Wet-Heating-Induced Maillard Conjugation Combined With Rosemary Extract Co-Encapsulation Improves the Stability of Complex-Coacervated Citronella Oil Microcapsules.

A combined treatment integrating black bean protein isolate-gum Arabic (BBPI-GA) wet-heating conjugation and rosemary extract co-encapsulation was employed to improve the physicochemical characteristics and stability of citronella oil microcapsules. Changes in color, turbidity, molecular weight, and protein secondary structure confirmed the formation of BBPI-GA conjugates, with an optimal heating time of 1 h. Wet-heating conjugation increased the encapsulation efficiency (EE) of citronella oil from 91.97% (non-conjugated control) to 97.62% and produced microcapsules with a denser morphology and smaller particle size (34.26 µm). In contrast, additional incorporation of rosemary extract had negligible effects on EE (97.67%), morphology, and particle size (34.84 µm). In addition, the combined treatment remarkably elevated the thermal, storage, and oxidative stability of the encapsulated citronella oil and helped maintain its antibacterial activity and antioxidant capacity over time. Experimental results indicate that the integration of wet-heating conjugation and antioxidant co-encapsulation serves as an effective strategy for enhancing the stability and functional performance of citronella oil microcapsules.