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

Подождите немного. Документ загружается.

barley) as well as microparticulate proteins (Sim-

plesse is an example of such a product).

0008 Many of the fat mimetics create the same mouth

feel as fats by offering a viscous yet homogeneous

texture. For example, tapioca dextrin can be hy-

drated to form a gel which can be used to replace

< 50% oil in products like salad cream, providing

viscous smooth mouth feel reminiscent of fat.

0009 Fat may be diluted by the addition of air or water.

In the past cynics have criticized the food industry

for adding water to certain products (e.g., glaze on

frozen foods). In contrast, the addition of air to

whipped desserts, icecream, and mousses is often

seen as desirable, producing a lighter, fluffier

texture – this is despite the fact that these products

are normally sold on a volume basis!

0010 Food emulsions consist of two immiscible

phases – a high-energy oil phase and the lower-

energy aqueous phase. The stability of emulsions

may be controlled by increasing the viscosity of

the continuous phase. In the case of oil-in-water

emulsions, one often adds hydrocolloid stabilizing

agents to the aqueous continuous phase, thus

maintaining a high apparent viscosity. Since the

gelation of such emulsions depends largely on

the hydrocolloid concentration, one can effect-

ively reduce the fat content while maintaining the

texture. The texture of many hydrocolloids is

smooth and creamy, thus furthering the illusion,

without the energy from the fat.

0011Another approach is to produce a three-phase

water-in-oil-in-water emulsion in which oil drop-

lets within the aqueous phase are further thinned

out by a suspension of smaller water droplets

inside. Multiple emulsions are normally achieved

by two-stage homogenization. First, fine droplets

of water are dispersed in oil emulsion using a

lipophilic emulsifier. This primary emulsion is

then dispersed in an aqueous phase using low

concentrations of a hydrophilic emulsifier and a

relatively gentle homogenizer pressure.

0012A limited number of products may be produced in

the conventional way and subsequently have the

fat removed by solvent extraction to produce

reduced-fat foods. Solvent extraction has long

been used in the production of cooking oils by

extracting them from seed cake. One drawback

of solvent extraction is the potential loss of desir-

able fat-soluble flavor compounds; this is relevant,

as much of the flavor of volatiles in fried foods is

produced during frying.

0013Supercritical carbon dioxide has also been used

to produce low-fat foods by extraction of fractions

from conventional products such as potato crisps.

A solid food like a flaked almond, whose shape

and structure are defined, can have almost half the

Toffee

Sponge cake

Shortbread

Short pastry

Mozzarella cheese

Margarine

Icecream

Grilled sausage

Grilled beefburger

Fruit cake

Digestive biscuit

Chocolate mousse

Chocolate (plain)

Chocolate (milk)

Chicken nuggets

Cheddar cheese

5000 1000 1500 2000

Energy per 100 g (kJ)

2500 3000 3500

fig0001 Figure 1 Energy contribution from fat.

LOW-FAT FOODS/Types and Manufacture 3613

fat removed without any appreciable loss in shape.

The result is a lower-energy, lower-bulk-density

nut with a relatively high protein content.

Considerations when Reducing Fat

0014 To achieve successful reduction in the fat content of

foods one needs to understand the roles which it plays

during processing and subsequent storage, for

example, its effect on the rheological and thermal

properties of the food, its influence on the chemical

and physical stability during storage, and, most

importantly, its impact on sensory properties.

0015 It has been suggested that one deciding factor in the

enjoyment of fat is the smooth, creamy, homogeneous

viscous mouth feel. Fats tend to be plastic in behavior

and, when they melt, lubricating oils are produced.

This is the desirable characteristic of cocoa butter

with its unusually sharp melting point of 34



which happens to be just below internal temperature

of the mouth, hence cocoa butter in chocolate elicits

the sensation of melting away to a smooth creamy

texture in the mouth.

0016 The resolving power of the tongue and palate to

small particles is in the region of 3 mm. Particulate

materials with a diameter which is less than the re-

solving power of the tongue are therefore perceived as

smooth homogeneous materials and can be used to

mimic the smooth creamy mouth feel of fats. Micro-

particulate materials which have been used include

microcrystalline cellulose, milk, and egg proteins.

0017 Since fats are made up of mixtures of triglycerides,

each with its own melting point, fats exhibit varying

physical properties with temperature. When cold they

tend to be solid and hard; as the temperature rises

they soften as some of the triglycerides melt. Conse-

quently melting occurs over a broad temperature

range. Melting behavior is further complicated by

the ability of fats to crystallize into different poly-

morphic forms, each with its own structure and

melting point. For example, cocoa butter has six

polymorphic forms (denoted I–VI). Type V is the

most desirable, giving commercial chocolate its

characteristic appearance; however if the chocolate

melts during storage and then cools slowly, the more

stable type VI can form with its less attractive appear-

ance. The tempering step during chocolate manufac-

ture is intended to form the desired polymorph

preferentially.

0018 In bakery shortenings, the b

polymorph is reputed

to be necessary to whip air into batters. This stabiliza-

tion has been attributed to the lower level of crystal–

crystal interaction compared with the b polymorph;

this allows the b

polymorph to adsorb as a dense

layer at the interface, raising the interfacial viscosity.

0019Within emulsions, fats are of structural import-

ance, providing one of the bulk phases. A high viscos-

ity in the continuous phase helps to achieve emulsion

stability. In the case of water-in-oil emulsions fat

crystals present within the oil phase are found to

adsorb on to the interface of the aqueous droplets

and can help to stabilize the emulsion. Moreover as

the crystals grow they form a solid matrix around the

aqueous-phase droplets.

0020People sometimes ask ‘why do fried foods taste so

good?’ In addition to the residual frying fats on the

surface, with its lubricating properties, chemical

changes such as the Maillard reaction occur during

frying, which leads to the development of flavor,

brittle, crisp textures, and characteristic golden-

brown colors.

0021Many flavor volatiles are fat-soluble and may be

introduced to the food in fatty ingredients. Replacing

fats with substitutes or mimetics can significantly

reduce the overall flavor.

Technological and Sensory Aspects of

Selected Low-Fat Foods

Food Emulsions

0022Numerous food emulsions exist; the small size of

the dispersed-phase droplets gives rise to the desirable

sensation of creaminess. The high-calorie oil phase of

emulsion-based foods makes them prime candidates

for calorie replacement. Emulsion-based foods in-

clude margarine and butter substitutes, icecream,

mousses and frozen desserts, salad cream, sandwich

spread, and mayonnaise. Emulsions require stability

against phase separation and attempts to replace their

fat must take this into account. Emulsions also occur

as intermediate products in the manufacture of other

items, such as cakes, and emulsion stability during

processing is important for product success.

0023Frozen desserts such as icecream are often high-fat

products. A variety of fat replacers have been tried in

frozen milk systems; temperature is a key parameter

in terms of both product melting and ingredient solu-

bility. It has been shown that carbohydrate-based fat

mimickers are not able to achieve the high overruns

found in conventional icecreams; moreover their con-

sistency adversely affects the sensory properties of the

products (making them coarser, more watery, and less

creamy).

0024Intensity of flavor volatiles is reduced at low tem-

peratures and clearly oil-soluble flavors are affected

by replacing fat with microparticulate or hydrocol-

loid-based substitutes. Changes in flavor intensity

become more apparent with storage and compensa-

tion in the product formulation is necessary.

3614 LOW-FAT FOODS/Types and Manufacture

0025 Low-fat alternatives for butter are a burgeoning

market. Several approaches have been taken in creat-

ing these products, for example, the formation of

multiple-phase emulsions which dilute the dispersed

fat droplets by filling them with smaller droplets of

water. Another approach has been the incorporation

of fat replacers into the formulation.

0026 Melting of characteristics of low-fat spreads is im-

portant in producing the right mouth feel. Some

starch-based low-fat spreads have long melting pro-

files on heating, which contrast with the melt-in-the

mouth behavior of butter. Another important charac-

teristic is rheological behavior. Spreads should behave

as plastic solids, that is to say, they must resist

small stresses and then start to flow when a small

yield stress has been applied.

0027 When dealing with products that contain raw egg,

the protective effects of hydrocolloids must be con-

sidered if pathogens are to be destroyed during

pasteurization. Such effects are well documented

and rates of destruction of pathogens have been stud-

ied. It has been found that the destruction of Listeria

monocytogenes is directly correlated with aqueous-

phase concentration, thus reduced-calorie mayon-

naise dressings offer greater protection than

traditional mayonnaise.

Dairy Products

0028 Though its composition changes with season, breed,

and feed, the fat content of bovine milk is in the

region of 4%. Removing the fat results in a change

in the viscosity and color. Moreover the appearance

markedly affects the perceived thickness and residual

mouth coating of the milks. Attempts to enhance the

color of skimmed milk have included the addition of

whiteners such as titanium dioxide.

0029 Low-fat, lite or light cheeses have had their fat

content reduced by 50%, while reduced-fat cheeses

have a fat content which is at least 25% less than the

original reference fat content. Reduced-fat cheeses

have been produced since the mid-1950s, though,

as with other low-calorie products, demand has in-

creased in recent years. Most of the work on fat

replacement in cheese has tended to focus on a small

number of cheeses, notably cheddar and mozzarella.

Two basic approaches have been taken to achieve

low-fat cheese and these are based on either modifi-

cations to the manufacturing procedure or the incorp-

oration of fat replacers.

0030 As far as modifying the manufacturing is con-

cerned, increasing the moisture content can provide

some of the creamy mouth feel offered by fat. Water

content of the final cheese can be increased in a

variety of procedures such as lowering the cook tem-

perature, shortening the cook time, or curd washing.

Flavor of low-fat cheese can be a problem. Rapid

growth of the starter culture can lead to accelerated

acid production which results in bitter flavors. It is

better to have a small inoculum of starter culture to

limit acid production and possibly to incorporate

adjunct cultures which produce specific flavor com-

pounds through increased proteolysis. Some adjunct

cultures are deliberately attenuated by heat treatment

to achieve particular flavor nuances. Commonly used

adjunct cultures include Lactobacillus spp. and the

growth of conditions in cheddar cheese requires a salt

concentration of 1.8%. Considering that the market

for low-fat cheese is likely to be a health-conscious

one, concern about salt concentrations have promp-

ted product development of low-fat, low-salt cheese

replacing salt with potassium chloride.

0031A variety of fat replacers, including sucrose polyes-

ters, microparticulate proteins, and hydrocolloid

products, such as pectin or gelatin, have been used

to produce low-fat cheeses. While fat substitutes suc-

cessfully produce a similar mouth feel to full-fat

cheese, they do not necessarily provide the flavor

characteristics of the traditional product and some

recipe compensation may be required. In practice,

combining the two approaches of modifying the

manufacturing process and incorporating fat re-

placers may give products of optimum quality. (See

Cheeses: Types of Cheese.)

0032The essential properties of a cheese have to reflect

the use to which it is being made, for example, when

it is an ingredient used as a pizza topping, its melt-

ability and rheological properties are fundamental.

Microparticulate fat replacers interact with the casein

from the milk, becoming embedded in the curd and

forming links between adjacent bits of curd. Rela-

tively large microparticulate fat replacers therefore

create wide serum channels and a high degree of

openness in the cheese. When melted, fat-replaced

cheeses have a similar viscosity to conventional

cheese.

0033Milk fat is often used as a food ingredient and

consequently when fat replacement is an issue, the

melting characteristics and consistency at different

temperatures become important. If sucrose polyesters

are used to replace milk fat in foods, then care must

be exercised in the choice of the fatty acid esters used,

as the chain length affects the hardness and melting

characteristics. (See Milk: Physical and Chemical

Properties.)

Reformed Meat Products

0034The main approach in fat reduction within meat

products is to increase the water-holding capacity of

the meat. A certain amount of water is lost from

meats as a result of postmortem drip; further losses

LOW-FAT FOODS/Types and Manufacture 3615

can occur if the meat is cured because the curing salts

draw water and soluble proteins out of the flesh by

osmosis. With the advent of mechanization in food

processing, attempts were made to speed the curing

process and to limit the amount of water lost during

curing. One solution is to incorporate water-binding

salts, such as phosphates, into the brining solution.

A similar approach has been taken in enhancing

the water-holding capacity of reformed meat prod-

ucts, by adding phosphates. In the case of frankfurt-

ers, the addition of acid phosphate allows the

incorporation of more connective tissue into

the meat emulsion, thus adding to the value of the

product and further diluting the fat content. The

arguments for using phosphates in restructured meat

products is not just one of economy, for, in addition to

the ability to reduce the proportion of fat, added

phosphates and water improve on some of the tex-

tural characteristics such as juiciness, tenderness, and

overall palatability in meat patties.

0035 Water binding of restructured meats has also been

achieved by incorporating grain or bean flours,

starches, as well as purified hydrocolloid gums like

carrageenans or cellulose esters. These materials bind

water but tend to modify the texture of the product.

By way of reiterating the need to reflect on the desired

product characteristics when selecting a fat replacer,

consider the use of l-carrageenan which has been

investigated as a water-binding agent in a variety of

low-fat meat products such as beef patties, restruc-

tured pork nuggets, and bologna sausage. This gum

appears to soften products such that beef patties are

juicier and more tender, but a firm product like bol-

ogna is also softer than the normal high-fat version.

0036 Addition of low-fat protein extenders can also

serve as a means of reducing the relative fat content

of comminuted meat products. Lean meats such as

goat can be incorporated into patties replacing 60%

of the beef without consumers detecting any differ-

ence. Other extenders which have been used to extend

the protein and lower the fat include connective tissue

and soya flour.

Flour Confectionery

0037 Butter has traditionally been used as the fat in most

flour confectionery. Industrialization brought with

it butter substitutes such as shortenings which, unlike

butter, are not emulsions and contain little water.

Butter, margarines, and shortenings are used in

many bakery products such as cakes, cookies,

crackers, and pastries. It has been observed that the

addition of certain surfactants to biscuit dough and

cake batters can help to maintain the texture of

reduced-fat biscuits. Many commercial bakery short-

enings actually have high levels of emulsifier.

(See Emulsifiers: Phosphates as Meat Emulsion

Stabilizers.)

0038In puff pastry the fat is laminated into the dough

and forms an impervious layer which traps steam

during subsequent baking, resulting in the formation

of a light flaky characteristic texture. Various ap-

proaches have been taken to reduce the calorie con-

tent of the laminating material. Carbohydrate-based

fat replacers are unsuitable as their hydrophilic

properties prevent them from being able to form an

impervious layer which means that steam is not

trapped during baking. Instead it is necessary to use

an oil-soluble, restructured lipid to form a water-in-

soluble barrier.

0039A variety of sweet biscuits and cookies have been

the subject of fat replacement. A simple removal of fat

without the addition of any substitute leads to a hard

biscuit, with a reduction in spread during baking and

a pale appearance. The incorporation of emulsifiers

helps to soften the dough, enabling some spread

during baking and resulting in a softer biscuit. Since

reducing the fat content of biscuits generally makes a

harder product, it might be assumed that reducing the

fat of soft dough-type cookies is more difficult to

achieve. Oat fiber may be used to replace 30% of

the fat in soft-type cookies. The increased water con-

tent required to handle the dough insures a reduction

in calories by one-third and also assists them to rise

during baking. Care has to be exercised to avoid large

particles of oat fiber which might result in a gritty

mouth feel.

0040High levels of fat replacement in biscuits using

microparticulates can lead to an increased mouth

coating, a reduction in the fracturability and sensory

firmness, as well as a reduction in the flavors. Being

water-based, carbohydrate fat replacers lead to an

increase in the moisture content which in turn results

in denser and tougher biscuit. Overall it can be seen

that studies on the replacement of fat in biscuits have

not been altogether successful; only limited reduc-

tions in the fat content have been achieved and re-

placement tends to result in artifacts compared to the

conventional product.

0041In cake batters the fat has several functions: it acts

as a vehicle for some of the oil-soluble volatile flavor

compounds; it traps air during mixing, and then

during baking it becomes integrated into the protein

matrix, adding to the tenderness of the final crumb.

Complete substitution of fat in high-ratio cakes has

been achieved using a variety of hydrocolloid-based

fat replacers; however this is accompanied by a re-

duction in batter overrun, leading to a reduced baked

volume.

0042Bakery fillings and coating mixtures are conven-

tionally based on a fatty formulation. Usually such

3616 LOW-FAT FOODS/Types and Manufacture

materials have a continuous phase of fat into which

sugar, milk solids, and cocoa are dispersed. When the

coating is in the mouth, the fat melts, releasing

the flavors and the characteristic creamy mouth feel.

If the continuous phase is replaced with a water-

soluble hydrocolloid, such as microcrystalline cellu-

lose, then the sugar present forms a concentrated

solution which may be pumped to the enrobing ma-

chines in the factory. When the mixture is cooled the

sucrose solution becomes saturated, the solids present

dominate, and the mixture sets. The higher tempera-

ture in the mouth causes the coating to liquefy, releas-

ing the flavor and the same characteristic creamy

mouth feel of a fat.

Frying Oils and Batters

0043 The high-fat content, yet desirable characteristic

flavors and textures of fried foods, make them

important targets for fat replacement. The high

temperatures involved in frying make most of

the hydrocolloid-based and microparticulate fat

mimetics unsuitable for the operation. High-boiling,

noncalorific fat replacers such as sorbitol esters or

polyorganosiloxanes may be used as alternatives to

frying oils.

0044 A different approach to reducing fat uptake during

deep-fat frying is the incorporation of materials

which provide barrier properties to the batter or

breaded layers of the food. For example, an edible

film of hydroxypropyl methylcellulose can reduce the

fat uptake of chicken pieces by one-third.

0045 Fried food analogs such as ‘oven-ready’ foods often

have coatings or batter mixtures which contain fats

with the intention that during cooking they yield

some of the flavors and textures of their fried coun-

terparts.

0046 Some low-fat fried snack foods are produced in the

conventional way and then the fat is extracted using

supercritical carbon dioxide.

Conclusions

0047 The promise of low-fat foods has enticed our society

and captivated food technologists. Simple reduction

in the fatty ingredients can result in a change in the

sensory and functional properties of the food. Three

approaches to reducing fat have been taken: (1) sub-

stitution of the fat with one or more functional ingre-

dients; (2) dilution of the fat with water or air; and (3)

extraction of the high-calorie constituents after con-

ventional manufacture.

See also: Colloids and Emulsions; Meat: Sausages and

Comminuted Products; Sensory Evaluation: Texture;

Sweets and Candies: Sugar Confectionery

Further Reading

de Bruijne DW and Bot A (1999) Fabricated fat based foods.

In: Rosenthal AJ (ed.) Food Texture: Measurement

and Perception, Gaithersburg: Aspen Publishers. pp.

185–227.

Rosenthal AJ (1998) Technological factors in the develop-

ment of low-calorie foods. In: Henry CJK and Heppell

NJ (eds) Nutritional Implications of New Food

Ingredients and Processes, Gaithersburg: Aspen Pub-

lishers. pp. 24–44.

Low-fat Spreads

J Dosta

lova

, Institute of Chemical Technology,

Prague, Czech Republic

Introduction

0001It is now generally recognized that a high-calorie diet

with inadequate physical activity results in over-

weight or obesity, which in turn could lead to diseases

such as noninsulin-dependent diabetes, hypertension,

cardiovascular diseases, endometrial cancer, and gall-

stones. The apparent connection between diet and

health has increased awareness for ‘healthier’ eating;

the reduced-fat diet is especially in vogue. This trend

is reflected, in particular in the USA and in Europe, in

the increased market for low-fat products, including

low-fat spreads. Most of the market surveys carried

out in recent years indicate that the demand for

‘healthier’ food will increase, but not at the cost of

sensory quality and at too high a price. The sensory

characteristics (flavor, taste, color, and texture) of

low-calorie products have to be comparable with

those of traditional products. These requirements

present the industry with a challenge and an oppor-

tunity to develop new technologies and new and

novel additives and food ingredients. A great deal of

these targets were realized with the development of

low-fat and very-low-fat spreads or fat-free spread

products.

Brief History

0002Margarine, which was developed in France in 1869,

must contain a minimum of 80% fat. Health concerns

have led to the development of many low-fat spread

products, which have lower energy content. Some

interesting data from the history of margarine with

lower fat content are as follows:

LOW-FAT FOODS/Low-fat Spreads 3617

.0003 Diet margarine, containing half the calories of

regular margarine, was introduced in 1964 in the

USA. The US Food and Drug Administration

(FDA) questioned the legality of the product

but lost an ensuing court case, which confirmed

diet margarine as a table-spread product. (See

Margarine: Types and Properties; Methods of

Manufacture.)

0004 A product containing 60% fat was introduced in

1975 that could not be identified as either

margarine, as it did not contain 80% fat, or diet

margarine, which must contain 40% fat or half

the calories of a regular margarine.

0005 In 1981 margarine butter blends containing as

much as 40% to as little as 5% butter were intro-

duced by several margarine and butter processors.

Some were in the low-fat form. These premium

products, priced between butter and margarine,

had a more characteristic butter flavor, but im-

proved spreadability and the health benefits of

margarine.

0006 Lower-fat-content spreads of less than 20% fat

were introduced in 1989.

0007 In the 1990s, low-fat spreads containing plant

sterols which decrease cholesterol level in human

blood serum were developed.

0008 Spreads, which ranged from zero to 68% fat, and

were free of trans fatty acids, were introduced

in 1997. (See Emulsifiers: Organic Emulsifiers;

Phosphates as Meat Emulsion Stabilizers; Fatty

Acids: Properties.)

0009 Statistical data in the western countries identify the

shift in consumer table-spread popularity to low-fat

spreads. The spread market share increased, for

example, in the USA from less than 5% in 1976 to

more than 74% in 1995. In the European Union, 75–

80% of commercial spreads in 1985 contained 80%

fat. By 1993, 75–80% of spreads marketed contained

40% fat.

Description, Terminology, and

Classification

0010 The food category referred to as table spreads con-

sists of several types of products, including butter and

margarine. Commercial table spreads now exist that

contain fat levels ranging from a high of 80% all the

way down to 0%. The standards in most countries

require that butter and margarine contain not less

than 80% by weight of fat. Products resembling mar-

garine containing less than 80% fat are usually called

spreads. After regulations in some countries, only

products containing less than 80%, but more than

40%, fat, 40–70% fat, 62–80% or less than 75%

fat are labeled as spreads. Products with 60–80%

fat or with 41–60% are reduced-fat spreads, and pro-

ducts containing less than 40% fat are referred to as

low-fat spreads. The term very-low-fat spread is used

for spreads of 5–15% fat and even less. The spreads

with extremely low fat content are sometimes called

ultra-low-fat products.

0011The terminology and classification are not unified

and they are laid down by national legislation in

accordance with the needs of each individual country.

Therefore different terms can be found for low-fat

spreads, e.g., halvarine, minarine, half-fat margarine,

margarine 40, margarine with low fat content, light

or lite margarines, etc.

0012The sixth edition of the Dictionary of Nutrition

and Food Industry defines halvarine as ‘a name some-

times given to low-fat spreads with less than the

statutory amount of fat in a margarine.’ The same

definition is used for minarine in this encyclopedia.

0013Codex Alimentarius defines minarine as follows:

‘minarine is a food in the form of spreadable emul-

sion, which is mainly of the type water/oil, produced

principally from water and edible fats and oils which

are not solely derived from milk, and in which the fat

content is not less than 39% m/m and not more than

41% m/m.’

0014The term ‘halvarine’ is sometimes used for a prod-

uct with the same fat content as minarine, defined

by Codex Alimentarius, i.e., a fat product with fat

content of not less than 39% m/m and not more than

41% m/m.

0015The above-mentioned definitions for minarine

and halvarine are more precise than the definitions

used in the Dictionary of Nutrition and Food

Industry.

0016It is possible to find other terms for low-fat spreads

with a fat content of not less than 39% m/m and not

more than 41% m/m in national legislations as well.

For example, half-fat margarine in Germany and

Austria, margarine 40 in Denmark, margarine with

low-fat content in the Czech Republic.

0017Fat products with a fat content less than 39% m/m

and more than 41% m/m but less than 80% m/m are

called spread fat x% m/m in the above-mentioned

national legislation, with the exception of products

with a fat content not less than 60% m/m and not

more 62%. Those products are called three-quarter-

fat margarines in Germany and Austria, margarine

60 in Denmark, margarine with reduced fat content

in Czech Republic, and elsewhere mellarines.

0018In some literature and legislative sources, products

with 40% fat or less are identified as ‘light’ or ‘lite’

margarines. The ‘light’ product must contain no more

than one-half the fat and one-half the energy of the

reference product.

3618 LOW-FAT FOODS/Low-fat Spreads

0019 There are no published regulations for some types

of low-fat spreads in some countries but labels on

such products must list the total percentages of fat,

and in some countries, sources of fats in weight order

as well.

0020 Products based only on all-vegetable oil and fats

blends are mostly defined as low-fat spreads. From

the nutritional and culinary points of view, spreads

with low fat content based on milk fat (milk-fat prod-

uct) or blends of vegetable oils and fats with milk fat

(mixed-fat products) are also considered to be low-fat

spreads. The terminology of these products is analo-

gous to that of vegetable low-fat spreads. Half-fat

butter or half-fat blend are terms for products with a

fat content of not less than 39% m/m and not more

than 41% m/m. Fat products with a fat content less

than 39% m/m and more than 41% m/m but less than

80% m/m are called dairy spread fat x%m/mor

blended spread fat x% m/m, with the exception of

products with fat content not less than 60% m/m and

not more than 62%. These products are called three-

quarter-fat butter or three-quarter-fat-blend. The terms

low-fat butter (blend) or ‘light’ butter are used as well.

0021 Low-fat mayonnaise with a thick texture can serve

as fat spread on bread or biscuits as well. Hence, we

can also rank low-fat mayonnaise (fat content can be

less than 30%) among low-fat spreads. The compos-

ition of an oil phase of low-fat mayonnaise resembles

the oil phase of low-fat spreads, but low-fat mayon-

naise differs significantly from low-fat spreads in that

it is an ‘oil-in-water’ emulsion. Various food ingredi-

ents (vegetables, spices, etc.) are often added to those

products.

0022 Classification systems used for global national stat-

istical purposes do not differentiate spreads according

to their fat content in most cases. For example, the

list of the industrial production Prodcom (product

of the European Community), which is obligatory

in the states of the European Union, only differenti-

ates the group ‘spreads with reduced or low content

of fat (less than 80% fat).’

0023 The Procome (Eurostat (Statistical Office of the

European Communities) version) used for household

budget survey data only groups together ‘margarine

and other vegetable fats.’ The new classification system

Eurocode 2 was proposed, therefore, by the Cost

Action 99 project. This system classifies spreads as

follows:

0024 fat spread > 65% fat, > 25% saturated fatty acids

0025 fat spread > 65% fat, < 25% saturated fatty acids

0026 fat spread 45–65% fat, > 25% saturated fatty acids

0027 fat spread 45–65% fat, > 25% saturated fatty acids

0028 fat spread 30–45% fat

0029 fat spread < 30% fat

Formulation and Processing

0030Low-fat spreads designed for spreading on bread and

biscuits from a refrigerated store are now typically

based on all-vegetable-oil blends in the form of water-

in-oil emulsions. In the margarine, fat or oil is the

continuous phase and the majority phase; water is

the discontinuous phase and the minority phase of

the emulsion. In low-fat spreads the oil-continuous

phase is still a major factor (in ultra-low-fat products

water is the continuous phase). The oil phase must

still have a structure which is determined by the size,

shape, and arrangement of fat crystals. This network

of crystals determines the distribution of melt point

types and provides the form and texture of the fin-

ished spread. The amount of these crystals, expressed

as the solid fat index or solid fat content, is important.

In addition to the amount of solid fat, the crystalline

form is also very important.

0031Two considerations – formation and stability of the

emulsion, and the structure of the aqueous phase –

take on greater importance in low-fat spreads in

comparison with full-fat products.

0032The formation of an emulsion requires the presence

of surface-active agents (called emulsifiers or surfac-

tants) to facilitate the formation of the dispersion of

one immiscible liquid (water) into another (oil). The

emulsifier reduces the interfacial tension between

the aqueous phase and the oil phase, and stabilizes

the spread during its storage by preventing the aque-

ous phase from coalescing. The stabilization of emul-

sion becomes more important as the percentage of

fat phase is lowered and the percentage of the aque-

ous phase is increased. Therefore, low-fat spread

should contain larger amounts or more efficient

emulsifiers. Water is still the dispersed phase of the

emulsion but becomes the majority phase of the emul-

sion. The volume of water fraction is much larger and

can create a far greater degree of instability in low-fat

spreads.

0033Structuring of the aqueous phase is the second

focus to obtain long-term shelf stability. Low-fat

spreads can be stabilized in the following ways:

0034Adding bulk ingredients (e.g., maltodextrin) to

take up or hold the increased level of added water.

Some of these ingredients may also increase the

viscosity and thickness of the aqueous phase and

contribute to better sensory quality similar to that

of ‘full-fat’ products.

0035Using various gelling agents which reduce synere-

sis, such as alginate, pectin, carrageenan, starch,

whey protein, soy protein, casein, and gelatin.

0036Adding gelled microparticles which have a spher-

ical or globular shape which act as fat mimetics.

LOW-FAT FOODS/Low-fat Spreads 3619

0037 Very-low-fat spreads are water-continuous systems

(oil-in-water emulsions). It is not difficult to disperse

oil in water but it is difficult to provide a good sensory

quality of a spread, comparable with that of full-fat

products. Several systems have been developed for

this purpose, mostly on the basis of proteins, polysac-

charides, or blends of them.

0038 The composition of the fat phase in low-fat spreads

is very important. Low-fat spreads are usually formu-

lated from the same fat and oil blends as those used

for regular margarines, but certain basic features

must be considered in terms of the solid fat content.

The solid fat index profile determines spreadability,

defines how the fat blend melts in the mouth, and

determines the thickness on the palate, and speed of

flavor release. Processors modify and blend oils in

order to achieve optimal characteristics. It is now

becoming increasingly appropriate to define oil blends

for spreads by their triacylglycerol types. Nutritional

aspects as well as shelf-life must be considered.

0039 There are varieties of blends used, adjusted

according to the fat level and sensory and nutritional

characteristic targets. Selectively and nonselectively

hydrogenated oils, interesterifed fractions, vegetable

fats, or their selected fractions and blends are utilized

as hardstock.

0040 Milk fat is also used in some products. Margarine

products usually contain milk fat maximum 3% of

total fat and mixed-fat products minimum 15%,

maximum 80% of total fat. Restrictions with respect

to the proportion of milk fat to other types of fat may

be imposed in accordance with national or other

relevant legislations.

0041 The use of other ingredients in low-fat spreads

differs form their use in full-fat products in the

following points:

0042 Most spread formulations are milk- and milk pro-

tein-free, because milk protein acts as an oil-water

emulsifier and consequently, the use of milk,

casein, or caseinates can result in a phase reversion.

0043 Emulsifier levels are increased to improve physical

characteristics of the emulsion and its stability.

0044 Lecithin may decrease the emulsion stability and

increase the tendency to oil off. However, it also

functions to slow down emulsion breakdown in the

mouth. Therefore, the use of lecithin and its level

must be evaluated for each formulation.

0045 Hydrocolloids, such as gelatin, pectin, carragee-

nans, agar, xanthan gum, starch, alginates, or

methyl cellulose derivatives, are used in some

spreads as thickening agents to improve the body.

0046 Flavor content and types must be defined to pro-

duce oral response similar to full-fat products be-

cause the higher emulsifier levels used for spreads

can produce tighter emulsions, and gelling or

thickening agents can affect the rate and how flavor

is perceived.

0047Preservatives are more important in spreads than

in regular margarines because of higher moisture

content.

0048The light reflection of a spread is different from

that of a regular margarine because of the increased

number of water droplets present. Therefore, it is

necessary to add about twice the amount of color

used in normal margarine to obtain the same color

intensity in low-fat products.

During processing of low-fat spreads the preparation

of an emulsion becomes of greater importance.

Chilling and crystallization may be similar to those

used for margarine.

0049Finished low-fat products have to meet all sensory

requirements as for full-fat products – clean and full

taste and smell, uniform and sheen color, even and

smooth surface and pleasing melt in the mouth.

Spreadability from the refrigerator and at room

temperature must be good, without syneresis and

separation.

Composition

Essential Composition of Minarine according to

Codex Standard

. 0050Raw materials: water and/or milk and/or milk

products; edible fats and/or oils, or a mixture of

these, whether or not they have been subjected to

a process of modification.

0051Fat content: not less than 39% m/m and not more

than 41% m/m.

0052Water content: not less than 50%, as determined by

loss on drying.

0053Optional ingredients: the following substances may

be added: vitamins (vitamin A and its esters, vita-

min D, vitamin E and its esters, other vitamins), egg

yolk, sodium chloride, sugars, suitable edible pro-

teins, gelatin, natural starches.

Food Additives for Minarine According to Codex

Standard

. 0054Colors: the following colors are permitted: beta-

carotene, annatto extracts, curcumin or turmeric,

beta-apo-8

-carotenal, methyl and ethyl esters of

beta-apo-8

carotenoic acid.

0055Flavors: natural flavors and their identical syn-

thetic equivalents, except those which are known

to represent a toxic hazard, and other synthetic

flavors approved by the Codex Alimentarius Com-

mission are permitted.

3620 LOW-FAT FOODS/Low-fat Spreads

.0056 Antioxidants: propyl gallate, butylated hydroxy-

toluene (BHT), butylated hydroxyanisole (BHA),

tertiary butyl hydroquinone (TBHQ), any com-

bination of propyl gallate, BHA, BHT and/or

TBHQ, natural and synthetic tocopherols,

ascorbyl palmitate, ascorbyl stearate, dilauryl

thiodipropionate.

0057 Antioxidant synergists: citric acid, sodium citrate.

0058 Thickening/stabilizing agents: agar, ammonium

alginate, carboxy methyl cellulose, carrageenan

(including furcelleran), guar gum, methyl cellulose,

pectin (amidated and nonamidated), alginate (K,

Ca, Na salts), locust bean gum, propylene glycol

alginate, sodium carboxy methyl cellulose,

xanthan gum.

0059 Emulsifiers: lecithin, mono- and diacylglycerols,

polyglycerol esters of interesterified ricinoleic

acid, polyglycerol esters of fatty acids, polyoxy-

ethylene (20) sorbitan mono-oleate, monopalmi-

tate, monostearate, tristearate.

0060 Preservatives: sorbic acid and its sodium, potas-

sium and calcium salts, benzoic acid and its

potassium and sodium salts.

0061 pH-correcting agents: lactic acid and its sodium and

potassium salts, citric acid and its sodium salt,

sodium hydroxide, sodium carbonate, sodium

phosphate, sodium tartrate.

The composition of fatty acids in the product depends

on the type and ratio of oils and fats used. Table 1

presents the fatty acid composition of 10 low-fat

spreads produced in Europe and the USA. From

a nutritional point of view, the composition of indi-

vidual low-fat spreads does not differ too much. All

low-fat spreads have a relatively high content of

unsaturated fatty acids.

Dietary Importance and Use

0062Nutrition value, including energy value, of low-fat

spreads is in good agreement with health authority

recommendations for the populations of developed

industrial countries to reduce their intake of energy,

total fat, saturated fat, and cholesterol. The amount

of energy in low-fat spreads containing 40% fat is

reduced to 50% in comparison with classical margar-

ine or butter. Average daily intake of fat spread used

for spreading on bread or biscuits is 20–25 g, and this

represents 16–20 g fat in the case of classical margar-

ine. The same amount of low-fat spread represents

only 8–10 g fat. The reduced intake of fat (about 15%

average recommended daily fat intake) is not negli-

gible. As has been discussed elsewhere, the decrease

of fat in low-fat spreads is partially compensated by

an increase in the consumption of complex carbohy-

drates. Hence, the total energy intake is not much

lower but nutrition balance is better because fat

intake is lower and complex carbohydrate intake is

increased. Low-fat spreads help consumers to meet

their needs in terms of low intake of saturated fat and

high intake of polyunsaturated fatty acids.

0063Research over recent years has shown that trans

fatty acids have adverse affects on health with regard

to coronary heart disease, and therefore companies

are now offering some low-fat spreads free of trans

fatty acids.

0064Low-fat spreads are free of cholesterol (except trace

amounts, which are insignificant from a nutritional

point of view). In contrast, they contain serum choles-

terol-lowering plant sterols (phytosterols) and there-

fore they have a significant role in decreasing the risk

of heart disease. Clinical studies indicate that an intake

of 2–3gday

1

of these plant sterols or stanols reduces

serum cholesterol level. Therefore plant sterol-enriched

margarines or low-fat spreads have been developed.

These contain 8 g plant sterols or stanols per 100 g, so

that 25 g of margarine or low-fat spread ensures a

recommended daily intake of 2–3 g plant sterols. This

dose will reduce total cholesterol by around 10% and

low-density lipoprotein-cholesterol by 10–15%, with

minimal change in high-density lipoprotein-cholesterol

and triacylglycerols. (See Cholesterol: Properties and

Determination; Absorption Function, and Metabol-

ism; Factors Determining Blood Cholesterol Levels.)

0065Low-fat spreads are formulated to supply amounts

of fat-soluble vitamins (A, D, E) which are similar to

or higher than those supplied by butter, and absorp-

tion is unlikely to be impaired. Low-fat spreads might

thus be viewed positively as a vehicle for lipophilic

nutrients without excessive lipid, and can contribute

to fulfillment of the recommended daily intake of A,

D and E vitamins.

tbl0001 Table 1 Contents of saturated, monosaturated, and poly

un-saturated fatty acids in 10 low-fat spreads (40% fat)

produced in Europe and the USA (% of total fatty acids)

Spread Saturated

fatty acids

Monounsaturated

fatty acids

Polyunsaturated

fatty acids

1 30.4 43.3 26.3

2 21.3 36.4 42.3

3 32.7 22.3 45.0

4 32.3 23.6 44.1

5 17.2 39.0 43.8

6 19.5 49.7 30.8

7 22.4 38.4 39.2

8 27.3 38.1 34.6

9 17.6 45.1 37.3

10 20.7 42.2 37.1

1–4, low-fat spreads produced in Europe (Czech Nutrient Database).

5–10, low-fat spreads produced in the USA (USDA Nutrient Database for

Standard Reference).

LOW-FAT FOODS/Low-fat Spreads 3621

0066 Low-fat spreads are intended solely as spreads on

bread or biscuits. They should not used for cooking or

baking and definitely not for frying, on account of

their high water content and in some cases (low-fat

butter, low-fat blends) of their high protein content.

Safety

0067 The safety of low-fat spreads is assured by special

regulations. The use of raw material, optional ingre-

dients, and food additives are regulated by national

standards. Contents of contaminants are regulated as

well. The products have to be prepared in accordance

with the general principles of food hygiene. A safety

issue, which is not commonly discussed in relation

to light products, is that relating to microbiological

stability and hazard. Where traditional foods are re-

placed by light foods with a higher water activity, the

consumer may not recognize that they must be stored

differently from traditional foods unless they contain

preservatives. In traditional butter and margarine,

salt is present not only for sensory reasons. The

amount of 2% salt in whole butter is equivalent to

13–14% in the aqueous phase and exerts a significant

preservative effect. Low-fat substitutes of butter with

a higher water content are not preserved in this way

and should be stored in a refrigerator. Instructions on

special storage requirements need to be displayed

prominently on the label so that the risks of spoilage

and pathogenic mold growth are avoided.

0068 Low-fat spreads are generally filled in plastic tubs,

which are designed not only to give mechanical pro-

tection but also to protect the product from light and

oxygen. Evaporation of water from the surface,

which leads to an unsightly dark-yellow coloration,

is prevented by use of a sealed aluminum foil.

0069 Nutritional demands have led to the manufacture

of blends containing a high content of polyunsatur-

ated fatty acids. These products are more susceptible

to oxidative deterioration and damage of texture, and

therefore require storage and transport at low tem-

peratures, preferably at less than 5



C; these condi-

tions reduce the risk of oiling out, and maintain flavor

and textural qualities. Oxidative changes may be

diminished by the use of antioxidants.

Conclusions

0070Low-fat spreads belong to progressive food products.

They meet the demands of consumers for ‘healthy

eating’ very well. Now, many types of low-fat spreads

with varying fat content are available on the market.

They have a high content of polyunsaturated fatty

acids, and many of them are trans fatty acids-free.

The sensory characteristics of low-fat spreads are

comparable to those of full-fat products. The main

trends in the development of low-fat spreads are to-

wards tailor-made products to provide health bene-

fits, e.g., low-fat spreads with plant sterols or stanols,

n-3 fatty acids of fish origin as added ingredient.

See also: Dressings and Mayonnaise: The Products and

Their Manufacture; Emulsifiers: Uses in Processed

Foods; Fats: Uses in the Food Industry; Fatty Acids:

Dietary Importance; Food Safety; Gums: Food Uses;

Legislation: Codex; Low-fat Foods: Types and

Manufacture; Margarine: Types and Properties; Methods

of Manufacture; Composition and Analysis; Dietary

Importance; Storage Stability: Parameters Affecting

Storage Stability; Vegetable Oils: Types and Properties