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European Pharmaceutical Students’ Association
Extraction of polyphenols from grape pomace using mixtures of non-ionic surfactants Author: Jovan Baljak Scientific Coordinator: Mariola Herbet Institution: Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Novi Sad, Republic of Serbia
INTRODUCTION: Grape pomace is a by-product accounting for 25% of grape mass used in the winemaking process and represents an economically viable source of polyphenols. The advantages of polyphenol extraction from pomace using surfactant solutions are solvent nontoxicity and process simplification. AIM: Investigation of the influence of concentration and pH value of the solutions of non-ionic surfactants Brij® S20, poloxamer 407 and their mixtures on the efficiency of polyphenol extraction from pomace, based on the determination of total phenolic content and antioxidant capacity. Another aim was to determine the content of individual phenolics in extracts.
ability to solubilize water-insoluble polyphenol quercetin (2.38 mg/L), as well as watersoluble gallic acid (0.78mg/L), comparing to solutions of non-ionic surfactants (1.92 mg/L for quercetin and 0.67 mg/L for gallic acid). CONCLUSION: Efficiency of the extraction depends on the extraction medium and factors such as concentration and pH value. Better extraction efficiency of surfactant mixtures is probably due to the synergistic effect in mixed micelles as a result of improved packaging of hydrophobic surfactant parts in the core of mixed micelles and increased micelles stability.
MATERIAL AND METHODS: Extraction of polyphenols from Cabernet Franc grape pomace was performed using solutions of non-ionic surfactants Brij® S20, poloxamer 407 and their mixtures (mass ratios: 9:1, 1:1, 1:9) in concentrations 3% and 5%, and pH by-product; values of 3,4 and 5. The total phenolic content KEYWORDS: in extracts was determined by the Folin- poloxamer 470; solubilization Ciocalteu method, antioxidant potential by the DPPH assay and the content of individual polyphenols by HPLC. RESULTS: Optimal conditions for the polyphenol extraction from pomace by surfactant solutions were pH value 4 and mass concentration 3%. Extracts with the highest total phenol content (54.80 mg GAE/g grape pomace) and the highest antioxidant potential (IC50=1.80 µL/mL) were obtained using mixtures of Brij®S20 and poloxamer 407 (9:1 and 1:1), comparing to using solutions of non-ionic surfactants (34,82 mg GAE/g grape pomace and IC50=2.68 µL/mL). Mixtures of surfactants (9:1) show the greatest
Brij®
S20;
