Abstract: The effect and regulatory mechanism of urea on the properties and non-covalent intermolecular forces of heat-induced myofibrillar protein gel were studied. The relationship between intermolecular forces and gel properties was explored. This study discussed whether urea addition is a scientific method for studying gel hydrogen bonding and hydrophobic interaction. Heat-induced myofibrillar protein gels containing 0.0?0.4 mol/L urea were prepared. The electrostatic interaction was measured using a zeta potential analyzer. The hydrophobic interaction and hydrogen bonding were measured using a Raman spectrometer. The water-holding capacity, hardness and springiness of the gels were measured by a centrifugation method and a texture analyzer. As urea concentration increased, the absolute value of zeta potential of the gels decreased from 7.83 to 5.55 mV, and the surface hydrophobicity (S0-ANS) of myofibrillar protein increased from 698.5 to 885.3. The I760 cm-1/I1 003 cm-1 ratio (normalized intensity) decreased from 0.957 1 to 0.849 3, while the I850 cm-1/I830 cm-1 ratio declined first and then increased. The water-holding capacity, hardness and springiness exhibited a declining trend. Correlation analysis showed that electrostatic interaction, surface hydrophobicity and hydrophobic interaction had a significant effect on water-holding capacity and texture characteristics of heat-induced protein gel.

Key words: myofibrillar protein gel, urea, electrostatic interaction, hydrophobic interaction, hydrogen bond