Physical Properties of Gelatin-Based Hydrogels Incorporated with Soybean Straw Nanocellulose Obtained by Enzymatic Hydrolysis.

Gelatin hydrogels for food packaging applications have aroused interest in recent years. However, these hydrogels exhibit several limitations, such as poor mechanical strength and low swelling and water uptake. To overcome these challenges, nanocellulose can be used as a nanofiller. Thus, cellulose nanofibrils (CNFs) were obtained from soybean straw and used as a nanofiller for hydrogels produced with type A and B gelatin. The effects of the biopolymer type and the influence of CNF concentrations (0-3.0%, w/w) on the properties of hydrogels were studied. The CNFs exhibited a fiber morphology with micrometer length and nanometer diameter (16.8 ± 1.2 nm). The addition of CNFs (0-3%, w/w) caused a decrease in the stress (~50%) and elongation (~14%) at the fracture of the hydrogels for both type of gelatin. However, the elastic modulus increased (~20%). The addition of CNFs increased the hardness of the hydrogels up to 25%. The swelling capacity decreased by ~30% when the CNF concentration increased from 0 to 3%, while the thermal properties and chemical structure were not altered. These findings provide valuable insights for ongoing research into the incorporation of nanocellulose in biopolymer-based hydrogels produced by physical and sustainable methods for food packaging applications.