Lactobacillus-fermented oats as future probiotics

Oat-derived products are popular dairy alternatives in the Nordic countries due to their rich nutrient profile and adaptability to temperate climates. However, there is still a lack of oat-based replacements for fermented dairy products such as probiotic-rich yoghurts and fermented milks. This study had a two-fold objective: i) to achieve growth of the exopolysaccharide (EPS)-producing probiotic strain Lactobacillus delbrueckii subsp. bulgaricus on the oat substrate, and (ii) to determine the impact of fermentation on the lipid profile of the oat substrate. Bacterial growth was investigated at 37°C and 30°C, which are optimal for growth and EPS production, respectively. Cell growth was closely monitored, with the highest viable count recorded at 1×10⁷ cells/mL, as determined using a Neubauer chamber. The prebiotic EPS produced during fermentation was extracted after maximum growth. Bacterial EPS is typically indicated by the presence of O-H, C-H, and C=O bonds, which corresponds to FTIR absorption bands at 3400 cm^-1, 2925 cm^-1, and 1640 cm^-1. These bands were detected in the samples. These results suggest that the Lactobacillus strain was able to produce EPS when cultivated on oats. A significant (p<0.05) increase in the total lipid content of the fermented oats (5.26 ± 0.04%) was observed, including a marked increase in mono- and polyunsaturated fatty acids such as oleic (1.84± 0.01%) and linoleic acid (2.09± 0.02%), as measured by gas chromatography. Thus, these beneficial nutritional improvements suggest that fermented oats could serve as a promising dairy-free probiotic alternative.