Physicochemical and Structural Characterization of Composite Gels of Commercial Hemp Seed Protein Concentrate and...

Hemp seed protein hydrolysate (HSPH), despite its high digestibility and solubility, exhibits severely impaired gelation properties due to extensive hydrolysis, thereby limiting its food applications. This study analyzed the effect of homogeneously incorporating commercial hemp seed protein concentrate (HSPC) into HSPH on physicochemical and structural properties of the resultant composite gels. As the HSPC concentration increased from 100 to 150 mg/mL, the composite gels exhibited a significant enhancement in hardness (p < 0.05), increasing from 1.63 to 5.74 N, along with an improvement in water-holding capacity (WHC) from 45.52 to 55.46 g/g. Concurrently, the storage modulus (G') and gelation temperature increased, with the latter rising from 65 to 78 °C. SDS-PAGE analysis suggested that the enhanced composite gel properties were attributed to its high-molecular-weight protein fractions (10-15 kDa and 40-50 kDa) of HSPC, which functioned as the primary structural components of the gel network. In addition, the formation of denser yet irregular microstructures was observed by scanning electron microscopy (SEM) analysis when HSPC incorporation increased from 0 to 200 mg/mL. Fourier-transform infrared (FTIR) further suggested that these improvements were due to increases in β-turn and random coil contents by approximately 9.60 and 7.73%, respectively. These findings provided insights into the utilization of HSPH and HSPC in plant-based foods and contributed to food security and sustainable agriculture.