Arabinogalactan in the metabolism technology of probiotic culture in a plant-based drink medium

Plant-based oat milk drinks, serving as a source of beneficial fiber, essential amino acids, fats, and carbohydrates, as well as vitamins and minerals, represent an alternative to traditional dairy products. However, plant-based drinks may contain bioactive components that hinder the absorption of nutrients, and enhancing the nutritional value of plant-based drinks, improving their sensory characteristics, possibly through fermentation, is feasible. Increasing fermentation activity is possible by introducing prebiotics, particularly arabinogalactan, which is the focus of our research. As a basis for the plant probiotic drink, oat milk was chosen, and a complex probiotic culture starter was used: Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus casei, with arabinogalactan added at a concentration of 0.5 to 3 % by weight of the drink. Preliminary studies have shown that the most favorable addition of arabinogalactan occurs during the fermentation stage along with the starter culture. The efficiency of the fermentation process was assessed by changes in titratable acidity, accumulation of lactic acid, exopolysaccharides, and the antioxidant activity of the produced probiotic drinks. The conducted research has demonstrated the ability of the complex probiotic culture starter, including Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus casei, to thrive in the plant-based oat drink environment. Under optimal conditions for the development of these microbial strains, a fermented product with high sensory properties is produced. The introduction of the arabinogalactan polysaccharide during the fermentation stage of the plant-based medium activates the fermentation process, resulting in an intensification of changes in titratable acidity and accumulation of lactic acid - on average by 9-22.7 %, an increase in the amount of exopolysaccharides by 15.8-54 %. Improvement in the functional properties of probiotic plant-based drinks has also been observed, particularly in enhancing their antioxidant activity by 37.7-93.4 %. These changes are reflected in the consistency and uniformity of the drink structure, as well as its aromatic and flavor profile.