Enlarging calcium alginate liquid-core capsules: Manufacturing, microstructure, and beverage packaging applications.

Calcium alginate liquid-core capsules (LCCs) are generally produced at the micrometer scale, limiting their application as beverage packaging units. In this work, a freeze-reversed spherification route was developed to fabricate centimeter-scale LCCs and to link alginate chain architecture with shell microstructure, mechanics, and leakage. Using frozen hemispheres of 3% (w/v) CaCl2 as a template, LCCs were formed by incubation with sodium alginate (average G-block length 4.48 ± 0.50) for 7 min. After secondary immersion optimization, the bursting force increased by 19.5%. The resulting LLC exhibited a denser outer layer with reduced interlayer spacing, favorable pore dimensions, and improved water retention. Spectroscopy and molecular descriptors indicated stronger Ca2+-carboxylate binding, higher dimer packing density (α3), and shorter interchain distance (R2), consistent with improved mechanical integrity and reduced leakage during handling. These capsules successfully encapsulated kiwi-fruit and corn juices and maintained sensory quality during storage, supporting their potential in sustainable beverage packaging.