The removal of colour, carotene and acidity from crude olive oil by using sepiolite

Abstract

The capacity of sepiolite to adsorb colouring matters in olive oil was studied. The effects of adsorption time, temperature and solid:liquid ratio were selected as parameters. The effect of bleaching of olive oil was evaluated for determining the % free fatty acid (FFA), % bleachability and residual carotene by using both thermally activated sepiolite (AS) and acid-activated sepiolite (AAS). Results reveal that thermally acid-activated sepiolite was more efficient than thermally activated sepiolite. The adsorption equilibriums of carotene and FFA on AS and AAS were described by the Freundlich models. A higher adsorption coefficient (K) was observed for AAS (K-carotene = 2.73 x 10(-3)mgg(-1), K-FFA = 0.98mgg(-1)) compared to AS (K-carotene = 2.63 x 10(-7)mgg(-1), K-FFA = 0.21mgg(-1)). Moreover, the rate constants obtained for carotene and colour by using AAS (k(color) = 0.0241 min(-1), k(carotene) = 0.0217min(-1)) were higher than that of AS (k(color) = 0.01min(-1), k(carotene) = 0.0165min(-1)).