A coating composition comprising a starchy material, said material having: a number average molecular weight (Mn) of 3 500 to 20 000 Daltons, a granular structure before solubilisation, a solubility at pH 7 and 20.degree. C. (S1) of 30-90%, and a solubility at pH 10 and 35.degree. C. (S2) which is at least 10% greater than S1.