The invention relates to substance mixtures which contain (a) sodium carboxymethyl cellulose and (b) at least one bitter principle selected from the group consisting of xanthines, phenolic glycosides, flavanoid glycosides, hydrolysable or non-hydrolysable tannins, flavones and the glycosides thereof, caffeic acid and the esters thereof, terpenoid bitter principles, catechin, epicatechin, epigallocatechin, gallocatechin, gallocatechin-3-gallate, leucine, isoleucine, valine, tryptophan and phenylalanine, protein hydrolysates, peptides and metal salts and their mixtures, and optionally (c) dextrins, with the proviso that the components (a) and (b) are in the weight ratio of from 1:1 to 1:1,000.