Diffusion of sucrose and aspartame in kappa-carrageenan and gellan gum gels

In the process of sweetness release from the food to the human papillae, di ffusion of the sweetener through the food is one of the steps. Information on diffusion behaviour of small molecules like sucrose has been studied mai nly in connection with blanching or osmotic processes. In this paper, diffu sion constants (D) of both sucrose (100 and 150 g/l) and aspartame (0.8 and 1.2 g/l) in model systems-kappa-carraoeenan and gellan gum gels at two dif ferent concentrations-have been determined at 37 degreesC (mouth temperatur e). Mean D values for sucrose (5.9-7.3 x 10(-10) m(2) s(-1)) and for aspart ame (6.1-7.7 x 10(-10) m(2)s(-1)) in soft kappa-carrageenan gels were signi ficantly higher than in the other gels (3.8-5.1 X 10(-10) m(2)s(-1) for suc rose and 3.9-5.9 x 10(-10) m(2)s(-1) for aspartame). Higher concentrations of sweetener detected in the diffusing medium in the case of soft kappa-car rageenan gels could be partially affected by incipient melting of the gel. Upper values in these ranges corresponded to higher initial sweetener conte nts. (C) 2001 Elsevier Science Ltd. All rights reserved.