Abstract: Carrot juice was pressurized under different ultra-high pressure processing conditions and the aim was to study the effects of ultra-high pressure physical energy on the carotenoid geometric isomers in the carrot juice. The carotenoid geometric isomers in the juices treated by 100,300,500 and 700 MPa for 5min were separated respectively by HPLC equipped with a photodiode array detector and a C30 column. According to the chromatographic behavior,spectral characteristics and geometrical transition of the carotenoid geometric isomers catalyzed by iodine,the isomers of all -trans-β-carotene,15-cis-,13-cis-,9-15-di-cis-,9-cis-β-carotene,and all -trans-α-carotene were identified respectively. The results showed that to some extents,the ultra high pressure physical energy can lead to the isomerization of all-trans-carotenoids such as 9-,13-,15-carotenoids with low bond energies or the degradation to some small molecular fragments.

Key words: ultra-high pressure physics energy, HPLC, C30 column, carotenoid isomers