[Influence of hydrothermic and enzymatic treatments on the nutritive value of Faba beans: in vitro study].

Abstract

In order to improve the digestibility of the Faba bean flour an hydrothermic enzymic and fermentation treatment has been thought out (US patent 395 8015, Ets Ury, M. Gay). This study aims at stemming out the nutritionnal and structural repercusions of this treatment on the Faba proteins. The nitrogen distribution is deeply changed : total nitrogen increase (47%), water soluble nitrogen decrease (41%), water soluble non-protein nitrogen increase. The treatment can enrich the flour in nitrogen but the proteins supplement is insoluble in water. The treatment changed the electrophoretic behaviour of flour proteins letting disappear precipitable pH 4,5 proteins. Amino acid composition is slightly changed, however there is an increase of lysine and methionine (15 et 25%) and a decrease of cysteine (28%). The chemical score shows sulfur amino acids and tryptophan deficiency. Enzymatic (pepsine and pancreatine mixture) liberation of all amino acids is low and is not improved by the treatment but for the lysine. Cell proteins supplement, which appeared during the treatment (61%), water insoluble, could improve nutritive value of the flour if a more complete destruction of the cell walls permitted their liberation and their solubilization.