TRUE PROTEIN DIGESTIBILITY AND DIGESTIBILITY-CORRECTED AMINO-ACID SCORE OF RED KIDNEY BEANS (PHASEOLUS-VULGARIS L)

True digestibility of protein (TDP) and digestibility-corrected amino acid score (AAS(TDP)) for thermally processed red kidney beans were ev aluated using rat balance assay. High fecal protein (based on Kjeldahl N) relative to low protein digestibility was observed. The fecal prot ein content was 43.8% from rats fed the raw bean diet and 25.6-36.0% f rom rats fed the processed bean diets. Heat processing appeared to hav e a greater (P < 0.05) impact on protein intake than on fecal protein output, which indicated that protein digestibility for beans may depen d on protein intake rather than fecal protein output. AAS(TDP) values of beans (ranging from 13.9 to 74.6) were similar to digestibility-cor rected essential amino acid index (EAAI(TDP)) and digestibility-correc ted available lysine (AL(TDP)) values. This suggests that EAAI(TDP) an d AL(TDP) might be considered another approach for assessing protein q uality of beans. True digestibility of total fat, carbohydrate, and en ergy for beans was also measured.