Storage stability, micronisation, and application of nutrient-dense fraction of proso millet bran in gluten-free bread

Abstract

This study aimed to valorise the underutilised by-product of proso millet decortication. Millet bran was sieved into three fractions with substantially different nutritional profile. The fraction with diameter <500 μm had the highest nutrient density (14% protein, 26% starch, 36% dietary fibre, 9% fat, and 3 mg GAE/g phenolics (d.w.)) and was analysed for oxidative stability, micronisation effect under cryogenic or ambient conditions (2, 4, 8, 12 min), and baking applicability. The bran was oxidatively stable under refrigerator conditions for 150 days. Micronisation slightly increased the antioxidant activity measured by FRAP and ABTS assays as well as the content of fibre soluble in water and 78% ethanol as the bran particle size decreased from 171 μm to 26–46 μm. Gluten-free bread containing 10% of the nutrient-dense fraction of millet bran had higher dietary fibre (76%) and phenolics content (117%), improved volume and crumb softness, regardless of the bran particle size (diameter of 50th percentile 171 vs. 26 μm).