Incorporation of 2-hydroxypropyl beta-cyclodextrin in a biomolecule-based low-transition temperature mixture (LTTM) boosts efficiency of polyphenol extraction from Moringa oleifera Lam leaves

A novel LTTM composed of glycerol and sodium acetate was used to assess the effect of 2-hydroxypropyl beta-cyclodextrin (CD) on the effectiveness of polyphenol extraction from M. oleifera leaves (MoL). The extraction process was based on a 2(3)-full factorial design and response surface methodology, to evaluate simultaneously the effect of CD concentration (C-CD), liquid-to-solid ratio (R-L/S) and temperature (T). By employing optimized conditions (C-CD= 1%, R-L/S=40mL g(-1), T = 40 degrees C), the yield in total polyphenols (Y-TP) was 67.18 +/- 5.04mg gallic acid equivalents per g dry weight. This yield was significantly higher than that achieved with the extraction performed with LTTM alone or 80% aqueous ethanol. The extraction kinetics suggested that the extraction rate was slowed down in the presence of CD, without compromising the higher extraction capacity of the LTTM/CD. Extract characterization by means of liquid chromatography-mass spectrometry showed that there was no selective extraction of any particular polyphenol, indicating that CD acted only as an extraction booster.