Microencapsulation of blue maize (Zea mays L.) polyphenols in two matrices: their stability during storage and in vitro digestion release

Blue maize owes its coloration to a high anthocyanin content, and is therefore a promising source of unstable bioactive compounds. Spray-drying microencapsulation (SDM) can maintain the integrity of labile compounds during storage and digestion. We microencapsulated blue maize polyphenols by SDM in two matrices, maltodextrin (MD) and maltodextrin-pectin (MP) mixture. Morphology, degradation kinetics during storage and release were analyzed. Particle size ranged from 3 to 5 µm, with spherical morphology and surface depressions. The compounds and antioxidant activity had longer half-life in the MP matrix. Both matrices showed near complete release under simulated digestion (~ 95%), the majority of the compounds in the MP matrix were released during the intestinal phase, while those in the MD matrix were released during the gastric phase. These results suggest that microencapsulating blue maize polyphenols allows their incorporation into other products, and the addition of pectin improves the protective properties of MD, possibly due to its lower reactivity.