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Lecithin treatment / Lecithination – summary

 

 

The lecithin treatment or lecithination refers to the coating of powders by a wetting agent consisting of lecithin dissolved in butter oil or another low melting oil. The concentration of lecithin in fat is between 10 to 60% and the wetting agent is added in such amounts as to achieve lecithin content in the powder of 0.2-0.5%.

 

The wetting agent is sprayed by means of a fluid nozzle either directly on the powder under vigorous fluidization in a vibrating or static fluid bed or or it falls through a funnel feeding the inlet of a fluid bed. The lecithination equipment includes:

 

1. preparation tank with agitator and heating jacket for dissolving powdered lecithin in fat or oil
2. transfer pump, which is a centrifugal pump, for pumping

       the wetting agent from the preparation tank to the supply tank,

c)    supply tank with agitator and heating jacket

d)    dosing pump with variable speed control

e)    electric heater for compressed air

f)     fluid nozzles placed in the powder flow

g)    heat traced pipes for both lecithin and compressed air

h)    special 4-way valve allowing combinations of lecithin

       and compressed air flow :

 

                 - both lecithin and compressed air to the nozzle

                 - lecithin to recirculation to the supply tank and compressed air to

                    both passages of the fluid nozzle.

 

i) vegetable oil tank for rinsing the supply pump and pipeline

  

Basic lecithin treatment plant schematic

 

             

 

  a) PREPARATION TANK

  b) TRANSFER PUMP

  c)  SUPPLY TANK

  d) DOSING PUMP

  e) AIR EL-HEATER

   f) FLUID NOZZLE

  h) 4-WAY VALVE

   I) RINSING OIL TANK

 

For effective lecithination, the temperature of wetting agent must be 50-60°C and compressed air 60-80°C. The spraying angle must be adjusted to 70-90° and the powder kept in vigorous fluidization by warm air also after applying lecithin so as to maintain the final powder temperature at the powder outlet at least 45°C so as not to harden the oil before it has had the time to fully migrate to the powder evenly

 

Lecithination nowadays is provided as an integrated part of the spray drying installation. It can however be an independent unit, consisting of two fluid beds with lecithination spraying conducted in between. The duty of the first fluid bed is to heat the powder prior to lecithination to about 45°C, the second ensures good mixing for uniform distribution of lecithin within the treated powder. Powder is usually fed from a silo by means of a dosing equipment. Separate lecithination is advantageous especially when shipping non-lecithinated powder in bulk from the area of production to the point of market distribution. However, for obtaining the best powder quality, filling the lecithinated powder into tins should be linked directly with lecithination process.

 

 

 

 

For process design or project assistance contact jw@dairyconsultant.co.uk