Microencapsulation of probiotics by multiple emulsion using protein– polysaccharide blends: seawater stability and viability for aquaculture

The stability and viability of probiotic strains L. acidophilus and L. plantarum microencapsulated via double-emulsion (W₁/O/W₂) coupled with spray drying were characterized for shrimp larval culture. Three protein–polysaccharide blends (A: WPI/CMC/PEC; B: WPI/GA/MD; C: WPI/MD) were tested in a factorial design at 5, 8 and 10% total solids. Microcapsules were characterized by particle size, dissolution, buoyancy, and survival to the drying process. Two-way ANOVA revealed a significant blend × solids interaction (p < 0.001); blend B at 10% solids (B10) exhibited the lowest dissolution (4.5%, 95% bootstrap CI 4.10–4.90) and was re-encapsulated at two probiotic loads. Viability, quantified by plate counting and LIVE/DEAD fluorescence, showed close agreement (Lin's CCC = 0.997; paired permutation p = 0.43). After six months at 4°C, both formulations retained > 10⁸ CFU g⁻¹. An indicative resampling-based projection suggested that the high-load formulations maintain > 10⁸ CFU g⁻¹ beyond the tested period, pending confirmation with additional timepoints. The system emerges as a robust, sustainable alternative to antibiotics for shrimp larviculture. Beyond aquaculture, this encapsulation approach illustrates how biopolymer design can safeguard sensitive bioactive microorganisms during processing and storage, with promising applications in functional foods and veterinary science.