Process for the production of a composition substantially consisting of yeast cell walls, which comprises steps of dispersing exhausted yeast cells in an aqueous medium to obtain a first suspension of yeast cells； treating the suspension with a proteolytic enzyme； centrifuging the suspension obtaining a first pellet and a supernatant； dispersing the first pellet in an aqueous medium, obtaining a second suspension of yeast cells； centrifuging the second suspension obtaining a second pellet, which constitutes the above-mentioned composition substantially consisting of yeast cell walls.
