Emulsifiers

1. Substances which reduce the surface tension at the interface of two normally immiscible phases, allowing them to mix and for an emulsion due to their molecular structure(surface-active agents/surfactants)

1.1. Polar head groups (affinity for water)

1.1.1. anionic

1.1.1.1. -ve electrical charge

1.1.1.2. influenced by pH and ionic strength

1.1.1.3. e.g. Stearoyl lactylates, diacetyl tartaric esters of monoglyceride (DATEM), succinylated monoglcerides

1.1.1.3.1. Stearoyl Lactylates

1.1.2. cationic

1.1.2.1. +ve electrical charge

1.1.2.2. amine compounds

1.1.2.3. Not used as food additive (toxic)

1.1.3. amphoteric

1.1.3.1. +ve & -ve charges (anionic/ cationic emulsifiers depending on pH of system)

1.1.3.2. Protein (lecithin - egg yolk/ soy bean (commercial))

1.1.3.2.1. baked goods, low - fat baked goods, chocolate, infant food, confectionery products & cooking spray

1.1.4. nonionic (uncharged molecule)

1.1.4.1. insensitive to effects of pH & salt content

1.1.4.1.1. Used in determination of sitable emulsion based on HLB value

1.1.4.2. Mono- & diglycerides

1.1.4.2.1. high lipophilic; HLB values of 1 - 10

1.1.4.2.2. Produced by transesterification of glycerol and triacylcerides

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

1.1.4.3. Sucrose esters (HLB values of 7 - 13)

1.1.4.3.1. Are the mono-, di-, & tri-esters of sucrose with fatty acids

1.1.4.4. Sorbiton esters

1.1.4.4.1. Reaction of sorbitol and stearic acid

1.1.4.4.2. Sorbiton monoesterate (SPAN 60)

1.1.4.4.3. HLB = 4.7

1.1.4.4.4. Used with polysorbates in oil toppings, cake mixes

1.1.4.5. Polisorbates - Polyoxyethylene sorbiton esters (reaction of sorbiton esters with ethylene oxide)

1.1.4.5.1. Polysorbate 60

1.1.4.5.2. Polysorbate 65

1.1.4.5.3. Polysorbate 80

1.2. nonpolar group (affinity for oil) - Lipophilic tails

1.2.1. C16 (palmitate) / Fatty acid

2. Stability of an emulsion depends on

2.1. degree of division of the inner phase

2.2. quality/stability of the interfacial film

2.3. viscosity of the outer phase

3. Function

3.1. To promote emulsion stability

3.1.1. stabilize aerated systems

3.1.2. control agglomeration of fat globules

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

3.3. To improve the texture of fat - based food by controlling the polymorphism of fats

4. HLB

4.1. Balance of size and strength of the hydrophilic & lipophilic groups on the emulsifier [*NONIONIC EMULSIFIERS]

4.2. HLB > 10 indicates more polar (hydrophilic) molecules HLB = 1 - 10 indicates more lipophilic emulsifiers

4.2.1. HLB of 3 - 6 : good w/o emulsifier

4.2.2. HLB of 7 - 9 : good wetting agent; (w/o & o/w emulsifier)

4.2.3. HLB of 10 - 18 : good o/w emulsifier

5. Applications

5.1. Breads, Rolls, Buns

5.1.1. Dough conditioner/ dough strengthener

5.1.1.1. less tacky and more extensible dough (fermentation, mechanical handling, shaping and transport, proofing & first part of baking time

5.1.1.2. Ca/Na stearoyl lactylate (SSL), ethoxylated moniglyceride (EOM), succinylated monoglyceride (SMG) & Polyoxyethylene sorbiton monostearate (PS 60)

5.1.2. Crumb softener

5.1.2.1. Anionic emulsifier that forms complex with amylse of starch & retard starch crystallization or retrogradation which is responsible for staling

5.1.2.2. lactylates & SMG, mono- & diglycerides, hydrated distilled monoglycerides, DATEM        (0.5 - 1% of flour weight)

5.2. Cakes

5.2.1. Stabilize aerated structure

5.2.2. Aerating agent

5.2.3. Promote a finer distribution of fat droplets & increase viscosity of water phase --> contributes to a higher volume and more uniform cell structure in finished product

5.2.3.1. Alpha-tending emulsifier

5.2.3.1.1. acetic acid/lactic acid esters of monoglyceride

5.2.3.1.2. propylene glycol esters

5.3. Confectionery Products & Coatings

5.3.1. Inhibit bloom

5.3.1.1. Bloom - occurs when fat crystal undergo transition from β' form to the most stable crystalline form,β causing the cocoa butter to separate from the brown nonfat phase

5.3.1.1.1. emulsifier retard bloom defect by functioning as crystal modifiers - stabilize the intermediate β' crystalline form of the fat

5.3.2. Stabilize gloss

5.3.3. Improve palatability

5.4. Frozen dairy product - ice cream

5.4.1. Foam stabiliser

5.4.1.1. de-stabilize product's emulsion

5.4.2. Emulsifiers displace the protein from the fat globule surface to the aqueous phase--> increase the cream's viscosity and allows the fat globules to agglomerate. The increased viscosity promotes aeration, while the agglomerates stabilize the air cells once the air is incorporated.

5.5. Noodle & pasta

5.5.1. Make a rigid complex with starch to protect starch granules and improve the quality of starchy food

5.5.1.1. Fresh noodles - easy to handle dough, incraeses water absorption rate by 1 - 2% . The surface of noodles becomes smooth, uniform & less sticky

5.5.1.2. Instant noodles - improve absorption and decrease cooking time.

5.5.1.3. Macaroni & spaghetti - elasticity, smooth uniform surface (inhibits sticking after boiling)

6. Emulsion - A dispersed two-phase system (an intimate mixture of two immiscible liquids under normal conditions)

6.1. Dispersed phase (fine droplets); Continuous phase (medium in which the droplets are dispersed)

6.2. Water= dispersed phase, Oil = continuous phase  (Water in Oil emulsion) [e.g. Butter] Oil= dispersed phase, Water= continuous phase (Oil in Water emulsion) [e.g. fresh milk & mayonnaise]