Emulsifiers

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Emulsifiers

How to Select an Emulsifier?

Determine the HLB requirements for the food system – involves screening emulsifiers over a range of HLB values & several concentrations

Select an emulsifier after considering the functional requirements of the food system, the method of processing, and the form of the finished product

Applications of Emulsifiers

Noodle & Pasta

macaroni and spaghetti, emulsifiers provide a feeling of elasticity, and a smooth uniform surface which inhibits sticking after boiling.

fresh noodles, an emulsifier makes easy to handle dough and increases the water absorption rate by 1 to 2%.

make a rigid complex with starch to protect starch granules and improve the quality of starchy foods

Frozen dairy products – Ice Cream

displace the protein from the fat globule surface to the aqueous phase

emulsifiers stabilize the foam by actually de-stabilizing the product's emulsion.

function as aerating agent and foam stabiliser

Confectionery Products & Coatings

The bloom defect can be retarded with the use of emulsifiers functioning as crystal modifiers

Emulsifiers are used primarily to inhibit bloom, stabilize gloss, & improve palatability

Cakes

Emulsifiers added to fat-containing batters function to (1) stabilize the aerated structure and (2) promote a finer distribution of the fat droplets.

Cake batters have been described as complex w/o emulsions or air-in-fat foams, consisting of suspended flour particles, dissolved sugar, and proteins.

Bread, Rolls, Buns

Examples of dough conditioners: calcium stearoyl lactylate, sodium stearoyl lactylate (SSL), ethoxylated onoglycerides (EOM), succinylated monoglycerides (SMG), and polyoxyethylene sorbitan monostearate (PS60)

Dough conditioning/strengthening – emulsifiers that aid in development of less tacky, more extensible dough that are processed through machinery without tearing or sticking – exert their effect during fermentation, mechanical handling, shaping and transport, as well as during proofing and the first part the baking time

Hydrophilic-Liphophilic Balance (HLB)

" HLB of 3 – 6 : a good w/o emulsifier " HLB of 7 – 9 : a good wetting agent; can be used for w/o or o/w emulsifier " HLB of 10 – 18 : a good o/w emulsifier

used to describe the emulsifying properties of nonionic emulsifiers

High HLB values (HLB > 10) indicate relatively more polar (hydrophilic) molecules; More lipophilic emulsifiers have HLB values from 1 – 10

expresses the balance of size and strength of the hydrophilic (water loving or polar) and the lipophilic (oil loving or nonpolar) groups on the emulsifierSubtopic

How does emulsifier work?

stabilise emulsions by means of monomolecular interfacial films & also by formation of steric and/ or electrical barriers that prevent coalescence of the dispersed droplets

presence of both regions on the emulsifier molecule allows them to orient themselves at the phase interface & lower the interfacial energy that leads to instability

have both a polar group with an affinity for water (hydrophilic), and a nonpolar group with an affinity for oil (lipohilic).

reduce surface tension between the two immiscible phases due to their molecular structure.

Function of Emulsifier

improve the texture of fat-based foods by controlling the polymorphism of fats

modify texture, shelf life, and rheological properties by complexing with starch and protein components

emulsion stability, stabilize aerated systems, and control agglomeration of fat globules

Properties of Some Common Food Emulsifiers

Lecithin and Derivatives

Widely used in baked goods, low-fat baked goods, chocolate, instant foods, confectionery products, and cooking spray

Rich in egg yolk

example of amphipilic emulsifiers

Stearoyl Lactylates

Especially valuable in baked products

Form strong complex with gluten in starch

example of ionic emulsifier

Sorbitan Esters

Used in conjunction with polysorbates in oil toppings, cake mixes, etc.

HLB = 4.7

Produced by the reaction of sorbitol and stearic acid

Sucrose Esters

Usually with HLB values from 7 to 13

Are the mono-, di-, and triesters of sucrose with fatty acids

Mono- & Di-glycerides

Used in bakery products, frozen desserts, icings, toppings, and peanut butter

Highly lipophilic with HLB values range from 1 to 10

Most commonly used emulsifiers

Types of emulsifier

Amphoteric

e.g., various lecithins; may act as anionic or cationic emulsifier, depending on pH of the system.

Possess both positive and negative charges

Cationic

e.g., amine compounds. Not used as food additive (toxic)

Possess a positive electrical charge topic

Anionic

e.g., Stearoyl lactylates, diacetyl tartaric esters of monoglycerides (DATEM), succinylated monoglycerides; functionality may be markedly influenced by pH and ionic strength.

posess a negative electrical charge

Nonionic

Example: mono- and diglycerides, sorbitan esters, sucrose esters, polysorbates, polyoxyethylene glycol oleates (all contain an – OH functional group)

uncharged molecules relatively insensitive to effects of pH and salt content. Most commonly used food emulsifier type.

The stability of an emulsion depends on

ratio & the specific weight of the volumes of the two phases

viscosity of the outer phase

quality/stability of the interfacial film

degree of division of the inner phase

Emulsion

Two types of simple emulsion

oil in water (o/w)

water in oil (w/o)

belong to the general class of compounds called surface-active agents or surfactants.

substances which reduce the surface tension at the interface of two normally immiscible phases, allowing them to mix and form an emulsion.

dispersed two-phase system, i.e., an intimate mixture of two liquids that are immiscible under normal conditions, whereby one phase is dispersed in the other in the form of fine droplets.