Acylated carbohydrates with at least one carboxyalkyl group etherified with the carbohydrate of the following general formulaKH(--O--CHR.sub.1 --(CH.sub.2).sub.p --(COOH or COO.sup.-)).sub.n (--O--CO--R.sub.2).sub.m,wherein KH (carbohydrate) is a monosaccharide, disaccharide, trisaccharide or polysaccharide, and whereinif KH is a monosaccharide, then n=1 to 4 and m=1 to 4 with n+m=2 to 5;if KH is a disaccharide, then n=1 to 7 and m=1 to 7 with n+m=2 to 8;if KH is a trisaccharide, then n=1 to 10 and m=1 to 10 with n+m=2 to 11; andif KH is a polysaccharide, then n=0.2 to 2.8 and m=0.2 to 2.8 with n+m=0.4 to 3 (with polysaccharide referred to the monosaccharide unit of the KH), and whereinR1 is=H or a moiety with 1-9 carbon atoms, in particular an alkyl or acyl moiety, andR2 is a moiety with 1-9 carbon atoms, in particular an alkyl or acyl moiety, and wherein p=0 to 9.