Microstructure and physicochemical functional properties of germinate and non-germinate Euryale ferox seed kernels

In order to investigate the primary factors influencing the germination of Euryale ferox seed, two varieties of E. ferox seed, thorny and thornless, were selected as test materials. After an accelerated germination test, the physicochemical components, enzyme activities, microstructure, and functional properties of the germinate and non-germinate seed kernels were analyzed and compared.

The results indicated that the starch content from germinate seed kernels significantly decreased, whereas the α-amylase activity, protease activity, glucose content, soluble protein content, free amino acid content, and total phenol content all significantly increased (P < 0.05). Compared with non-germinate samples, a greater proportion of spherical aggregates in germinate seed kernels exhibited damage, presumably due to the hydrolytic action of endogenous enzymes. Rapid viscosity analysis demonstrated that germination significantly decreased the peak viscosity, final viscosity, and thermal stability of the seed kernels. In comparison with non-germinate seeds, germinate seed kernels exhibited a substantial enhancement in both solubility and swelling power. Additionally, the proportions of α-helix and β-turn decreased significantly (P < 0.05) in proteins from germinate seed kernels, while the proportions of antiparallel β-sheet, parallel β-sheet, and random coil significantly increased (P < 0.05). Furthermore, the short-range order of starch molecules in germinate seed kernels was reduced.

In summary, the activation and elevated activity of endogenous enzymes, particularly α-amylase and protease, are pivotal drivers of E. ferox seed germination. The process entails extensive component transformation and structural remodeling within the seed kernel, primarily mediated through enzymatic hydrolysis, which collectively determines germination potential. © 2026 Society of Chemical Industry.