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

Abstract

A novel LTTM composed of glycerol and sodium acetate was used to assess the effect of 2-hydroxypropyl β-cyclodextrin (CD) on the effectiveness of polyphenol extraction from M. oleifera leaves (MoL). The extraction process was based on a 23-full factorial design and response surface methodology, to evaluate simultaneously the effect of CD concentration (CCD), liquid-to-solid ratio (RL/S) and temperature (T). By employing optimized conditions (CCD = 1%, RL/S = 40 mL g−1, T = 40 °C), the yield in total polyphenols (YTP) was 67.18 ± 5.04 mg 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.