Production of chokeberry pulp powder by convective and freeze-drying foam-mat techniques: effects on physicochemical properties, bioactive content, and antioxidant activity†

Abstract

Chokeberry has gained popularity due to its high anthocyanin content. However, its high-water content shortens its shelf life, leading to potential waste, while its high pectin content limits its application as a food ingredient. A viable approach is using mature fruits to produce bioactive-rich pulp powder as a functional food ingredient. This study investigated the production of chokeberry fruit pulp powder by foam-mat drying, for the first time, via freeze and convective drying at different temperatures (50, 60, and 70 °C) and evaluate it in terms of powder properties, bioactive content, and antioxidant activity. Regarding the color of the produced powder, the lowest redness and highest yellowness values were observed in the freeze-dried powder. Bulk density, tap density, and the Carr index were found to be higher in convectively dried products. Freeze drying produced a powder with the highest bioactive content, including phenolic (41.14 ± 0.22 mg g⁻¹), flavonoid (6.03 ± 0.12 mg g⁻¹), and anthocyanin (4.42 ± 0.27 mg g⁻¹) compounds, as well as the strongest antioxidant activity. Although convective drying reduced bioactive content, drying at 50 °C preserved key properties, making it a cost-effective alternative. The two-term model at 50 °C best described the drying kinetics, further supporting CD 50 °C as an efficient option with favorable powder characteristics.