The specifications of lecithin are mainly classified by the following indicators: phosphatidylcholine content, acetone insoluble matter, color, viscosity, acid value,Hexane Insolubles (HI). The terms
used when specifying lecithins are:
Phosphatidylcholine (PC)
Amphiphilic molecule and main emulsifier in lecithin. PC is the major component of biological membranes and supplements the diet with natural choline.
Acetone Insolubles (AI)
Expressed as a percentage. This is a measure of the surfaceactive portion of a lecithin, comprised mainly of phospholipids and glycolipids.
Acid Value (AV)
Expressed as meq KOH/kg. This is a measure of total acidity afforded by ionizable groups of phospholipids and free fatty acids added to some liquid lecithins to stabilize viscosity.
Color
Measured against the Gardner scale. Most lecithin products range from having a light honey (11 on the scale) to dark amber (17 on the scale) color.
Hexane Insolubles (HI)
Expressed as a percentage (usually under 0.1%). Measures residual non-fatty material, composed mainly of soybean meal fines.
Moisture (H2O)
Measured by the Karl Fisher method, a potentiometric titration specific for water. Powder and liquid lecithins typically contain approximately 1% water.
Viscosity
Reported in centipoise (cP) at 25ºC/77ºF, after evaluation with a Brookfield rotary viscometer.
Peroxide Value (PV)
The peroxide value is a measure indicative of a product’s degradation. Lecithin and phospholipids have naturally occurring unsaturated fatty acids which contribute to their nutritional benefits. In the absence of gentle processing and storage conditions the unsaturated double bonds that are present can undergo an auto-oxidation process which in turn creates free radicals. Modern day diets are intentionally fortified to fight free radicals in the body which can change DNA, cause inflammation and stress to cells, etc. American Lecithin Company specifies the lowest possible peroxide values possible.
HLB Value
Emulsification properties of different lecithins are a function of their water-or fat-loving qualities, known in the industry as Hydrophilic-Lipophilic Balance or HLB.