Microencapsulated functional ingredients from a Moringa oleifera leaf polyphenol-rich extract: Characterization, antioxidant properties, in vitro simulated digestion, and storage stability

Abstract

Functional ingredients, particularly Moringa oleifera, have been highlighted as promising substances for combatting the harmful effects of oxidative stress. However, the physicochemical factors can easily influence its properties. To overcome this problem, this study aimed to achieve the microencapsulation of its leaf extract (CE-L) and phenolic-rich fraction (EF-L) and evaluate their chemical constituents, antioxidant properties, stability, and bioaccessibility. CE-L and EF-L microcapsules in maltodextrin were prepared by spray drying with inlet temperatures of 120 °C and 180 °C. The EF-L microcapsules prepared at a wall-to-core ratio of 10:0.05 and an inlet temperature of 120 °C (PE005120) showed the highest microencapsulation efficiency. The CE-L microcapsules prepared at a wall-to-core ratio of 10:1 and an inlet temperature of 180 °C (CE10180) exhibited the highest contents of chlorogenic acid, epicatechin, ellagic acid, and myricetin and the highest ABTS free radical-scavenging activity. Increases in antioxidant activity following in vitro simulated digestion were recorded. There were no significant changes in the TPC, or antioxidant activity of the powders preserved at either 4 °C or 37 °C. This promising evidence reveals the potential for the application of naturally unstable M. oleifera leaf extracts with unfavorable colors as phenolic-rich ingredients for the functional food industry.