A study on the influence of fucosterol on thermal polymerisation of purified high oleic sunflower triacylglycerols

Delta(5)-Avenasterol, an ethylidene side-chain phytosterol, was described a s an anti-polymerisation agent for thermooxidised oils. This paper investig ates the potential of its commercially available geometrical isomer, fucost erol, as an antipolymerisation agent for high oleic sunflower oil (HOSO). P urified triacylglycerols were prepared from HOSO and incubated in an oven, at 180 degrees C, with or without fucosterol, sitosterol and stigmasterol. Analysis of polymers and dimers (by high-performance size exclusion chromat ography) showed that fucosterol did not affect the rate of polymerisation o f purified HOSO triacylglycerols in our model. Comparison with alpha-tocoph erol, showed that this tocol inhibited the polymerisation of the oil while fucosterol did not. (C) 1999 Society of Chemical Industry.