Carotenoid, Tocopherol, Phenolic Acid, and Antioxidant Properties of Maryland-Grown Soft Wheat

Consumers' desires to either reduce the risk of or manage a specific health condition through improved diet have stimulated the research of agricultural products for their potential health beneficial components such as tocopherols and natural antioxidants. Soft wheat is one of the major crops in Maryland, with little information available about its potentially beneficial components. This study examined eight selected Maryland-grown soft wheat varieties or experimental lines for their potential beneficial components including tocopherols, carotenoids, total phenolics and phenolic acids and their antioxidant properties, including Fe²⁺ chelating capacity and free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH^• ), radical cation ABTS^•+, and oxygen radical (ORAC). The results showed that all tested soft wheat grain samples contained α-tocopherol, with a range of 3.4−10.1 μg/g. Lutein was the primary carotenoid present in the grain samples at a level of 0.82−1.14 μg/g, along with significant amounts of zeaxanthin and β-carotene. Vanillic, syringic, p-coumaric, and ferulic acids were found in soluble free, soluble conjugated, and insoluble bound forms in the grain extracts, with ferulic acid as the predominant phenolic acid. The eight soft wheat varieties differed in their antioxidant properties. The tested wheat grain samples exhibited ED₅₀ values against DPPH^• of 23−27 mg of grain equiv/mL, ORAC of 32.9−48 μmol of Trolox equiv (TE)/g, and ABTS^•+ scavenging capacity of 14.3−17.6 μmol of TE/g. These data suggest the possibility of producing soft wheat varieties rich in selected health beneficial factors for optimum human nutrition though breeding programs.

Keywords: Soft wheat; tocopherol; carotenoid; phenolic acid; phenolic; chelating; radical