Metagenomic analysis of microbial dynamics in water kefir grains: influence of soy protein on biomass growth and the development of an alternative beverage

Abstract The primary aim of this article is to determine changes in the microbial community within current water kefir grains when developed in a protein-supplemented medium through metagenomic analysis. The nutrient media directly alter the structures containing complex microbial communities in nature. Considering the much more complex human gut microbiota, many articles indicate changes due to nutrition. This study also confirms that this grain system changes with the applied nutrients. The second aim is to create alternatives for the current water kefir beverage, increase its consumption, and provide recommendations for the industry. The second objective is to create alternatives for the current water kefir beverage and increase its consumption. The properties of these beverages were determined through chemical, sugar composition, microbiological, and sensory analyses. The research identified that the microbial content in water kefir grains changes, resulting in a high biomass structure due to the increased presence of bacteria producing excessive exopolysaccharides. Based on all analysis findings, the ginger and basil-flavoured beverage group was determined to be the most suitable product. Further research is required to optimise other flavour components.