ANALYTICAL METHODS FOR THE DETERMINATION OF PHENOLIC PHYTONUTRIENTS IN FOODS
Location: Food Composition and Methods Development Lab
Title: Are we Efficiently Extracting Phenolic Phytochemicals from Foods and Dietary supplements?
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 30, 2006
Publication Date: June 30, 2007
Citation: Luthria, D.L. 2007. Are we Efficiently Extracting Phenolic Phytochemicals from Foods and Dietary supplements? Trends in Sample Preparation 2007 Conference, June 26-30, 2007, Seggau Castel (Styria), Austria.
Phenolic phytochemicals are one of the most diverse classes of natural products that are ubiquitously distributed throughout the plant kingdom. Approximately 8000 different phenolic compounds have been isolated from natural sources. These compounds are known to exist in free aglycon and conjugated forms with sugars and organic acids. In addition, phenolic phytochemicals can occur in soluble, suspended, colloidal, or in covalent combinations with cell wall components. This structural diversity, solubility, and interaction with the matrix imposes a significant challenge in extraction and analysis of phenolic phytochemicals in foods and dietary supplements. This presentation will illustrate the problems associated with optimum extraction of phenolic compounds as documented in current peer-reviewed published literature [1,2], and highlight our research results on the influence of extraction techniques and conditions on the assay of phenolic compounds from parsley flakes (herb), Black Cohosh (dietary supplement), eggplant (vegetable), soybean (legume), and potato skin (vegetable waste) [3-6]. Comparison of current (pressurized liquid extraction and ultrasonic assisted extraction) and classical extraction approaches (Soxhlet, stirring, vortexing, wrist, and rotary shakers) on the assay of phenolic phytochemicals from different plant matrices will be presented. Influence of delipidation, extraction temperature, time, number of cycles, solid-to-solvent ratio, and pressure on the assay of phenolic compounds and their profiles will also be presented. A systematic outline to optimize procedures for extraction of phenolic phytochemicals from different food matrices will also be covered during the presentation. Accurate quantitation of phenolic phytochemicals will allow researchers to accurately determine the dietary intake levels and safety guidelines necessary to achieve the desired health-beneficial effects. Supported by the ARS/USDA, and Dionex, Inc., USA.