Plant-Based Milk Alternatives in Kefir Production: A Review

Kefir is a traditional fermented beverage enriched with microorganisms, predominantly lactic acid bacteria (LAB) and yeasts, and is conventionally produced from animal-derived milks. However, the rising prevalence of lactose intolerance, the growing adoption of vegan diets, and increasing environmental sustainability concerns have stimulated interest in the utilization of plant-based milk alternatives for kefir production. Plant-based milks, such as those derived from soy, rice, oats, almonds, hemp, coconuts, and legume-based milks, present diverse nutritional compositions, bioactive compound profiles, and fermentation behaviors. Their protein, carbohydrate, and lipid contents directly influence the metabolic activity and growth of the symbiotic microbiota in kefir grains. Plant-based kefirs are of particular interest as functional foods, owing to their cholesterol-free composition, presence of phytochemicals such as phenolic compounds and phytosterols, and lactose-free nature. Nevertheless, challenges remain in achieving desirable sensory attributes, ensuring microbial adaptation, extending shelf life, and standardizing industrial-scale production processes. This review critically evaluates the suitability of plant-based milks for kefir production by integrating findings from recent studies and highlights their potential to align with sustainable food manufacturing, food safety considerations, shelf-life requirements, and evolving consumer health preferences.