Abstract:Compared to All-E lycopene, Z-isomers had higher biological activity and bioavailability, but tending to oxidative degradation and conversion to E-isomer. In the paper, YMC Carotenoid C30-HPLC system were used to detect the influence of temperature on isomers' stability. The results showed that the proportion of cis-isomer lycopene could reach 78-85% in ethyl acetate by combining refluxing-crystal techniques. Storage stability test showed that the lower the temperature was, the smaller of degradation rate constant(k) of lycopene isomers was, indicating that the slower rate of degradation, more stable the storage. While the model parameters indicated that under isothermal conditions, kAll-E＜k9-Z＜k13-Z. The activation energies of 9-Z, 13-Z, All-E and All-Z isomers were 46.42 kJ/mol, 29.19 kJ/mol, 56.94 kJ/mol and 32.45 kJ/mol during storage respectively. So stability order of three major lycopene isomers was: All-E＞9Z＞13Z. And the activation energy of high proportion of Z-lycopene isomer product was 33.76 kJ/mol.
