Oral delivery of microbiome-modulating synbiotics derived from kefir via alginate encapsulation systems

• Main Author: Tan, Li Ling
• Other Authors: Loo Say Chye Joachim
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Biomaterials; Science::Biological sciences::Microbiology
• Online Access: https://hdl.handle.net/10356/164624
• Institution: Nanyang Technological University

Probiotics and prebiotics, collectively known as synbiotics, have become increasingly popular in recent years as preventative health nutritive ingredients, due to their ability to modulate the human gut microbiota. A search for novel probiotics and prebiotics exists to add diversity to existing candidates and unlock different mechanisms for health efficacies. This research zooms in on the fermented beverage, kefir, as a source of novel probiotics and prebiotics, and is interested in the characterisation of these components for use as functional health ingredients. Various phenotypic and genotypic screening assays were conducted to identify kefir probiotic strains with highest probiotic potential, while material extraction, structural analysis, and screening methods were employed to derive potential prebiotic materials from kefir. The synergistic effects of kefir prebiotics and prebiotics was also studied, and the resultant synbiotics formulation was evaluated for its inhibitory properties against enteric pathogens, effects on simulated large bowel microbiota communities, and short chain fatty acids production. In addition, this research explores methods of encapsulating probiotics to facilitate their delivery to the human intestine and incorporation into food and beverage products. Two techniques, extrusion and spray-drying were used for probiotics encapsulation. These encapsulation systems were found to improve the acid survivability, bile resistance, and shelf-life stability of encapsulated probiotics, and facilitated incorporation of probiotics into beverages, such as carbonated sodas and beers. This thesis has established several interesting probiotic strains and prebiotic materials, and demonstrated the utility of probiotic encapsulation systems based on extrusion and spray-drying techniques. Moving forward, in vivo animal testing and clinical trials are required to further realise the commercial potential of these kefir-derived synbiotics and probiotics delivery systems in various industrial applications, including in the pharmaceuticals, dietary supplements, food and beverages, and animal feeds sectors.