Experimental and computational insights into starch pasting as influenced by amino acids with different R-groups

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Corn starch (CS) is a widely used biopolymer with versatile applications.
• Understanding the interaction between corn starch and other molecules is crucial for modifying its functional properties.

Purpose of the Study:

• To investigate the impact of glutamic acid (GLU), glutamine (GLN), and theanine (THE) on the pasting and structural characteristics of corn starch.
• To elucidate the molecular interactions between these amino acids and corn starch.

Main Methods:

• Differential Scanning Calorimetry (DSC) for pasting enthalpy.
• Rheological measurements for storage and loss modulus.
• Fourier Transform Infrared Spectroscopy (FTIR) and quantum computation for interaction analysis.
• Molecular dynamics simulations to reveal interaction mechanisms.

Main Results:

• Glutamic acid decreased corn starch viscosity, while glutamine and theanine increased pasting enthalpy.
• All amino acid-starch systems exhibited enhanced storage and loss modulus, indicating increased structural integrity.
• Glutamic acid increased short-range order, whereas glutamine and theanine decreased it.
• Non-covalent interactions (electrostatic and van der Waals forces) were confirmed between amino acids and starch.

Conclusions:

• Amino acids differentially modulate corn starch pasting and structural properties.
• Glutamic acid's interaction with starch weakens starch-water hydrogen bonds, promoting starch chain cross-linking.
• Glutamine and theanine interact via electrostatic and van der Waals forces, respectively, altering starch glycosidic bond configurations.