Rita Alves and others at the Universidade do Porto made the finding after analysing 19 different drinks on the Portuguese market.
The results were published in the Food Science and Technology Journal.
Alvez et al. compared samples for total phelonics, total flavonoids and ascorbic acid content to determine the level of antioxidant activity.
“Nowadays, new emerging products claiming antioxidant properties are becoming more frequent. However, information about this topic in their labels is usually scarce.”
“In general, beverages containing green tea and hibiscus showed higher phenolic contents and antioxidant activities than those without these ingredients,” said the study.
Tea based products
The researchers analysed two distinct categories: tea-based products and juices.
They found that a tea formulation containing green tea, aromas, hibiscus and pineapple had the highest antioxidant activity of all beverages analysed.
This recipe was the highest in phelonics and showed the strongest DPPH scavenging activity.
A borututu roots infusion was found to have the lowest antioxidant activity of the teas.
“Although borututu roots were described in the label as a phelonics-rich product, the recommended sample/volume ratio for the infusion preparation was very low,” said the study.
The researchers added that green tea syrup could be an interesting alternative for consumers who dislike plant infusions or tea-based drinks.
Juices
In juices, a mixture of pomegranate juice, grape juice and carrot concentrated juice, which also contained hibiscus and green tea extract, was found to display the highest antioxidant.
Blackberry and Raspberry-based juices were seen to show among the lowest activity.
The samples used in the study were selected at random from supermarkets and herbalist shops in Portugal, with a preference for those claiming antioxidant properties. Brands of the selected products were not revealed.
Citation: Costa, A. S. G., et al., ‘Teas, dietary supplements and fruit juices: A comparative study regarding antioxidant activity and bioactive compounds’, LWT - Food Science and Technology (2012), doi:10.1016/j.lwt.2012.02.030