Title: Influence of UV Light on Phenolic Acid Content of Broccoli Samples (Brassica oleracea) Authors
Submitted to: International Conference of Polyphenols
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2008
Publication Date: July 8, 2008
Citation: Luthria, D.L., Krizek, D.T. 2008. Influence of UV Light on Phenolic Acid Content of Broccoli Samples (Brassica oleracea). XXIV International Conference on Polyphenols, July 8-11, 2008, Salamanca, Spain. Technical Abstract: Influence of environmental factors (such as rainfall, pests, soil, irrigation levels, and fertilization) on the phenolic composition of fruits and vegetables is well documented in the literature. We have evaluated the significance of ultraviolet light on the phenolic composition of broccoli samples. Two cultivars of broccoli, Flash and Packman (RS), were grown in fields and in two high tunnels which were covered with two contrasting covering materials of similar thickness (0.152mm) and durability (4-year polyethylene). One material (Dura-film Super 4) blocked UV radiation (< 380 nm) whereas the other material (Tyco Tufflite IV) transmitted UV radiation. Three to five sets of broccoli samples were collected for each cultivar grown under three conditions: one in presence of UV light (UV+), one that partially blocked ultraviolet light (UV-), and the third set collected from the field. All samples were assayed for phenolic acid content after extraction of free phenolic acids obtained after base hydrolysis of the freeze-dried broccoli samples. All samples were extracted and assayed in triplicate by a high performance liquid chromatography (HPLC) procedure with diode array detection (DAD). The total phenolic (TP) content of the broccoli extracts was determined by a colorimetric Folin-Ciocalteu (FC) and FRAP assay procedures. Both field and +UV samples showed similar phenolic content. The phenolic acid content of the broccoli sample grown under UV- conditions was significantly lower (by more than 10%) than those grown in field or UV+ conditions. Supported by USDA ARS CRIS Project No. 1235-52000-048-01N.