Stabilisation of Haemoglobin by Maltose: A Comprehensive Ultrasonic, Volumetric, and Compressibility Study

The stabilisation of haemoglobin (Hb) by maltose in aqueous solution was investigated using density and ultrasonic velocity measurements at five temperatures (303.15-323.15 K) and five concentrations (0.02-0.10 mol kg-1). From the experimental data, four acoustico-physical parameters were derived: adiabatic compressibility (βs), compressibility lowering (Δβs), specific acoustic impedance (Z), and relative association (RA). The systematic decrease in βs and the concurrent increase in Δβs, Z, and RA with rising maltose concentration indicate that maltose strengthens the hydrophobic, electrostatic, and hydrogen-bonding interactions within the haemoglobin structure, thereby impeding denaturation. The results are interpreted in terms of preferential hydration of the protein in the presence of maltose, which amplifies the hydrophobic effect and promotes a compact, folded conformation. These findings provide quantitative insight into the stabilisation mechanism relevant to pharmaceutical formulation, blood substitute development, and food-protein technology.