A pilot‐plant cellulose acetate gel bead column for the removal of limonin from citrus juices

A description is given of a pilot‐plant column packed with cellulose acetate gel beads for the removal of the bitter principle limonin from pasteurised citrus juices, at about 20 °C. The column had a bed volume (BV) of 11.5 litres and in a representative run the passage of juice (11 BV) through the column at a flow rate of 2.5 BV h −1 reduced the limonin content of the juice from 19.2 to 10.9 mg litre −1 . The adsorptive process can be described by standard mathematical equations and from these equations the theoretical performance of units consisting of two or more columns in series or parallel can be calculated. For example, passage of juice (20 BV) containing 35 mg litre −1 limonin through two columns in series would reduce the limonin content to 14 mg litre −1 compared with 19 mg litre −1 following passage through parallel columns. Treatment of fresh, unpasteurised juice reduced limonin contents by only 15% but treatment of freshly pasteurised juice was almost as successful as that of 1‐day‐old pasteurised juice. Since, like freshly extracted juice, freshly pasteurised juice is not bitter, it is suggested that two non‐bitter limonin precursors are involved in bitterness development, only one of which is adsorbed by cellulose acetate.