Soybean Lecithin (CAS NO : 8002-43-5)

Crude lecithin typically favors W/O systems (HLB~ 3.5 - 4.5). To increase the HLB for O/W systems (e.g., beverages, sauces), the lecithin is chemically or enzymatically modified (hydrolyzed). This process increases the proportion of polar components (like Lysophosphatidylcholine), raising the HLB to ~ 8 - 12.

In non-Newtonian systems like chocolate, lecithin's amphiphilic molecules adsorb onto the surface of solid particles (e.g., cocoa, sugar) in the fat phase. This shields the polar parts of the particles, minimizing particle-particle friction and agglomeration, which dramatically lowers the plastic viscosity (the energy required to make the fluid flow).

Due to the presence of unsaturated fatty acids, liquid lecithin is susceptible to oxidation, leading to off-flavors (rancidity). Measures include storage under inert nitrogen blanket, adding synergistic antioxidants (e.g., Tocopherols), and ensuring storage temperature is maintained as low as feasible.

Fluid Lecithin is the crude product, containing ~ 60 - 70% Phospholipids (PL) and 30 - 40% residual soybean oil. Deoiled Lecithin (powder/granules) has been extracted with a solvent (e.g., acetone) to achieve ≥ 95% PL content. Deoiled is used where higher emulsification power, less residual fat, and powder form are critical (e.g., instant mixes, dietary supplements).