High-pressure homogenization and maltodextrins mixtures to microencapsulate vanilla (vanilla planifolia) extract through freeze-drying

Microfluidization followed by encapsulation through freeze-drying was performed in order to assess the effect of high pressure homogenization (70 MPa, one and two cycles) and the coating material composed of maltodextrins (MD) mixtures with different dextrose equivalent (DE) values, DE 10 (MD10) and DE 20 (MD20) at 10% (w/w) total solids content, on the feasibility of concentrated vanilla extract (VE) encapsulation. The rheology of five different formulations was determined before microfluidization, while particle size was determined after such processing stage. After freezedrying, it was determined the encapsulation efficiency (%EE), also the microcapsules were analyzed by laser scanning confocal microscopy, X-ray diffraction and differential scanning calorimetry. The Herschel-Bulkley and Ostwald-deWaele models were found to adequately describe the rheology of formulations so that the consistency coefficient increased with content of MD10. The particle size was markedly lowest for the formulation containing only MD10; this formulation presented a semi-crystalline X-ray pattern while formulations containing MD20 indicated an amorphous pattern and glass transition temperature in the order of 65 °C. MD20-MD10 mixtures 90:10 and 95:05 reported the highest %EE after one microfluidization cycle. In the present work, it was possible to obtain matrix-type microcapsules of VE with high %EE (> 95%).