Effect of Germination on Physico-chemical Properties of Lentil Starch and its Components

Abstract

The effect of germination on starch composition and its physico-chemical characteristics inLens culinarisvar. vulgaris have been investigated. Granular starch from raw and germinated lentils was isolated and characterized by its physico-chemical properties, morphology as demonstrated in scanning photomicrographs, the microstructure of low-sheared starch suspensions (80 g/kg) heated at 70 and 90 °C, the amylose:amylopectin ratio, and susceptibility to α-amylase hydrolysis. Physico-chemical methods, through their iodine binding capacity and their behaviour in aqueous solution, such as gelatinization, were used in the characterization of starch polysaccharides. Scanning electron microscopy indicated some alteration of the starch granule surface after germination, which resulted in higher resistance to temperature changes. Raw and germinated lentil starch showed a gelatinization temperature of 70 °C. The ratio of amylose and amylopectin was 26:74 in raw starch and 24:76 in starch from germinated seeds. The debranching of amylopectin with isoamylase showed a bimodal distribution of fractions containing long and short chains, illustrating the relation between the molecular structure and the type C starches. The germination process in lentil seeds has had little effect on either the properties of starch or its components, but enzymic hydrolysis of the raw and germinated starch with porcine pancreas α-amylase showed that the digestibility of starch was greatly improved with germination.