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Journal of Food Quality
Volume 2017, Article ID 2159183, 14 pages
Research Article

Extraction Optimization and Antioxidant Properties of African Eggplant (Solanum macrocarpon) Leaf Polyphenols

1Department of Food Science and Technology, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria
2Department of Soil and Land Resources Management, Faculty of Agriculture, Obafemi Awolowo University, Ile-Ife, Nigeria
3Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
4Department of Agronomy, Osun State University, Osogbo, Nigeria

Correspondence should be addressed to A. A. Famuwagun; moc.liamg@treblaalosnika

Received 15 July 2017; Revised 29 September 2017; Accepted 6 November 2017; Published 29 November 2017

Academic Editor: Riccarda Antiochia

Copyright © 2017 A. A. Famuwagun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Optimization of the yield, total phenolic content (TPC), and total antioxidant activities (TAA) of polyphenol concentrates extracted from Solanum macrocarpon leaves was studied using response surface methodology. The process variables investigated included extraction temperature (30, 50, and 70°C), extraction time (2, 4, and 6 h), and dried leaf powder : water ratio (1 : 10, 1 : 20, and 1 : 30 w/v). Box–Behnken design resulted in 15 experimental runs. The results showed the following optimum extraction conditions: temperature, 49.05°C; extraction time, 243 min; leaf powder : water ratio, 1 : 22 w/v. The optimized extraction conditions gave polyphenol concentrate yield, TPC, and TAA values of 24.94%, 421.09 mg GAE/g, and 23.81 mg AAE/g, respectively. Results of the in vitro antioxidant activities of the polyphenol concentrate showed 2, 2-diphenyl-2-picrylhydrazyl hydrate, metal chelating ability, and ferric reducing ability values of 76.78%, 80.22%, and 56.46 mg AAE/g, respectively. The study concludes that the experimental values compared closely with the predicted values, which indicates suitability of the model employed for polyphenol extraction optimization from dried S. macrocarpon leaves.