Impact of limited trypsin hydrolysis on Bambara protein-gum arabic interaction and the formation of soluble complexes

Soluble protein-polysaccharide complexes are of growing interest for food and beverage applications. However, due to the compact structure of globular proteins, forming stable complexes across a wide pH range is challenging. In this study, the effects of limited trypsin hydrolysis on Bambara protein and its interaction with gum arabic to form these complexes were investigated. Proteins were hydrolysed to degrees of hydrolysis (DH) 2, 5, and 7.5, and analysed for structural characteristics. Among the studied hydrolysates, DH 5 produced the most stable soluble complexes over a broader pH range (7.0-4.3), showing enhanced binding strength and structural stability. This was evidenced by its rheological fingerprints, a shift in thermal transition temperature, increased negative charge, and surface hydrophobicity. Limited hydrolysis at DH 5 is the most effective in enhancing the formation and stability of Bambara protein-gum arabic soluble complexes. The stability of Bambara protein-gum arabic soluble complexes for bioactive compound encapsulation may be further investigated to support industrial applications. • Soluble complexes usually occur within a narrow pH range characterised by weak interactions • The compact structure of globular proteins limits their interaction with polysaccharide • Limited trypsin hydrolysis of Bambara protein significantly improves its complexation behaviour • DH 5 hydrolysate showed substantially higher binding strength with stable complex structure formed with gum arabic • Trypsin hydrolysis broadened the pH range of soluble complex and improved stability.