Relationships of cereal β-glucan structural and physicochemical characteristics with Lactobacillus plantarum encapsulation and viability in alginate-based microgels.

The molecular structure of cereal-derived β-glucans is essential in determining their physicochemical properties. This study showed how β-glucan DP3:DP4 ratio affects self-assembly kinetics and network stability for probiotic protection. Barley β-glucan (BBG, DP3:DP4 = 2.4) formed rapid entanglement-driven 3D microporous gels, while oat β-glucan (OBG, DP3:DP4 = 1.8) formed slower lamellar networks. BBG's network structure limited ice crystal growth, with semi-crystalline domain resisted thermal collapse (melting peak >63 °C), and reduced osmotic swelling through chain entanglement. These properties allowed BBG to maintain probiotic viability after freeze-drying (65.7 % survival compared to OBG's 27.1 %), thermal sterilization (8.3 log CFU/g at 68 °C), and digestion (9.24 log CFU/g retention). At the molecular level, DP3-enriched chains increased crosslinking density and bacterial adsorption, synergistically protecting probiotics. These results emphasize the importance of β-glucan fine structure (DP3:DP4 ratio) in encapsulation performance, showing BBG as a better material for probiotic delivery systems.