Distribution of β-Glucan, Phenolic Acids, and Proteins as Functional Phytonutrients of Hull-Less Barley Grain

Abstract

Two hull-less barley varieties were roller-milled, and breaks (B) and reduction flours (C), shorts, and bran were collected. Shorts, which mainly originate from endosperm cells with a smaller amount of the outer layers, had the largest yield (48.87–51.54%). Ash (0.82–3.10%) and protein (9.95–14.8%) increased from flours toward shorts and bran, while starch decreased (82.31–48.69%). In contrast to clear distribution differences in protein content (bran > shorts > C > B), albumins/globulins content was lowest in bran (0.78–0.90 g/100 gdw), and their distribution between fractions was uneven and genotype dependent. Distribution of hordeins (6.69–10.49 g/100 gdw) was more distinct and generally decreased in order from bran > B > shorts > C. The proportion of nutritionally poor C-hordeins in total hordeins varied from 28.33% to 30.24%, without significant differences between fractions. The β-glucan content varied from 0.80% to 7.49% with decreasing content in the order bran, shorts > C > B. Shorts and bran could be classified as moderate and high β-glucan flour (5.70–7.22%). The total phenolic and antioxidant activities ranged from 0.91 to 2.21 mg GAE/gdw and 28.81–72.06%, respectively. Ferulic and sinapic acids determined by high-performance liquid chromatography (HPLC) were major contributors to the antioxidant activity (45.16–1026.91 ug/gdw and 18.93–206.52 ug/gdw), respectively. The yield and high content of phytonutrients make hull-less barley shorts suitable for the production of health-promoting food and food supplements.