Pulse germination as tool for modulating their functionality in wheat flour sourdoughs

Three different pulses, namely green lentils, broad beans and chickpeas, were subjected to germination under daylight conditions. Germination resulted in changes to proximal composition, protein solubility and protein digestibility, varying according to the investigated legume. Based on chemical scores of raw pulse flours, optimal 70:30 mixtures of wheat and pulse flours were further proposed for potential bread-making applications. The flour mixtures were fermented with lactic bacteria, eventually in admixture with yeast, to obtain sourdoughs. The functionality of the sourdoughs was assessed to estimate the possibility of using germinated pulses for enhancing the nutritional value and modulating the bread-making potential. Fermentation increased the antioxidant activity of sourdoughs, the highest values corresponding to the samples containing germinated pulses. The highest antioxidant activity corresponding to the lowest amount needed to obtain a 50% antioxidant effect (EC50 of 19.83 mg) was registered for samples containing germinated lentil fermented with Lactobacillus casei and Kluyveromyces marxianus, while control samples (unfermented) presented the lowest antioxidant activity of 206.56 mg. Rheological measurements indicated that wheat flour substitution by raw or germinated pulses flour caused the decrease in sourdough consistency. However, pulse flour addition to the wheat flour and the type of starter culture used to prepare the sourdough exerted no significant influence on the rheological performance of bread batters. Bread specific volume, crumb firmness and colour varied with the type of legume used to substitute the wheat flour and with the sourdough added. Compared to the wheat flour bread, only a slight decrease in the specific volume was observed for samples with broad bean and chickpea flours. The lentil flour bread samples had the lowest specific volume and the highest firmness.