Probiotic fermentation modifies the structures of pectic polysaccharides from carrot pulp

Area of Science:

• Food Science
• Biochemistry
• Carbohydrate Chemistry

Background:

• Water-soluble polysaccharides (WSP) from fermented carrot pulp (WSP-p) show enhanced anti-diabetic properties compared to unfermented WSP (WSP-n).
• Understanding the structural basis for these functional differences is crucial for optimizing their use in functional foods.

Purpose of the Study:

• To elucidate the molecular structural differences between WSP-p and WSP-n.
• To correlate structural variations with potential functional implications.

Main Methods:

• Comparative analysis of molecular weight distribution using weight-average molecular weight.
• Surface morphology examination via microscopy.
• Monosaccharide composition and methylation analysis.
• Nuclear Magnetic Resonance (NMR) spectroscopy (¹H and ¹³C) to determine linkage patterns.

Main Results:

• WSP-p fractions exhibited lower weight-average molecular weights than WSP-n fractions.
• Both WSP-p and WSP-n were identified as pectic polysaccharides, primarily rhamnogalacturonan-I type.
• NMR analysis revealed similar linkage patterns, but fermentation appeared to cleave inter-unit linkages.
• Surface analysis indicated more fragmented particles on WSP-n compared to WSP-p.

Conclusions:

• Probiotic fermentation of carrot pulp polysaccharides leads to reduced molecular weight and altered particle structure.
• These structural modifications, particularly the cleavage of linkages, are likely responsible for the enhanced anti-diabetic effects observed in WSP-p.