Recovery of bioactive compounds from beet leaves through simultaneous extraction: Modelling and process optimization

Abstract

Extraction of bioactive compounds from beet leaves was studied for the valorization of this by-product. The objective of this work was to optimize the extraction of total phenolic compounds (TPC), betacyanins (BC) and betaxanthins (BX) from beet leaves through a liquid:solid process with low environmental impact. For this propose, kinetic aspects of the extraction process at 30 and 80 °C were evaluated, finding that times higher than 60 min were unfavourable for betalainic pigments since degradation was observed. Thereafter a Plackett–Burman design was applied to study the effect of several extraction variables on the efficiency of the process. Accordingly, temperature, %EtOH and solid:liquid ratio were selected as the most significant variables for a further optimization. Finally, Response Surface Methodology was employed in order to simultaneously maximize the three responses. The extraction conditions that achieve this goal were: 61 °C, 80% EtOH and r of 1:10, under which the bioactive concentrations were: 31.7 mg AG/g DM, 0.78 mg/g DM, 2.17 mg/g DM for TPC, BC and BX, respectively. The study proposes a simple and reasonably efficient method to produce a rich in phenolics, bright red–purple extract, which can be later processed to be used in several applications for the food industry.