Storage time and deodorization temperature influence the formation of aniline-derived compounds in denatured rapeseed oils

In 1981 an epidemic, named Toxic Oil Syndrome, occurred in Spain as a resul t of ingestion of rapeseed oil denatured with 2% aniline, which had been im ported for industrial use but was fraudulently diverted and processed for h uman consumption. Two groups of chemical compounds have been identified in the ingested toxic oil: fatty acid anilides and amino-propanediol derivativ es. The objective of this work was to assess the effect of several refining process variables on the formation of 3-(N-phenylamino)-1,2-propanediol (P AP) esters. The amount of PAP esters in aniline-denatured oil increased dra matically when oil was heated from 250 degreesC to 300 degreesC. However, t he ones formed when 300 degreesC was reached were lost during processing at that temperature. The level maintained during the operation time at 300 de greesC was higher in denatured samples stored for 3 weeks before refining t han in denatured samples stored only for 1 week. Anilides were also analyze d. We found that anilides decreased very little with distillation time. In this paper we discuss the influence of storage time prior to refining and o f elevated refining temperature, such as temperatures that might occur in c lose proximity to a deodorizer coil. (C) 2001 Elsevier Science Ltd. All rig hts reserved.