The unfavorable bioaccessibility of polyphenols in cereal-based food limits their physiological functions as most polyphenols bind spontaneously to the cell-wall polysaccharides. Effects of β-glucan and various thermal processing methods including flaking and roasting, stir-frying, steam-flash explosion, and popping expansion on the bioaccessibility and antioxidant properties of polyphenols from hulless barley in vitro and in vivo were investigated in this study. The bioaccessibility and antioxidant capacity (via DPPH, ·OH, and ·O₂^– free radical scavenging, TAC, and FRAP assays) of polyphenol extracts from hulless barley treated by steam-flash explosion and popping expansion increased significantly before and after in vitro digestion compared to those from raw and other processed hulless barley. Further, the total polyphenol content of hulless barley elevated dramatically following hydrolyzing with β-glucanase, which was positively correlated with the antioxidant activity. Additionally, the hulless barley treated with steam-flash explosion exhibited potent antidiabetic effects and antioxidant capacity (via TAC, SOD, GSH-Px, CAT, and MDA assays) in type 2 diabetic rats. The absorption of individual phenolic compounds in the alimentary canal of rats was impacted obviously by thermal processing. This study provides new insights into enhancing the bioaccessibility of the polyphenols and suggests that β-glucans interact with polyphenols and proteins in the hulless barley matrix.

中文翻译：

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Hulless 大麦中多酚的体外和体内消化命运和抗氧化活性：各种热处理方法和 β-葡聚糖的影响

谷类食品中多酚的不利生物可及性限制了它们的生理功能，因为大多数多酚会自发地与细胞壁多糖结合。本研究研究了β-葡聚糖和各种热加工方法，包括压片烘烤、炒炒、蒸汽闪爆和爆裂膨胀对大麦多酚在体外和体内的生物可及性和抗氧化性能的影响。生物可及性和抗氧化能力（通过DPPH、·OH 和·O ₂ ^–与来自生的和其他加工的去壳大麦的相比，在体外消化前后，通过蒸汽闪爆和爆裂膨胀处理的去壳大麦的多酚提取物的自由基清除、TAC 和 FRAP 分析显着增加。此外，用β-葡聚糖酶水解后，去皮大麦的总多酚含量显着升高，这与抗氧化活性呈正相关。此外，经蒸汽闪爆处理的去壳大麦显示出有效的抗糖尿病作用和抗氧化能力（通过TAC、SOD、GSH-Px、CAT 和 MDA 测定）在 2 型糖尿病大鼠中。热处理明显影响大鼠消化道中个别酚类化合物的吸收。这项研究为提高多酚的生物可及性提供了新的见解，并表明 β-葡聚糖与去壳大麦基质中的多酚和蛋白质相互作用。