Nutritional evaluation of lentil flours obtained after short-time soaking processes

Abstract

Twenty-four short-time soaking (STS) processes were carried out to study the influence of some experimental variables (lentil/water ratio, temperature, illumination, elimination of the soaking medium and milling of the seeds) on the glucose, fructose, sucrose, total available soluble sugars, starch, vitamin B1, vitamin B2, available niacin, raffinose, ciceritol, stachyose, total α-galactosides and trypsin inhibitor activities of lentil flours obtained. The soaking process produced, in general, a reduction in the total available soluble sugars content of 8-70%. Glucose was not found in the raw lentils, but was present in the lentil flours obtained after soaking processes carried out in presence of light. Fructose increased in most of the experiments (22-967%) and sucrose decreased significantly (6-73%). Regarding the starch content, the soaking process produced a significant reduction (11-31%). The hydrosoluble vitamin content of lentils, in general, decreased or did not change. However, vitamin B2 and available niacin increased significantly in some experiments, especially in those carried out with ground lentils. The α-galactoside content suffered a large reduction (12-58%) and TIA levels were reduced by 2-33%. From the results obtained, it can be established that STS affects the nutrients and antinutrients of lentils in a different way depending on the experimental conditions. Lentil flours with a low level of antinutritional factors and a high vitamin level are obtained with ground lentils at 42 °C.