Biomedical Engineering Reference
In-Depth Information
TABLE 7.5 (continued)
Functional Properties of Lecithins
Food Processing Ingredients in:
Miscellaneous products
Peanut spreads
Crystallization control, emulsifier
Salad products
Flavor and color solubilization
Packing aid
Polymer package interior coating
Release agent, sealant
Can interior coating
Sausage casing coating
Stocking net
Processing equipment
Frying surfaces
Internal (in product) and/or external release agent,
lubricant
Extruders
Conveyors
Broilers
Dryers
Blenders
Evaporators
its emulsifying capabilities. When working with lecithins, one might readily con-
clude that lecithin products seem to emulsify on a very system-dependent basis. This
is due to amphoteric (+,-) polar ends on the individual phosphatides, which makes
it impossible to assign a general emulsifier rating (such as HLB) to lecithin products.
Most processed food emulsions, however, are not stabilized by emulsification
alone. The particle size of the dispersed phase has to be much smaller for dynamic
stability than is practically possible with foods. Emulsifier/stabilizer systems, how-
ever, are normally used to make stable food emulsions. Lecithin will break up
(emulsify) the particles, while a stabilizer (water-soluble polymer, etc.) will hold
the particles in a dispersed orientation giving a stable emulsion. Lysolecithins, which
are more hydrophilic, show stronger oil-in-water emulsifying properties.
Solubilization Applications
Lecithins have also been used for solubilization applications. Stable microemulsions
have been prepared with various fractionated lecithins and are used in direct appli-
cations as reservoirs for certain materials (flavors, pharmaceuticals, etc.) or as
microreactors for enzymatic reactions.
Sol Dispersing Power
Lecithin products are still one of the best, most effective surfactants for dispersing
sols. This seems to be due to lecithin's affinity for solid/liquid surface interfaces.
Phosphatides seem particularly attracted to particles containing metals and metal
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