When medical researchers use the term lecithin they are referring to a purified substance called phosphatidyl choline pc that belongs to a special category of fat soluble substances called phospholipidswhere is it found choline the major constituent of pc is found in soybeans liver porridge cabbage and cauliflower soybeans egg yolks meat and some vegetables contain pc lecithin containing 10 20 pc is added to many processed foods in small amounts for the purpose of maintaining t