Abstract: The subject of the invention is a process for modifying amylaceous (starchy) materials comprising a stage of chemical fluidification and a stage of stabilization, simultaneous or not simultaneous, these two stages being performed in the dry phase and by the use of a plycarboxylic organic acid. The acid can be chosen particularly from among citric acid, adipic acid, azelaic acid and their mixtures. The process is advantageously performed at a temperature between 90° C. and 170° C., at a pH below 4 and during a total period between 3 minutes and 8 hours. The starchy material subjected to fluidification and stabilization can be cationic.

Abstract: The invention relates to a process for the conversion of starchy substances including a chemical liquification stage and a stabilization stage, whether simultaneous or not, these two stages being carried out in the dry phase and using respectively: a mineral or organic acid, permitting the liquification of the starchy substance at a water fluidity valued (WF) of at least 10, preferably at least 45, and an aldehyde compound, in particular a condensate between an aldehyde and a nitrogenous compound, capable of stabilizing said starchy substance.

Abstract: The invention relates to a new composition for sizing paper and board, containing a cationic polysaccharide esterified by a dicarboxylic acid anhydride, characterized in that the said dicarboxylic acid anhydride is substituted with a carbon chain, saturated or unsaturated, of branched structure.The anhydride may for example consist of tetrapropenylsuccinic anhydride or of any one of its isomers.The composition for sizing according to the invention may, if necessary, contain an oxidizing agent such as a persulphate. It may advantageously be applied to the surface treatment of printing and/or writing papers, in particular of papers for envelopes and of papers for impact-free printing such as inkjet printing.

Abstract: The invention relates to a new composition for sizing paper and board, containing a cationic polysaccharide esterified by a dicarboxylic acid anhydride, characterized in that the said dicarboxylic acid anhydride is substituted with a carbon chain, saturated or unsaturated, of branched structure. The anhydride may for example consist of tetrapropenylsuccinic anhydride or of any one of its isomers. The composition for sizing according to the invention may, if necessary, contain an oxidizing agent such as a persulphate. It may advantageously be applied to the surface treatment of printing and/or writing papers, in particular of papers for envelopes and of papers for impact-free printing such as inkjet printing.