atiq's+emulsifiers

Emulsion A 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 I the form of fine droplets. Two types of simple emulsion: a) water in oil (w/o) b) oil in water (o/w) The stability of an emulsion depends on: ¨ degree of division of the inner phase ¨ quality/ stability of the interfacial film ¨ viscosity of the outer phase ¨ ratio and specific weight of the volumes of the two phases Emulsifiers - Substances which reduce the surface tension at the interface of two normally immiscible phase, allowing them to mix and form an emulsion - Surface-active agents - Surfactant
 * Dispersed phase ||  Continuous phase  ||
 * The dispersed droplets || The medium in which the droplets are dispersed ||

Functions of emulsifiers 1)To promote emulsion stability, stabilize aerated systems, and control agglomeration of fat globules 2)To modify texture, shelf life, and rheological properties 3)To improve the texture of fat- based foods How does emulsifier work? They have both:- - a polar group with an affinity for water (hydrophilic), and - a nonpolar group with an affinity for oil (lipophilic) Types of emulsifier: - nonionic - anionic  - cationic  - amphoteric Emulsifiers HLB- expresses the balance of size and strength of the hydrophilic and the lipophilic groups on the emulsifier. HLB of 3-6: a good w/o emulsifier; (lipophilic) HLB of 7-9: a good wetting agent; can be used for w/o or o/w emulsifiers HLB of 10: a good o/w emulsifier; (hydrophilic)