FRUIT BEVERAGES AND DIETARY FIBERS ANTIOXIDANT ACTIVITY AND FUNCTIONAL PROPERTIES

Abstract Fruit beverages provide antioxidants that support oxidative balance, while dietary fibers contribute to metabolic regulation and gut microbiota modulation. To evaluate these distinct but complementary functions, the phenolic compound content (PCC) and antioxidant capacity (AC) of commercial pomegranate, blueberry, and pineapple juices were assessed, together with the fat binding capacity (FBC) and glucose diffusion delay index (GDDI) of fibers from oat, wheat, and raspberry. The results highlight how antioxidants from fruit beverages and functional properties of dietary fibers can jointly contribute to health promotion. Materials Commercial pomegranate, blueberry, and pineapple juices were purchased from a supermarket chain in Murcia, Spain. Wheat, oat, and raspberry fibers were obtained from local producers, and sunflower oil was also purchased from a supermarket chain. Analytical reagents, including phosphate-buffered saline (PBS buffer), Folin–Ciocalteu, sodium carbonate, FRAP reagent, and glucose assay reagents, were supplied by Sigma-Aldrich. Results Pomegranate juice exhibited the highest PCC and AC values (3898±568 mg/L GAE and 13604±1357 μmol Trolox/L, respectively) clearly standing out from blueberry and pineapple juices. Oat fiber displayed the strongest FBC (54%), followed by raspberry (34,82%), and wheat (27%). In terms of GDDI, raspberry and oat fibers were the most effective in slowing glucose diffusion, while wheat fiber showed a progressive reduction over time. Conclusion The study highlights the complementary bioactive properties of fruit beverages and dietary fibers. Pomegranate juice stands out for its phenolic content and antioxidant activity, whereas oat and raspberry fibers showed relevant effects on fat binding and glucose diffusion. Together, these components may offer synergistic health benefits, particularly in the context of metabolic regulation and gut microbiota modulation. Oat and raspberry fibers exhibited the strongest glucose retention, particularly evident after 90 minutes, indicating a greater capacity to delay glucose diffusion. In contrast, wheat fiber showed only a moderate and progressive effect, suggesting a weaker influence on glucose release. These findings highlight the potential of oat and raspberry fibers to contribute more effectively to slowing glucose absorption and improving glycemic control. Note A typographical error was identified after publication (“BPS” should read “PBS”). This notice was added promptly upon discovery. The data and conclusions remain unaffected.