Studies have suggested that consumption of fruit juices prevents various ailments due to claimed antioxidant properties. As a result, many beverages made up of fruit juices and other antioxidants, such as green tea, are available in the market. These beverages were analyzed for their antioxidant properties in this study. Results showed that fruit juice-based drinks contained more antioxidant capacities compared to green tea-based drinks and antioxidant capacity was found to increase when they were added as supplements to the drinks. Results also showed that the antioxidant properties of the drinks remained nearly the same throughout the shelf life of the beverages.
Oxidative reactions in the body lead to oxidative stress that is thought to be the main cause of many ailments. Studies have shown that fruits and vegetables contain antioxidants that help combat these oxidative damages and may help in the prevention of such diseases as cancers and Alzheimer’s disease. Studies have also examined canned fruit juices on the market and observed similar benefits due to their antioxidant properties. Nowadays, these fruit and tea drinks are also fortified with vitamins and minerals. This study was conducted to analyze the antioxidant capacity of fruit-based beverages commercially available in Italy and to also see if the antioxidant values of these drinks were sustained throughout their shelf lives.
* The 18 tested samples were purchased between September 2008 and February 2009. They were stored per the instructions on the labels.
* The test samples were compared for their antioxidant capacity with three natural citrus juices, namely red orange, grapefruit and natural orange juices.
* Apart from various tests to measure antioxidant properties, the samples were also tested for their antioxidant content by measuring the levels of such chemicals as phenolic and flavonoid levels.
* Results showed that drinks that had more green tea were lower on antioxidants.
* The results of total phenolic and flavonoid contents showed that concentration of total phenolics varied widely among samples and on an average, flavonoids made up 15 to 20 percent of the total phenolic composition. The finding suggests that additives had only a marginal effect on the flavonoid composition of the beverages.
* It was observed that most of the green tea drinks contain vitamin C as a supplement. Researchers found that unless this supplementation was present, the antioxidant properties tended to be even lower.
* When kept under refrigeration, these drinks retained their antioxidant properties even 10 days after opening the package. This duration is longer than what is advised by the manufacturers of the beverages.
Authors agree that although there is a lower antioxidant content in natural pasteurized juices compared to ready-made juices, the difference is not always significant. They suggest that antioxidant capacity can be improved through the use of additives. However, it is also found that samples containing additives do not have a significantly higher antioxidant capacity than do natural juices.
This study reveals that fruit-based juices are a better choice than green tea-based drinks in terms of antioxidant content. This study emphasizes the fact that both kinds of juices – fruits and green tea-based – are so enriched only because of the antioxidant additions made to them. This is also true to an extent when compared to natural fruit juices. Authors suggest that this is the reason behind the higher cost of these antioxidant drinks. This study also showed that the antioxidant properties of these drinks remained stable even after the package was opened, provided it was stored in adequate and advised levels of refrigeration.
For More Information:
Evaluation of Antioxidant Capacity of Antioxidant-declared Beverages Marketed in Italy
Publication Journal: Italian Journal of Food Science, 2010
By P. Zucca; E. Sanjust; Università di Cagliari, Cittadella Universitaria, Monserrato, CA, Italy
*FYI Living Lab Reports Are Summaries of the Original Research.