Functional characterization of the riboflavin-overproducing and dextran-producing Weissella cibaria BAL3C-5 C120T strain for the development of biofortified plant-based beverages

Riboflavin (vitamin B₂) is essential for human beings and it has to be provided by healthy nutrition. The use of fermentation with riboflavin-overproducing lactic acid bacteria (LAB) represents an ideal strategy to generate, by in situ biofortification, functional drinks. These beverages can positively contribute to consumer health and address nutritional deficiencies. In the present work, the functional capabilities of Weissella cibaria BAL3C-5 C120T for riboflavin-overproduction and dextran-production during fermentation of oat-, rice-, soybean- and almond-based drinks have been evaluated. It was confirmed that the strain was capable of producing riboflavin and dextran in the analysed drinks. This property was especially pronounced in the oat-based drink, where after 24 h of fermentation the strain was able to increase riboflavin and dextran levels up to 3.4 mg/L and 3.2 g/L, respectively. Moreover, under optimized conditions the strain was able to enrich the fermented oat-based drinks with the prebiotic oligosaccharide panose (up to 6.6 g/L). In addition, in the oat-based drinks BAL3C-5 C120T showed a good pH-lowering ability (from 7.0 to 3.8) as well as a high 80 % cell viability after one month of storage. Rheological analysis of the resulting fermented oat-based beverages revealed a thixotropic structure related to a gel-like behaviour which was not observed in the non-fermented control drinks. In summary, these results confirmed the unique characteristics of W. cibaria BAL3C-5 C120T strain for the development of biofortified and functional plant-based beverages with improved nutritional and rheological properties. Analysis of the BAL3C-5 C120T strain survival under gastrointestinal conditions and its autoaggregation properties, also indicated its potential use as a probiotic delivered in an oat-based fermented beverage. In this context, this study also promotes the utilization of W. cibaria species in health and food industries where it has not yet been used as a starter or adjunct culture.