There is an increasing need for food systems with tailored properties using essential ingredients. This review provides an overview of how interactions between different ingredients, such as proteins, polysaccharides and lipids can be used to design different biopolymer composites, and how isotropic and anisotropic composites can be created. Preparation of protein-polysaccharide complexes, protein fibrils, polysaccharide nanorods, and macromolecular biopolymer assembly is discussed. These composites can be used to design emulsions, for which different preparation techniques are compared. Different functionalities such as stability under environmental stresses, controlled release for encapsulated components, and retardation of lipid digestion are addressed.