).

0053Influence of ionic strength An increase in gel

strength can be observed at a higher ionic strength.

This is usually explained by the neutralization of the

polymers by the extra ions, which allows the chains to

be closer, leading to a more organized and cohesive gel.

0054Influence of water activity As the solids level

increases, calcium requirements decrease. However,

for most pectins, a higher solids level accelerates gel-

ling, and increases the setting temperature and the

final gel strength. It also reduces the optimum cal-

cium window, thus increasing the risk of pregelation.

0 20406080100

Low-ester amidated

pectin

Low-ester

conventional pectin

Gel strength

mg Ca

−1

pectin

fig0010 Figure 10 Influence of calcium on low-ester pectin gels.

PECTIN/Properties and Determination 4447

In practice, this leads to a choice of pectin with a

higher degree of esterification (less calcium-reactive)

at a higher solids level.

Properties of Low-Ester Pectin Gels

0055 The properties of low-ester pectin gels are very de-

pendent on the type of pectin used (conventional or

amidated) along with the procedure and formulation

employed to make the gel. Typically, they are thermo-

reversible and show a high degree of thixotropy. In

specific conditions it is however possible to obtain

heat-resistant or very brittle gels with no shear revers-

ibility.

Protein Stabilization with High-Ester Pectins

0056 In acidified conditions, casein and, more generally,

food proteins will tend to agglomerate and sediment

if the viscosity of the system is low enough. In these

conditions the proteins are also very sensitive to

dehydration and can easily become sandy after heat

treatment. With the rapid development of acidified

dairy beverages worldwide, now expanding with

other protein sources such as soy, the need for effect-

ive protein stabilizers in a low-pH environment is

growing strongly. High-ester pectin has proven to be

a very useful stabilizer in these conditions.

0057 Mechanism It is generally accepted that, at suffi-

cient pectin concentrations, the adsorption of the

carboxyl blocks of the pectin molecule to the protein

surface will stabilize the protein system through steric

repulsion (Figure 12). So, the presence of blocks of

free carboxyl groups on the galacturonic backbone

has an important influence on the protein-stabilizing

property of pectin.

0058Due to the lower proportion of carboxyl groups,

high-ester pectin has a weaker electrostatic inter-

action with protein than low-ester pectin but proves

to be more effective. Indeed, it seems to be important

that significant parts of the pectin molecule do

not interact with the protein surface in order to

achieve the steric repulsion effect. It is also the key

to minimizing interactions between pectin and

cations available in the system.

0059Both the DE of the pectin and the distribution of

the esters on the polymer affect its stabilization prop-

erties. Excessively large blocks of carboxyl groups

will tend to interact with the ions present in the

system, such as calcium, rather than with the protein

– an interaction which will lead to an increase in

viscosity or even gelation.

0060Conditions Most food proteins (isoelectric point

around 5) can form complex coacervates with anionic

polysaccharides such as pectin (isoelectric point

around 3.5) in the intermediate-pH region, where

the two macromolecules carry opposite net charges:

pH above the isoelectric point of the polysaccharide

but below that of the protein.

0061In the case of pectin–protein interaction, the

strength of the complex will depend on several

factors, such as the distribution of the carboxyl

groups on the galacturonic acid backbone, but also

on the three-dimensional protein structure and the

distribution of ionizable groups on its surface. The

whole interaction will also depend on several system

parameters such as pH, ionic strength, presence of

sugars, or fat.

0062Through its role in the ionization of both the protein

and pectin molecules, pH is the most significant factor

affecting electrostatic pectin–protein interactions. It

3.10

100

120

140

160

3.30 3.50 3.70 3.90 410

Breaking strength (g)

100 mg Ca

200 mg Ca

fig0011 Figure 11 pH influences on Ca-curves in low-sugar system (31% soluble solids), with high reactive amidated pectin. Triangles,

100 mg Ca; squares, 200 mg Ca.

4448 PECTIN/Properties and Determination

also plays a very significant role in the protein struc-

ture and how proteins interact in a complex system

such as milk.

0063 The optimum pH range for interaction between

high-ester pectin and casein is 3.6–4.5. At a lower

pH, the block structures of the high-ester pectin

will not be sufficiently ionized for proper protein

binding as the pH is too far below the pKa of the

pectin. Above the isoelectrical point of the protein,

the protein–polysaccharide complex is very weak or

nonexistent and the electrostatic protein–protein

repulsion is dominant. It is, however, clear that

this repulsion is not sufficient to stabilize the proteins.

Conclusion

0064 Pectin exhibits a wide range of functional properties

and enjoys a very good public image as a natural

product derived from fruit. Today it is widely used

as a textural ingredient and stabilizer in a variety of

food applications, and there is little doubt that its

usage will grow as new functionalities are revealed.

See also: Cholesterol: Absorption, Function, and

Metabolism; Citrus Fruits: Composition and

Characterization; Dietary Fiber: Physiological Effects;

Fermented Milks: Types of Fermented Milks; Gums:

Properties of Individual Gums; Food Uses; Dietary

Importance; Jams and Preserves: Methods of

Manufacture; Chemistry of Manufacture; Pectin: Food

Use; Protein: Interactions and Reactions Involved in Food

Processing; Rheological Properties of Food Materials;

Rheology of Liquids; Stabilizers: Types and Function;

Applications

Further Reading

Dickinson E (1998) Stability and rheological implications

of electrostatic milk protein–polysaccaride interactions.

Trends in Food Science and Technology 9: 347–354.

Kravtchenko TP, Voragen AGJ and Pilnik W (1994) Char-

acterization of industrial high methoxyl pectins. Gums

and Stabilizers for the Food Industry 7: 27–35.

May CD (1990) Industrial pectins: sources, production and

application. Carbohydrate Polymers 12: 19–99.

Rolin C and De Vries J (1990) Pectin. In: Harris P (ed.) Food

Gels, pp. 401–434. London: Elsevier.

Thakur BR, Singh RK and Handa AK (1997) Chemistry

and uses of pectin – a review. Critical Reviews in Food

Science and Nutrition 37: 47–73.

Walter RH (ed.) (1991) The Chemistry and Technology of

Pectin. London: Academic Press.

Food Use

L Flutto, Danisco, New Century, KS, USA

Introduction

0001Pectin has been used traditionally in food ever since

man started cooking fruits and vegetables. As a

Lack of binding sites

Optimal binding site

Marked block

structure

Hairy surface provides steric stabilization

Rhamnose

Galacturonic acid

Methylated

galacturonic acid

Neutral sugar

Part of casein

fig0012 Figure 12 Theoretical picture of interaction between pectin and protein.

PECTIN/Food Use 4449

natural component of plants, pectin is a desirable

texturizing and stabilizing agent for use in all kinds

of processed foods available today. In this chapter, we

take a brief look at the most important food uses of

pectin and its key properties in each system.

Function in Foods

0002 Pectin is traditionally used for its gelation properties,

with more than a third of the pectin commercially

available being utilized by the jam and jelly industry.

Pectin is used to ‘set’ or gel jams, jellies, and pre-

serves. The pectin holds fruit pieces suspended within

the gel structure, trapping water between cross-linked

pectin molecules. The result is a gelled food that is

shelf-stable. However, in more complex applications

such as fruit preparations for dairy products, pectin

is used to impart specific rheological properties

during the manufacturing and storage of the fruit

preparation, as well as during blending with the

dairy product and all during the shelf-life of the fin-

ished product. Pectin is also widely used for its unique

protein stabilization properties in acidic conditions.

The general acceptance of pectin as a natural material

and a soluble food fiber has made it desirable for use

in a variety of applications (Table 1).

Jams and Jellies

0003 Jams, jellies, and preserves can be divided into two

categories. Traditional products have a solids range

usually above 60%. Reduced sugar products have a

soluble solids content in the range of 25–55%.

0004 High-ester pectins are used in the production of

jams, jellies, and preserves with soluble solids above

60% and a pH below 3.6. As high-ester pectin gels

are not shear-reversible, it is of utmost importance

that the jars be filled at a temperature above the

setting temperature of the pectin in order to avoid a

broken gel and syneresis. Various high-ester pectins

used in recipes with different soluble solid contents

will have different optimum pHs (Figure 1).

0005The choice of pectin will also be dependent on

the type of product made. A fast-setting pectin is

preferred for preserves where fruit pieces have to be

suspended evenly throughout the container. By con-

trast, a slow setting pectin is used for jellies in order

for air bubbles to escape prior to gelling, resulting in a

fully transparent product. The size of the packaging

will also influence the choice of pectin, with fast-

setting pectin recommended for larger jars, as the

cooling rate is slower, and a quick gelling is necessary

to keep the fruit pieces in place. It is important,

however, to note that for very large containers

(several kilograms to several hundred kilograms), it

is necessary to cool down the product before filling as

the cooling rate is too slow in the center of the prod-

uct, and the pectin is degraded when exposed to high

temperatures for an extended time. In this case, a

slow-set pectin or even a low-ester pectin is required

to allow for cooling prior to filling without breaking

the gel network. When filling in small packages and

especially in food-service single-serve packages, the

use of a slow-set pectin is also required as the filling

time can be quite long. The temperature of the prod-

uct in the holding tank before the packaging line will

need to be reduced to avoid pectin degradation in

time and insure consistent gelling from the first to

the last package of the batch. Low-ester pectins are

used when conditions for gelling a high-ester pectin

are not met. Typically, this is the case when the sugar

content is reduced below 60%. They are, however,

also used in high-soluble-solids formulations when a

tbl0001 Table 1 Function of pectin in food applications

Function Food application Typical use

level (%)

Viscosity building Juice beverage, soft drinks 0.01–0.20

Sauces 0.10–0.50

Sorbet (avoids crystallization) 0.10–0.40

Protein stabilization Yogurt drinks 0.15–0.60

Milk–Juice drinks 0.15–0.60

Acidified soy drinks 0.20–0.60

Gelation Jams, jellies, preserves 0.30–1.20

Fillings, glazes 0.30–1.20

Desserts 0.50–1.00

Confectionery 0.50–2.50

2.5 3.0

Gel strength

3.5

65% soluble solids

60% soluble solids

RS pectin

SS pectin

RS pectin

fig0001Figure 1 Choice of high-ester pectin and slow-set pectin (SS)

content to determine the optimal pH for the gelation. RS, rapid

set.

4450 PECTIN/Food Use

spreadable texture is desired. These pectins gel in the

presence of calcium ions, which is the main factor

controlling the gelling. The soluble solids level and

pH are only secondary parameters, but they have an

influence on the gelling temperature and the texture.

0006 As the soluble solids are decreased, the greatest

challenge for the manufacturer is to keep an even

distribution of fruit pieces. Indeed, the main influence

of the soluble solids level will be on the viscosity of

the jam at high temperatures during the process.

0007 The choice of a low-ester pectin is therefore mostly

based on the solids level. The use of low-ester ami-

dated pectins with increasing calcium reactivity is

usually recommended when the soluble solids are

decreased. This insures a faster set with an even dis-

tribution of fruits. In low-brix formulations, the add-

ition of calcium may be required to supplement the

calcium brought by the fruits and the water and to

insure a fast and homogeneous gelling.

0008 To further avoid the flotation issues, a combination

of low-ester amidated pectin and conventional pectin

is commonly used. The low-ester conventional

pectin forms a network at a higher temperature than

the amidated counterpart and helps to keep the fruit

well distributed. Other gums such as locust bean gum

or guar are also often used in combination with a

low-ester pectin to provide viscosity in low-solids

formulations (Table 2).

0009A rapidly growing category in jams and jellies field

is products where refined sugars have been replaced

by fruit-juice concentrates. These products usually

have between 40 and 50% soluble solids and rely on

low-ester pectin gels. The only difference with stand-

ard reduced sugar recipes is in the ionic balance, as

the fruit concentrates add a significant amount of

calcium, as well as magnesium and potassium, to

the formulation. This influences the choice of pectin

as well as the amount of calcium to be added to the

product. It is important to position the product on the

flat part of the calcium curve and use a pectin with a

broad tolerance to calcium in order to obtain a con-

sistent texture, despite the usual variations in calcium

content of the natural raw materials (Figure 2).

Fruit Preparations

0010The fruit preparation industry constantly juggles be-

tween retaining the identity of the fruit, perfect fruit

tbl0002 Table 2 Typical reduced-sugar jam formulations with a low-ester amidated pectin

Jam final soluble solids content

25% 35% 45%

Ingredients Dosage

(%)

Soluble

solids (%)

Dosage

(%)

Soluble

solids (%)

Dosage

(%)

Soluble

solids (%)

High-calcium reactive low-ester amidated pectin 0.8 0.8 0.7 0.7

Medium-calcium reactive low-ester amidated pectin 0.6 0.6

Locust bean gum 0.1 0.1

Sugar I 3.6 3.6 2.8 2.8 2.4 2.4

Water I 18.0 14.0 12.0

Fruit, 10% soluble solids 45.0 4.5 45.0 4.5 45.0 4.5

Sugar II 15.9 15.9 26.9 26.9 37.4 37.4

Water II 21.1 15.1 7.1

K-sorbate, 20% w/v 0.2 0.04 0.2 0.04 0.2 0.04

Na-benzoate, 20% w/v 0.3 0.06 0.3 0.06 0.3 0.06

Citric acid, H

O, 50% w/v As required As required As required

Flavoring As required As required As required

Total 105.1 25 105.1 35 105.1 45

Evaporation 5.1 5.1 5.1

Yield 100.0 100.0 100.0

pH 3.2 3.2 3.2

Filling temperature (



C) 40–50 45–55 55–65

Procedure (regardless of targeted soluble solids)

1. Dry-blend the low-ester pectin (the locust bean gum if present) and sugar I, and add the blend to 80



C hot water I, agitating

vigorously

2. Mix fruit, sugar II and water II and heat the blend to approx. 80



3. Add the pectin solution, agitating continuously

4. Evaporate to the desired content of soluble solids

5. Add preservatives and adjust pH with citric acid

6. Add flavoring

7. Cool to filling temperature and fill

PECTIN/Food Use 4451

distribution throughout large totes, unique formula-

tions able to accommodate fruits with a varying

calcium content, and the texture and flavor of the

final dairy product in which the fruit preparations

are used. These challenges, combined with the pres-

sure on manufacturers to develop new fruit prepar-

ations quickly and the need to create process-friendly

formulations, call for the use of highly functional and

versatile stabilizers. Pectin has found a natural appli-

cation in these systems and is widely used.

Use of Pectin in Fruit Preparations

0011 Pectin is used in fruit systems for various purposes.

However, fruit preparations should only be thickened

and not fully gelled. This requires pectin capable of

giving fruit preparations a high degree of thixotropy.

0012 The texture of the fruit preparation can be con-

trolled by various parameters, as outlined in Table 3.

Use of a High-ester Pectin

0013 When more than 55% soluble solids are used, a high-

ester pectin with a typical dosage of 0.3% can

successfully impart viscosity and control syneresis in

a fruit preparation.

0014It is also possible to use a high-ester pectin with less

than 55% soluble solids in order to yield a special

texture. In these cases, a high-ester pectin typically

gives the fruit preparation a high degree of shine and

smoothness, although higher dosages are necessary.

0015Special high-ester pectins developed for their inter-

action with casein can also be used to obtain a high

degree of texture carry-through in the white mass. At

a usage level of 1–2%, the pectin gives the fruit

preparation the required texture and significantly

increases the viscosity of the finished stirred yogurt.

It also helps maintain a constant viscosity and reduce

syneresis during the shelf-life of the dairy product

(Figure 3).

Use of a Low-ester Pectin

0016Conventional and amidated low ester pectins are

widely used in fruit systems. While conventional

pectins require a slightly higher dosage and high

level of calcium, special ones have extreme processing

flexibility and can be used with great success in a

broad variety of formulations from 30 to 50 Brix

with various pH values. It is common to include low

ester conventional pectin in fruit on the bottom for-

mulations. Low-ester amidated pectin can prove

more economical with the possibility of lower

dosages, although it tends to be more sensitive to

calcium variations (see Figure 2). When the calcium

level is adjusted, it is possible to achieve an excellent

fruit suspension with a high level of shear reversibil-

ity. This allows low viscosity during pumping for

maximum fruit identity.

Calcium Addition for Texture and Postreaction

Control

0017When using a low-ester pectin, it is usually necessary

to add calcium salts to obtain the full texture. The

necessary quantity will depend on the calcium source,

pH, soluble solids, fruit type, and content of the

preparation. Specific calcium salts should be selected

according to the speed of release and labeling consid-

erations. Calcium chloride, -lactate, and -citrate is

Gel strength

Low-ester amidated

pectin

Low-ester

conventional pectin

0 20406080100

Milligrams of Ca

per gram of pectin

fig0002 Figure 2 Low-ester-pectin calcium curves.

tbl0003 Table 3 Parameters influencing the texture of fruit preparations

Choice of pectin High-ester, low-ester conventional, and low-ester amidated pectins perform differently and allow a

variety of textures

Pectin dosage A higher pectin dosage results in a thicker texture

Calcium level The calcium level needs to be adjusted with consideration for a possible reaction in the white mass;

higher calcium levels usually increase viscosity, but pregelation can occur if too much calcium is

added

Soluble solids Higher soluble solids usually result in a shorter texture

Filling temperature Lower filling temperatures usually result in a more fluid texture

Use of other hydrocolloids Locust bean gum, guar gum, xanthan gum and starches can be successfully used in combination with

pectin to achieve specific textures

4452 PECTIN/Food Use

most commonly used to supplement the calcium

contained in the fruit.

0018 If the calcium content of the fruit preparation is too

low, the pectin present in the fruit preparation may

react with the calcium of the yogurt, resulting in a

grainy texture (stirred yogurt) or a gelled preparation

(fruit on the bottom). To avoid this type of postreac-

tion, it is highly recommended that the appropriate

amount of calcium is added to the fruit preparation.

Bakery Fillings

0019 In principle, bakery fillings are a form of fruit prepar-

ation. However, they deserve a separate paragraph as

the demands on these products are fairly specific.

Applied on or inside the dough, they usually need to

be heat-resistant and have a level of water activity low

enough to minimize water transfer from the filling

to the dough. This is especially important for long-

shelf-life cookies and cereal bars, which tend to be

where there is greatest demand. As is the case for fruit

preparations for the dairy industry, the trend is for the

bakeries to outsource the production of fillings and

transport them in larger containers.

0020 Most bakery fillings have a high solids content

typically between 60 and 80%. Thus, a high-ester

pectin seems a natural choice also because these gels

are thermally irreversible. However, high-ester pectin

gels are completely nonthixotropic and lose their

entire structure after pumping. So, pure high-ester

pectin gels, which require cooling prior to filling and

mechanical pumping at the bakery, are not adequate

for packaging in large containers. High-ester pectin

gels would be destroyed by such processes and show

syneresis and a very poor bake stability.

0021High-ester pectins may, however, be used success-

fully for cold gelation systems, also called delayed

setting systems. These are gel systems in which all

the gelling conditions for a high-ester pectin are met,

with the exception of the pH, which is kept too high.

This viscous syrup can then be shipped to the bakery,

where the acid is then added upon depositing the

filling on the dough.

0022For other types of bake-stable fillings, specific low-

ester pectins can prove ideal. Even if low-ester pectin

gels are typically characterized as being thermally

reversible (a property used in glazes), they can be

made bake-stable by using an optimized formulation.

Low-ester conventional pectins are usually preferred,

as they show a higher bake stability due to a stronger

binding with calcium. The choice of the correct

calcium salt as well as its dosage is the key to both

the texture of the filling and its heat stability. In very

high solids formulations, the use of pectin in combin-

ation with alginate can prove useful in improving the

filling appearance and its bake stability.

Glazes and Bakery Decor

0023Glazes are widely used to cover fruit tarts and

other types of cakes where they not only add con-

sumer appeal but also extend shelf-life by forming a

Fruit preparation with

30% soluble solids

Fruit preparation with

55% soluble solids

Yogurt

white base

Yogurt with

reference

fruit preparation

Yogurt with

fruit preparation

made with special hi

h-ester pectin

Viscosity of yogurt (mPas)

7 days after fruit-preparation addition

fig0003 Figure 3 Use of a special high-ester pectin in a fruit preparation to increase the viscosity of yogurt.

PECTIN/Food Use 4453

barrier to dehydration and microbiological contamin-

ation. The high transparency and shine of pectin gels

make the use of this hydrocolloid an ideal choice for

this application. In some specific applications, it is

possible to use combinations of pectin with alginate

or carrageenan.

0024 Contrary to most bakery fillings, in glazes and

bakery decorations, the heat reversibility of the

system is usually of paramount importance. These

products are most often sold to bakery shops in con-

centrated form and reheated and diluted with water

before application. The gel must then form quickly

and keep for several days, even on fruits with a high

water content. In industrial applications, the gel has

to be so completely reversible such that the product

can be sprayed. Clearly, these requirements are best

met with low-ester amidated pectins.

0025 The use of specific calcium sources with controlled

release together with calcium sequestrants is neces-

sary to control the gelling of a low-ester pectin and

secure an optimum performance after reheating.

Confectionery

0026 Pectin is widely used in traditional confectionery

items such as ‘pa

te de fruit,’ or Zefir. However, it is

also an important textural agent in a number of other

confectionery articles, where its superior flavor

release, high transparency, and clean bite are sought

after.

0027 Jelly candies typically have a soluble solids content

of between 75 and 80% and a pH of around 3.5. Due

to the high solids level, it is important to use a very

slow setting high ester pectin and include buffer salts

in the formulation to avoid any pre-gelling before

depositing.

0028 The standard process usually involves making a

pectin solution with the buffer salts, heating the

sugars and fruits when present, and mixing in the

pectin solution before cooking to reduce the water

level and obtain the desired solids content. Immedi-

ately before depositing, acid, color, and flavorings are

added. Pectin jellies can be deposited in starch or

rubber molds or in large trays for further cutting. It

is also possible to use pectin on jet cooking equipment

where all the ingredients are mixed together, and the

pectin actually dissolves at a very high temperature

(around 140



C) with all the solids present. This pro-

cedure usually requires the use of specific pectins with

particular dissolution properties.

0029 In most cases, the pectin chosen for confectionery

will be an extra-slow setting type to guarantee a low

setting temperature. Even with this type of pectin, the

gelling temperature of the system is usually around



C, and the depositing temperature needs to be

above this level if the full gelling potential of the

pectin is to be used. This is a major difference from

the commonly manufactured gelatine candies, which

have a much lower setting temperature. Another sig-

nificant difference is the speed of gelation, as pectin

jellies can be demolded quickly after depositing since

a firm gel is obtained very quickly. As with all high-

ester pectin gels, typical pectin jellies are not ther-

mally reversible.

0030The buffer salts commonly used with pectin in

confectionery include sodium citrate and sodium

potassium tartrate. The latter tends to give the jellies

a somewhat firmer texture.

0031High-ester pectin is also often used in combination

with other ingredients such as gelatine, starch, or agar

to give intermediate textures. In the case of gelatine

candy, pectin is also used in small amounts to increase

the melting point of the confectionery pieces in warm

climates, thus insuring a better appearance through-

out their shelf-life without significantly affecting the

texture.

0032In specific candy pieces where a neutral flavor such

as vanilla is used, the use of a low-ester pectin is

necessary in order to obtain a gel at a higher pH. As

with high-ester pectins, it is usually necessary to reduce

the setting temperature. In these systems, calcium

sequestrants such as sodium hexametaphosphate are

used. Turkish delight is one such traditional candy

based on a low-ester pectin gel with or without the

addition of starch.

0033High- and low-ester pectins are also widely used

for confectionery fillings, which are then either

enrobed usually with chocolate or, for example,

panned into jelly beans.

Fruit Beverages and Soft Drinks

0034Pectin is used as a viscosifier in beverages and soft

drinks, and high-ester pectins may be used as a mouth-

feel improver. This use has been widely developed for

juice drinks with a reduced juice content or sugar-free

soft drinks.

0035Low-concentration pectin solutions can be con-

sidered Newtonian and show a low viscosity. This is

of great relevance for the use of pectin in fruit bever-

ages and soft drinks as the concentration used rarely

exceeds 0.5%. Indeed, the clean mouth feel imparted

by pectin compared with the tendency towards a

slimy mouth feel with some other gums could be

related to the low viscosity of pectin solutions at the

shear rate applied in the mouth. This property makes

pectin an ideal choice when trying to replace the

mouth feel lost by the reduction in sugar content.

0036As most juice beverages and soft drinks contain

calcium, pectin with a high degree of esterification is

4454 PECTIN/Food Use