A method for preparing alkaline hydrolysates of vegetable proteins, includes the following steps: 1) placing the vegetable proteins in suspension in water so as to have a concentration of 15 to 30 dry weight %, at a temperature of 70 to 80° C. and a pH of 9.5 to 10.5 by adding an alkaline hydroxide selected from the group made up of sodium hydroxide and potassium hydroxide； 2) allowing the suspension to incubate for 10 to 15 hours, at a temperature of 70 to 80° C. and a pH of 9.5 to 10.5； 3) neutralizing the heated suspension with a mineral acid； and 4) drying the neutralized suspension so as to obtain the alkaline hydrolysate.
