Enzymatic generation of galactose-rich oligosaccharides/oligomers from potato rhamnogalacturonan I pectic polysaccharides

• RG I from potato was efficiently used for generation of galactose-rich oligosaccharides/oligomers.
• Multi-enzymatic preparations with higher activity toward side chains resulted in the highest oligo-RG I yield.
• Major proportion of oligo-RG I products were galactooligosaccharides with DP of 2–12.
• Multi-enzymatic product generates more oligomers (DP 13–70) than monocomponent enzymes.

Potato pulp by-product rich in galactan-rich rhamnogalacturonan I (RG I) was investigated as a new source of oligosaccharides with potential prebiotic properties. The efficiency of selected monocomponent enzymes and multi-enzymatic preparations to generate oligosaccharides/oligomers from potato RG I was evaluated. These overall results of yield were dependent on the activity profile of the multi-enzymatic preparations. Highest oligo-RG I yield of 93.9% was achieved using multi-enzymatic preparation (Depol 670L) with higher hydrolytic activity toward side chains of RG I as compared to its backbone. Main oligo-RG I products were oligosaccharides with DP of 2–12 (79.8–100%), while the oligomers with DP of 13–70 comprised smaller proportion (0.0–20.2%). Galactose (58.9–91.2%, w/w) was the main monosaccharide of oligo-RG I, while arabinose represented 0.0–12.1%. An understanding of the relationship between the activity profile of multi-enzymatic preparations and the yield/DP of oligo-RG I was achieved. This is expected to provide the capability to generate galacto- and galacto(arabino) oligosaccharides and their corresponding oligomers from an abundant by-product.