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Research Project: Developing Technologies that Enable Growth and Profitability in the Commercial Conversion of Sugarcane, Sweet Sorghum, and Energy Beets into Sugar, Advanced Biofuels, and bioproducts-Bridging Project

Location: Commodity Utilization Research

Title: Electroactivity of polyphenols in sweet sorghum (Sorghum bicolor (L.) Moench) cultivars

item Uchimiya, Sophie
item Knoll, Joseph - Joe

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2020
Publication Date: 7/14/2020
Citation: Uchimiya, M., Knoll, J.E. 2020. Electroactivity of polyphenols in sweet sorghum (Sorghum bicolor (L.) Moench) cultivars. PLoS One. 15(7):e0234509.

Interpretive Summary: Sugarcane aphid continues to be the major problem for sorghum production in the U.S. Deterrents are the chemicals naturally produced by the host, sorghum, to act against aphids. Deterrents offer a pest management strategy for the current production practice, and selection for improved varieties by breeding. This study illustrates underlying chemistry responsible for the pest resistance. Particular emphasis is given to describe the performance of electron shuttling structures, and effects of other phytochemicals on their reactivity.

Technical Abstract: Polyphenols and other potential health-promoting components of sorghum (Sorghum bicolor (L.) Moench) drove its recent growth in the U.S. consumer food industry. Linear sweep (cyclic voltammetry, CV) and differential (cyclic differential pulse) voltammetry methods were developed to detect target polyphenols and amino acids in sweet sorghum juice without interference from the dominant secondary (trans-aconitic acid) and primary (sucrose) metabolites. Of 24 cultivars investigated, No 5 Gambela showed the highest electron-donating capacity, as indicated by the highest peak area, height, and peak anodic potential. Pearson's correlation analysis indicated the contribution of polyphenols (rather than amino acids) on CV voltammograms of juice samples. The Eh-pH values of 173 sweet sorghum juice samples collected in 2017 aligned with quercetin model polyphenol. Accumulation of quercetin-like polyphenols in No. 5 Gambela could offer antioxidant-rich juice for conversion to edible syrup as well as an increased tolerance against a recently emerged pest, sugarcane aphid [(Melanaphis sacchari (Zehntner)].