Protein Contents,Amino Acid Compositions and Nitrogen-to-Protein Conversion Factors for Cassava Roots

Root protein contents of 15 cassava varieties ( Manihot esculenta Crantz) ranged from 5 to 19 g kg⁻¹ dry matter. Intervarietal differences in amino acid profiles of cassava roots were evident. Differences in the levels of aspartic acid, glutamic acid and arginine were most notable. The nitrogen-to-protein conversion factors ( k _AA ) based on nitrogen recovered from total amino acid analyses including ammonia ranged from 4·75 to 5·87, showing that the traditional conversion factor of 6·25 was not valid for cassava root proteins. Conversion factors ( k _P ) for 15 cassava varieties based on Kjeldahl nitrogen ranged from 2·49 to 3·67. Therefore an average k _P value of 3·24±0·31 may provide a better estimate of the protein content in cassava roots.