Metal-phenolic networks enhanced the protection of excipients for probiotics during freeze-drying

Probiotic powder using a single protective method during freeze-drying is insufficient vitality because it lacks adequate protection. Here we developed a protection strategy through biointerfacial phenolic self-assembly to enhance the protection of excipients for probiotics to address existing challenges during freeze-drying. This strategy could strengthen the connections of excipients and phenolic protective layers containing hydroxyl groups with water molecules, improving the hydration layer's preservation and shielding bacteria from damage. The results indicated that, compared with origin probiotics, protected probiotics maintained higher viability at approximately 91 % and higher ATPase activity and exhibited a better survival rate in various environmental challenges after freeze-drying. The broad applicability of this protection strategy was confirmed across other LAB strains. Additionally, the protected probiotics demonstrated superior shelf life during 30 days of storage, indicating promising prospects for preparing bacterial powder via freeze-drying.