Submitted to: Acta Horticulture Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2008
Publication Date: 7/15/2008
Citation: Luthria, D.L. 2009. Phenolic compounds analysis in foods and dietary supplements is not the same using different sample preparation procedures. Acta Horticulturae Proceedings (ISHS). 841:381-388.
Interpretive Summary: Phenolic micronutrients are ubiquitously distributed throughout the plant kingdom. The quantities of phenolic compounds present in foods are influenced by genotype, storage, processing, extraction procedure and environmental conditions. This manuscript evaluates the influence of different sample preparation parameters (extraction techniques and solvent composition, temperature, number of cycles, solid-to-solvent ratio, and pressure) on the amount of phenolic compounds extracted from different plant matrices. Optimization of different sample preparation parameters will allow researchers to accurately quantify the amount of phytochemicals present in different matrices. Accurate estimation will enable researchers to correctly evaluate the role of phenolic compounds as it relates to health and provide precise dietary and safety guidelines on consumption of these phenolic phytochemicals.
Technical Abstract: Recent epidemiological studies suggest a positive correlation between diets rich in fruits and vegetables and a reduced incidence of chronic diseases. This beneficial effect is partially attributed to secondary phenolic phytochemicals. Phenolic compounds are the most complex group of phytochemicals which provide flavor and color to fruits, vegetables, and grains. More than 8000 different phenolic phytochemicals belonging to different subgroups have been identified. The large number of phenolic compounds, their structural diversity and their interaction with sample matrix present a considerable challenge to develop an efficient procedure for optimum extraction and accurate analysis form different plant matrices. This paper illustrates the issues related to extraction of phenolic compounds as described in peer-reviewed literature. It discusses the importance of optimizing sample preparation procedures for accurate estimation of phenolic compounds from foods (eggplant, soybean, and parsley) and dietary supplements (Black Cohosh). Comparison of current and classical extraction procedures for the extraction of phenolic phytochemicals will also be presented. Influence of different extraction parameters such as extraction solvent composition, particle size, temperature, solid-to-solvent ratio, pressure, and number of cycles will be presented. A systematic approach for optimum extraction of phenolic phytochemicals from different plant matrices will also be discussed. Accurate quantification of bioactive phenolic phytochemicals will allow researchers to provide better guidelines on dietary intake levels necessary to achieve the desired health-beneficial effects.