食物与营养失调杂志

Total Antioxidant Capacity of Commonly Consumed Fresh Squeezed Fruit Juices, Name Brand Fruit Juices and Private Label Juices Available in the Greek Market

Despoina N Anagnostopoulou, Katerina P Skenderi, Chrysanthi I Papanastasopoulou and Nikolaos M Sitaras

Total Antioxidant Capacity of Commonly Consumed Fresh Squeezed Fruit Juices, Name Brand Fruit Juices and Private Label Juices Available in the Greek Market

The beneficial health effects of fruits and fruit juices have been extensively studied; scientific interest in this area is avid and growing. In order to obtain updated information on the antioxidant function of consumed juices, we measured the total antioxidant capacity of 41 ready to drink (RTD) juices and 8 fresh squeezed fruits, using ascorbic acid and 6-hydroxy-2,5,7,8-tetramethylchroman- 2-carboxylic acid (Trolox) as standards for the DPPH• and ABTS•+ assay, respectively. Along with this total phenolics and flavonoids were measured and their colour was recorded using the CIELAB uniform colour space. Each sample of fruit (orange, red apple, pineapple, red and yellow grapefruit, pomegranate, peach and lemon), purchased from Greek supermarkets were analysed. Moreover, the fruit juices were distinguished in name brand (NB) juices and private label (PL) juices. Our results indicate a strong antioxidant capacity, using the DPPH method, the fresh squeezed juices showing a higher DPPH value (7.87 ± 2.77) mM/l VCEAC in comparison with the RTD juices (3.74 ± 0.54) mM/l VCEAC, p=0.019. PL juices had less content of phenols (527.3 ± 48.0) than NB juices (824.7 ± 120.8). Fruits with a strong red colour, such as pomegranate have a higher phenolic content, positively correlated with coordinate a*(p=0,018, r=0,336). Also, fresh juices have higher phenolic concentration (777.0 ± 177.4) mg/l GAEs, than fruitdrinks (FD) (81.9 ± 10.5) mg/l GAEs, (p=0.007). The RTD juices maintained in room temperature exhibited a 2-fold lower antioxidant capacity (6.14 ± 0.68) mM/l TEAC, than that of juices with a shortshelf life (13.32 ± 1.43) mM/l TEAC, maintained under refrigeration. Fresh squeezed pomegranate juice and RTD pomegranate juice contain more antioxidants than any other fruit. It appears that the consumption of RTD juices in an everyday diet can provide beneficial effects on health, especially red fruits, as pomegranates contain more antioxidants than any other fruit. Furthermore, different manufacturing production processes and commercial type of products results in different antioxidant capacities.