Abstract
Wet-milled quinoa fibres show strong potential as ingredients in nutritionally enhanced food products, offering a valuable strategy to address dietary fibre deficiencies. In this study, white, red, and black Royal Bolivian quinoa were wet-milled to produce fibre-rich fractions and assess their nutritional and techno-functional properties. All fibre-rich fraction samples showed a marked increase in dietary fibre content compared to whole grain flours-about six-fold in white quinoa and eight-fold in red and black. Insoluble fibre remained predominant, increasing by approximately eight to ten times, with the highest increase observed in red quinoa, while soluble fibre increased by two to three times, likely due to partial solubilisation during processing, reaching its maximum in black quinoa. A 5 g serving of these fractions could supply 10-14% of the WHO's daily fibre recommendation (25 g), compared to only 2% from whole quinoa flour. Fibre recovery was highest in black quinoa, followed by white and red. Calcium and iron contents increased in the isolated fibres, while zinc decreased, especially in red and black varieties. Phytate content, a mineral absorption inhibitor, was significantly reduced (by 45-85%), which can enhance mineral bioavailability. Notably, the black variety showed favourable phytate-to-mineral molar ratios, indicating no inhibition of calcium or zinc absorption. Functionally, red quinoa fibre exhibited better water and oil retention and higher swelling capacity, properties desirable in bakery and meat product formulations, while black quinoa fibre stood out for its high total fibre content. Overall, wet-milled quinoa fibres offer promising potential as functional, fibre-rich ingredients for healthier food formulations.