Porcine rib cartilage and bone residues after chicken frame deboning were hydrolyzed at 60 degrees C for 12-48 h to recover glycosaminoglycans and gelatin. The process efficiency was expressed as the amt. of isolated chondroitin sulfate and hydroxyproline. Total recovery of chondroitin sulfates and gelatin from cartilage was achieved after 24 h of extn. with papain (concn. 8 mg/g) or with proteinase (6 mg/g). Complete recoverty of glycosaminoglycans from the bone residues was achieved after 48 h. When proteinase was used, the max. degree of collagen-to-gelatin hydrolysis was only about 60%.