Enhancement of industrial pectin production from sugar beet pulp by the integration of surfactants in ultrasound-assisted extraction followed by diafiltration/ultrafiltration

Abstract

To recover industrial pectin from sugar beet pulp (SBP), a combined surfactant and ultrasound-assisted extrac- tion, followed by a concentration with ultrafiltration/diafiltration membranes is proposed. First, the operation conditions of the extraction were optimized for synthetic (Tween80, PEG4000) and natural (Saponin) surfac- tants. Tween 80 and Saponin provided maximum galacturonic acid (GalA) concentrations (5.5 and 5.8 g/L, respectively) under the best extraction conditions (4 gsurfactant/L, pH = 1, amplitude = 90%, and time = 90 min). The extracted liquid was purified and concentrated through membranes. The final retentate maintained 73% of the initial GalA and eliminated a high percentage of oligosaccharides. Finally, the pectin was precipitated with ethanol, and the precipitate solid contained 57 g GalA/100 g GalA of SBP with a high degree of esterification (DE = 81%) and MW (930 kDa). The pectin yield for the global process was 24.6%. The ultrasound-assisted extraction with surfactants followed by diafiltration/ultrafiltration could become a promising process for the chemical industry, able to provide pectin-enriched products of commercial interest from sugar beet pulp.