Flavonoid composition and antioxidant activity of pigmented sorghums of varying genotypes /

Bibliographic Details
Main Author: Dykes, Linda
Other Authors: Rooney, Lloyd W. (Thesis advisor)
Format: Thesis eBook
Language:English
Published: [College Station, Tex.] : [Texas A&M University], [2010]
Subjects:
Online Access:Link to OAK Trust copy
Description
Abstract:A wide variety of sorghum genotypes with a pigmented pericarp were grown in varying environments and were analyzed for total phenols, condensed tannins, flavan-4-ols, and in vitro antioxidant activity. In addition, sorghum flavonoids were separated, characterized, and quantified using HPLC-PDA and LC-MS. Total phenols and in vitro antioxidant activity increased when sorghums had a pigmented testa causing the presence of condensed tannins. Flavan-4-ol levels were highest in sorghums with a black pericarp (5.8-16.1 abs/mL/g), followed by those with a red pericarp (1.1-9.2 abs/mL/g). Sorghums with a black pericarp had the highest 3-deoxyanthocyanin levels (173-1054 μg/g) and these were increased when the grain had minimal weathering and was darkest in color. Sorghums with a lemon-yellow pericarp had the highest flavanone levels (134-1780 μg/g) with eriodictyol being the main flavanone. Flavanone levels were increased when the grain was bright yellow with minimum weathering and were high compared to those found in common sources (106-574 μg/g, fresh wts.). No flavonoids were predominant in sorghums with a red pericarp. Flavonoid composition varied when all sorghums were grouped by secondary plant color. Sorghums with tan secondary plant color, including those with a white pericarp, had higher levels of flavones (19-386 μg/g) than those with red/purple secondary plant color (0-57 μg/g). On the other hand, 3-deoxyanthocyanin levels were higher in red/purple plant sorghums (8-1054 μg/g) than in tan plant sorghums (0-12 μg/g). Among red/purple plant sorghums, lemon-yellow pericarp sorghums had the highest levels of flavones (20-67 μg/g). Environment and weathering had an effect on flavonoid levels. The 3-deoxyanthocyanins were reduced for sorghums grown in a dry environment (i.e. Lubbock, TX) and flavonoid levels were increased in grains with minimum weathering or molding. This study reports that all sorghums, including those with a white pericarp, have flavonoids and their levels and compositions are affected by the genotype. This information will be helpful for plant breeders, food scientists, and the pharmaceutical/nutraceutical industries in selecting sorghums with desired healthy components.
Item Description:"Major Subject: Food Science and Technology"
Title from author supplied metadata (automated record created 2010-03-12 12:08:51).
Electronic resource.
Physical Description:1 online resource.
Bibliography:Includes bibliographical references.