Mechanism of L-arginine improving the macroscopic and microscopic qualities of Acipenser schrenckii surimi gel under low-salt conditions and microwave irradiation: Significance of moisture migration and distribution

Abstract

This study explored the mechanism by which L-arginine (L-Arg) enhanced the characteristics of low-salt sturgeon (Acipenser schrenckii) surimi gels under microwave (MW) irradiation, focusing on the changes in the distribution and migration of water molecules. The findings indicated that L-Arg shortened the gel formation time from MW 3 min to MW 2 min. Moreover, the addition of 2% L-Arg optimized the gel properties, achieving the highest water holding capacity (83.24%), resilience (48.34 cm), and cohesion (0.80) at MW 3 min (P < 0.05). Additionally, cryo-scanning electron microscopy showed that the fractal dimension and porosity of the gel network enhanced and decreased, respectively, with the increasing content of L-Arg. These improvements in macroscopic and microscopic qualities were related to the transformation of free water into immobilized water and the more uniform distribution of hydrogen protons under the MW irradiation promoted by L-Arg, as demonstrated by the magnetic resonance imaging and Pearson correlation analysis. This study provided novel insights into overcoming the challenges associated with MW processing in surimi products.