Dextrans of Weissella cibaria DSM14295: Microbial production, structure and functionality

Area of Science:

• Food Microbiology
• Biochemistry
• Material Science

Background:

• Weissella bacteria contribute to food fermentations but lack starter culture status due to safety assessments.
• Some Weissella strains produce exopolysaccharides, like dextrans, with potential techno-functional properties.

Purpose of the Study:

• To investigate the techno-functionality of dextrans from W. cibaria DSM14295.
• To correlate dextran structure and macromolecular properties with fermentation conditions.

Main Methods:

• Cultivation of W. cibaria under varying conditions, including a "cold shift" temperature regime.
• Characterization of dextrans using HPSEC-RI/MALLS, methylation analysis, and HPAEC-PAD.
• Assessment of dextran functionality in acid milk gels and analysis of moisture sorption and branching properties.

Main Results:

• High dextran yield (23.1 g/L) achieved with the "cold shift" method.
• Dextrans exhibited diverse molecular masses (9-22×10^8 Da), intrinsic viscosities (52-73 mL/g), and branching degrees (3.8-5.7%).
• Dextran concentration linearly correlated with increased stiffness in acid milk gels.

Conclusions:

• Dextrans from W. cibaria DSM14295 possess significant potential for food applications.
• Fermentation conditions can tailor dextran functionality and properties.
• Further research is needed to address safety assessments for Weissella starter culture applications.