Acetylation of normal and waxy maize starches as encapsulating agents for maize anthocyanins microencapsulation

• Purple maize anthocyanins were microencapsulated by spray drying.
• Modified normal and waxy maize starches were used as wall materials.
• Starches were hydrolyzed with acid, acetylated and extruded.
• Starch derivatization improve solubility as well as microencapsulation efficiency.
• Esterified normal maize starch showed superior anthocyanin retention after storage.

Encapsulation by spray drying of purple maize anthocyanins was carried out using encapsulating agents produced from maize starch derivatives. Normal and waxy maize starches were hydrolyzed with hydrochloric acid and were esterified with acetic anhydride before extrusion process. The influence of different derivative starches as encapsulating agents were investigated regarding the morphology (SEM), encapsulation efficiency (EE), adsorption isotherms and anthocyanins retention (AR) after 30 days of storage at different aw (0.11–0.94) at 40 °C. SEM images showed spherical microparticles with rough surfaces. The values of EE were higher in starch derivatives with respect to hydrolyzed native normal and waxy maize starches. After storage, microparticles produced with acetylated normal maize starch had the highest AR in the range of 0.11–0.75 aw. It was found that the experimental data were well represented by means of the GAB and Peleg models.