Novel design for alginate/resistant starch microcapsules controlling nisin release

This study aimed to develop a novel nontoxic, biocompatible, biodegradable, and cost-efficient matrix for the encapsulation of antimicrobial component (nisin) to be used as bio-preservative agent in cheddar cheese. Nisin A loaded beads were prepared from alginate at 0.5%, 1% and 2%; and hi-maize resistant starch at 0.5 or 1%. Beads were characterized by microscopic examination and transmission electron microscopy. Molecular structures were investigated by FTIR, and particle size distributions were measured. The Entrapment efficiency (EE) was measured microbiologically by agar diffusion. The encapsulated nisin showed similar inhibition activities in all developed formulas with an inhibition zone of 15 ± 2 mm. The FTIR analysis confirmed the compatibility of the nisin with sodium alginate and starch. The formulas composed of 1% Alginate and 0.5% Non-Gelatinized Starch had the highest encapsulation efficiency among other formulas (33%). Moreover, that formula allowed the protection and gradual release of the encapsulated nisin during a long-term storage for up to two months. Application in cheddar cheese proved the inhibition of encapsulated nisin on the growth of C. tyrobutyricum at the large-scale production. In conclusion, the alginate (Alg)/non-gelatinized resistant starch formula is suitable for the protection and controlled release of nisin in food applications.