Structural, Physicochemical, and Functional Properties of Electrolyzed Cassava Starch

Area of Science:

• Food Science
• Materials Science
• Electrochemistry

Background:

• Cassava starch is a widely used biopolymer with potential for modification.
• Oxidation can alter starch properties, but traditional methods may have limitations.
• Electrochemical oxidation offers a controlled and potentially greener approach.

Purpose of the Study:

• To investigate the electrochemical oxidation of cassava starch using varying sodium chloride (NaCl) concentrations.
• To characterize the physical and chemical changes in the starch granules.
• To evaluate the impact of oxidation on starch molecular weight, retrogradation, swelling, and clarity.

Main Methods:

• Cassava starch was oxidized via an electrolysis system.
• Sodium chloride (NaCl) concentrations ranged from 0.5% to 5.0% (w/v).
• Characterization included whiteness measurement, scanning electron microscopy, Fourier-transformal infrared spectroscopy (FTIR), X-ray diffraction (XRD), intrinsic viscosity measurements, and analysis of swelling factor and clarity.

Main Results:

• Starch whiteness increased proportionally with NaCl concentration.
• Surface dents were observed on starch granules, and carbonyl/carboxyl groups increased.
• Oxidized starch retained its A-type crystalline structure, with modifications primarily in amorphous regions.
• Average molecular weight significantly decreased (2.09- to 13.22-fold) with increasing NaCl concentration.
• Higher NaCl content correlated with increased starch retrogradation.
• Swelling factor and clarity showed negative and positive correlations, respectively, with NaCl concentration across various temperatures.

Conclusions:

• Electrochemical oxidation effectively modifies cassava starch properties.
• NaCl concentration is a critical factor influencing the degree of oxidation and resulting starch characteristics.
• The method offers a tunable approach to alter starch molecular weight, whiteness, and thermal properties.