EFFECT OF CHEMICAL MODIFICATION OF SODIUM CASEINATE ON DIFFUSIVITY OFAROMA COMPOUNDS IN AQUEOUS-SOLUTIONS

The concentration profiles obtained from a gel were used to measure di ffusion of volatiles in water and in aqueous solutions of sodium casei nate glycosylated or not. The physicochemical interactions between sol utes and substrates were studied by exponential dilution. As the aroma retention by sodium caseinate increased, the diffusion coefficient de creased. Chemical modification of sodium caseinate affected both the a ctivity and the diffusion coefficients of the volatiles. These variati ons were interpreted in terms of a relation between the change in stru cture and the different physicochemical properties of the proteins. Th e glucosylated and galactosylated proteins exhibited the highest visco sity and induced a decrease in the diffusion coefficients, contrary to lactosylated and maltosylated proteins. The cause of increased viscos ity is the variation of the quantity of bound water between the two ty pes of substituted proteins.