Comprehensive analysis of changes in the quality, functional properties, flavor, and metabolome of blueberry pomace by different drying methods

Abstract

Blueberry pomace is rich in bioactive compounds but limited by high moisture content. This study evaluated eight drying methods, including natural sunlight drying (ND-S), no-sunlight natural drying (ND-NS), hot-air drying at 45/160 °C (HAD45/HAD160), microwave drying (MD), vacuum freeze-drying (VFD), and combined steam explosion drying (SE-HAD and SE-VFD), for their effects on physicochemical properties, bioactive compounds, flavor, and inhibitory activity against α-glucosidase of blueberry pomace powder. MD and HAD160 caused severe browning and significant bioactive losses, while VFD best preserved anthocyanins. SE-VFD showed the highest phenolic and flavonoid contents and achieved 96.37% α-glucosidase inhibition. Metabolomics revealed that steam explosion contributes to the enrichment of metabolites associated with flavonoid biosynthesis pathways, and molecular docking demonstrated that procyanidins B1 and B3 strongly interacted with α-glucosidase through hydrogen bonds and van der Waals forces. Entropy analysis ranked SE-VFD as the highest in overall functional quality, followed by HAD45/VFD and SE-HAD. SE-VFD is promising for functional product development, whereas HAD45 may be a promising candidate for industrial production.