Effect of heating on solid β-carotene

The effect of heating on isomerisation and stability of solid β-carotene was investigated, and the products generated by heating were analysed by a number of analytical techniques, including high-performance liquid chromatography (HPLC), UV/VIS-spectroscopy (UV) and gel permeation chromatography (GPC). For the first time, isomerisation of cis- to all-trans-isomer was demonstrated in partly melted solid β-carotene when β-carotene was heated at 90 and 140 °C. Only a few high molecular weight components were detected by GPC when β-carotene was heated in a nitrogen environment. In contrast, more high molecular weight polymers, as well as low molecular fragments, were produced when β-carotene was heated and exposed to air, suggesting that polymerisation was one of the dominant side-reactions of β-carotene change, in addition to degradation.