Protein hydrolysate was prepared from pre-treated sheep visceral mass (including stomach, large and small intestines) by enzymatic treatment at 43 +/- 1 degrees C (at the in situ pH 7.1 +/- 0.2 of the visceral mass) using fungal protease. The enzyme readily solubilized the proteins of the visceral mass as indicated by the degree of hydrolysis (34%) and nitrogen recovery (> 64%). Hydrolysis with an enzyme level of 1% (w/w of total solids) at 43 +/- degrees C with a pH around 7.0 for 45 min was found to be the optimum condition. The yield of protein hydrolysate was about 6% (w/w). The amino acid composition of the protein hydrolysate that was very hygroscopic, was comparable to that of casein. (c) 2005 Elsevier Ltd. All rights reserved.