Extraction of Pectic Oligosaccharides from Cranberry Pomace

Naturally occurring polysaccharides have been of great interest for applications in the food and biomedical industry owing to their ability to self-assemble into gels with the help of different cross-linkers. Cranberry Pomace has been shown to contain pectic oligosaccharides, which are composed of a branch of sugars called xyloglucan. Xyloglucan is a structural oligosaccharide, found primarily in plant cell walls, with a basic structure of a glucose backbone chain with alternating xylose residues attached to every first and fourth or sixth glucose subunit. Most xyloglucan oligosaccharides contain more than just one type of residue in their structure such as galactose, arabinose, rhamnose, etc. which provides an overall hydrophobic and/or hydrophilic oligosaccharide.

Thermoresponsive gelation is achieved by altering the hydrogen bonding between the main chain and side chain with the help of physical cross-linking. However, in order to modulate the sol-gel temperature, the side chain residues in structure play a vital role in controlling the hydrophilicity. Here, we have used a sequential extraction strategy to isolate oligosaccharides from cranberry pomace. We started with obtaining the alcohol insoluble solids (AIS) and followed a series of extraction steps involving solutions with known ionic strength to remove undesired oils and acids to isolate oligosaccharides at the end. 1H NMR spectroscopy was used for qualitative characterization of the final product.