Green transformation of hemp seed protein: structural modification and functional enhancement with hydrogen-rich...

Recently, various extraction techniques have focused on producing high-quality, low-cost, and eco-friendly proteins; however, they typically demand advanced equipment and substantial energy and solvent use. Molecular hydrogen (H₂) has emerged as a sustainable alternative for protein extraction, demonstrating reduced environmental impacts. Hydrogen-rich water (HRW) enhances protein extraction because of its low surface tension, high solubility, and rapid diffusion rate. The research aimed to elucidate the mechanisms involved in modifying the structure and techno-functional properties of hemp seed protein isolate (HPI) using HRW and to demonstrate its effects on protein yield. In this study, H₂ was bubbled into the alkaline water, and extraction processes were conducted over 15-60 min. Structural assessments (FTIR and FE-SEM) indicated that a 30-min HRW treatment led to significant particle fragmentation, modifications in protein secondary structures, and a reduction in disordered structures. Notably, colloidal stability improved, evidenced by a reduction in zeta potential to -33.07 ± 0.61 mV and particle size to 213.73 ± 8.71 nm. Functional properties were enhanced, including solubility (26.2 ± 1.87% at pH 11), foaming capacity (200 ± 3.13%), emulsion stability (273.14 ± 7.04%), optimal gelling capacity (8%), and oil (2.01 ± 0.02 g/g) and water adsorption capacity (2.23 ± 0.03 g/g). Furthermore, it resulted in higher free sulfhydryl group content (20.85 ± 0.09 μmol/g) and lower disulfide bond content (0.61 ± 0.03 μmol/g). The amino acid profile shifted toward greater hydrophobicity, aligning with improved functional properties. This study is the first to highlight the significant role of HRW in influencing the structural and techno-functional properties of HPI, suggesting its potential as a scalable, sustainable, and effective protein extraction technique.