Fresh or frozen? Deep-frozen orange juice packs extra health punch, study finds

12 Jun 2018 --- Deep-freezing orange juice increases the overall bioaccessibility of healthy compounds such as carotenoids, a study has found. Conducted by Researchers at the Laboratory of Food Color and Quality at the University of Seville, the study concluded that although fresh juice has the highest concentration of carotenoids, juice that has undergone deep freezing has an increased number of carotenoids that are eventually absorbed into the blood.

“Consumers tend to think that treated juices are ‘less healthy’ than fresh juices. However, in this study, it has been shown how, at least in relation to the content of carotenoids that reaches the blood and tissue to protect us from disease, this is not always correct,” says Antonio J. Meléndez, Professor at the University of Seville, Pharmacy Faculty.

The bioaccessibility of a compound is the quantity of that compound that is freed from the food and is capable of being absorbed by the intestinal wall so that it eventually accumulates in the different organs and tissues.

The researchers detail how the cold treatments had two opposite effects on the juice. On the one hand, they caused the carotenoids to degrade (negative effect) and, on the other hand, they generated an increase in the bioaccessibility of the carotenoids (positive effect). Taking these two effects into account, the researchers concluded that deep-frozen juices that are defrosted to room temperature or in a microwave are potentially better at increasing the level of carotenoids in the body.

During this project, three types of juice were analyzed: fresh orange juice, deep-frozen juice that had been defrosted to room temperature and pasteurized juices. The analysis focused on two carotenoids in particular, phytoene and phytofluene, because: “These compounds are increasingly acquiring importance among the scientific community as there are ever more studies that indicate their various benefits for health and cosmetics,” says Paula Mapell, University of Seville Professor.

Although all the cold treatments analyzed were found to have a loss in carotenoid levels, the deep-frozen juices that were defrosted to room temperature or in a microwave were better sources of bioaccessible carotenoids than the fresh juice.

“That is to say, despite the fact that the concentration of carotenoids in the deep-frozen juices was less than in the fresh juice, the reduction in the size of the particles and the destruction of the cellular material that these treatment produced means that the amount of carotenoids that can be absorbed by the intestine is higher,” Mapell adds.