Optimization and characterization of pectin extracted from hawthorn by deep eutectic solvent

Abstract

In this study, hawthorn pectin was extracted from dried hawthorn with deep eutectic solvent(DES) and compared with the traditional extraction methods such as acid extraction (AE) and ultrasonic-assisted extraction (UAE). Under optimal conditions, with a molar ratio of choline chloride to urea at 1:3, a water content of 30 %, a liquid-to-solid ratio of 30:1 (mL/g), an extraction temperature of 80 °C, an extraction time of 60 min, and a pH of 1, the yield of hawthorn pectin was 4.33 % ± 0.02 %. The measured results were consistent with the prediction. In addition, compared with AE and UAE, the experimental results showed that DES had a higher yield, a lower degree of esterification, and a slightly different monosaccharide composition from other extraction methods. The results of infrared spectroscopy and scanning electron microscopy showed that DES had a fine microstructure and coarser surface, and the main chemical structure of DES didn't change. The rheological analysis showed that DES had lower apparent viscosity than AE and UAE. These results represent a green source for pectin extraction with high pectin yield and good performance. In conclusion, the deep eutectic solvent has good application prospects in extracting hawthorn pectin.