W. Wu et al., AMINO-ACID AVAILABILITY AND AVAILABILITY-CORRECTED AMINO-ACID SCORE OF RED KIDNEY BEANS (PHASEOLUS-VULGARIS L), Journal of agricultural and food chemistry, 44(5), 1996, pp. 1296-1301
Thermal effect on availability of individual amino acids (AIAA) of red
kidney beans was evaluated. Sulfur amino acids (SAA), methionine and
cystine (Met + Cys), are the limiting amino acids (AA) and have the lo
west availability among the AAs in nine treatments. The availability o
f SAA (ASAA) ranged from -18.6% in raw beans to 39.8-68.0% in thermall
y processed beans. Autoclaving at 121 degrees C for 10-90 min graduall
y reduced ASAA values. The mean availability for each AA (MAEAA) is th
e average of the AIAA values for the same AA. MAEAA values ranged from
82.1% (arginine) to 50.4% (Met + Cys). The mean availability in each
treatment (MAET) is the average of the AIAA values in the same treatme
nt. The difference between MAET and true digestibility of protein (TDP
) was less than 7%. However, the differences between ASAA and TDP (16-
37%) and between ASAA and MAET (14-30%) were large. The ASAA-corrected
amino acid score (AAS(ASAA)) for raw beans was negative (-29.4%) and
ranged from 61.8 to 42.1% for thermally processed beans. From a compar
ison among the protein quality indexes, AAS(ASAA) is the preferred met
hod to evaluate protein quality of beans.