Encapsulation of beetroot extract (Beta vulgaris L.) obtained by internal and external ionic gelation: a comparative study

Natural pigments, like betalains found in beets, are sensitive to environmental conditions, which may impact their reactivity and shelf-life. Microencapsulation is an attractive alternative for delivering these compounds, offering protection through polymeric microcapsules. The aim of this study was to compare two ionic gelation methodologies, external (EG) and internal gelation (IG), in the microencapsulation of beet aqueous extract. Particles were obtained by mixing sodium alginate with the aqueous extract of beetroot and crosslinking with calcium chloride solution using the extrusion method. Encapsulation characteristics and physical, morphological features were evaluated. The particles showed 10.72 and 89.90% encapsulation efficiency for EG and IG, respectively. Loading capacity was 18.90% for EG and 25.60% for IG. Those IG particles showed superior water absorption capacity during rehydration. Texture analysis indicated that EG particles showed greater hardness. Release kinetics indicated that EG particles followed the Korsmeyer-Peppas model, while IG particles followed the Higuchi model. Thus, the appropriate encapsulation technique should be selected depending on the food matrix to be used and the specific objective of delivering the active encapsulated molecules.