Optimized methodology for the simultaneous extraction of glucosinolates, phenolic compounds and antioxidant capacity from maca (Lepidium meyenii)

Abstract

Maca is a highly appreciated Andean crop with multiple attributed health claims due to its assortment of bioactive compounds. The extraction parameters of glucosinolates (GLs), total phenolic compounds (TPC) and antioxidant capacity (AC) of maca (Lepidium meyenii) hypocotyls were optimized using response surface methodology (RSM). The effect of different extraction parameters: temperature (°C), liquid-to-solid ratio (ml/g), time (min) and ethanol concentration (%) on GLs, TPC and AC extraction yields were investigated using a Box–Behnken design (BBD) based on response surface methodology (RSM). Maximum yields of 16.4μmol/g of dried matter (DM), 9.89mg of gallic acid equivalents (GAE)/g of DM and 61.4μmol of trolox equivalents (TE)/g were obtained at conditions of 47, 70 and 70°C, liquid-to-solid ratio of 10, 16 and 10ml/g, extraction time of 90, 30 and 48min and ethanol concentration of 60%, 60% and 50%, for GLs, TPC and AC respectively. Optimal extraction conditions for the simultaneous extraction of GLs, TPC and AC determined by RSM were 70°C, 10ml/g, 90min and 58% ethanol with extraction yields of 14.2μmol/g of DM, 9.3mg of GAE/g of DM and 56.9μmol TE/g for GLs, TPC and AC respectively. Under these conditions, glucotropaeolin represented 79% of total GLs and catechins and gallocatechin derivatives represented 97% of total phenolics. The optimized conditions could be successfully employed by the Nutraceutical industry to extract bioactive compounds from maca flour.