Binding mechanism and structural characteristics of alloyed protein complex for enhanced solubility of hemp seed protein isolate

Despite the numerous health benefits and high digestibility of hemp seed protein isolate (HPI), its low solubility at neutral pH limits its utilization in the food industry. Therefore, we subjected insoluble HPI and soluble mung bean protein isolate (MBPI) to pH co-shifting under extremely alkaline conditions to form an alloyed protein complex (A-HM). At a mass ratio of HPI:MBPI of 50:50, A-HM exhibited the highest solubility (95.30 ± 0.99 %), and also had high resistance to heat treatment. Native PAGE demonstrated the formation of alloyed protein complexes, and particle size analysis revealed that A-HM exhibited small particle sizes and dispersion in water without aggregation of HPI. Owing to their small size, numerous hydrophobic residues and aromatic ring of HPI were exposed on the surface. Hydrophobic interactions predominantly governed the binding force involved in the formation of A-HM. Our findings may enhance HPI applications in the food industry, particularly in plant-based beverages.