Characterization and antioxidant activity of an exopolysaccharide produced by Leuconostoc pseudomesenteroides JF17 from juçara fruits (Euterpe edulis Martius)

[Display omitted] •An EPS was produced from L. pseudomesenteroides JF17 isolated from juçara fruit.•The dextran is formed by d-glucose units linked by α-(1→6) bonds.•The EPS have excellent thermal stability, highly porous structure and solubility.•The EPS have good ability to sequestration different free radicals.•The EPS has great potential to industry use as a natural additive or ingredient. Juçara palm tree is considered an important species in the Atlantic forest ecosystem and the exploitation of its fruits is a main sustainable strategy adopted to its maintenance. Among several microorganisms in the juçara fruits, were found lactic acid bacteria (LAB) highly capable of synthesizing exopolysaccharides (EPS). Thus, the EPS synthesized by Leuconostoc pseudomesenteroides JF17 was characterized according to its chemical structure, physicochemical properties and antioxidant activity. HPLC analysis showed that the EPS consisted of a homopolysaccharide composed of glucose units, FT-IR spectroscopy revealed a dextran, confirmed by 1H and 13C NMR spectra which showed the composition of the polysaccharide, d-glucose units bound by α-(1→6). The EPS showed high water retention capacity, 507.812 ± 47.471 %, and may be related to the porous structure revealed by SEM images. Thermal analysis indicated that the EPS had excellent thermal stability with degradation temperature of 320.8 °C and melting point at 279.81 °C, with the enthalpy of 106.557 J/g. The EPS also presented sequestration ability on different free radicals tested, indicating high antioxidant activity. The results suggest that L. pseudomesenteroides JF17 might be widely used in the production of dextran which has potential qualities for applications in the food industry.