Effects of L-glutamic acid on wheat starch structure and functionality: multiscale characterization and molecular...

Area of Science:

• Agricultural Science
• Biochemistry
• Material Science

Background:

• L-Glutamic acid (L-Glu) plays a key role in carbon-nitrogen metabolism.
• Its specific effects on starch quality, grain metabolism, and starch structure are not fully understood.

Purpose of the Study:

• To investigate the impact of L-Glu on grain metabolism and starch structure under drought conditions.
• To elucidate the mechanisms by which L-Glu modulates starch physicochemical properties.

Main Methods:

• Integrated field and in vitro experiments.
• Utilized untargeted metabolomics, microscopy, structural characterization (Raman, FTIR), physicochemical analyses, and molecular dynamics simulations.

Main Results:

• L-Glu spraying under drought reprogrammed grain metabolome, enriching aminoacyl-tRNA biosynthesis and starch/sucrose metabolism pathways.
• In vitro, L-Glu altered starch's molecular structure (Raman, FTIR), enhanced digestibility, reduced swelling power and paste transparency.
• L-Glu decreased short-term starch retrogradation but reduced freeze-thaw stability, forming hydrogen bonds with amylose and water.

Conclusions:

• L-Glutamic acid influences grain metabolism and directly modulates starch structure and properties.
• L-Glu shows potential for modifying starch characteristics, impacting digestibility and retrogradation.
• Further research is needed to optimize L-Glu application for desired starch functionalities.