Chemical profiling, molecular docking, and harnessing Manuka honey's antimicrobial and prebiotic potential in probiotic milk and yoghurt

Abstract

The nutritional and therapeutic properties of Manuka honey (MH) constituted a major interest of the scientific community. The current study characterized the chemical composition of New Zealand MH via LC-HRMS/MS unveiling its richness in 59 compounds. MH antimicrobial activity was assessed against 7 microbial strains where E. coli was the most sensitive followed by P. aeruginosa. Two longitudinal studies were conducted, one examined MH potential use as a prebiotic with Bifidobacterium bifidum in functional probiotic milk, while the other examined its feasibility as a natural antimicrobial additive against E. coli ATCC 25922 in lab-manufactured yoghurt while maintaining the starter culture activity. MH (10 %) had no adverse effect on yoghurt starter culture activity despite significantly enhancing B. bifidum growth in probiotic milk (p > 0.05). MH-fortified yoghurt showed higher sensory acceptability with no significant difference compared to control group (p < 0.05) despite the lower overall acceptability score of MH-fortified milk. Furthermore, E. coli viability was significantly reduced by two logs in 10 % MH-fortified pasteurized milk by the end of the 14th day and completely disappeared by the 5th day of storage period of 10 % MH-fortified yoghurt (p < 0.05). Additionally, molecular docking studies in E. coli DNA gyrase and Pseudomonas quorum sensing QscR enzymes manifested the role of eleven of MH components as powerful binders of these enzymatic pockets; thus, further confirming its antimicrobial and quorum sensing inhibitor activities in the biological system. Finally, this study emphasized that MH is an exquisite natural functional alternative, which opens new avenues for MH's application in dairy sector, not only as a natural sweetener but also as a prebiotic and natural antimicrobial food preservative.