Comparative evaluation of microwave-assisted extraction and preheated solvent extraction of bioactive compounds from a plant material: a case study with cabbages

摘要

Preheated solvent extraction (PSE) was evaluated via the analysis of the extraction kinetics, microstruc-ture of extracted samples and energy consumption as alternative to microwave-assisted extraction (MAE). Cabbage outer leaves and ethanol were used as test material and extraction solvent, respectively. MAE was first optimised in terms of glucosinolates and phenolics yields; total antioxidant activity of the extracts was also assessed. MAE at a specific absorbed power of 0.37 W g~(-1) for 9 min was selected as optimum condition to extract glucosinolates and phenolics, while PSE was optimised at 6 min of the extraction. The highest normalised total glucosinolates and phenolic contents as well as antioxidant activities of the extracts obtained via MAE were not significantly different from those obtained via PSE. Con-focal laser scanning microscopy revealed no significant differences in cabbage cell damages rendered by MAE and PSE. PSE nevertheless exhibited slightly higher specific energy consumption than MAE.