Certain types of cold treatment used by the citrus juice processing industry greatly impact the color of orange juice and the concentration and bioaccessibility of the carotenoids present in the juice, according to a study published in the Journal of Functional Foods.
The researchers analyzed fresh orange juice, pasteurized orange juice, and ultra-frozen orange juice thawed at room temperature, in a microwave oven, and in a refrigerator. The results showed that while there was some loss of carotenoids in the juices that underwent cold treatments, the juices that were ultra-frozen and then thawed at room temperature or defrosted in a microwave had more bioaccessible carotenoids than fresh juice. Thermal treatments affect the structure of carotenoids, reducing the size of the particles and degrading cellular material. The researchers believe that this may help with the release of carotenoids from the matrix that are then absorbed by the intestines.
The researchers plan to conduct another study to determine the content of certain carotenoids in the blood of subjects after they consume various samples of orange juice that underwent the processing conditions.