Cationic oxidized microporous rice starch: Preparation, characterization, and properties

Area of Science:

• Materials Science
• Biochemistry
• Chemical Engineering

Background:

• Rice starch (RS) is a widely used biopolymer with potential for functionalization.
• Modifying RS can enhance its properties for various industrial applications.
• Existing methods for RS modification have limitations in performance enhancement.

Purpose of the Study:

• To functionalize rice starch (RS) through a combination of enzymolysis, oxidation, and cationic etherification.
• To investigate the impact of these modifications on the physicochemical properties of RS.
• To explore the potential applications of the modified RS, particularly as an adsorbent.

Main Methods:

• Compound enzyme enzymolysis of RS.
• Oxidation of RS using sodium hypochlorite.
• Cationic etherification of RS with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMA).
• Analysis of structural, thermal, pasting, and morphological properties of modified RS.

Main Results:

• Oxidation and etherification improved acid/alkali resistance and thermal stability of RS.
• All modifications reduced RS crystallinity degree but did not alter its A-type crystalline structure.
• Enzymolysis, oxidation, and etherification decreased RS setback and breakdown, altering pasting properties.
• Oxidation damaged RS particles, while enzymolysis and oxidation more severely affected the crystalline region.
• Cationic etherification enhanced Cu2+ adsorption, while low oxidation had a minor effect.

Conclusions:

• The combined functionalization of RS yields a material with enhanced stability and modified properties.
• Modified RS exhibits potential for use as an adsorbent, slow-release agent, and flocculant.
• The resulting cationic oxidized microporous rice starch is suitable for applications in food, medicine, papermaking, and wastewater treatment.