BENEFITS AND LIMITATIONS OF A NOVEL CHLOROPHYLL ADSORBENT

Silica hydrogels acidified with strong mineral acids, such as sulfuric acid, are highly effective chlorophyll and phospholipid adsorbents relative to traditional acid-activated bleaching earth (ABE), but they are not effective beta-carotene adsorbents. When an acidified silica is used as the only bleaching agent, sulfuric acid leaches into the oil, and after deodorization, Tintometer red and yellow (R/Y) numbers are higher than those for ABE bleached and deodorized oils. The fixed RN colors do not arise solely from the decomposition of beta-carotene during deodorization. Sequential treatments of canola oils with sulfuric acid/silica and ABE can be performed to overcome all of the drawbacks associated with sulfuric acid/silica treatment alone, such that finished oils can be produced by lower overall adsorbent dosages.