Lamellar phase refers generally to packing of polar-headed long chain nonpolar-tail molecules in an environment of bulk polar liquid, as sheets of bilayers separated by bulk liquid. In biophysics, polar lipids (mostly, phospholipids, and rarely, glycolipids) pack as a liquid crystalline bilayer, with hydrophobic fatty acyl long chains directed inwardly and polar headgroups of lipids aligned on the outside in contact with water, as a 2-dimensional flat sheet surface. In lamellar lipid bilayers, polar headgroups of lipids align together at the interface of water and hydrophobic fatty-acid acyl chains align parallel to one another 'hiding away' from water. The lipid head groups are somewhat more 'tightly' packed than relatively 'fluid' hydrocarbon fatty acyl long chains. The lamellar lipid bilayer organization, thus reveals a 'flexibility gradient' of increasing freedom of motions from near the head-groups towards the terminal fatty-acyl chain methyl groups.
2. INTRODUCTION
❏ Lamellar phase refers generally to packing of polar-headed long chain
nonpolar-tail molecules in an environment of bulk polar liquid, as sheets of
bilayers separated by bulk liquid.
3. Types of lamellar phase
Micelle -
❖ Micelles are approximately spherical in shape
but bilayers , are also possible.
❖ Polar in nature.
❖ USES
● Micelle formation is essential for the
absorption of fat-soluble vitamins and
complicated lipids within the human body.
4. Liposome-
❖ A liposome is a spherical vesicle having at least one
lipid bilayer
❖ Bounded by bilayer of amphiphilic lipid.
❖ Contains aqueous solution inside the vesicle.
❖ USES
● Oral delivery of certain dietary supplements.
Bilayer sheets-
❖ Biological bilayers are usually composed of amphiphilic
phospholipids and form a SANDWICH-like structure.
❖ Hydrophilic phosphate head and a hydrophobic tail
consisting of two fatty acid chains.
6. Applications of lamellar phase
1) Gels-
❖ The lamellar phase transforms into a gel phase when cooled
below its Krafft point.
❖ Its structure is similar to lipid bilayer(lamellar structure).
❖ Fatty acids hydrocarbon chains in gels are like α-crystals.
USES
A. Monoglyceride coagels are used as texturising agents in low-fat foods
(e.g. spreads).
B. Very effective aerating agent and commercial emulsifier gel products.
7. 2) Emulsifiers-
❖ When we mix two immiscible liquids(eg- oil and water),there is formation of
suspended drops which results in formation of two different phases.
❖ When we add an emulsifiers to it in respective content,the phase separation
vanishes.
8. USES
● Lecithin - . When dispersed in water, egg lecithin forms lamellar phases or
multilamellar vesicles.
Phosphatidylcholine and phosphatidylinositol present in lecithin form lamellar
phases with water.
A. Improve shelf life of some products.
B. Provide texture to spreads and creams.
C. Increases volume and stabilizes fermentation.
9. ● Sodium stearoyl lactylate(SSL)- At pH greater than 5, the fatty acids are
ionised and lamellar phases form at a temperature of 45–85 °C.
A. To improve the aeration of bakery products (cakes), low-fat whipping creams.
.
● Glycerol monostearate -
A. Provides smooth texture to cakes and cream.
B. Anti-staling agent in breads
