Review on kefir beverages from milk and water: health benefits, processing and applications

Kefir is a trending and highly valued fermented beverage known for its beneficial microbes and giving a wide spectrum of health benefits. It includes milk kefir and water kefir which have gained separate attention. Although milk kefir is more heard of than water kefir, it is essential to understand both in greater details in terms of similarities and differences. The key health benefits such as probiotics, protection in the gastrointestinal tract, control of glucose level, antioxidant, antimutagenic, anticarcinogenic, regulating cholesterol, antimicrobial and improving lactose digestion are discussed and supported with recent in-vivo or in-vitro scientific evidences. This review addresses the gap of individual focus of each kefir by direct comparison of its microbial diversity, processing and physicochemical qualities. It provides updated information on lactic acid bacteria by species from advanced techniques of metagenomic analysis and also highlights the potential of kefiran, exopolysaccharides of milk kefir grains in food, biopharmaceutical and packaging industries.