Study of solute–solute and solute–solvent interactions of l-methionine in aqueous-sucrose solutions at different temperatures

Densities, ρ, ultrasonic speeds, u, and viscosities, η, of solutions of l-methionine in aqueous-sucrose solvents (5%, 10%, 15%, and 20% of sucrose, w/w in water) were measured at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K. From these experimental results, the apparent molar volume, VϕVϕ, limiting apparent molar volume, Vϕ∘ and the slope, Sv  , apparent molar compressibiliity, Ks,ϕKs,ϕ, limiting apparent molar compressibility, Ks,ϕ∘ and the slope, Sk  , transfer volume, Vϕ,tr∘, transfer compressibility, Ks,ϕ,tr∘, Falkenhagen coefficient, A, Jones–Dole coefficient, B and temperature derivative of B-coefficient, dB/dT, hydration number, Hn  , free energy of activation of viscous flow per mole of solvent, Δμ1∘# and per mole of solute, Δμ2∘# were calculated. The results are interpreted in terms of solute–solvent and solute–solute interactions in these systems. It is observed that there exist strong solute–solvent interactions in these systems, which increase with increase in sucrose concentration. It is observed that l-methionine act as structure-breaker in aqueous-sucrose solvents. The thermodynamics of viscous flow has also been discussed.

► The study reports interactions of l-methionine with sucrose in aqueous media.
► Provides data to estimate physicochemical properties of proteins in these media.
► Provides better understanding biological phenomena involving l-methionine.
► Correlates physicochemical properties of l-methionine with its behaviour in solution.