Heat-killed Lacticaseibacillus casei OS1423 retains immunoprotective functionality across ingredient and adlay tea...

Area of Science:

• Food Science
• Immunology
• Microbiology

Background:

• Functional foods increasingly seek microbial ingredients with probiotic benefits, independent of cellular viability.
• Heat-killed (HK) probiotics offer potential advantages for food applications due to enhanced stability.

Purpose of the Study:

• To evaluate the immunomodulatory activity of heat-killed Lacticaseibacillus casei OS1423 and Lactobacillus paracasei OS1213.
• To assess the feasibility of incorporating HK probiotics into food matrices, specifically a grain-based beverage.

Main Methods:

• A cyclophosphamide (CP)-induced immunosuppressed mouse model was used to compare live and HK probiotic preparations.
• Immune parameters including cytokine responses, splenocyte proliferation, and immunoglobulin production were measured.
• HK L. casei OS1423 was incorporated into an adlay tea to assess beverage application feasibility.

Main Results:

• HK probiotic preparations partially restored cytokine responses, splenocyte proliferation, and immunoglobulin production in immunosuppressed mice.
• Supplementation modulated gut microbiota composition, aiding recovery of homeostasis-associated bacteria.
• The adlay tea fortified with HK L. casei OS1423 retained key immunomodulatory activities, including mucosal cytokine recovery and IgA restoration.

Conclusions:

• Heat-killed probiotics maintain significant immunomodulatory functions despite loss of viability.
• HK probiotics are viable functional ingredients for food applications, particularly grain-based beverages for immune health support.