Abstract: The invention relates to novel amphiphilic complexes, a method for their preparation, and the compositions containing them. Said amphiphilic complexes result from the reaction, at a temperature between ambient temperature and 80° C., between a protein or polypeptide whose average molecular mass is greater than or equal to 5,000 Daltons and a fatty chain whose carbon atom number is between 4 and 30 selected from fatty acid, fatty alcohol, fatty amine, with the exclusion of undecylenic acid ; the protein or polypeptide/fatty chain weight ratio ranging from 1000/1 to 1/10.

Abstract: Cosmetic and pharmaceutical compositions comprising amphiphilic or hydrolipidic complexes of plant proteins modified with fatty chains are presented. The modified proteins are obtained from the reaction carried out at a temperature between ambient temperature and 80° C. with plant proteins having an average molecular mass is greater than or equal to 10,000 Daltons and one or more fatty chains whose carbon atom number is between 4 and 30, selected from fatty acid anhydrides and fatty acid halides, with the exclusion of undecylenic acid.