2013 Annual Report
1a.Objectives (from AD-416):
This research project is to develop analytical methods for phenolics and antioxidants in samples provided by USDA-ARS Western Wheat Quality Laboratory.
1b.Approach (from AD-416):
Samples provided by USDA-ARS Western Wheat Quality Laboratory will be initially used for optimization of sample preparation procedures for extraction of phenolic phytochemicals from wheat samples. Different cultivars of wheat samples will be used to collect spectral fingerprints and determine whether spectral fingerprinting methods can be used to differentiate wheat samples based on cultivar or other phytochemical traits.
Phytochemical content in different fractions of flour, dough, and bread (upper crust, central crumb, and bottom crust) have been analyzed in two wheat cultivars, ‘Louise’ (soft white) and ‘Macon’ (hard white). The anti-proliferative activity of whole wheat bread extracts against HT-29 was positively correlated with total phenolic acids, but not correlated with total carotenoids and total tocopherols content. The results indicate that baking reduces the concentrations of the carotenoids and the tocopherols. Changes in the phenolic acid concentrations were different for refined and whole grain bread.
In addition, phytochemicals composition (phenolic acids, carotenoids, and tocopherols) and anti-proliferative activities of bran samples of the ten soft winter wheat varieties grown in Maryland were investigated. All extracts were also assayed for total phenolic content, free radical scavenging capacities, and cellular antioxidant activity (CAA). Ferulic acid was the predominant phenolic acid in all ten wheat bran samples with concentration ranging between 1.1 to 1.7 mg g-1. The levels of lutein, zeaxanthin, and ß-carotene ranged between 1.0-1.4, 0.2-0.3, and 0.1-0.2 µg g-1, respectively. A significant amount of a-tocopherol (2.3 to 5.3 µg g-1) was quantified in all bran samples. No significant correlations between ferulic acid, tocopherols, and carotenoids content and in vitro antioxidant radical scavenging assays or total phenolic content were observed. The Jamestown wheat bran demonstrated significant anti-proliferative activities against both HT-29 and Caco-2 colon cancer cells at concentration of 50 mg bran equivalent (BE) mL-1. This research suggests the need for careful investigation of other phytochemicals present in bran fraction.