Oxidative cross-linking of pectic polysaccharides from sugar beet pulp

Area of Science:

• Food Science
• Biochemistry
• Polymer Chemistry

Background:

• Pectin, a complex polysaccharide, is widely used in the food industry.
• Understanding pectin cross-linking is crucial for controlling its functional properties.
• Oxidative reactions offer potential for modifying pectin structure and performance.

Purpose of the Study:

• To investigate the oxidative cross-linking of beet pectin extracts.
• To analyze the impact of different oxidative systems on pectin viscosity and gel formation.
• To identify the specific pectin components involved in cross-linking.

Main Methods:

• Extraction of pectin from beet sources using autoclaving and acid treatments.
• Oxidative cross-linking using hydrogen peroxide/peroxidase and ammonium persulfate.
• Viscosity measurements and gel formation concentration determination.
• Analysis of molecular weight changes and dehydrodimer formation.

Main Results:

• Hydrogen peroxide/peroxidase treatment increased viscosity and formed gels at specific concentrations (1.5-3%).
• Autoclaved pectin cross-linking involved rhamnogalacturonans and possibly arabinans.
• Ammonium persulfate decreased viscosity and molecular weight in autoclaved extracts but increased viscosity in acid-extracted pectin.
• The 8-5 dehydrodimer was the predominant cross-linking product in both systems.

Conclusions:

• Oxidative cross-linking significantly alters beet pectin properties, enabling gel formation and viscosity modification.
• The choice of oxidative agent and pectin extraction method influences the cross-linking mechanism and outcomes.
• Rhamnogalacturonans are key structural elements participating in oxidative cross-linking of beet pectin.