Effect of processing on the soluble carbohydrate content of lentils

Abstract

Lentils (Lens culinaris), like other legumes, are important both nutritionally and agriculturally. Soaking of lentil drastically reduce the quantities of a-galactosides present in the raw material (45-100% reduction). Analysis of the soaking medium (distilled water, 0.1% citric acid solution, 0.07% sodium bicarbonate solution) showed that these losses could not be explained by leaching alone, since the a-galactosides in the soaking medium amounted to only 1-10% of the recorded losses. Other monosaccharides (fructose and glucose) underwent a conspicuous increase (120 and 280% respectively) after soaking. The results indicate that during the 9 h soaking period the sugars in the lentils underwent a metabolic mobilization reminiscent of the changes taking place during germination. Cooking of the soaked lentils modified the agalactoside content only slightly. On the other hand fructose, glucose, and sucrose decreased significantly during cooking. Soaking and cooking in water led to removal of a substantial proportion of the flatulence-causing oligosaccharides.