A multiphase product in the form of, e.g. foam, has an interface water-air, water-oil or water-solid comprising complex formed by a mixture of a protein (or peptide) and a polysaccharide oppositely charged, or the mixture of two proteins oppositely charged, in which the total amount of protein and polysaccharide is 0.01-5 wt.%. A multiphase product in the form of foam, emulsion, foamed emulsion, dispersed emulsion, or foamed dispersion, has an interface water-air, water-oil or water-solid comprising complex formed by a mixture of a protein (or peptide) and a polysaccharide oppositely charged, or the mixture of two proteins oppositely charged. The product is in a pH range within which the electrostatic interaction between both compounds oppositely charged occurs and in which the total amount of protein and polysaccharide is 0.01-5 wt.%. Independent claims are also included for: (a) preparing a foam product by injecting a solution or a bulk mass of protein and a solution or a bulk mass of polysaccharide, or a solution or a bulk mass of one protein and another solution or a bulk mass of one protein, with the air in a bulk mass or directly in the air； and (b) a device for carrying out the process comprising a frame (4)； and pipes (1-3, 5, 6) for the arrival of an emulsion or dispersion with a protein, for the arrival of the gas, and for arrival of an emulsion or dispersion with a polysaccharide, which pipes arriving on a main channel, being disposed perpendicular and staggered on the main channel, such that the first pipe forms the central pipe on the main channel, the second pipe forms the intermediate pipe on the main channel, and the third pipe forms the external pipe on the main channel, and in which an outlet on the main channel of the central and the intermediate pipe are staggered.
