Amino acid profile of raw and extruded blends of African yam bean (Sphenostylis stenocarpa) and cassava flour

Abstract

The main purpose of this work is to improve the low protein content of cassava based products. African yam bean (AYB) (Sphenostylis stenocarpa) seeds and cassava (Manihot exculenta, c) tubers were processed into flours. Extrusion runs were conducted using different ratios of feed blends in a single screw extruder (0.54:99.46; 20:80; 50:50; 80:20; 99.46:0.54) cassava flour/AYB flour. The raw and extruded products were subjected to amino acid analysis. All the amino acids in the raw samples appeared in the extruded products and were proportionally increased as the percentage of AYB increased. The results of the amino acid profile of cassava flour were generally lower except for arginine and glutamic acid, the highest level of loss for AYB was obtained in lysine (62.4%), followed by glycine (47.43%) and aspartic acid (44.96%). Leucine had the lowest percentage loss of 14.14%. The results indicated that extrusion cooking altered the amino acid profile of the extrudates and that blending increased the nutritional value of the products.