Effect of reconstitution and Na2Co3 on tannin content and in vitro protein digestibility of faba bean cultivars.

Two faba bean cultivars (317/99/81 and Giza/402) obtained from Shambat Research Station in Northern Sudan, were used for this study. Investigation showed that the tannin contents of untreated seeds were 0.077% and 0.067% for cultivars 317/99/81 and Giza/402. In vitro protein digestibility values were 80.68% and 81.48% for the two cultivars, respectively. The extractable tannin content of the faba bean cultivars was markedly reduced by imbibing water or Na2CO3 solution into whole seeds and incubating them at 30 degrees C for 1, 3, 6, 12 or 24 hours, or at 100 degrees C for 5, 10 or 20 minutes. The extent of reduction depended on time, temperature, and Na2CO3 concentration; the percent tannin extracted and percent in vitro protein digestibility increased with time or Na2CO3 concentration, while application of high temperature reduced the time.