Temperature Effect on Binding of Volatile Flavor Compounds to Soy Protein in Aqueous Model Systems

Abstract

ABSTRACTThe thermodynamics of binding was determined for soybean glycinin and β‐conglycinin and flavor ligands butanal, pentanal, hexanal, octanal, 2‐ and 3‐hexanone, 2‐ and 5‐nonanone, hexanol, and hexane. Hexane had affinity for these proteins only at 5oC. Affinities of binding for all flavor ligands were greater for glycinin than β‐conglycinin. Affinity for aldehydes increased with increasing chain length for glycinin, but remained constant for β‐conglycinin. ΔGo, ΔHo, and ΔSo for binding were determined. ΔGo was negative for all ligands and ranged from −1.74 to −4.16 Kcal/mol. All enthalpies of binding were positive except butanal and hexanol. Change in free energy of binding per CH2 in homologous aldehydes was greater for glycinin than β‐conglycinin.