Optimization of the extraction of antioxidant compounds from quinoa (Chenopodium quinoa Willd.)

Abstract

Argentina contains a great biodiversity of natural foods such as quinoa that can be included in the human diet because of their nutritional characteristics and content of bioactive compounds. Among other properties, these bioactive have an antioxidant capacity that protects biomolecules from oxidant damage. Bioactive compounds contribute beneficially to diverse antimicrobial, anti-inflammatory and anti-carcinogenic physiological activities. The objective of this study was to optimize the parameters for the extraction of antioxidant compounds from quinoa: drying temperature of the grain, liquid/solid ratio (L/S), and ethanol concentration in the extraction solvent, based on an experimental design of three variables at three levels. A face-centered central composite design was used. The proposed levels were 40°C, 60°C and 80°C; 20:1, 30:1 and 40:1, and 30%, 50%, and 70% v/v of ethanol. Antioxidant capacity was determined by the capture of the DPPH free radical. The values obtained were from 16.3 mg to 161.5 mg of equivalent trolox (ET) 100 g-1 of quinoa. The maximum antioxidant capacity was obtained for the L/S ratio of 28:1, and the drying temperature of the grain was 58°C and 39% v/v of ethanol in the extraction solvent. The ethanol concentration was the most influential variable in the antioxidant compound extraction.