Changes in 3-chloro-1,2-propanediol and glycidyl esters content during post-bleaching of palm olein

Refined, bleached and deodorised (RBD) palm olein imported after long shipment may require post-bleaching and deodorisation to restore quality. In this study, an RBD palm olein imported from an overseas country was bleached using a range of bleaching earths (BEs) to determine their effects on the content of 3-chloro-1,2-propanediol esters (3-MCPDE) and glycidyl esters (GE), and on some quality parameters such as peroxide value (PV), colour, conjugated diene and trienes. Four types of bleaching earths (Tonsil® A, B, C and D) were used at 0.5-3.0% (w/w). Tonsil® A and B were acid-activated, Tonsil^® C was an acidic earth while Tonsil^® D was a neutral one. The results showed that the highest reductions in PV and GE contents were achieved by acid-activated BEs (Tonsil^® A and B) used at 3.0% (w/w). On the other hand, 3-MCPDE content was not significantly affected by the BE type and ratio although some reductions were detected using neutral earth. Conjugated triene and L* values increased with the increase of the earth ratio while some decreases were observed in the redness, b* and conjugated diene values.