Enzymatic depolymerization of sugar beet pulp: Production and characterization of pectin and pectic-oligosaccharides as a potential source for functional carbohydrates

In order to obtain solids extracts rich in hemicellulose from sugar beet pulp (SBP), an enzymatic depolymerization process with pectinolytic enzymes was evaluated. Both enzymatic preparations (Rohapect DA6L and Macer8 FJ) contributed to achieve rich fractions of hemicellulose; however Rohapect DA6L always showed a higher release of pectic oligosaccharides (pectin removal yield of 94.9%). The characterization of the obtained solid residue resulted in 30.6% hemicellulose, 25.95% cellulose, 12.1% lignin, 0.83% pectin and 4.86% protein. The total carbohydrates and reduced sugars in the hydrolysate were 143.5 and 5.24 g/L, respectively. The extracted pectin infrared spectrum revealed that it corresponds to low methoxyl pectin, confirmed by titrimetric method (DM: 56%). It can be stated that enzymatic treatment (with commercial pectinases) of SBP can be used in the recovery of valuable by-products, such as pectin oligosaccharides and solid fractions rich in hemicellulose. (C) 2012 Elsevier B.V. All rights reserved.