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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #421499

Research Project: Adaptation of Grain Crops to Varying Environments Including Climates, Stressors, and Human Uses

Location: Plant Genetics Research

Title: Optimization of polyphenol extraction from purple corn pericarp using glycerol/lactic acid-based deep eutectic solvent in combination with ultrasound-assisted extraction

Author
item KUMAR, RAVINDER - University Of Missouri
item Flint Garcia, Sherry
item SALAZAR-VIDAL, MIRIAM NANCY - University Of Missouri
item CHANNAIAH, LAKSHMIKANTHA - University Of Missouri
item VARDHANABHUTI, BONGKOSH - University Of Missouri
item SOMMER, STEPHAN - University Of Missouri
item WAN, CAIXIA - University Of Missouri
item SOMAVAT, PAVEL - University Of Missouri

Submitted to: Antioxidants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2024
Publication Date: 12/25/2024
Citation: Kumar, R., Flint Garcia, S.A., Salazar-Vidal, M., Channaiah, L., Vardhanabhuti, B., Sommer, S., Wan, C., Somavat, P. 2024. Optimization of polyphenol extraction from purple corn pericarp using glycerol/lactic acid-based deep eutectic solvent in combination with ultrasound-assisted extraction. Antioxidants. 14(1). https://doi.org/10.3390/antiox14010009.
DOI: https://doi.org/10.3390/antiox14010009

Interpretive Summary: Purple corn contains valuable pigments and plant-based bioactive compounds (phytochemicals) with health promoting properties and which can be used as natural food dyes. Previously, we investigated the extraction potential of so called “green solvents” that are renewable, non-toxic, biodegradable, and economically viable. We found several deep eutectic solvents (DESs, liquids created from mixing two solids) that combined with ultrasound were effective at extracting various classes of phytochemicals. In this study we optimized the extraction procedure to maximize phytochemical yield by testing combinations of extraction times, temperatures, water concentrations, ultrasound signals, and solid to liquid ratios. We found a combination that was the most efficient at extracting the desired phytochemicals in significantly less time and greater energy savings than other extraction methods. The results of this study are useful to processors who wish to add value to the US corn crop and support agricultural communities.

Technical Abstract: Purple corn pericarp, a processing waste stream, is an extremely rich source of phytochemicals. Optimal polyphenol extraction parameters were identified using response surface methodology (RSM) by combining a deep eutectic solvent (DES) and ultrasound-assisted extraction (UAE) method. After DES characterization, Plackett–Burman design was used to screen five explanatory variables, namely, time, Temp (temperature), water, Amp (amplitude), and S/L (solid-to-liquid ratio). The total anthocyanin concentration (TAC), total polyphenol concentration (TPC), and condensed tannin (CT) concentration were the response variables. After identifying significant factors, the Box–Behnken design was utilized to identify the optimal extraction parameters. The experimental yields under the optimized conditions of time (10 min), temperature (60 .C), water concentration (42.73%), and amplitude (40%) were 36.31 ± 1.54 g of cyanidin-3-glucoside (C3G), 103.16 ± 6.17 g of gallic acid (GA), and 237.54 ± 9.98 g of epicatechin (EE) per kg of pericarp, with a desirability index of 0.858. The relative standard error among the predicted and experimental yields was <10%, validating the robustness of the model. HPLC analysis identified seven phytochemicals, and significant antioxidant activities were observed through four distinct assays. Metabolomic profiling identified 57 unique phytochemicals. The UAE technique combined with DES can efficiently extract polyphenols from purple corn pericarp in a short time.