Optimization and fractional characterization of exopolysaccharides produced by Leuconostoc mesenteroides subsp. jonggajibkimchii obtained from Kanji and their utilization in vitamin D nanoemulsion-fortified yogurt as stabilizers.

Bacterial polysaccharides are significant substitutes for plant polysaccharides in fermented foods and have a potential role in drug delivery systems, especially for lipophilic compounds. Several studies have focused on optimizing fermentation parameters to enhance exopolysaccharide production. The present study aimed to optimize the fermentation conditions for exopolysaccharide production from Leuconostoc mesenteroides subsp. jonggajibkimchii NCCP 961 obtained from the fermented Daucus carota drink "Kanji". The composition of the medium was optimized using the Plackett-Burman design and central composite rotatable design with response surface methodology to maximize the exopolysaccharide yield. Exopolysaccharide-based cholecalciferol nanoemulsion-fortified yogurt was made, and its sensory attributes were studied. L. mesenteroides subsp. jonggajibkimchii NCCP 961 produced a maximum yield of 898.2 mg L-1 after 48 h of incubation at optimized levels of 9.749% sucrose, 6.141% glucose, 0.015% CaCl2, and 0.680% tryptone. Characterization techniques revealed that this native strain produced an exopolysaccharide based on dextran with β-(1-6) glycosidic linkages, exhibiting a highly porous, predominantly amorphous, non-crystalline structure and higher thermal stability. The functional attributes such as water-holding capacity, oil-holding capacity, emulsion capacity, and foaming ability were 505.18% ± 13.32%, 545.05% ± 10.56%, 40.14% ± 6.57%, and 30.25% ± 3.87%, respectively. The nanoemulsion-fortified yogurt showed remarkable texture, uniformity, odor intensity, and taste values. Additionally, using this exopolysaccharide based on dextran with nanomaterials or copolymers holds promise for addressing vitamin D deficiency via fortification.