Physicochemical properties of dietary fibers extracted from gluten-free sources: quinoa ( Chenopodium quinoa ), amaranth ( Amaranthus caudatus ) and millet ( Panicum miliaceum )

Dietary fiber from three gluten-free sources (quinoa, amaranth, and millet) was recovered via enzymatic, enzymatic-ultrasonic and ultrasonic extraction. Two raw materials were used for this study: commercially available flour and whole seeds. Various physicochemical and nutritional parameters were evaluated. Generally, the highest extraction yield was observed from enzymatic-ultrasonic extraction. In millet samples (ML-F and ML-W), ultrasonic extraction was characterized by yields than enzymatic extraction. Bulk density in millet samples achieved results exceeding 0.8 g · cm−1, indicating that apart from bigger particle size, millet dietary fiber particles were more dense and thus heavier. Amaranth samples had relatively higher amounts of soluble fractions of dietary fiber. The most prominent differences in color between raw material and dietary fiber were observed within quinoa samples. Results reveal that quinoa, amaranth, and millet could act as substantial sources of dietary fiber with various physicochemical properties.