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United States Department of Agriculture

Agricultural Research Service

Research Project: FINGERPRINTING AND PROFILING METHODS FOR CHARACTERIZATION OF FOODS AND DIETARY SUPPLEMENTS Title: Influence of conventional and organic agricultural practices on the phenolic content in eggplant pulp: Plant-to-plant variation

Authors
item Luthria, Devanand
item Singh, Ajay -
item Wilson, Ted -
item Vorsa, Nicholi -
item Banuelos, Gary
item Vinyard, Bryan

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 15, 2009
Publication Date: December 23, 2009
Citation: Luthria, D., Singh, A.P., Wilson, T., Vorsa, N., Banuelos, G.S., Vinyard, B.T. 2010. Influence of conventional and organic agricultural practices on the phenolic content in eggplant pulp: Plant-to-plant variation. Food Chemistry. 121(2):406-411.

Interpretive Summary: This research focuses on the extraction and analysis of 5-caffeoylquinic acid, the most abundant phenolic acid from eggplant pulp grown under either organic and conventional farming practices. In this study, we also assayed total phenolics in eggplant extracts by the Folin-Ciocalteu assay. In addition, plant-to-plant variation in phenolic content was also investigated for phenolic content by two independent assay procedures, HPLC/LC-MS and Folin-Ciocalteu assay. The results of the HPLC analysis showed significant plant-to-plant variation (22% to 48%) in 8 eggplant samples collected from 8 different plants belonging to same cultivar and grown under similar conditions. The Millionaire variety showed higher phenolic content when compared to the Blackbell variety. No significantly consistent trend in the phenolic content of eggplant samples grown with organic versus conventional farming practices was observed with either eggplant variety; however a strong correlation between total phenolic content as assayed by Folin-Ciocalteu assay and 5-caffeoylqunic acid was observed. The results of this study will be of interest to plant researchers, farmers involved with organic farming, and eggplant producers and consumers.

Technical Abstract: Consumer awareness, pesticide and fertilizer contaminations, and environmental concerns have resulted in increased demand for organically grown farm products. The present study evaluates the influence that organic versus conventional farming practices exert on the total phenolic content in eggplant samples belonging to two cultivars, Blackbell (American eggplant) and Millionaire (Japanese eggplant) grown by conventional and organic farming practices with similar climatic conditions. In addition, plant-to-plant variation in phenolic content was also investigated with eight different eggplant samples collected from different plants grown at various field positions that were collected and separately assayed for phenolic content by two different assay procedures---HPLC/LC-MS and the Folin-Ciocalteu assay. The results of the HPLC analysis showed significant plant-to-plant variation (% RSD ranged from 22% to 48%) in the 8 eggplant samples collected from 8 different plants belonging to the same cultivar and grown under similar conditions. The Millionaire variety showed higher phenolic content as compared to the Blackbell variety. No significantly consistent trend in the phenolic content of eggplant samples grown with organic versus conventional farming practices was observed with either eggplant variety. A strong correlation (R2 = 0.87) between total phenolic content as assayed by the Folin-Ciocalteu assay and 5-caffeoylqunic acid, a major phenolic acid in eggplant extract, was observed.

Last Modified: 12/21/2014
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