Determination of molecular driving forces involved in heat-induced corn germ proteins gelation

• Molecular forces involved in corn germ protein gelation were determined by various reagents.
• Both covalent and non-covalent bonds were involved in corn germ protein gelation.
• Disulfide bond played a major role in maintaining gel stiffness.
• Hydrogen bond was more important than hydrophobic interaction.

Molecular forces involved in corn germ proteins (CGP) gelation were investigated using a rheometer. With the inclusion of urea and guanidine hydrochloride (GuHCl), the storage moduli (G′) of CGP gels tends to decrease. This is an indication that hydrophobic interactions and hydrogen bonds are present. The involvement of propylene glycol (PG) provides evidence that hydrogen bonds and electrostatic interactions are present. The impact of thiocyanate (NaSCN) and sodium sulfate (Na2SO4) further proves the involvement of hydrogen bonds. The effects of 2-mercaptoethanol (2-ME) and N-ethylmaleimide (NEM) reveal that involvement of disulfide bonds contribute to CGP gel stiffness. Reheating and recooling tests revealed that during the initial cooling phase the gel is thermally reversible and higher levels of G′ suggested more hydrogen bonds are formed when recooled. It can be deduced that hydrogen bonds play a greater role than hydrophobic interactions from the increasing G′ during cooling and recooling.