Tertiary enzyme synergistic network-mediated starch-directed transformation into resistant starch

Area of Science:

• Food Science
• Biochemistry
• Material Science

Background:

• Resistant starch (RS) offers health benefits but requires structural modification for enhanced production.
• Enzymatic hydrolysis is a key method for altering starch structure and properties.
• Pea starch is a viable substrate for modification due to its availability and composition.

Purpose of the Study:

• To investigate the structural changes in pea starch modified by different enzyme combinations.
• To evaluate the impact of enzymatic modification on resistant starch content and glycemic index.
• To explore the potential of enzyme-modified pea starch as a functional ingredient.

Main Methods:

• Pea starch was modified using combinations of α-amylase, 4-α-glucanotransferase, and pullulanase.
• Structural analysis included determination of branching degree, crystal structure, and chain length distribution.
• Resistant starch content and glycemic index were measured before and after cooking.

Main Results:

• Triple-enzyme modification reduced branching degree by 37.51% and shifted crystal structure from C-type to B-type.
• Crystallinity increased to 37.21%, with elevated proportions of B1 and B2 chains.
• Maximum resistant starch content reached 56.77%, and glycemic index decreased by 9.43%; modified starch retained >30% RS after cooking.

Conclusions:

• Enzymatic modification, particularly triple-enzyme treatment, effectively enhances resistant starch content and reduces glycemic index in pea starch.
• Structural reorganization, including reduced branching and altered crystallinity, underpins these functional improvements.
• This study provides a foundation for developing novel functional starches with improved health attributes.