Molecular distillation for recovering tocopherol and fatty acid methyl esters from rapeseed oil deodoriser distillate.

Tocopherol and fatty acid methyl esters (FAME) were recovered through a process involving acid-catalysed methyl esterification and crystallisation of sterols followed by molecular distillation from rapeseed oil deodoriser distillate (RODD), a by-product of vegetable refining edible oil. The effects of evaporating temperature, feed flow rate and wiper rolling speed on yield of tocopherol were systematically studied by response surface methodology (RSM) based on the separation of fame previously. The first fraction, which was collected at 50 °C at 2·66 Pa, contains mainly hydrocarbons, ketones and aldehydes. The second fraction, which was collected at 100–110 °C at 5·32 Pa, contains mainly FAME and the content of FAME in the second distillate was above 90% by analysis of gas chromatography–mass spectrometry (GC–MS). The fraction collected at 200–230 °C at 2·66 Pa was rich in tocopherol (nearly 35%). The overall recovery of tocopherol and FAME were around 50% and 90%, respectively, of the original content in RODD.