Obtaining a fiber-rich ingredient from blueberry pomace through convective drying: Process modeling and its impact on techno-functional and bioactive properties

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This study aimed to optimize the convective drying of blueberry pomace (BP) to enhance fiber functionality and bioactive compound retention. BP was dried at 50−90 °C with an airflow of 2.5 m s−1. Drying kinetics were modeled using five mathematical models, with the Page model showing the highest accuracy (R2 = 0.9965−0.9996). Higher temperatures increased drying rates (3.7 × 10−3 to 1.2 × 10−2 kg H2O kg−1 db min−1) and moisture diffusivity (4.00 × 10−8 to 2.17 × 10−7 m2 s−1), with an activation energy of 39.55 kJ mol−1. Total dietary fiber remained stable (20.85 ± 0.17 g 100 g−1 db), while soluble fiber increased (3.11–4.66 g 100 g−1 db) with temperature. Water- and oil-holding capacities decreased (10.86–8.61 mL g−1 db and 3.85 to 3.44 mL g−1 db, respectively). The highest total phenolic content (13.65 ± 0.12 mg GAE g−1 db) and antioxidant activity (6.65 mg AAE g−1 db for DPPH) were observed at 70 °C. Energy consumption decreased significantly (13.88–6.95 kW h−1), leading to reduced CO2 emissions. This study demonstrates the effective use of the Page model to optimize convective drying at 70 °C, reducing production costs by 47% and highlighting its potential to produce fiber-rich ingredients from BP with enhanced techno-functional and bioactive properties.