Linhagens de feijão (phaseolus vulgaris L.): composição química e digestibilidade protéica

Abstract

Bean represents the main source of proteins for the low income populations, though the digestibility of those proteins is relatively low. Consequently, the programs of plant genetic breeding have been working on the search for new lines with higher protein levels. Thus, with the purpose of supplying information to the researchers, in this work 21 bean (Phaseolus vulgaris L.) lines were analyzed for the centesimal and mineral composition, protein digestibility, phenolic compounds and trypsin inhibitor. The entirely randomized experimental design was used with 21 treatments (lines) and three repetitions. All values were within the following ranges: 22.34 to 36.28g of crude protein/100g of dry matter (DM); 7.56 to 20.91g of neutral detergent fiber/100g DM; 0.53 to 2.55g of fat/100g DM and 2.97 to 4.87g of ashes/100g DM. The levels, in g/100g DM, of P, K, Ca, Mg and S varied from 0.45 to 0.72; 1.51 to 2.48; 0.03 to 0.28; 0.18 to 0.34 and 0.28 to 0.45, respectively. Regarding Cu, Mn, Zn and Fe, the levels in mg/kg DM, varied from 11.37 to 17.73; 14.93 to 28.90; 36.67 to 69.90 and 71.37 to 126.90, respectively. The in vitro protein digestibility varied from 18,03% to 48,32%. The levels of phenolic compounds varied from 0.28 to 1.08mg of acid tanic/100g DM and the one of trypsin inhibitor from 59.93 to 151.07 TIU/mg DM. Among the lines with higher protein contents, "ESAL 569" (beige with brown stripe) presented the largest protein digestibility and also considerable levels of minerals. "P-180" (beige with brown stripe) was one of the lines with higher crude protein contents and digestibilities, and also presented high levels for most of the minerals. No relationship between protein digestibility and the contents of phenolic compounds and trypsin inhibitor was observed.