Juices and beverages with a controlled phenolic content and antioxidant capacity

The aim of the study was to design sensory-attractive beverages containing a significant but naturally occurring level of total phenolics and with a potentially high antioxidant effect. The concentrated fruit juices (cranberry, raspberry, black currant and others as references) and herbs (tea and dried elderberry fruits) were selected as raw materials. The study was realised in three steps: (1) development of the sensory-accepted herbal extracts and fruit beverages – characterised as phenolic sources, (2) development of the fruit-herbal beverages based on the pattern formulae of the selected fruit products, (3) determination of the total phenolics, antioxidant capacity and sensory properties of newly developed fresh compositions, and after six months of storage. It was found out that the total phenolics of fruit-tea beverages exceeded significantly those of their fruit counterparts and, except for one, those of the reference red grape juice. The fruit-tea drinks and red grape juice were recognised among all products tested as revealing comparable and the highest antioxidant capacities. The antioxidant capacity of the fruit and fruit-herbal beverages analysed correlated with their total phenolic content (r=0.85; p£0.02), which could be accepted as the basic characteristic of the antioxidant properties of the products declared as functional. Fruit and mixed beverages were categorised in accordance with both of these characteristics. The total phenolics, antioxidant and sensory properties of developed fruit-herbal beverages stored did not undergo substantial changes during six months. So, the products could be proposed as good sources of antioxidants supporting the organism defence system against oxidative stress.