Abstract. Functional foods are a crucial component for maintaining individuals’ well-being and nutrition in individuals with specific constraints, for example, gastrointestinal issues, intestinal disorders, lactose and gluten intolerance. The ability to modify the composition of food products by lactic acid bacteria (LAB) fermentation processes makes it possible to obtain functional products that could be the basis of healthy or wellness nutrition. The study examined the potential use of Lactobacillus delbrueckii for the fermentation of apple juice and investigated the organoleptic properties, as well as the concentration of macro- and microelements, total acidity, and vitamin C content. Organoleptic indicators are better in fermented juices than in non-fermented ones because they have a richer taste and aroma. The apple aroma is less strong in the sample without glucose added at the beginning of fermentation than in the sample with glucose added at the beginning of fermentation. The work showed that fermented L. delbrueckii apple juice with pre-added glucose at a final concentration of 2% before the start of fermentation, has more potassium and vitamin C content than unfermented juice. There was no significant influence on the content of magnesium and glucose in fermented apple juice. During fermentation, the total acidity of fermented apple juice with pre-introduced glucose decreased by 12%. The obtained results indicate that adding glucose at the beginning of fermentation allows for better modification of the final properties of the juice. It has been demonstrated that this method could be used to develop a functional product based on apple juice.