Storage stability of the natural colourant from Justicia spicigera microencapsulated in protective colloids blends by spray-drying

Muitle (Justicia spicigera), a Mexican native plant, produces a purple aqueous extract (MAE) because of its anthocyanin content. The aim of this work was to microencapsulate MAE by spray-drying in two different protective colloids blends in a 1:1 weight ratio:gum Arabic-mesquite gum (GA50-MD50) and mesquite gummaltodextrin DE10 (MG50-MD50), yielding the microcapsules MGA50-MD50 and MMG50-MD50. The minimum integral entropy of the microcapsules was determined at 20, 35 and 40 degrees C, and the resulting water activities (a(W)) were 0.555, 0.592, 0.627 for MGA50-MD50 and 0.581, 0.587, 0.648 for MMG50-MD50, respectively. These aW temperature sets were considered as the most adequate conditions for achieving maximum storage stability of the microcapsules. Total anthocyanin content (TAC) and total colour change (DE) suffered considerable degradation at all storage conditions, but that degradation was significantly inhibited by encapsulating MAE in the biopolymers blends especially that made up by MG50-MD50.