Abstract: A substantially completely water-soluble and pepsin-digestible protein is obtained by the hydrolysis of the keratin contained in animal structures with saturated steam at a pressure of from about 50 to about 250 p.s.i.g. or higher and from about 5 to about 30 parts of liquid water per part of the keratin source, by weight, at the temperature of saturated steam at the pressure employed. Conversion of the keratin to soluble protein and meal is about 80%; the yield of water-soluble protein being as high as about 70%. The water-soluble protein is an excellent animal food.

Abstract: The apparatus includes a plurality of elongated, vertically spaced and horizontally oriented chambers that are interconnected for the sequential flow therethrough of the material to be rendered. Each chamber has the material discharge, inlet, and product steam vents located in the chamber ends so that the chamber is heated along its entire length and has agitator means also extending along its entire length for an efficient heat transfer to the material and removal of the water vapor developed.