Comprehensive Study of Hydrothermal Extraction of Pectin From Sugar Beet Pulp

In this work one-stage, no presence of acidic catalyst hydrothermal extraction of pectin from sugar beet pulp (SBP) as a batch process was investigated, leading to increasing the value of this by-product of sugar beet industry. The comprehensive study of the effect of the extraction temperature and the extraction time on the yield and composition of the pectin-enriched products, the water soluble product fractions and the water insoluble product fractions, were used that are feasible for industrial upscaling. It was shown that the highest yield of satisfactory purity of pectin extract (136.3 g kg−1) was obtained at a temperature of 120 °C and a holding time of 20 min. Both further increase of the extraction temperature and extending extraction time favor the occurrence of partial hydrothermolysis of pectin and hemicellulose contained in the SBP, leading to the production of uronic acids, monosaccharides, carboxylic acids and furfurals. In the applied extraction conditions, other components of the SBP: cellulose, lignin and protein did not undergo depolymerization and were still present in the solid post-extraction residue. This work provides an important method for the recovery of pectin from SBP using environmentally friendly technique and should help to facilitate further studies to develop a new process for the hydrothermal production of pectin from waste biomass.