Impact of germination on the physicochemical and rheological properties of flours and starch granular morphology of Panicum miliaceum (Proso millet), Paspalum scrobiculatum (Kodo millet), and Setaria italica (Foxtail millet)

Germination is an inexpensive and effective technique that can increase the nutritional quality of flours and change their physicochemical and rheological properties. In this study, three underutilized millet species, namely, Panicum miliaceum, Paspalum scrobiculatum, and Setaria italica were germinated and subsequent changes in their carbohydrate composition, functional characteristics, rheological properties, antinutritional factors and starch granular morphology were analyzed and compared. Germination resulted in significant (p < 0.05) decreases of starch, amylose, amylopectin, and resistant starch contents while increasing the dietary fiber content of the studied millet flours. Water holding capacity and oil holding capacity significantly (p < 0.05) increased; meanwhile the swelling power and water solubility significantly (p < 0.05) decreased in all studied millet flours. Starch granule morphologies were proved by the changes in starch degradation upon germination process. Antinutrients such as phytate and oxalate were significantly lower in germinated millet flours. These findings impress the application of germination in developing nutritionally rich flours with altered functional and rheological properties to incorporate into functional food formulations.