Studies on Citrus Carotenoids

Part VIII. Carotenoid pattern of Citrus Unshiu flesh and purity analysis of orange juice

Abstract

Changes of carotenoids contents and carotenoid pattern of Citrus Un hiu juice at each manufacturing process were examined and the application of carotenoids pattern for the analysis of juice purity was discussed.
1) Qualitative changes of carotenoids would not occured in any proccess of domestic main juice extracting plants.
2) Carotenoid patterns of Citrus Unshiu juice obtained from several plants and procedures were almost the same and it was found that the content of monols and hydrocarbons was 65-75% and 10% or less respectively.
3) Total carotenoids decreased in clarification procedure, especially in the second pulp elimination by centrifugal process, on the other hand little decrease was observed during the heat pasteurization and the concentration process.
4) Total carotenoids contents of juice had close relation with the pulp contents and increased with high pulp content. The ratio of carotenoid to pulp was found to be nearly constant.
These results suggested that each manufacturing procedure of each juice should be investigated in order to judge the juice purity from the carotenoid contents which was reported previously.
But, the carotenoid pattern was not altered by any process examined, so it would be possible to detect if the juice was added with any carotenoid pigment. The ratio of carotenoid to pulp content was nearly constant. This would be another indication of juice purity, although some more investigations were required on maturity or variety of orange, manufacturing process and so on.