Jonsson L
SIK, Swedish Institute for Food Research, Göteborg.
Adv Exp Med Biol. 1991;289:75-82. doi: 10.1007/978-1-4899-2626-5_6.
Raw carrot juice contains a considerable amount of alpha- and beta-carotene, which makes carrot an excellent source of vitamin A. Heat treatment of the juice at temperatures comparable to those at pasteurization and boiling does not change the carotenes, while heating at temperatures used during sterilization results in rearrangement of the carotene molecules and a decrease in total carotenes. The all-trans alpha- and beta-carotenes appear partly as cis-isomers, especially the 13-cis-isomer. Isomerization of the carotenes leads to a decrease in their vitamin A activity. Carotenes also seem to be anticarcinogens but the extent to which this property is influenced by isomerization is still unknown.
生胡萝卜汁含有大量的α-胡萝卜素和β-胡萝卜素，这使得胡萝卜成为维生素A的优质来源。在与巴氏杀菌和煮沸相当的温度下对果汁进行热处理不会改变胡萝卜素，而在杀菌过程中使用的温度下加热会导致胡萝卜素分子重排，总胡萝卜素含量降低。全反式α-胡萝卜素和β-胡萝卜素部分以顺式异构体形式出现，尤其是13-顺式异构体。胡萝卜素的异构化导致其维生素A活性降低。胡萝卜素似乎也是抗癌物质，但这种特性受异构化影响的程度仍不清楚。
