Effects of milling behavior on the distribution of nutrients and storage properties of highland barley graded powder

Abstract

Effects of gradual milling on the distribution of nutrients, bioactive components, and storage properties of highland barley graded powder (HBP) were investigated in this study. The results suggested that the contents of protein, crude fiber, total phenolics, total flavonoids, and γ-aminobutyric acid were the highest in the outermost layer (F-1), which were 16.01 ± 0.54 g/100 g, 9.18 ± 0.12 g/100 g, 717.34 ± 10.86 mg GAE/100 g, 209.68 ± 2.49 mg QE/100 g, 1.10 ± 0.03 mg/g DW, respectively. Conversely, the innermost layer (F-5) displayed the greatest β-glucan level with a value of 8.40 ± 0.18 g/100 g DW, which was 4.3 times of the amount of F-1. Additionally, the samples were subject to the heat-moisture steam treatment for 30 min (HM-30) and enjoyed optimal storage suitability. Consequently, the enzyme activity and free fatty acid value of the external fraction (mixture) and the removed-bran fraction (remainder) under HM-30 fell far below those of the control group. The remainder fraction presented a more stable storage ability as compared to the mixture fraction. Overall, these findings would gain a better insight into the comprehensive effect of milling on HBP and provide possible opportunities for building tailored-health highland barley in versatile foods.