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Friberg ES and Larsson K (eds) Food Emulsions,

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in bread and fine baked products. Advances in Cereal

Science 6: 139.

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195–200.

Phosphates as Meat Emulsion

Stabilizers

L Knipe, Ohio State University, Columbus, OH, USA

Introduction

0001 The emulsifying capacity of phosphates in meat emul-

sions may take several approaches, depending upon

the definition of emulsification. A finely chopped

meat mixture is conventionally referred to as a

‘meat emulsion.’ However, this is now considered to

be a misnomer. The so-called meat emulsion consists

of solid fat particles dispersed in a mixture of water

and many fibrous particles, including connective

tissue and muscle fibers. A true emulsion is a stable

suspension of two liquids (oil and water) which are not

normally soluble in each other. It might be more ap-

propriate to refer to a meat emulsion as a matrix,

whose stability is dependent upon the water-holding

capacity or binding capacity of the meat proteins in

the matrix. However, a finely chopped meat mixture

will be referred to as an emulsion in the remainder of

this article.

0002If the proper combination of meat ingredients is

combined with the proper processing procedures

(e.g., grinding, chopping, emulsifying), a stable emul-

sion will be prepared which will hold up well during

the cooking process. Examples of meat emulsions are

bologna sausages or wieners, which have such fine

meat particles that they are not distinguishable on the

smooth product surface. However, if either the quan-

tity or quality of meat ingredients or the processing

methods are inadequate, the meat mixture will be

unstable and result in a poor-quality product upon

cooking. (See Meat: Sausages and Comminuted

Products.)

0003If it is assumed that a meat emulsion is not a true

emulsion, then phosphates are probably not true

emulsifiers, but stabilizers of meat mixtures. There

are many factors involved in the stability of meat

emulsions which can be affected by the addition of

inorganic phosphates. The main effects of phosphates

in finely chopped meat systems are on the pH, ionic

strength, protein extraction, divalent cation binding,

and viscosity. (See Colloids and Emulsions; Stabil-

izers: Types and Function; Applications.)

Phosphate Classification and

Nomenclature

0004Inorganic phosphates are classified by the number of

phosphorus atoms in the phosphate molecule. The

types of phosphates that are important to the meat

industry include the orthophosphates, the pyro-

phosphates, and the straight-chain phosphates.

0005Orthophosphates contain only one phosphorus

atom per molecule. The pyrophosphate molecule con-

sists of two phosphorus atoms linked by a shared

oxygen atom. An inorganic phosphate of such struc-

ture is referred to as a condensed phosphate. The two

pyrophosphates approved by the US Department of

Agriculture’s Food Safety Inspection Service (USDA

FSIS) are sodium acid pyrophosphate and tetra-

sodium pyrophosphate.

0006Inorganic phosphates of three or more phosphorus

atoms are referred to as polyphosphates. Sodium or

potassium tripolyphosphates consist of three linked

phosphorus atoms. Sodium hexametaphosphate is a

EMULSIFIERS/Phosphates as Meat Emulsion Stabilizers 2077

misnomer for a long straight-chain polyphosphate.

The ‘meta’ designation is correctly given to cyclic

polyphosphates. Hexametaphosphate contains an

average of 10–15 phosphorus atoms. The name

‘sodium hexametaphosphate’ has been deleted from

USDA regulations and replaced with ‘sodium poly-

phosphate, glassy’ (Graham’s salt) and ‘sodium meta-

phosphate, insoluble’ (Maddrell’s salt).

Phosphates and pH

0007 Phosphates affect the pH of both water and meat. The

pH values of 1% solutions of the phosphates ap-

proved for use in meat products, by the USDA FSIS,

appear in Table 1. Whereas meat contains 60–70%

moisture, the phosphate effect on the pH of meat, as

determined by standard pH measurements, is some-

what less than their effect in water, due to the buffer-

ing capacity of meat. Alkaline phosphates increase

meat pH in the range 0.1–0.6 units, depending upon

the phosphate chosen. The following list indicates

the decreasing order of impact on increasing meat

pH – pyrophosphates, tripolyphosphates, and hex-

ametaphosphates. Hexametaphosphates are con-

sidered to be rather neutral and often have no effect

in increasing meat pH. Acid pyrophosphates often, in

fact, decrease the pH of meat systems. There is, how-

ever, some debate among researchers as to the true

importance of meat pH changes, due to the addition

of phosphates, on the stability of meat emulsions.

(See pH – Principles and Measurement.)

Water-Holding Capacity of Meat

Emulsions

0008 The water-holding capacity of meat could be com-

pared to the action of a sponge and is important to

meat processing in that as proteins are able to hold

more water they become more soluble. The water-

holding capacity of meat is at a minimum at the iso-

electric point (pI) of meat proteins. At this point, equal

positive and negative charges on the protein molecules

result in amaximum number of bonds between peptide

chains and a net charge equal to zero. The pI of meat

(where water-holding capacity is at a minimum) is in

the pH range of 5.0–5.4, which is also the ultimate

pH of meat or the pH of meat after it has gone

through rigor mortis.

0009The water-holding capacity of meat is greatly

affected by pH. Increasing or decreasing the pH on

either side of the pI will result in an increased water-

holding capacity by creating a charge imbalance. A

charge imbalance is a predominance of either positive

or negative charges which will result in a repulsion

of the charged protein groups of the same (positive

or negative) charge. This repulsion results in increased

capacity for water retention and could be compared to

the repulsive effect of like charges on two magnets.

0010An increase in predominance of negative protein

charges, due to the addition of phosphates, may also

cause better distribution of fat particles in emulsified

products. The better fat particle distribution may

prevent the clumping of fat particles that occurs

during overchopping and which results in an unstable

emulsion.

Phosphates and Ionic Strength

0011Phosphates also affect the ionic strength of meat mix-

tures. Inorganic phosphates ionize in water to form

polyelectrolytes. This ionization causes a masking of

positive sites on the meat proteins which further

causes an electrostatic repulsion of the proteins. An

electrostatic repulsion between meat proteins allows

more space between proteins for binding water, which

increases the water-holding capacity. This effect is

sometimes hard to differentiate from the pH effect

on the water-holding capacity of meat. In addition to

the repulsion theory, the long-chain phosphates have

numerous charged anions along the chains, which

allows direct binding of phosphates to water mol-

ecules. This is especially true for the long-chain phos-

phates, such as the hexametaphosphates.

Protein Extraction and Solubilization

0012During the formation of a meat emulsion, meat pro-

teins are extracted from the fibrous muscle structure

and are solubilized to form a solution. This protein

extraction is enhanced by the optimal ionic strength

and pH of the solution in which the protein is sub-

mersed. Once solubilized, with additional chopping

or mixing, the liquid proteins are dispersed around

the bundles of muscle cells and fat particles. When the

mixture is then cooked, the protein solution de-

natures and coagulates (like egg white) to form a gel

around the muscle bundles and fat particles. This gel

tbl0001 Table 1 pH values for 1% water solutions of US Department of

Agriculture-approved phosphates

Inorganicphosphate pH

Tetrasodium or tetrapotassium pyrophosphate 10.2

Sodium or potassium tripolyphosphate 9.8

Disodium or potassium orthophosphate 8.8

Sodium polyphosphate, glassy 7.0

Sodium metaphosphate, insoluble 6.5

Monosodium or potassium orthophosphate 4.4

Sodium acid pyrophosphate 4.2

From Ellinger RH (1972) Phosphates as Food Ingredients. Cleveland, OH:

CRC Press with permission.

2078 EMULSIFIERS/Phosphates as Meat Emulsion Stabilizers

serves to stabilize the matrix of the meat mixture or

emulsion. (See Protein: Functional Properties.)

0013 Phosphates have a very valuable role in extracting

proteins from muscles. In fact, tetrasodium pyrophos-

phates are known to have a specific effect on meat

proteins in that they are able to extract muscle pro-

teins, and stabilize meat emulsions, to a degree much

greater than normally possible considering the effects

of tetrasodium pyrophosphates on ionic strength, and

pH compared to other phosphates. Part of the specific

effect is that pyrophosphates serve to dissociate, or

separate, actomyosin into its component parts, actin

and myosin. This is very advantageous, as myosin by

itself is more beneficial in producing a stable emul-

sion than actomyosin. Phosphates are also known to

extract myosin more readily from fast (white) muscle

fibers than slow (red) muscle fibers.

0014 Commercially available phosphates are ranked in

the following descending order of impact on extrac-

tion of muscle proteins from meat: tetrasodium or

potassium pyrophosphates, sodium or potassium tri-

polyphosphates, sodium hexametaphosphates. There

are cases, however, where it has been shown that level

of protein extraction in a meat system was not well

correlated to the emulsion stability of the final cooked

product.

Phosphates and Divalent Cations

0015 Phosphates also bind divalent cations, which are

native to meat proteins and which are detrimental to

finished processed-meat quality. Divalent cations,

such as those of calcium, magnesium, and iron, are

often found in untreated or unsoftened water sup-

plies, as well as meat, and are known to decrease the

water-holding capacity of meat. This is believed to be

due to bridging and binding between several groups

of proteins, similar to that which occurs during rigor

mortis. Another theory is that divalent cations screen

the negatively charged protein groups, minimizing

any repulsive effect. However, there is some evidence

that increased magnesium concentration enhances

the myosin-extracting ability of pyrophosphates.

0016 There is still some debate among researchers as to

whether phosphates bind cations which are already

bound to the muscle or bind only to free cations in

solution within muscle. In either case, the binding

of cations in a meat system increases the water-hold-

ing capacity. One indication that phosphates are

binding divalent cations is in the antioxidant effects

of phosphates added to meat products. (See Antioxi-

dants: Synthetic Antioxidants.)

0017 The long-chain phosphates, such as sodium

hexametaphosphates, are most active in chelating

calcium ions and short-chain phosphates, such as

tetrasodium pyrophosphates, bind magnesium cations

most readily.

Viscosity of Meat Emulsions

0018Phosphates are also important in the physiochemical

aspects of meat processing. For example, phosphates

reduce the viscosity of meat mixtures. This is import-

ant because, in the chopping or mixing steps, meat

temperatures will rise due to frictional energy pro-

duced as the chopper or emulsifier knives are cutting

and moving through the meat mixture. Chopping

emulsions containing a soft fat, such as pork fat,

to excessively high temperatures will result in an

unstable product.

0019However, when meat is finely chopped to make a

stable emulsion-type sausage product, the fat par-

ticles need to be reduced to a small enough size so

that the extracted meat proteins can coat or entrap

the fat. If the fat particles are too large, a coarse,

unstable emulsion will result but, if the fat is chopped

too much, the fat surface area may be too large or too

many fat cells may be broken, also resulting in an

unstable product. By reducing the viscosity, a mixture

can also be chopped or mixed longer, either to reduce

fat particle size or extract more protein to stabilize the

mixture further, with less temperature rise. Without

phosphates, long chopping or mixing times would

result in unstable products.

Phosphates and Sodium Chloride

0020The functionality of phosphates is greatly affected by

the addition of common table salt or sodium chloride

to meat emulsions. The effects of combining salt and

phosphates in meat emulsions is considered to be

synergistic, which means that the measurable effects

of the two ingredients combined is greater than the

combined effects of the two ingredients added indi-

vidually. It seems that phosphates exert more effect

on the pH and protein solubility and salt exerts more

effect on the ionic strength and water-holding

capacity. The phosphate effect on muscle proteins

appears to diminish at higher salt concentrations

(> 0.6 mol l

1

sodium chloride).

See also: Antioxidants: Synthetic Antioxidants; Colloids

and Emulsions; Meat: Sausages and Comminuted

Products; pH – Principles and Measurement; Protein:

Functional Properties; Stabilizers: Types and Function;

Applications

Categories

0010 Food emulsifiers can be categorized (Table 1) on the

basis of several characteristics, including: origin,

either synthetic or natural; potential for ionization,

nonionic versus ionic; HLB; and the presence of

functional groups.

0011 Some biopolymer-type emulsifiers, such as whey

proteins, will function both as an emulsifier and as a

thickener. For underprocessed emulsions, the droplets

may not be dispersed finely enough. Overprocessing

an emulsion may reduce or eliminate the maximum

networking ability of a stabilizing macromolecule

colloid (protein or polysaccharide), due to the

excessive mechanical or thermal treatment.

0012 An example of an anion-type food emulsifier is

sodium stearoyl lactylate. When combined with dis-

tilled, saturated monoglycerols (1:1, w/w), vesicles

form that are relatively stable in food systems. These

work well for such applications as aerating or textur-

ing low-fat foods.

0013When adding an emulsifier–water mesophase as a

part of a food formulation, it is important to realize

that phase changes may take place due to the effect

of the food ingredients (fats, oils, proteins, salts, etc.)

on the mesophase, as well as the effect of temperature

during pasteurization, sterilization, or freezing of

foods.

Functionality

0014Surface active compounds operate through a hydro-

philic head that is attracted to the aqueous phase, and

a lipophilic tail that partitions into the oil phase. The

surfactant is positioned at the oil–water interface,

where it can act to lower the surface or interfacial

tension. Lipophilic tails are generally composed of

C16 or longer fatty acids. Emulsifiers with shorter

fatty acid chains can act as emulsifiers but may hydro-

lyze to cause soapy or other undesirable off-flavors.

0015The concentration of added emulsifiers in foods is

usually too low to result in any formation of liquid

crystalline phases during food processing; neverthe-

less, some may be formed during processing by the

polar lipids present in the food ingredients. This is the

case with bakery products such as bread, rolls, and

buns based on wheat flour, which contains polar

lipids, such as glycolipids and phospholipids. Another

example is mayonnaise and salad dressings where the

phospholipids from the eggyolk can form liquid

crystalline structures. Acetic acid or lactic acid esters

of monoglycerols or propylene glycol monostearate

are used in whippable emulsions, such as creams,

toppings, etc.

0016Emulsifiers have a wide range of functional proper-

ties in addition to the obvious property – stabilization

of food emulsions. Table 2 lists the functional proper-

ties of food emulsifiers compiled from a variety of

sources including product brochures from several

emulsifier manufacturers.

tbl0001Table 1 Some food emulsifier categories

Emulsifier

Mono- and diglycerols

Propylene glycol monoesters

Lactylated esters

Polyglycerol esters

Sorbitan esters

Ethoxylated esters

Succinated esters

Fruit acid esters

Acetylated mono- and diglycerols

Phosphated mono- and diglycerols

Sucrose esters

Adapted from Zielinski RJ (1997) Synthesis and composition of food grade

emulsifiers. In: Hasenhuetti GL and Hartel R (eds) Food Emulsifiers and

their Applications, pp. 11–38. New York: Chapman and Hall.

EMULSIFIERS/Uses in Processed Foods 2081

0017 Petroswski has compiled a good list of some of the

commercial emulsifiers and described their nature,

iodine, HLB values, and melting points.

Uses

0018 -Cereal-based products Baked products without

emulsifiers have been described as undesirable in

terms of texture, taste, and appearance. Current pro-

cessing, distribution, and storage techniques used for

baked products require the use of additives that

maintain quality and freshness.

0019 Reviews by Schuster and Adams and Stampfli and

Nersten cover research on emulsifiers with respect to

baked goods and include excellent discussions on

the mechanism of emulsification, the interaction of

emulsifiers with starch, and a wide range of applica-

tions.

0020A series of bakery blends have been formulated

for several fat-free, low-fat, or reduced-fat bakery

applications, including muffins and sweet doughs,

cakes and frostings. Emulsifiers function as dough

conditioners, giving the product increased resistance

to mixing and mechanical abuse, stronger side walls,

more uniformity, and improved slicing characteristics.

Several different types of bakery products, in addition

to bread produced via conventional methods, benefit

from added emulsifiers, including white bread pro-

duced by a highly mechanized process, buns and

rolls, yeast-raised sweet rolls and doughnuts, plus var-

iety breads that contain a significant portion of non-

wheat flour components. (See Biscuits, Cookies, and

Crackers: Methods of Manufacture.)

0021Certain emulsifiers can also function as crumb soft-

eners, another type of dough conditioner. Soft crumb,

a characteristic of freshly baked bread, can be

retained longer if the appropriate emulsifiers are

added. Crumb firming, associated with staling and

starch retrogradation, can be delayed for 2–4 days

with the addition of emulsifiers. When shortening is

added to a wheat dough, it will improve the volume.

0022Cake volume and crumb texture are both related to

the number of air bubbles present in the aerated

batter. Commercially manufactured gel phases are

available for use as aerating agents in low-fat cakes

(Table 3.)

0023Investigators have attributed the effect of emulsi-

fiers on the delay of crumb firming to the ability of

emulsifiers to function as foam stabilizers.

0024Most investigators have found that lecithin has the

same characteristics as other dough conditioners on

bakery products: increased water absorption, reduced

mixing time, improved machinability, and longer

freshness. Lecithin can also improve the wettability

of cake mixes. Phospholipids, treated with phospho-

lipase to alter functionality, have been utilized in

wheat dough to improve product characteristics.

(See Phospholipids: Properties and Occurrence.)

0025The wheat proteins, gliadin and glutenin, form a

viscous colloidal complex called ‘gluten’ when mixed

into a dough. The properties of the dough are influ-

enced by lipid emulsifiers. Emulsifiers interact with

starch to form a complex that slows down the staling

process. A blend of whey proteins, mono- and digly-

cerides, lactic acid fatty acid esters, and lecithin

will increase the spreadability, reduce stickiness,

increase creaminess, and contribute body to the

baked product. (See Wheat: Grain Structure of

Wheat and Wheat-based Products.)

0026A cake batter is a fat-in-water emulsion, where the

aqueous phase contains dissolved sugar and sus-

pended flour particles. In layer cakes, emulsifiers

aid in aeration, lubrication, and crumb texture.

tbl0002 Table 2 Functional properties of food emulsifiers

Functions Product examples

Starch complexer Marcaroni, pasta

Antispattering agent Margarines

Gloss enhancer Confectionery coatings

Emulsification, water-in-oil

emulsions

Margarine

Emulsification, oil-in-water

emulsions

Mayonnaise

Aeration Whipped toppings

Whippability Whipped toppings

Inhibition of fat crystallization Candy

Softening Candy

Antistaling Bread

Dough conditioner Bread dough

Improve loaf volume Bread

Reduce shortening

requirements

Bread

Pan release agent Yeast-leavened and other

dough and batter products

Fat stabilizer Food oils

Antispattering agent Margarine and frying oils

Antisticking agent Caramel candy

Protective coating Fresh fruits and vegetables

Surfactant Molasses

Control viscosity Molten chocolate

Improved solubility Instant drinks

Starch complexation Instant potatoes

Humectant Cake icings

Plasticizer Cake icings

Defoaming agent Sugar production

Stabilization of flavor oils Flavor emulsions

Promotion of ‘dryness’ Icecream

Freeze–thaw stability Whipped toppings

Improve wetting ability Instant soups

Inhibition of sugar

Crystallization Panned coatings

Adapted from Hasenhuettl GL (1997) Overview of food emulsifiers. In:

Hasenhuetti GL and Hartel R (eds) Food Emulsifiers and their Applications,

pp. 1–9. New York: Chapman and Hall and Artz WE (1990) Emulsifiers. In:

Branen AL, Davidson MP and Salminen S (eds) Food Additives, pp.

347–393. New York: Marcel Dekker.

2082 EMULSIFIERS/Uses in Processed Foods

Nonflour lipid additives such as polar lipids (surfac-

tants or emulsifiers) are commonly included in stand-

ard baking recipes today. Their effects on dough or

cake batter and on the final product include an im-

provement in texture and an extended shelf-life. The

disadvantages of using oil alone in bread include a

weak dough, dull crumb, and reduced loaf volume.

Emulsifiers can alter the solid fat index and the crystal

polymorphism of shortening.

0027 The deleterious effect of wheat bran on bread qual-

ity can be offset by the addition of emulsifiers and vital

wheat gluten. Lecithin (0.5%) is used in shortening,

but it is slightly less effective than 0.5% of ethoxylated

monoglycerides, sucrose monopalmitate, or diacetyl

tartaric esters for improving whole wheat bread.

0028 A mixture of hydrophilic and lipophilic emulsifiers

provides the best dispersibility for bakery products.

Diacetyl tartaric acid ester of monoglycerides, a

widely used emulsifier in Europe for bread products,

appears to act as a dough strengthener and a crumb

softener. It can also improve loaf volume and delay

staling, and it shows synergistic activity with mono-

glycerides for some functions.

0029 A family of starch–lipid composites, prepared by

passing aqueous mixtures of starch and lipid through

a steam jet cooker, offer flavor and texture advan-

tages when combined with food products, particu-

larly ground beef. The jet-cooked dispersions are

stable and do not phase-separate, even after pro-

longed standing. They can be drum-dried and milled

to yield dry powders that are not oily to the touch.

The lipid component is dispersed within the starch or

starch–water matrix as droplets, about 1–10 mmin

diameter. The products, trademarked as Fantesk

are a new type of starch–lipid composite prepared

by a continuous steam jet cooking process. (See

Bread: Breadmaking Processes.)

0030Flat bread products are consumed extensively in

the Middle East, North Africa, and the Indian sub-

continent. Like other bread products, the flat breads

will stale upon storage. The addition of sodium

stearoyl-2-lactylate and monoglycerides reduces the

degree of firmness upon storage of flat breads. The

addition of sucrose esters to chapaties, a flat bread

product, allows the substitution of 40% of the whole

wheat flour with nonglutenous flour (e.g., corn, sor-

ghum, millet, or soy) with only a slight loss in quality.

This would facilitate soy flour fortification of chapa-

ties to improve the nutritional quality of the product.

0031There is a wide range of baked products, other than

bread, with improved characteristics as a result of the

addition of emulsifiers. Emulsifiers can be used to

prevent, inhibit, or control starch gelation in maca-

roni, spaghetti, and snack foods, and maintain cooked

rice in a dry and nonsticky condition.

0032Cookie characteristics (volume, top grain, and

spreadability) can be improved by the addition of

the appropriate emulsifier. The interaction of emulsi-

fiers with starch alters the effect of heat on starch.

Puddings, for example, have an increased freeze–

thaw stability and increased resistance to retort

processing, whereas starch-based sauces have an

improved freeze–thaw stability and increased stabil-

ity during holding at high temperatures.

0033Sucrose esters of fatty acids are used as nonionic

food emulsifiers in nondairy based whipping cream

tbl0003 Table 3 Influence of emulsifiers on production and quality of baked products

Process Influence of emulsifier Advantages

Mixing . Improvement of wettability

. Stabilization of phases

. Better distribution of phases

. Interaction of emulsifier/lipid

. Interaction of emulsifier/starch surface

. Interaction-emulsifier/protein

. Decrease of mixing and speed

. Reduced shortening levels

. Improvement of mixing

. Greater shock tolerance

. Improvement of machinability

Fermentation . Interaction-emulsifier/protein . Improvement of gas-retaining properties

. Shorter fermentation

. Greater shock tolerance

Baking . Emulsifier–starch complex formation . Improvement of gas-retaining properties

. Improved loaf volume

. Better texture

. Better crumb grain

. Better uniformity

. Decreased water loss

Storage . Emulsifier–starch complex formation . Improvement of crumb softness and longer shelf-life

Modified from Orthoefer FT (1997) Applications of Emulsifiers in Baked Foods. In: Hasenhuetti GL and Hartel R (eds) Food Emulsifiers and their

Applications, pp. 211–234. New York: Chapman and Hall.

EMULSIFIERS/Uses in Processed Foods 2083

and dessert toppings, icecream, bread cakes and

sponge products, beverage whiteners, and pasta and

noodles.

0034 -Dairy products Milk is a complex food emulsion.

The emulsion component is composed of fat droplets

dispersed in an aqueous phase containing protein.

0035 Ice cream Icecream is both a foam and an emulsion,

containing ice crystals and an unfrozen aqueous phase

whose freezing point is depressed due to the presence

of salts, sugars, and polysaccharide stabilizers.

0036 Many emulsifiers used in icecream have a low HLB

value. A number of comparisons of the effects of

different emulsifiers in icecream have been made

and established that emulsifiers impart desirable

structural characteristics to icecream. The emulsifier

enables icecream to be extruded into shapes for wrap-

ping, or to retain its shape when it is filled into a cone

from a counter freezer. Monolaurate, monooleate,

and monostearate are effective in icecream emulsifi-

cation destabilization, which is also enhanced by the

addition of eggyolk solids and butter milk solids due

to their surface-active lipid content. The function of

emulsifiers in icecream may be summarized as:

0037 After homogenization, a minimum amount of

emulsifier is needed to prevent coalescence. The

emulsion is then stabilized by adsorbed milk

proteins.

0038 Emulsifiers reduce the amount of protein needed,

possibly through the involvement of a meso-

morphic phase at the interface.

0039 Saturated emulsifiers promote crystallization of

the emulsified fat.

0040 Emulsifiers promote the destabilization of the

emulsion during freezing.

0041 Emulsifiers are particularly useful with formed

specialty products, such as icecream sandwiches,

slices, and factory filled cones. Emulsifiers coat the

milk fat, increasing the ability of the protein film to

surround the air cells in the icecream. The results are

an improved whippability, smoother texture and

body, drier appearance, and slower melting rate.

The smoother texture is favored since both ice crystal

and air cell sizes are reduced. Two types of emulsi-

fiers are used: (1) mono- and diglycerides and (2)

polyoxethylene derivatives of sugar alcohol fatty

acid esters.

0042 The polyoxyethylene derivatives of the sorbitan

fatty acid esters are particularly effective in imparting

stiffness to icecream immediately upon leaving the

freezer. The emulsifiers are added not to stabilize the

mix, but to impart desirable end-product qualities.

Selection of a suitable emulsifier should be based

on HLB since optimum product characteristics are

dependent on the emulsifier HLB. The optimum

emulsifier HLB is 16. Icecream production has been

characterized as a deemulsification process due to a

combination of agitation, freezing, and the presence

of an emulsifier. Emulsifiers give the icecream the

dryness and stiffness required by agglomerating the

finely dispersed fat globules to properly. (See Dairy

Products – Nutritional Contribution.)

0043Other dairy products Cream liqueurs represent an

unusual type of dairy emulsion that requires long-

term stabilization of dispersed fat in an alcoholic

environment. Soluble sodium caseinate can be used

to stabilize an emulsion that shows finely dispersed

fat.

0044Flack found that mono- and diglycerides, citric acid

esters of monoglycerides, lactic acid esters of mono-

glycerides, and distilled monoglycerides affected the

whippability and foam stability of dairy whipping

cream that had been pasteurized and homogenized.

Lactic acid esters produced a stable foam with a high

overrun that was substantially different from a fresh

whipped cream, whereas a mixture of citric acid fatty

acid esters and distilled monoglycerides produced a

foam similar to that of fresh whipped cream. Blends

of xanthan gum, carageenan, and galactomannans

act as good stabilizers for frozen and chilled dairy

products, such as icecream, sherbet, sour cream, ster-

ile whipping cream, and recombined milk.

0045Processed cheese consists of fat droplets dispersed in

a concentrated protein gel network. The emulsion sta-

bility in the fat droplets is controlled primarily by

adsorbed caseins or hydrolyzed casein fractions.

Some manufacturers add mono- and diglycerols as

emulsifiers. To control the structure of processed

cheese, ‘emulsifying’ salts, such as polyphosphates,

are employed. Although these emulsifying salts are

not surface-active, they can play an important role

in modifying the activity of the surface-active casein.

Cheese yield can be increased with the addition of an

emulsifier, such as lecithin. Lecithin was added in

quantities of 0.001–0.066% by weight of milk. Stud-

ies have reported the use of coconut protein as an

emulsion stabilizer in cheese analogs. (See Cheeses:

Chemistry of Gel Formation.)

0046In concentrated milk products, emulsifiers can aid

in emulsion formation and stabilization. Some can

increase the heat stability of milks and milk proteins.

Usually, low-molecular-weight emulsifiers are util-

ized, particularly mono- and diglycerides. With cer-

tain butter products, phospholipids can be added as

antispattering agents to prevent fat spattering during

pan and grill frying.

2084 EMULSIFIERS/Uses in Processed Foods

0047 Confectionery The benefits of emulsifiers in both

chocolate and sugar confectionery products have

been well established. The most common example in

confectionery products is the use of lecithin in choc-

olate to reduce product viscosity and to facilitate

handling. Another emulsifier used in chocolate is

polyglycerol polyricinoleate, which is used to modify

the viscosity of chocolate coatings. (See Sweets and

Candies: Sugar Confectionery.)

0048 Sorbitan monostearate inhibits the migration of

fat retarding bloom and extends the shelf-life of

chocolate coatings. ‘Chocolate bloom’ may be de-

fined as the mottled discoloration of confectioners

coatings followed by a loss of the gloss. This defect

occurs when the coating starts to melt, and some of

the melting fat migrates to the surface. The cocoa

components that impart the color are left behind

inside the coating. Upon cooling, the melted frac-

tions resolidify on the surface to form lighter colored

blotches.

0049 Emulsifiers are often used with both semisweet

and milk chocolate. Emulsifiers aid in processing by

reducing the weep or exudate that occurs with heavy

sugar pastes during processing. For example, a

marshmallow-based frozen confectionery product is

prepared with 0.2–0.8% emulsifier with an HLB

between 3 and 9.

0050 Peanut butter contains about 50% peanut oil sus-

pended in peanut fibers. Upon standing, the oil can

separate from the peanut fibers, which impairs the

product’s appearance and palatability. Mono- and

diglycerides can be added to emulsify part of the oil

during processing, thereby preventing phase separ-

ation. Other benefits include an improved stability

and spreadability.

0051 Chewing gums contain fats and emulsifiers that

soften the gum base and act as carriers for color and

flavor. Lecithin is generally used for this purpose.

Emulsifiers (sucrose fatty acid esters, sorbitan fatty

acid esters, glycerol fatty acid esters, or propylene

glycol fatty acid esters) have been used to improve

the shelf stability of center-filled chewing gum. The

emulsifiers are added to the flavored liquid center at

0.01–0.5% by weight. Some emulsifiers, such as

the saturated ethoxylated monoglycerols, can be

adsorbed on to starch granules. This property can

be used to modify the texture of starch-based sugar

confectionery.

0052 Miscellaneous Liquid nondairy creamers (coffee

whiteners) are used in the beverage industry. The

nondairy whitener modified for use in a hot, acidic

environment (coffee) can be prepared by pasteurizing

and homogenizing a water-rich lipid emulsion con-

sisting of 6–15% edible fat, approximately 0.6–2%

mixed emulsifier (constituting approximately 0.3–

1% low-HLB mono- and diglycerides). These whiten-

ers are popular in dry powder form. Evaluation of

emulsion stability for liquid coffee whiteners has

revealed that if the emulsion is unstable, coagulation

can occur. However, with the addition of the correct

mixture of emulsifiers, optimum product characteris-

tics are maintained.

0053To improve the wetting characteristics in instant

cocoa drinks, the powder is agglomerated. Lecithin

facilitates agglomeration during spray drying. During

the spray drying process, the hydrophobic portion

of the emulsifier dissolves in the cocoa butter,

orienting the hydrophilic portion of the phospholipid

towards the surface of the particle. This results in an

increased affinity of the cocoa powder for water, thus

aiding dispersion and wetting.

0054Margarine exists as a water–oil emulsion for only a

short period of time prior to chilling, during which

time, the emulsion is converted to a dispersion of

water in a semisolid fat phase. Upon solidification,

the product stability is greatly enhanced, since coales-

cence is essentially eliminated. Emulsifiers fulfill three

functions in margarine: (1) assistance in emulsion for-

mation, (2) modification of the crystal structure in the

vegetable fat, and (3) antispattering during frying.

Typically, a mixture of lecithin or citric acid monogly-

cerides and monoglycerides is used. A stable emulsion

during frying reduces the coalescence of water droplets

to form large drops. This facilitates gradual water

evaporation, rather than explosive evolution or spat-

tering, during frying. An additional explanation may

be that the lecithin sludge formed during frying serves

as nuclei for the formation of small vapor bubbles.

0055To reduce sandiness and ‘oiling out’ in margarine

due to recrystallization, emulsifiers can be added.

Sorbitan monostearate and citric acid esters of mono-

glycerides are effective in preventing recrystallization

in tristearin. However, to be effective in margarine,

the emulsifier must be very soluble in the oil phase.

Other emulsifiers used include polysorbates and poly-

glyerol esters of fatty acids. To produce a low-calorie

imitation dairy product, emulsifiers are usually added

to the product. The caloric content can be signifi-

cantly reduced by replacement of part of the fat

with the appropriate emulsifier system. For low-fat

margarine containing approximately 40% fat, a mix-

ture of saturated and unsaturated monoglycerides

and lecithin has been used successfully. Similarly,

emulsifiers are used for partial fat replacement in

low-fat, butter-flavored, liquid spreads. The stability

of milk fat and water emulsions is dependent on the

amount of emulsifier added.

0056Mayonnaise is an oil–water emulsion containing a

high percentage of oil (> 70%). Owing to the high

EMULSIFIERS/Uses in Processed Foods 2085

percentage of fat, coalescence, rather than creaming,

is the primary problem. Different protein sources are

utilized because of their effectiveness in reducing

coalescence.

0057 The manufacturing procedure for mayonnaise is

critical since the product contains a very high percent-

age of oil. Lecithin, contained in the added eggyolk, is

usually the only emulsifier added. However, the vege-

table oil may contain emulsifiers added to inhibit

crystallization, e.g., ethoxylated sorbitan monooleate

and monostearate. To inhibit cloud formation in

salad dressings and salad oils, emulsifiers can also

be added. (See Dressings and Mayonnaise: The Prod-

ucts and Their Manufacture.)

0058 Emulsifiers can be used to produce emulsions that

can deliver flavor, color, and a dispersed lipid phase in

a cooked food product. Blending pork volatiles with

the appropriate emulsifier, such as the polyglycerol

ester of palmitic acid, and warming it will produce a

relatively stable, flavored emulsion. The product can

be used to replace part of the fat in a pork analog

product. The fat level of such a product is 50% that

of the regular pork product. In emulsion sausages, the

product properties are dependent on a meat–protein

matrix, a gel that gives the hot dog, for example, its

characteristic sensory properties. The meat proteins

are important in forming and stabilizing the emulsion.

See also: Bread: Breadmaking Processes; Cakes:

Methods of Manufacture; Cheeses: Processed Cheese;

Dressings and Mayonnaise: The Products and Their

Manufacture; Chemistry of the Products; Emulsifiers:

Organic Emulsifiers; Phosphates as Meat Emulsion

Stabilizers; Ice Cream: Methods of Manufacture;

Margarine: Methods of Manufacture; Sweets and

Candies: Sugar Confectionery; Whey and Whey

Powders: Production and Uses