Journal of Food Science and Technology (ISSN: 2141-5455) Vol. 5(2) pp. 53-59, February, 2014. DOI: http:/dx.doi.org/10.14303/ajfst.2014.014. Copyright © 2014 International Research Journals

 

Full Length Research Paper

Optimization of the extraction of antioxidants from guarana (Paullinia cupana) and grape (Vitis labrusca var. Izabel) pomace using response surface methodology

*Luciana Cristina Brigatto Fontes, Elizabeth Aparecida Ferraz da Silva Torres, Lina Yonekura

Department of Nutrition, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo, 01246-940, Brazil.

*Corresponding Authors e-mail: lcbfonte@gmail.com

 Received  January 13, 2014; Accepted January 20, 2014

Abstract

 

The aim of this study was to optimize the extraction of antioxidant compounds from guarana and grape pomace using the response surface methodology. A rotatable central composite design was performed to evaluate the extraction efficiency of antioxidants by water-organic solvent mixtures, using two independent variables: water (20-80%) and the acetone:methanol ratio within the organic fraction (0-100%). Extracts were analyzed for total phenolics, procyanidins and oxygen radical absorbance capacity. The multiple regression analysis and significance test (p<0.05) were realized using the Statistica. The highest total phenolic value from guarana (112.22) was detected at acetone:methanol ratios higher than 70%. Likewise, extraction efficiency of proantocyanidins was optimum (79.41) at higher acetone:methanol ratios, but with lower water percentages in the solvent composition (<29%). The water percentage must be above 80% to give maximum response (4518.79) for ORAC. The optimized conditions that maximized the yields of TP and PC were: water 20% and acetone:methanol ratio 70%, translating into a solvent mixture composed of water:acetone:methanol 20:56:24 (v:v:v). The maximum value of TP from grape pomace (25.36) was detected at acetone:methanol ratios higher than 50% and water percentage lower than 29%. The highest PC value (23.74) was detected at lower water percentages in the solvent composition (<20%). The extracts with maximum ORAC (1493.76) were those resulting from high water percentages and acetone:methanol ratios: 80% and 70%, respectively. The optimized conditions that maximized the yields of TP and PC from grape pomarce were: water 20% and acetone:methanol ratio 50%, translating into a solvent mixture composed of water:acetone:methanol 20:40:40 (v:v:v)

Keywords: Guarana, grape pomace, antioxidants, response surface methodology.