All proteins yield amino acids when hydrolyzed, since a protein molecule may contain hundreds or thousands of amino acid groups. The amino acids are united through an acid amide type of bond called a peptide linkage. Just as is the case with acid amides, the peptide linkages in proteins are resistant to hydrolysis and require prolonged boiling with relatively strong acids or alkalies for complete liberation of each amino acid. The developed technology for producing fungal protein in the Bureau of Solid Waste Management's Research and Development Laboratories is the result of research efforts directed toward recycling both starchy and cellulosic wastes. The quality of the protein produced by fermentation depends upon the amino acid profile which was determined by a quantitative amino acid analysis with an Automatic Amino Acid Analyzer. However, prior to an analysis, hydrolysis of the protein must take place to produce individual amino acids. The subject procedure uses acid hydrolysis under vacuum conditions. The use of a vacuum eliminates the oxidizing atmosphere which would result in oxidation or loss of the amino acids. This hydrolysis procedure can be applied to any protein bearing material, plant or animal.