Effects of Thermal Processing on the Degradation and Isomerization of Carotenoids in Coloured-tomatoes

• 1、School of Food Science and Technology,Jiangnan University,Wuxi 214122
• 2、Food college, Shihezi University, Shihezi 832003
• 3、Xinjiang Guannong Fruit & Antler Co.,Ltd, Korla City 841000
• 4、 Food college, Shihezi University, Shihezi 832003

Abstract：Carotenoid composition in colored tomatoes are different and so are their changes, eg. isomerization and degradation, during thermal processing.The carotenoids of two orange tomato varieties and one red tomato variety were analysed using YMC Carotenoid C30-HPLC system. Additionally, effects of the thermal processing on degradation and isomerization of carotenoids in these tomatoes were evaluated. The results showed that the mass fraction of cis-lycopene of orange tomato-1 reached 99.24%, which was much higher than 8.48% of red tomato. For orange tomato-2, it showed the similar colour to orange tomato-1, β-carotene was its main carotenoid compound, and the cis-isomers only accounted for 6.74%. The results of heat treatment showed that , for red tomato and orange tomato-2, the degradation and isomerization were not obvious in whether lycopene or β-carotene. Differently, for orange tomato-1, the loss of total lycopene was obvious, and tetra-cis-lycopene was gradually isomerized to all-trans-, 5-cis, and other-cis-lycopene. Meanwhile, the colourless carotenoids (phytofluene and phytoene) remained stable and the isomerization was not observed in phytoene. These information was useful to make use of the great material and research and develop tomato products with high bioactivty.

Keywords： food science tomato carotenoids isomers degradation isomerization