Abstract: A liquid protein food of mild and pleasant taste is made by digesting powdered defatted bones including the bone marrow with trypsin, amylase and lipase which may be used in their pure state or mixed with other material. A pancreatin product, preferably Viokase, which contains the trypsin, amylase and lipase of suitable activity gives highly satisfactory results.The digestion results in a liquid containing the solubilized protein of the marrow, and a solid residue which is mainly collagen and calcium phosphate. A soluble collagenous product and a substantially pure mineral product is made from the residue by hydrolyzing it at a pH of 2-5. Pancreatin or other enzyme containing material effective in hydrolyzing collagen may be used.The defatted bones which are preferred for use in the digestion process are made by mixing bones including their marrow in an organic liquid fat solvent, such as ethylene dichloride, which forms an azeotrope with water.The mixture is heated at a moderate temperature such as 60.