SURFACTANTS - EMULSIFIERSSURFACTANTS EMULSIFIERS

An emulsion is a mixture of two or more immiscible (un-blendable) liquids. Emulsions are part of a more general class of two-phase systems q p g p yof matter called colloids.

Although the terms colloid and emulsion are sometimes usedAlthough the terms colloid and emulsion are sometimes used interchangeably, emulsion tends to imply that both the dispersed and the continuous phase are liquid. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase)dispersed phase) is dispersed in the other (the continuous phase)

A. Two immiscible liquids, not yet emulsifiedemulsified.

B. An emulsion of Phase II dispersed in Phase I.

C. The unstable emulsion progressively separates.

D Th f t t ( l tli dD. The surfactant (purple outline around particles) positions itself on the interfaces between Phase II andinterfaces between Phase II and Phase I, stabilizing the emulsion

Emulsions are made up of a dispersed and a continuous phase; the boundary between these phases is called the interface.the boundary between these phases is called the interface. Emulsions tend to have a cloudy appearance, because the many phase interfaces scatter light that passes through the emulsion. Emulsions are unstable and, thus, do not form spontaneously.

The basic color of emulsions is white. If the emulsion is dilute, the Tyndall effect will scatter the light and distort the color to blue; if y da e ect scatte t e g t a d d sto t t e co o to b ue;it is concentrated, the color will be distorted toward yellow.

Microemulsions and nanoemulsions tend to appear clear due to the small size of the disperse phase.

Energy input through shaking, stirring, homogenizing, or spray processes is needed to initially form an emulsion.

Over time, emulsions tend to revert to the stable state of the phases comprising the emulsion, an unstable emulsion that will quickly separate unless p g , q y pshaken continuously.

Whether an emulsion turns into a water-in-oil emulsion or an oil-in-waterWhether an emulsion turns into a water in oil emulsion or an oil in water emulsion depends on the volume fraction of both phases and on the type of emulsifier.

In general, the Bancroft rule applies: Emulsifiers and emulsifying particles tend to promote dispersion of the phase in which they do not dissolve very well; for

l t i di l b tt i t th i il d t d t f il iexample, proteins dissolve better in water than in oil and so tend to form oil-in-water emulsions (that is they promote the dispersion of oil droplets throughout a continuous phase of water).

There are three types of instability:flocculation, creaming, and coalescence.

Flocculation describes the process by which the dispersed phase comes out of suspension in flakes.

Coalescence is another form of instability, which describes when small droplets combine to form progressively larger ones. E l i l d i th i ti f f th b tEmulsions can also undergo creaming, the migration of one of the substances to the top (or the bottom, depending on the relative densities of the two phases) of the emulsion under the influence of buoyancy orcentripetal force when a centrifuge is used.

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Orijinal Emülsiyon Flokulasyon Koalesens

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Kremleşme Kırılma

Surface active substances (surfactants) can increase the kinetic stability of emulsions greatly so that, once formed, the emulsion does not change significantly over years of storage.

Surfactants are compounds that lower the surface tension ofSurfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants may act asbetween a liquid and a solid. Surfactants may act as

detergents,wetting agents,emulsifiers,foaming agentsfoaming agents, and dispersants.

A micelle the lipophilic tails of theA micelle—the lipophilic tails of the surfactant molecules remain on the inside of the micelle due to unfavourable interactions The polar "heads" of the

Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface They interactions. The polar heads of the

micelle, due to favourable interactions with water, form a hydrophilic outer layer that in effect protects the hydrophobic core of the

the liquid gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid liquid effect protects the hydrophobic core of the

micelle. The compounds that make up a micelle are typically amphiphilic in nature, meaning that not only are micelles soluble

adsorbing at the liquid-liquid interface.

meaning that not only are micelles soluble in protic solvents such as water but also in aprotic solvents as a reverse micelle.

Surfactant classificationSurfactant classification according to the composition of their head: nonionic, anionic, cationic, Amphoteric (pH dependent).

Uses Of Surfactants 1. Emulsifiers

W I Oil L Hlb Water In Oil - Low Hlb Oil In Water - High Hlb

2 F St bili 2. Foam Stabilizers 3. Lipid Crystal Modifiers 4. Wetting Agents 5. Solubilizers 6. Starch Complexers 7. Protein Modifierso od 8. Detergents

I i Of S f A i A Wi hInteraction Of Surface Active Agents With Food Components

1. Lipids 2. Water

3 Starch 3. Starch 4. Protein 5. Air

6 I 6. Ions

MOST SURFACTANTS INVOLVE INTERACTONSINVOLVE INTERACTONS

WITH LIPIDSWITH LIPIDS

Why do we add surfactants toWhy do we add surfactants to foods ?

Orange DrinkSolublizer for colors Stabilize orange oil Possible cloudPossible cloud

Bread Loaf volume Entrap gas,

Soften Soften, Reduces stalingg

CSL, PS 60, DATEM

EMULSIFIERS IN BREADEMULSIFIERS IN BREAD BAKING During mixing

Improves wetability Improves distribution of shortening Interacts with starch, protein and fat

Results in: Decreased mixing time Decreased shortening usageg g Improved mixing tolerance Improved physical characteristics of the doughImproved physical characteristics of the dough

EMULSIFIERS IN BREADEMULSIFIERS IN BREAD BAKING During fermentation

R l i b i Results in better gas retention During baking

d Improved gas retention Improved loaf volume

D d t l Decreased water loss Finer, more uniform texture

During Storage During Storage Increased softness

Less staling Less staling

Pudding Emulsification Wetting agent in powder

Texture modifier Texture modifier

Ice cream Emulsion stability and destability, Foam stability,

Candy Bar Lecithin to stabilize fat crystals "bloom",

control viscosity and thus coating

Cookie Control spread

protein and fat interaction

Note: altering sugar may be a bigger Note: altering sugar may be a bigger factor

Surfactants 172 Listed Under Multipurpose Additives

Dioctyl Sodium Sulfosuccinate Glyceryl Tristearate Hydroxylated Lecithin Methylglucoside- Coconut Oil Ester Oxystearin Sodium Lauryl Sulfate Sodium Stearyl Fumarate

Surface Active Agents Acetylated Monoglycerides Succinylated Monoglycerides Ethoxylated Mono And Diglycerides Polysorbate 60 Polyoxyethylene (20) Sorbitan

Monostearate Aka Tween 60P l b t 65 P l th l (20) S bit Polysorbate 65 Polyoxyethylene (20) Sorbitan TristearatePolysorbate 80 Polyoxyethylene (20) Sorbitan Polysorbate 80 Polyoxyethylene (20) Sorbitan Monooleate

Surface Active Agents

Sorbitan Monostearate Aka Span Calcium Stearoyl-2- Lactylate Sodium Stearoyl-2-Lactylate Lactylic Esters Of Fatty Acidsy y Lactylated Fatty Acid Esters Of Glycerol And

Propyleneglycolpy g y Glyceryl-Lacto Esters Of Fatty Acids Polyglycerol Esters Of Fatty Acids Polyglycerol Esters Of Fatty Acids

Surface Active Agents

Propylene Glycol Mono- And Diesters Of Fats And Fatty AcidsFats And Fatty Acids

Propylene Glycol Alginate Sucrose Fatty Acid Esters Fatty Acids Fatty Acids

Affirmed GRAS Emulsifiers Diacetyl tartaric acid esters of mono- and

diglyceridesdiglycerides. Glyceryl monooleate.

l l Glyceryl monostearate. Glyceryl behenate. Lecithin Mono- and diglycerides.g y Monosodium phosphate derivatives of mono-

and diglyceridesg y

Mono & diglycerides Most commonly used

Generally as mono & di Generally as mono & di Highly lipophilic with HLB values range from 1 to 10 produced by transesterification of glycerol and triacylcerides p y g y y used in bakery products, frozen desserts, icings,

toppings, and peanut butter

Sources

Mono and diglycerides occur naturally as food fat constituents and areMono- and diglycerides occur naturally as food fat constituents, and are also formed from triglycerides, being normal products of fat metabolism, during the digestion and absorption of food.

As such, they are always found in conjunction with triglycerides, glycerol and some free fatty acids subject to the manner in which they have been roduced.

They are produced commercially by a) heating triglyceride fats with an y p y y ) g g yexcess of glycerol, or b) direct esterification of glycerol with fatty acids.

The resulting composition is dependent upon the proportion of glycerolThe resulting composition is dependent upon the proportion of glycerol and temperature conditions used. The mono-ester is usually in the range 30–60%. The composition of the product will vary according to conditions butThe composition of the product will vary according to conditions, but glyceryl monostearate and glyceryl distearate are often major components.

Function in FoodEmulsifiers are used to disperse fat droplets in water or water droplets in fat. B h h f b h f d h h lBecause they act at the surface between the fat and the water, they are also known as surface-active agents or surfactants.

Monoglycerides and mixtures of mono- and diglycerides are by far the most important commercially of all the food surfactants known; in Europe, they represent no less than 50% of the total food emulsifier market and, in addition, p , ,the monoglycerides are important intermediates in the manufacture of DATEMs (diacetyl tartaric acid esters of monoglycerides) and other emulsifiers.

Mono- and diglycerides are used widely in a great many products and are the surfactant type most used in bread. Performance characteristics are controlled by the skilful combining of alpha mono beta mono di and tri glyceryl estersby the skilful combining of alpha-mono-, beta-mono-, di- and tri-glyceryl esters of mixtures of fatty acids. In bread, the effectiveness of the emulsifier is dependent upon its total monoester content as, in this application, the

f f th l h d b t f ti i il d i t ithperformance of the alpha- and betafractions are similar and superior to either the di- or triglycerides.

BenefitsIn the production of bread, the contribution made by the surfactant is to enable the gluten in the dough to remain plastic and pliable so that duringenable the gluten in the dough to remain plastic and pliable so that, during the kneading process, the strands of gluten can form a smooth extensible film, ensuring that the correct texture is produced in the finished product.

As a general rule, volume and texture are of the utmost importance in baking. For example, it can be shown that, in cake making, the air bubbles in the batter that contribute to volume are enclosed in films of protein in which the fat is dispersed.

The action of the surfactant is to improve the production of the initial air bubbles, ensuring their uniformity and thereby an improved texture of thefinished baked product.finished baked product.Typical ProductsBread, cakes and other baked goods; cereals, puddings; fresh pasta, instant (mashed) potatoes; frozen desserts ice cream and soft-serve;instant (mashed) potatoes; frozen desserts, ice cream and soft-serve; confectionery, e.g. chewing gums, toffees, caramels; and fats, e.g. margarines and shortenings.

Polysorbates Polyoxyenthyene esters of sorbitan monoesters

Polysorbate 60 Polysorbate 60 polyoxyethylene sorbitan monostearate or TWEEN 60 - HLB =

14.9

oil toppings, cake mixes, and cake icing Polysorbate 65

polyoxyethylene sorbitan tristearate polyoxyethylene sorbitan tristearate Permitted in ice cream, frozen custard

Polysorbate 80 polyoxyethylene sorbitan tristearate Special dietetic foods, fat soluble vitamine Special dietetic foods, fat soluble vitamine

Sorbitan monostearate- sorbitan monostearate approved for food use- HLB = 4.7 - used in conjunction with polysorbates in oil

t i k i ttoppings, cake mixes, etc.

Stearoyl Lactylates an ionic, hyddophylic emulsifier lactic acid ester of monoglyceride with sodium

or calciumf t l ith l t i t h d form strong complex with gluten in starch and especially valuable in baked products

Lecithin A mixture of phospholipids including phosphatidyl

cholines phosphatidyl ethanolamines inositolcholines, phosphatidyl ethanolamines, inositol phosphatides, etc

Can be chemically modified by provide a wide range of HLB l f i li tiHLB values for various applications

widely used in baked goods, low-fat baked goods, chocolate, instant foods, confectionery products, and cooking spray , y p , g p y

SourcesLecithin is a mixture or fraction of phospholipids, which are obtained from

i l bl f d ff ( i l d ) b h i lanimal or vegetable foodstuffs (mainly soya and egg) by physical processes.

They also include hydrolysed substances obtained by the use of enzymes.

The finished product must not show any residual enzyme activity. A number of different lecithins or lecithin fractions are available.

Function in Food

Phospholipids are the active ingredients of lecithin and have a two-part molecular structure. One part is lipophilic (high affinity to fat/non-polar phase) and the other is hydrophilic (high affinity to water/polar phase)and the other is hydrophilic (high affinity to water/polar phase).

The phospholipids tend to dissolve in fat and disperse in water. This surface ti it i th b i f th j it f l ithi li ti d ll thactivity is the basis for the majority of lecithin applications and allows the

formation of both water-in-oil and oil-in-water emulsions.

Besides nutritional benefits, phospholipids have the following functional properties in food products: emulsification and stabilisation of oil-in-water or water-in-oil emulsions; release and anti-spattering effects; adjustment of the ; p g ; jflow properties in chocolate masses; improvement of the wettability of instant products; as well as optimisation of the gluten network of baked goods.

BenefitsLecithin allows the production of fine stable emulsions with littleLecithin allows the production of fine, stable emulsions with little aggregation or coalescence. It is also used in chocolate manufacture to modify the flow characteristics of liquid chocolate y qfor both blocks and coating. Lecithin is used on the surface of powders to improve “instant” properties. In bakery applications, l ithi i d t i th t ibilit f th l t i b dlecithin is used to increase the extensibility of the gluten in bread making, and in batters to improve the overall distribution of ingredients in cakes and to assist the release of wafers from hotingredients in cakes and to assist the release of wafers from hot iron moulds.

Typical ProductsMargarines, dressings, chocolate and confectionery items, instantpo de s and bake goodspowders and bakery goods.

Emulsifier Usage in U.S.Emulsifier Usage in U.S. (millions of pounds) Emulsifier Bread Cake mix M,SD,S * Total

Mono&Di 116 23 30.5 200 Lecithins 1 10 42.5 MG 13.2 0.5 2.5 25 Polysorb. 1.5 1 .75 8 CSL/SSL 27 .75 .25 30CSL/SSL 27 .75 .25 30 SorbMS .1 2 PG ester 10 1.8 14.3

*Margarine, salad dressings, shortenings

Sorbitan Monostearate Calcium Stearoyl-2- Lactylate Sodium Stearoyl-2-Lactylate

Emulsifier UsageEmulsifier Usage

Product % of total US Bread and Rolls 49 Cake Mixes 11 Cookies and crackers 7 Sweet goods and icings 3g g Margarine, dressings, shortenings 14 Confectionaries 6 Confectionaries 6 Deserts and toppings 3 Dairy products 3 Dairy products 3

The Hydrophilic-lipophilic balance of a surfactant is a measure of the degree to which it is hydrophilic or lipophilic determinedof the degree to which it is hydrophilic or lipophilic, determined by calculating values for the different regions of the molecule

All surfactants must have an oil loving portion and a water loving portion or they would not have surface activityloving portion or they would not have surface activity

•The ratio of the oil loving portion to the water loving portion g p g pis what we call its balance

W thi b l b d l l i ht•We measure this balance based on molecular weight

•“HLB” stands for• HLB stands for

–HYDROPHILE / LIPOPHILE / BALANCE

Hydrophillic-Lipophillic BalanceHydrophillic Lipophillic Balance (HLB) This is a concept for choosing

emulsifiers. The value of HLB ranges from 1-20 The value of HLB ranges from 1-20. Low HLB emulsifiers are soluble in oil

while high HLB emulsifiers are soluble in water..

Bancroft's RuleThe type of emulsion (i.e. oil in water or

water in oil) is dictated by the emulsifier and that the emulsifier should beand that the emulsifier should be soluble in the continuous phase.

Low HLB emulsifier's are soluble in oil andLow HLB emulsifier s are soluble in oil and give rise to water in oil emulsions

Wh i h H B “ ”What is the HLB “system” story

•The “system” was created as a tool to make it easier to use•The system was created as a tool to make it easier to use nonionic surfactants•In general it applies to nonionic surfactants onlyg pp y•The basic principle of the system is:

–Surfactants have an HLB valueA li ti f f t t h HLB i t–Applications for surfactants have an HLB requirement

–Matching the requirement with the value saves time and moneymoney

What is the chemistry of a nonionic surfactant ?What is the chemistry of a nonionic surfactant ?

•Each surfactant has a hydrophilic group and a lipophilic y p g p p pgroup

–must have both or it would not be surface activeth h d hili i ll l h d i * l h l•the hydrophilic group is usually a polyhydric* alcohol or

ethylene oxide•the lipophilic group is usually a fatty acid or a fatty•the lipophilic group is usually a fatty acid or a fatty alcohol–* polyhydric-an alcohol with OH’s attachedp y y

The relationship ( or balance ) between the hydrophilic portion of the nonionic surfactant to the lipophilic portion p p p pis what we callHLB•All nonionic surfactants have an HLB Value

How do we determine the HLB “value” of a surfactant ?

•We calculate the water loving portion of thesurfactant on a l l i ht b i d th di id th t b b 5molecular weight basis and then divide that number by 5

•this keeps the HLB scale smaller and more manageable–the working scale is from 0 5 to 19 5–the working scale is from 0.5 to 19.5

•this number is then assigned to the nonionic surfactant

HLB VALUES OF SOME FOODHLB VALUES OF SOME FOOD EMULSIFIERS EMULSIFIER HLB VALUE Oleic acid * 1.0 Acetylated monoglycerides 1.5 Sorbitan trioleate 1.8 Glycerol dioleate 1.8y Sorbitan tristearate 2.1 Propyleneglycol monostearate 3.4 Propyleneglycol monostearate 3.4 Glycerol Monoleate 3.4 Glycerol monostearate 3 8 Glycerol monostearate 3.8

HLB VALUES OF SOME FOODHLB VALUES OF SOME FOOD EMULSIFIERS EMULSIFIER HLB VALUE

Acetylated monoglycerides (stearate) 3 8 Acetylated monoglycerides (stearate) 3.8 Sorbitan monooleate 4.3 Propylene glycol monolaurate 4 5 Propylene glycol monolaurate 4.5 Sorbitan monostearate 4.7 Calcium stearoxyl-2-lactylate * 5 1 Calcium stearoxyl 2 lactylate 5.1 Glycerol monolaurate 5.2 Sorbitan monopalmitate 6.7Sorbitan monopalmitate 6.7 Soy lecithin 8.0 Diacetylated tartaric acid estersy of monoglycerides 8.0

HLB VALUES OF SOME FOOD EMULSIFIERSEMULSIFIERS

HLB VALUEEMULSIFIER HLB VALUE Sodium Stearoyl lactylate * 8.3

Sorbitan monolaurate ) 8 6 Sorbitan monolaurate ) 8.6 Polyoxyethylene (20) sorbitan tristearate 10 5 sorbitan tristearate 10.5 Polyoxyethylene (20) sorbitan trioleate 11.0 sorbitan trioleate 11.0 Polyoxyethylene (20) sorbitan monostearate 14.9 Sucrose monolaurate 15.0 Polyoxyethylene (20) sorbitan monooleate 15.0

HLB VALUES OF SOME FOODHLB VALUES OF SOME FOOD EMULSIFIERS EMULSIFIER HLB VALUE Sodium Stearoyl lactylate * 8 3 Sodium Stearoyl lactylate 8.3 Sorbitan monolaurate ) 8.6 Polyoxyethylene (20) sorbitan tristearate 10.5 Polyoxyethylene (20) sorbitan trioleate 11.0 Polyoxyethylene (20) sorbitan monostearate 14.9 Sucrose monolaurate 15.0 Sucrose monolaurate 15.0 Polyoxyethylene (20) sorbitan monooleate 15.0 Polyoxyethylene (20) sorbitan monopalmitate 15.6

Stokes' Law Creaming or sedimentation is

i lproportional to: 1. Diameter of the particle squared 2. Difference in density between the

particle and the continuous phase And inversely proportional to:

3 Viscosity of the continuous phase 3. Viscosity of the continuous phase

Stokes’ Law Rate = [Diameter squared x density

difference x g] / [16 x viscosity] How can we change diameter? How can we change diameter? How can we change density difference? How can we change viscosity?

Amylose Complexing Index Distilled Monoglycerides

From hydrogenated lard (65% MS, 30% MP) 92 From hydrogenated soy oil (85%Mono Stearate) 87 From unhydrogenated lard 45% Mono olein 35 From soy oil (55% mono olein) 28

Acetylated mono glycerides 0 Saturated Mono and Di glycerides (50% mono) 42 Steroyl-2-lactylate 79 Sodium Steroyl-2-lactylate 72 Calcium Steroyl-2-lactylate 65

Lactylated monoglycerides 22y g y Diacetyltartaric esters of monoglycerides 49

Basic Rules1. For emulsions, if you don't have A clue,

use At 5% Of The fat.2 Use unsaturated emulsifiers with2. Use unsaturated emulsifiers with

unsaturated fats.3. Mixtures work better than a single

emulsifier when stabilizing foams And gemulsions.

Basic Rules4. Bancroft's Rule

E l i S bili I F d B S l bili I ThEmulsion Stability Is Favored By Solubility In The Continuous Phase i.e. High HLB----> oil/water

Low HLB-----> water/oilLow HLB-----> water/oil5. HLB and most other rules go out the window

when protein and (sometimes)when protein and (sometimes) polysaccharides enter the system.

6 Only saturated monoglycerides complex with6. Only saturated monoglycerides complex with starch.

Basic Rules 4. Bancroft's Rule

E l i S bili I F d B S l bili I Th Emulsion Stability Is Favored By Solubility In The Continuous Phase i.e. High HLB----> oil/water

Low HLB-----> water/oil Low HLB-----> water/oil 5. HLB and most other rules go out the

window when protein and (sometimes)window when protein and (sometimes) polysaccharides enter the system.

6 Only saturated monoglycerides complex 6. Only saturated monoglycerides complex with starch.

Basic Rules 7. Emulsifier forms affect functionality.

fl k d h d l flakes vs powder vs hydrates vs gels 8. Many functions are due to affects on

l hipolymorphism. 9. Emulsifier preparations frequently contain

nsat ation and ma be an impo tantunsaturation and may be an important contributor to off flavors.10 Emulsifier preparations are seldom pure 10. Emulsifier preparations are seldom pure and thus variation from manufacturer to manufacturer may be substantialmanufacturer may be substantial.

Basic Rules11. When you find a non-obvious usage of

emulsifiers the function is often related toemulsifiers, the function is often related to interaction with starch or protein.

12 Order of addition may be very important12. Order of addition may be very important.13. Processing steps like homogenization may

substantially change the function ofsubstantially change the function of emulsifiers.