Preparation of degraded alginate as a pH-dependent release matrix for spray-dried iron and its encapsulation performances

Low viscosity alginate is used as a spray drying encapsulant. This study investigated the properties of degraded alginate, degraded using cellulase, and its application as an iron encapsulant using the spray drying method. Degradation of 3% alginate using 350 ppm cellulase for 300 min reduced its viscosity from 1800 to 195 cPs, which allowed spray drying of alginate. The degraded alginate exhibits a better antioxidant activity, which protects iron from oxidation. It shows a melting point at ~570°C. The highest efficiency (87.23%) was obtained at the lowest iron concentration, while the highest loading (82.45%) and moisture content were found at the highest iron concentration. Higher entrapped iron increased the particle size. The encapsulated iron powders had a rougher and more cracked surface, which led to an iron burst in the first 30 min. Entrapped iron slightly interrupted with alginate crystallinity. The encapsulated iron showed a pH-sensitive property; a faster release of iron was observed in the neutral pH solution. The degraded alginate matrix offered protection of iron from oxidation, up to 98.3%, after 120 days. [Display omitted] •Cellulase fell alginate viscosity to 195 cPs & allowed alginate to be spray-dried.•More trapped iron rose encapsulation loading capacity but not the efficiency.•More particle cracks were observed in higher encapsulated iron, led to burst.•Higher released iron was observed in neutral pH solution than in acid solution.•The alginate protected iron from oxidation up to 98% after 120 days storage.