Different preparation methods affect the phenolic profiles and antioxidant properties of Qingke barley foods

Abstract

AbstractBackground and objectivesBarley is rich in bioactive compounds and can prevent some chronic diseases. With the increasing health awareness of the consumers, Qingke barley has been widely consumed in China in the Qingke barley fresh noodles (QBFN), Qingke barley dried noodles (QBDN), Qingke barley bread (QBB), and Qingke barley Chinese steamed bread (QBSB) forms. Preparation methods affect the phenolic profiles, content, and antioxidant capacity of these products. In this work, phenolic profiles and antioxidant activities of the above products were evaluated, and the effects of different preparation methods on the release of phenolic compounds were explained from the perspective of the destruction of the protein–phenol interaction by molecular docking method.FindingsThe main free phenols in these products were gallic acid, ferulic acid, and phloroglucinol, while the main bound phenols were syringic acid, epicatechin, and quercetin. The different preparation methods altered the free and bound phenolic compounds’ contents in different degrees. Compared with the mixed flour, the finished products showed fairly higher DPPH. Scavenging and reduction capacity, and QBB, QBSB showed a higher antioxidant capacity than the QBFN and QBDN. Molecular docking results predicted that phenols and proteins in these products form phenol–protein complexes bounded by hydrogen and hydrophobic bonds. Different preparation methods would breakdown these bonds, resulting in the release of phenolic compounds.ConclusionDifferent preparation methods changed the phenolic compounds content and antioxidant capacity in different degrees, QBB and QBSB have higher level of phenolic content and better antioxidant capacity than QBFN and QBDN. Different preparation methods may breakdown hydrogen and hydrophobic bonds between protein and phenolic compounds by different degrees, resulting in the release of phenolic compounds.