Valorization of agricultural waste into functional ingredients: Spray-drying microencapsulation of tomato pomace extract using native and enzymatically modified protein carriers

This study comparatively evaluates three protein carriers in both native and hydrolyzed forms for spray-drying microencapsulation of tomato pomace extract (TPE): whey protein concentrate (WPC/H-WPC), gelatin (GEL/H-GEL), and apricot kernel protein (AKP/H-AKP). The research validates whether agricultural waste-derived AKP can achieve competitive encapsulation performance compared to established animal-based carriers, implementing a dual agricultural waste valorization strategy that transforms both apricot processing waste (carrier) and tomato processing waste (bioactive source) into functional ingredients. Microcapsules were produced using these carriers and evaluated for particle morphology, encapsulation efficiency (EE), total phenolic content (TPC), antioxidant activity (DPPH and ABTS assays), powder properties (yield, density, flowability), and structural integration (FT-IR). Carrier type significantly influenced all measured parameters ( p < 0.05). H-WPC microcapsules displayed spherical, intact morphology with excellent flowability. Hydrolyzed carriers exhibited high solubility, resulting in improved feed solution properties and production yields ranging from 52.90% to 85.16%, with H-WPC achieving the highest value. AKP demonstrated promising performance with EE values of 79.45% (native) and 83.21% (hydrolyzed), while maintaining superior bioactive accessibility (TPC: 2.18-2.43 mg GAE/g DM) and antioxidant activities of 48.73% (DPPH) and 58.32% (ABTS) compared to the robust H-WPC matrix (TPC: 1.69 mg GAE/g DM, DPPH: 41.25%, ABTS: 52.18%). FT-IR analysis confirmed successful TPE incorporation into protein matrices. These findings highlight the critical impact of carrier selection on microparticle properties and bioactive accessibility, providing valuable insights for optimizing protein-based encapsulation of plant extracts and demonstrating the viability of agricultural waste-to-value approaches in sustainable food processing. • H-WPC yields spherical particles, high encapsulation, yield. • Carrier solubility key for yield and particle quality. • Robust matrix limits bioactive accessibility in analysis. • Apricot kernel protein explores novel food waste use. • Carrier choice impacts physical and functional properties.